Chronological List of Articles

SUMMARY:
Just as vital dentin is moist after removing the smear layer, avoiding collapse of the collagen matrix after acid-etching requires in vivo validation. This study hypothesizes that there is no difference between moist bonding performed in vitro or in vivo, and that excessive drying or wetting of vital acid-etched dentin produces inferior results. Resin-dentin interfaces bonded with a moist bonding technique (control), either in vitro or in vivo with Excite DSC (Vivadent), were examined with and without tracer penetration using transmission electron microscopy. Specimens bonded in vivo under excessively dry and wet conditions were also examined. The patterns of silver deposition were similar within the adhesive and hybrid layers created in vitro or in vivo. No hybrid layer was observed in vivo after excessive drying. Excessive wetting in vivo resulted in more extensive nanoleakage and water tree formation along resin-dentin interfaces.

SUMMARY:
In this in vitro study, voids inside a minimal occlusal restoration using different consistencies of resin composite and various application techniques were investigated.

One hundred and fifty-two simulated, minimally invasive preparations, including a prepared fissure and an excavated carious dentin lesion, were ground in perspex blocks. After applying an acrylic primer (Artglass Connector, Kulzer), the preparations were restored with the adhesive PhotoBond (Kuraray) and one of three resin composites: a packable composite (Prodigy Condensable-Kerr), a syringable composite (Clearfil Photo Posterior, Kuraray) and a flowable composite (Revolution, Kerr). The restorations were inserted according to eight protocols (n=19). In three groups, the composite was placed in bulk. In another three groups, a layer of flowable composite was placed first, then cured, followed by a second layer of one of the three composites. In two groups, the first layer of flowable composite was left uncured before a second layer of a packable or syringable composite was inserted. The perspex blocks were sectioned and inspected for the presence of voids. Statistical analysis was conducted using Fischer’s exact tests at p<0.05.

The results showed that restoring minimal preparations in the absence of porosities and voids was very difficult to achieve. Placing a layer of flowable composite that was left uncured, directly followed by injecting a medium-viscous composite, was the technique that resulted in the most homogeneous restoration.

SUMMARY:
A number of “high power” in-office bleaching products have recently been re-introduced into the market. The use of such strong oxidizing agents has raised questions as to possible adverse effects on tooth structure and restorative materials. This study evaluated the effects of 35% carbamide peroxide (Opalescence Quick) and 35% hydrogen peroxide (Opalescence Xtra) on the surface finish of four tooth-colored restorative materials (Spectrum TPH, Dyract AP, Reactmer and Fuji II LC). Twenty-seven matrix-finished specimens of each material were fabricated, stored in distilled water at 37°C for seven days and randomly divided into three groups. Specimens in Group 1 were stored in distilled water at 37°C (control). Specimens in Groups 2 and 3 were treated with 35% carbamide peroxide and 35% hydrogen peroxide, respectively. A total of three 30-minute bleaching sessions were conducted at one-week intervals. Storage medium during the hiatus period was distilled water at 37°C. Surface roughness measurements were carried out using profilometry after each bleaching session. Data was analyzed using ANOVA/ Scheffe’s test at a 0.05 significance level. No significant difference in surface roughness was observed between the bleached and the control groups for all materials. In-office bleaching products are not detrimental to the surface finish of composites, compomers, giomers and resin-modified glass ionomer cements.

SUMMARY:
Human enamel, with its prismatic, rod-like apatitic morphology, is an anisotropic material. Because of this structural anisotropy, variation in enamel bonding sites might influence the bonding ability of current adhesive systems. This study investigated the effects of regional enamel and the direction of enamel sectioning on the bonding ability of two commercially available resin adhesives: a self-etching primer system (Clearfil SE Bond) and a one-bottle adhesive system intended for use with a total-etch wet bonding technique (Single Bond). Two regions of enamel, cuspal and mid-coronal enamel, were chosen, then sectioned in three different directions, horizontally, axially and tangentially. Slices of the sectioned enamel were then bonded with each adhesive system and submitted to a micro-shear bond test. The results of a micro-shear bond testing showed that the bonding of a one-bottle adhesive system (Single Bond) to enamel was high at the surface perpendicular to the enamel prisms (40 MPa to 51 MPa) and low at the surface parallel to the enamel prisms (24 MPa to 27 MPa). In the case of a self-etching primer system (Clearfil SE Bond), 35 MPa to 45 MPa bond strengths were obtained from all surfaces. The bond strengths of the two adhesive systems were significantly influenced by the anisotropic structure of enamel (p<0.05). However, the effect of a self-etching primer system was less influenced by the orientation of the prismatic structure of enamel than that of a one-bottle adhesive system (p<0.05).

SEM and CLSM microphotographs showed that the self-etching primer effectively modified the smear layer without being excessively destructive to the enamel.

SUMMARY:
The relatively low bond strengths of resin cements to dentin may result in poor interfacial adaptation of composite inlays. This study determined whether the interfacial adaptation of composite inlays could be improved by applying an adhesive system and a low viscosity microfilled resin to the prepared cavity walls before making an impression. Ten MOD cavities were prepared on extracted human premolars with gingival margins located above and below the cemento–enamel junction. A “resin coat” consisting of a self-etching primer system (Clearfil SE Bond) and a low viscosity microfilled resin (Protect Liner F) was applied to the cavities of half of the prepared teeth, while the remaining teeth served as non-coated control specimens. All the teeth were restored with composite inlays (Estenia) fabricated by the indirect method and cemented with a dual-cured resin cement (Panavia F). After finishing the margins with superfine burs, the bonded inlays were thermocycled between 4°C and 55°C for 400 cycles. Specimens were sectioned with a diamond saw and the tooth-restoration interfaces were observed with a confocal laser scanning microscope. The data were analyzed with two-way ANOVA and Fisher’s PLSD test (p<0.05). The percentage length of gap formation at the dentin-restoration interface of the “resin coated” teeth (7.1 ± 3.5) was significantly less than that of the non-coated teeth (85.7 ± 6.7) (p<0.05). The concept of coating the prepared cavity with an adhesive system and a low viscosity microfilled resin resulted in observing fewer gaps at the internal dentin-restoration interface compared with the non-coated specimens.

SUMMARY:
This study investigated the effect of finishing/polishing techniques on the microleakage of resin-modified glass ionomer restorations. Class V preparations were made on the buccal and lingual/palatal surfaces of freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (FT [GC]) and Photac-Fil Quick (PF [3M-ESPE]) according to manufacturers’ instructions. Immediately after light-polymerization, gross finishing was done with eight-fluted tungsten carbide burs. The teeth were then randomly divided into four groups and finishing/polishing was done with one of the following systems: (a) Robot Carbides (RC); (b) Super-Snap system (SS); (c) OneGloss (OG) and (d) CompoSite Polishers (CS). The sample size for each material-finishing/polishing system combination was eight. After finishing/polishing, the teeth were stored in distilled water at 37°C for one week. The root apices were then sealed with acrylic and two coats of varnish was applied 1 mm beyond the restoration margins. The teeth were subsequently subjected to dye penetration testing (0.5% basic fuchsin), sectioned and scored. Data was analyzed using Kruskal-Wallis and Mann-Whitney U tests at a significance level of 0.05. Results of statistical analysis were as follows: Enamel margins: PF–OG<SS; FT-OG<RC; Dentin margins: PF–no significant difference; FT–OG & CS<RC. Regardless of the finishing/polishing technique, leakage at dentin margins was significantly greater than at enamel margins for FT. For PF, no significant difference in leakage scores was observed between dentin and enamel with the exception of finishing/polishing with OG. FT restorations had significantly less enamel and dentin leakage than PF restorations when treated with OG. The effect of finishing/polishing techniques on microleakage was both tissue and material dependent.

SUMMARY:
This in vitro study investigated the microleakage of flowable resin composite as a restorative material and as a liner (either light cured separately or co-cured with hybrid resin composite) in Class V cavities. A light-cured hybrid resin composite was used as a control. Twenty extracted human premolars were prepared with standardized Class V cavity outlines on the buccal and lingual surfaces. The occlusal margin of the cavities was on enamel and the gingival margin was on dentin. One bottle adhesive system (Single Bond) was used after etching enamel and dentin with 34.5% phosphoric acid for 15 seconds. The cavities were randomly divided into four groups of 10 each and restored according to the manufacturers’ instructions: Group I–Hybrid resin composite (Z100); Group II–Flowable resin composite (Filtek Flow); Group III–Flowable resin composite (Filtek Flow)+Hybrid resin composite (Z100); light cured separately; Group IV–Flowable resin composite (Filtek Flow)+ Hybrid resin composite (Z100); co-cured. The samples were thermocycled 200 times with a 30-second dwell time. They were then immersed in a 0.5% basic fuchsin solution for 24 hours, sectioned and analyzed by stereomicroscopy. The degree of dye penetration was recorded and analyzed with the Kruskal-Wallis and Mann-Whitney U tests.

The results of this study indicate that there was no leakage at the occlusal margin for either restoration. Statistically significant differences were found among the groups at the gingival margin. No statistically significant difference was observed between the occlusal and gingival margins except in Group IV.

The combination of flowable resin composite and hybrid composite light cured separately yielded the best result in this study. The most leakage was observed when this combination was co-cured. The resistance to microleakage of flowable resin composite as a restorative material is similar to that of hybrid resin composite.

SUMMARY:
This study investigated the effect of instrumentation time on the microleakage of resin-modified glass ionomer cements (RMGICs). Class V cavities were prepared on buccal and lingual/ palatal surfaces of 64 freshly extracted non-carious premolars. The cavities on each tooth were restored with Fuji II LC (FT [GC]) and Photac-Fil Quick (PF [3M-ESPE]). The restored teeth were randomly divided into two groups of 32 teeth. Finishing/polishing was done immediately after light-polymerization in one group and was delayed for one week in the other group. The following finishing/polishing systems were evaluated: (a) Robot Carbides (RC); (b) SuperSnap (SS); (c) OneGloss (OG) and (d) CompoSite Polishers (CS). The sample size for each instrumentation time, material and finishing/polishing system combination was 8. Storage medium for both immediate and delayed instrumentation groups was distilled water at 37°C during the hiatus period. The teeth were subsequently subjected to dye penetration testing (0.5% basic fushcin), sectioned and scored. Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests at significance level 0.05. For PF, significant difference in enamel leakage was observed between immediate and delayed instrumentation with SS and CS. Significant differences in dentin leakage were also observed between the two instrumentation times for SS. For FT, significant differences in leakage between instrumentation times were observed only in dentin and with RC. Where significant differences in dye penetration scores existed, delayed finishing/polishing resulted in less microleakage.

SUMMARY:
This study compared the effects of different finishing techniques on the surface of a traditional hybrid composite and three packable composites.

Four composites were used in the study (Herculite XRV/Kerr, Definite/Degussa, SureFil/ Dentsply and Solitaire/Heraeus-Kulzer). Fifty specimens were made of each material, sized 7 x 7 x 4 mm. Fifteen specimens of each material were subjected to the following finishing procedures: (1) a 30 µm diamond, (2) a 30 µm and a 20 µm diamond and (3) a 30 µm diamond followed by a tungsten carbide finishing bur. As a reference, five specimens of each material were treated by Sof-Lex discs (3M). For quantitative surface evaluation, laser-stylus profilometry was used. Roughness parameters included average roughness (Ra) and profile-length-ratio (LR). Statistical analysis was performed with one- and two-way Anova and Scheffé post-hoc tests. Qualitative surface evaluation in SEM was performed at a tension of 25kV.

Significant effects were found with both the composites and the finishing methods with respect to surface roughness (p<0.001 for Ra and LR). A 30 µm diamond caused the greatest roughness on all composites, with Ra ranging from 2.015 - 2.079 µm (p<0.001). After finishing using methods 2 and 3, the Solitaire surfaces were significantly smoother (p<0.001 for LR). The lowest roughness values were achieved after using disks; again, the Solitaire specimens yielded the lowest Ra and LR values (p<0.001 except for Sure-Fil). With scanning electron microscopy, surface areas with signs of destruction were found after using a 30 µm diamond on Definite specimens.

SUMMARY:
To evaluate the correlation between microtensile dentin bond strength (µTBS) and silver ion penetration, two total-etch 3-step and one self-etch 2-step system were investigated. OptiBond FL adhesive was applied to flat occlusal dentin on six non-carious human molars, and a resin composite “crown” was formed in 2 mm increments. After 24-hour water storage, the teeth were sectioned with a low-speed diamond saw to obtain four-square sticks (~2 mm X 2 mm) per tooth. Cylindrical tensile test specimens were formed with an 0.5 mm2 cross-sectional area. Nail varnish was applied to the dentin within 0.5–1.0 mm of the interface before immersing in 50% silver nitrate for 15 minutes. Following silver fixation, tensile testing was performed in a Zwick UTM at 1 mm/minute using a passive gripping fixture to obtain 72-hour µTBS [23.9 MPa]. The percentage area of silver penetration was measured on debonded specimens using light microscopy and Image-Pro Plus Software [89%]. The procedures were repeated using Scotchbond Multi-Purpose Plus [µTBS =27.8 MPa; nanoleakage = 67%] and Clearfil SE bond [µTBS = 36 MPa; nanoleakage = 55%]. No significant correlation between microtensile bond strength and nanoleakage was found for all systems. A weak-to-moderate negative relationship was found between µTBS and nanoleakage for OptiBond FL (Spearman r = -0.3844). No correlation was found for the remaining adhesive systems. The correlation between these two common laboratory measurements appears to be adhesive-system dependent.

SUMMARY:
Sixty-seven extracted molars were selected (134 samples). Dentin and enamel samples were prepared by buccal and lingual surface sectioning to expose a planar enamel or dentin surface.

For the roughness study, 80 samples were randomly assigned to eight groups. Enamel and dentin surfaces were etched with a 37% phosphoric acid solution, irradiated with an Er:YAG laser or irradiated with a Nd:YAP laser. Samples were then observed in SEM using BSE.

For the free-surface energy study, 54 samples received the same treatment as above. Two contact angle measurements were made on each surface using a goniometer. Data were analyzed by a non-parametric statistical test.

Morphological changes on enamel and dentin were greater with acid-etch and Er:YAG laser than with Nd:YAP laser. Free surface energy was significantly greater with acid-etch or Er:YAG laser than with Nd:YAP laser (p<0.001).

SUMMARY:
The effects of mechanical stress on apoptosis induction during pulp wound healing were examined. Mechanical stress cavities of two different sizes were prepared on individual rat molars, one twice the size of the other in the occlusocervical direction. The authors compared the distribution pattern and number of apoptotic cells of the two groups by terminal deoxynucleotidyl transferase-mediated labeling assay. At one hour and one day, significant differences were observed in the distribution patterns and number of apoptotic cells between the single-size and double-size group. Four days after injury, apoptosis still existed on pulp cells in the double-size group but not in the single-size group. At 14 days, no difference in the number of apoptotic cells between the two groups was observed. These results suggest that the magnitude of mechanical stress, such as cavity preparation, may modulate the induction of apoptosis during pulp wound healing.

SUMMARY:
The fracture resistance of provisional restorations is an important concern for the restorative dentist. The fracture resistance of a material is directly related to its transverse strength. Six specimens of similar dimensions were prepared from three resins (PMMA, PEMA and BIS acryl-composite). The resins were reinforced with glass and aramid fibers. The samples were tested immediately after the material set, following seven days of wet storage using three-point compression loading. The results were analyzed with an analysis of variance (ANOVA). Fracture resistance of the specimens was statistically different (p<0.001) among the materials. Specimens reinforced with glass fibers showed higher transverse strength (149.82 MPa). The fiber reinforcement of resin materials increased the strength values (20-50%). Within the limitations of this study, the transverse strengths of PMMA, PEMA and BIS acryl-resin composites were improved after reinforcement with glass and aramid fibers.

INTRODUCTION:
The Academy of Operative Dentistry has developed the following recommendations for diagnosis, treatment and prevention of non-carious cervical lesions. Patients should be informed of the possible etiologies, implications of the presence of these lesions, methods of minimizing their occurrence, treatment alternatives and expected outcomes. Failure to appropriately prevent and treat non-carious cervical lesions can result in continued loss of tooth structure, tooth sensitivity, weakening of the tooth, the need for endodontic therapy, or tooth loss and the occurrence of additional lesions in other teeth.

SUMMARY:
This three-month, single-blind clinical study compared two whitening treatments, at-home with 10% carbamide peroxide and in-office with 35% hydrogen peroxide, for the degree of color change of teeth, color relapse and tooth and gum sensitivity. The degree of color change and color relapse was evaluated by using a colorimeter, shade guide and color slide photography. Teeth and gum sensitivity were self-evaluated by the subjects, who recorded daily the tooth and gum sensitivity they experienced during the two weeks of treatment and one week post-treatment.

A 14-day at-home treatment was compared with 60 minutes of in-office treatment (two appointments, each with three 10-minute applications). The at-home treatment produced significantly lighter teeth than the in-office treatment during all active-treatment periods and follow-up visits according to all three-color evaluation methods. Color relapse for both treatments stabilized by six weeks. At-home treatment resulted in statistically significant higher gum sensitivity than in-office treatment during the latter part of the first week. For tooth sensitivity there were no significant differences between the treatments. Eighty four percent of the subjects reported at-home treatment to be more effective and 16% found no difference between the treatments. There were no subjects who reported the in-office treatment to be superior in tooth whitening to the at-home treatment.

SUMMARY:
This study compared excess formation of direct bonded Class II restorations using different matrix systems—metal or transparent. Sixty freshly extracted, non-carious, posterior human teeth were used. In all of the teeth, standardized MOD-cavities were prepared with the gingivoproximal margins located 1.0-1.5 mm cervical to the cemento-enamel junction. The prepared teeth were randomly assigned to six groups. Half were restored using metal matrices and wooden wedges; the other half were restored using transparent matrices and reflective wedges. Three different material systems were used to fill the cavities: 1) a hybrid composite (Tetric) plus an adhesive bonding agent (Syntac Classic), 2) a flowable composite (Tetric Flow) plus Syntac Classic and 3) a compomer (Dyract AP) together with an adhesive bonding agent designed for compomers (Prime & Bond NT). After the specimens were preserved in saline solution, scanning electron microscopy (SEM) assessed the amount of overhang formation at the restoration margins. The data collected indicated the use of transparent matrices resulted in significantly higher amounts of excess material at the restoration margins compared with metal matrices. Moreover, there was no significant difference between the materials when the same matrix was used. All of the dental restorations examined displayed material overhang. Based on these findings, the authors concluded that the type of matrix exerts a major impact on overhang formation, with metal matrices resulting in significantly less excess material buildup.

SUMMARY:
This in vitro study generated data on the quality of marginal adaptation, fracture resistance and retention of several indirect adhesive composite configurations on root-treated premolars before and after a long-term fatigue test and compared these results to a control group of adhesive onlays on “vital” teeth.

Six root-treated extracted human premolars per group, with four different restorative configurations with and without adhesive fiber posts, were evaluated. Another group of six premolars, “revitalized” by using diluted horse serum to simulate pulpal fluid and restored with adhesive composite onlays, served as the control. Marginal adaptation before and after long-term occlusal loading (1,200,000 occlusal loading cycles at max 49 N) was assessed by using the replica technique and quantitative evaluation in SEM at 200x magnification. The number of lost restorations was recorded after loading. Fracture resistance and fracture patterns were evaluated by using a universal-testing machine on the fatigued samples.

No significant differences (p>0.05) between groups were detected before and after loading for the percentage of “continuous margin” at the total marginal length. Loading had a significant (p<0.05) effect on the percentage of “continuous margin” for the total marginal length of two groups only. No significant difference (p>0.05) for fracture resistance was detected and no lost restorations were observed.

The results suggest that for both the less decayed and the more significantly decayed devital teeth, the minimally invasive adhesive restorative approach is promising.

SUMMARY:
Adhesion of resin composites into enamel is currently believed to rely on infiltration of bonding resin into the porous zone, establishing micro-mechanical retention to etched enamel. This study investigated the change in chemical composition of the enamel/resin interface using a laser Raman microscopic system (System-2000, Renishaw). Two-step bonding systems, Mac Bond II (Tokuyama Corp), Clearfil Mega Bond and Single Bond (3M/ESPE) were employed. Resin composites were bonded to bovine enamel wi ring) and alkyl group (1450cm-1, C-H) in the enamel/resin bonding area were calculated. From Raman spectroscopy, a gradual decrease in hydroxyapatite was observed, and it was estimated to extend 2.2~2.6 µm for Mac Bond II, 1.2~1.6 µm for Clearfil Mega Bond and 5.2~5.6 µm for Single Bond. Furthermore, the enamel/resin interface represents a gradual transition of bonding agent from the resin to tooth side. Evidence of poor saturation of adhesive resin in etched enamel with Single Bond was detected. From the results of this study, non-uniform resin infiltration into etched enamel was detected and the degree of resin infiltration was found to be different among the bonding systems used

SUMMARY:
Self-etching primers are now considered the new generation of dentin bonding systems that modify and incorporate the bacteria-containing smear layer into their bonding mechanism. The antibacterial effects of the self-etching primers Clearfil SE Bond, Mac Bond, Imperva FL Bond, One-Up BondF and Prompt L-Pop were evaluated using the bacteria Streptococcus mutans ATCC25175, Peptostreptococcus anaerobius, Peptostreptococcus prevotii, Peptostreptococcus asaccharolyticus, Lactobacillus acidophilus, Lactobacillus catenaforme, Lactobacillus jensenii, Actinomyces odontolyticus, Porphyromonas endodontalis, Clostridium ramosum, Prevotella oris, Prevotella denticola and Fusobacterium nucleatum, with a disk diffusion method. A single-bottle total-etch dentin adhesive (Excite) was used for comparisons and chlorhexidine (0.2%) was used as the positive control. After incubation, zones of inhibited bacterial growth were observed. One-Up BondF, Prompt L-Pop and Excite showed growth inhibition for all bacterial strains. The bonding agents of Clearfil SE Bond, Mac Bond and Imperva FL Bond were unable to inhibit the growth of Lactobacillus jensenii and Actinomyces odontolyticus, while the primers of these systems produced inhibition halos to all tested microorganisms greater than that of chlorhexidine.

SUMMARY:
This study evaluated the shear bond strength of repairs made with a composite (Herculite/Kerr) when two different surface treatment methods and two new generation bond materials were used. The bonding surfaces were prepared by sanding with 500-grit aluminum oxide sandpaper or air abrading with 25-micron aluminum oxide. Treated resin surfaces were acid etched, washed for one minute and air dried. Before adding the composite Herculite, either Optibond Solo (Kerr), Solobond M (Voco) bonding agent or no bonding agent (control group) was applied. The specimens were evaluated for shear bond strength after thermocycling. Fracture surfaces of some samples were also evaluated with SEM. Light microscope and SEM examination of fractured repair surfaces indicated mostly cohesive failure within the air-abraded group. The results showed that surface treatment with air abrasion plus Optibond Solo application had the highest shear bond strength.

SUMMARY:
This study verified the polymerization depth of the composite Z100 (3M Dental Products) by Knoop Hardness test using four photoactivation methods. Twenty cylindrical specimens (5 mm in diameter by 5 mm in height) were prepared in a metallic mold and photoactivated by one of the four methods: continuous light (520 mW/cm2 for 40 seconds); stepped light (150 mW/cm2 for 10 seconds followed by 520 mW/cm2 for 30 seconds); intermittent light (cycle of 1 second, 1/2 second with the light on and 1/2 second with the light off for 60 seconds at 520 mW/cm2) and Xenon plasma arc (1370 mW/cm2 for 3 seconds). Knoop hardness measurements were obtained on the surface, at the depths of 1.5 mm, 2.5 mm, 4.0 mm and at the bottom area by the HMV-2000 microhardness, with a load of 50 grams for 30 seconds. Twenty-five indentations were performed in each sample, and a total of five samples were prepared for each photoactivation method. The obtained values were submitted to ANOVA and Tukey’s test at the 5% significance level. The results indicated that (1) for the continuous light method, the values of hardness were statistically superior in the surface area when compared to other areas. For the other methods, there were no statistical differences between the surface area and 1.5 mm; (2) the continuous and stepped light methods showed the highest mean Knoop Hardness Number in all areas; (3) the Xenon plasma arc method was not statistically different from continuous and stepped light ones on the surface at 1.5 mm and 2.5 mm of depth. However, a great decrease in hardness was observed in the deeper areas; (4) the intermittent light method showed intermediate results.

SUMMARY:
The study tests the hypothesis that soft-start irradiation improves, whereas, high intensity irradiation compromises the margin quality and marginal seal of Class V resin based composite [RBC] restorations. Box-shaped Class V cavities were prepared in extracted, human third molars with cervical margins located apical to the CEJ. Cavities were restored using a multi-step bonding agent (Optibond FL, Kerr), a thin layer of flowable resin composite and two increments of fine hybrid resin composite (Filtek Flow/Filtek Z250, 3M ESPE; Revolution f2/Herculite XRV, Kerr). Light irradiation was performed using either the standard (40 seconds) or the soft-start mode (40 seconds with exponential increase) of a quartz tungsten halogen or an LED curing light (Elipar Trilight, Elipar Freelight, 3M ESPE); for high intensity irradiation, a Plasma Arc curing unit was used with three irradiations of three seconds (Apollo 95E, DMDS). After 30 days of water storage and thermal cycling (n=2500, 5-55°C), margin quality was assessed in the SEM using the replica technique and marginal seal was evaluated using dye penetration (AgNO3 50%). Few differences were observed between the light curing protocols. However, less leakage was observed in the case of the lower shrinking RBC Filtek Z250.

SUMMARY:
Capsulation should enable uniform propor- tioning and mixing of dental restoratives so that functional properties of the cementitious mass will not be susceptible to clinically induced variability. Mechanical mixing induces a definite pore distribution determined by the viscosity of the system. This study evaluated the mixing process on the performance of a range of glass ionomer dental restoratives.

Mean compressive fracture strengths and standard deviations and the associated Weibull Moduli (m) were determined for six glass ionomer restoratives that were either encapsulated or mixed by hand. Working characteristics were assessed using an oscillating rheometer. Scanning electron microscopy and image analysis was used to investigate the influence of the mixing method on pore distribution.

The fracture strength data for some encapsulated restoratives resulted in significant differences compared with hand-mixing. Rotomix (compared with the Capmix mechanical agitator) resulted in increased Weibull moduli and 10% failure stress for the two restoratives that were investigated. Encapsulated restoratives that were prepared utilizing Rotomix or Capmix resulted in no significant differences for working characteristics; however, the setting time for the ChemFlex in Caps was extended compared with the hand-mixed ChemFlex.

Not all restoratives had reduced porosity and improved performance following mixing with a Rotomix. This suggested that optimization of the initial viscosity of the system by manipulating the individual proportions of the constituents may not have been appropriate for all the restoratives investigated. The increased viscosity for hand-mixed ChemFlex prepared to a consistency of 3.8 g/ml compared with encapsulated ChemFlex in Caps prepared to a consistency of 3.5 g/ml was responsible for the reduced setting time.

SUMMARY:
It is well documented that glass ionomer cements absorb and release fluoride following single fluoride exposures. This study examined fluoride release among three glass ionomer-based restorative materials following multiple daily exposures to three topical fluoride regimens. Using a Delrin mold, 32 cylindrical specimens, each of a glass ionomer (Ketac-Fil), resin-modified glass ionomer (Photac-Fil) and polyacid-modified resin (Dyract AP) were created. Each specimen was subjected to one of four daily treatments (n=8): (1) no fluoride treatment (control); (2) application of a fluoride dentifrice (1000 ppm) for one minute once daily; (3) application of the same dentifrice for one minute twice daily; (4) the same regimen as (3), plus immersion in a 0.05% sodium fluoride (NaF) mouth rinse (225 ppm) for one minute immediately following the second dentifrice application. Each specimen was suspended in a polyethylene test tube containing 1.0 ml demineralizing solution (pH 4.3) at 37°C for six hours, then transferred to a new test tube containing 1.0 ml remineralizing solution (pH 7.0) at 37°C for 18 hours. Fluoride treatments were completed at the time of transfer daily for seven days. Media solutions were buffered with equal volumes of TISAB II; fluoride levels were measured using a digital ion analyzer and fluoride electrode. Fluoride release decreased significantly from Day 1 to Day 3 for all materials regardless of fluoride treatment (Repeated Measures ANOVA, Tukey HSD, p<0.05). All specimens released significantly more fluoride in demineralizing solution than in remineralizing solution. For Days 2-7, Treatment 4 produced greater fluoride release than both the control and Treatment 2 for all three materials (p<0.05); For each material, the fluoride release produced by Treatments 3 and 4 was statistically similar on most days throughout the study. By Day 7, Photac-Fil demonstrated both the greatest total fluoride release and the greatest rechargability, followed by Ketac-Fil and Dyract AP. Although subsequent daily fluoride release never approached that of Day 1, increasing daily fluoride exposures enhanced fluoride release for all three restorative materials.

SUMMARY:
The durability of a fluoride-free (SE Bond) and a fluoride-containing (KBF) self-etching primer/ adhesive system were compared by measuring the microtensile bond strengths (µTBS) of these adhesive systems to human dentin in vitro. After bonding, the restored teeth were serially sectioned into multiple slabs that were trimmed to a 1 mm2 cross-sectional area at the bonded interface. For the three and six month specimens, half were fully covered with nail varnish (SE+, KBF+), while the other half were incubated at 37°C in water without any protective varnish (SE-, KBF-). The µTBS of the one-day specimens were 44.6 ± 11.2 MPa for SE Bond and 39.8 ± 8.0 MPa for KBF (p>0.05). When unprotected specimens were incubated in water for three and six months, the µTBS fell to 26.3 ± 8.8 MPa and 23.6 ± 10.7 MPa for SE-, respectively, but did not change in the specimens protected with nail varnish (SE+, 41.9 ± 12.8 MPa and 41.8 ± 9.8 MPa, respectively). In contrast, in specimens bonded with a fluoride-containing resin, KBF, the bond strengths of the unprotected specimens did not change over three and six months KBF-. Values were 32.4 ± 6.1 MPa and 36.8 ± 2.3 MPa, respectively. Similarly, varnish-protected KBF+ specimens did not change over three and six months (39.3 ± 13.6 MPa and 40.9 ± 14.7 MPa, respectively). The results indicate that decreases in bond strength over six months’ storage are water-dependent but can be prevented by using fluoride-containing resins.

SUMMARY:
High-strength dental stone is widely used to produce dies for the fabrication of restorations with the lost-wax technique. It is normal to wait at least 24 hours for casts to dry and gain sufficient strength prior to initiating laboratory procedures. This waiting time may be greatly reduced by using microwave drying. This study determined the optimum microwave energy density for preserving working die accuracy of a Type IV high-strength dental stone (Silky Rock; Whipmix). Cylindrical die specimens were fabricated according to manufacturer’s instructions and allowed to set for one hour. The specimens were subsequently treated as follows: Group I (Control group)—air dried; Group II—microwaved at 700W for 40 seconds; Group III—microwaved at 490W for 60 seconds. The percentage weight loss of cylindrical specimens (n=6) and the percentage dimensional change (n=7) of die specimens in three axes (x, y and z) were determined at 30 minutes, 1 hour and 24 hours after air drying/microwaving. Weight loss was measured using an electronic digital balance, while dimensional changes were assessed using image analysis software. Data was subject to ANOVA/Scheffe’s tests at significance level 0.05. No significant difference in percentage weight loss was observed between air drying for 24 hours and microwaved specimens at all time intervals. Although no significant difference in percentage dimensional changes was observed between specimens microwaved at 490W for 60 seconds and specimens air dried for 24 hours, significant changes in x, y and z dimensions were observed after microwaving at 700W for 40 seconds at various time intervals. Microwave radiation at 490W for 60 seconds is recommended for drying Type IV high-strength dental stone. Further investigations are required to determine changes in physical properties associated with the aforementioned microwave power density.

SUMMARY:
This study evaluated the influence of three polymer468mW/cm2 for three or six seconds. One hundred and fifty-two “Vertical Slot type Class II cavities” at the mesial and distal surfaces were prepared and divided into eight groups (n=19). After the restorative procedures, the samples were thermocycled (1,000 cycles at 5°C and 55°C), then immersed in 2% methylene blue dye solution for four hours. The microleakage was evaluated and the results analyzed by the Kruskal–Wallis and Multiple Comparisons tests. Ten samples from each group were randomly selected, embedded in polyester resin, polished and submitted to the Knoop microhardness test. ANOVA (split-plot) and Tukey’s test (p<0.01) revealed significant differences among depths: the hardness at the top surface was significantly higher followed by the middle and bottom surfaces. There was no significant difference in microleakage among the techniques when microhybrid resin composite was employed. However, when using a “packable” resin composite, the conventional technique for polymerization was comparable to Soft-Start and better than PAC.

SUMMARY:
Bonding to tooth tissue can be achieved through an “etch&rinse,” “self-etch” or “glass-ionomer” approach. In this paper, the basic bonding mechanism to enamel and dentin of these three approaches is demonstrated by means of ultra-morphological and chemical characterization of tooth-biomaterial interfacial interactions. Further-more, bond-strength testing and measurement of marginal-sealing effectiveness (the two most commonly employed methodologies to determine “bonding effectiveness” in the laboratory) are evaluated upon their value and relevance in predicting clinical performance. A new dynamic methodology to test biomaterial-tooth bonds in a fatigue mode is introduced with a recently developed micro-rotary fatigue-testing device. Eventually, today’s adhesives will be critically weighted upon their performance in diverse laboratory studies and clinical trials. Special attention has been given to the benefits/drawbacks of an etch&rinse versus a self-etch approach and the long-term performance of these adhesives. Correlating data gathered in the laboratory with clinical results clearly showed that laboratory research CAN predict clinical effectiveness. Although there is a tendency to simplify bonding procedures, the data presented confirm that conventional three-step etch&rinse adhesives still perform most favorably and are most reliable in the long-term. Nevertheless, a self-etch approach may have the best future perspective. Clinically, when adhesives no longer require an “etch&rinse” step, the application time, and probably more importantly, the technique-sensitivity are substantially reduced. Especially “mild,” two-step self-etch adhesives that bond through a combined micromechanical and chemical interaction with tooth tissue closely approach conventional three-step systems in bonding performance.

SUMMARY:
This in vivo study determined the kinetics of 3% hydrogen peroxide in a bleaching gel within the first hour. The material used in this study was 3% hydrogen peroxide gel (Perfecta 3/15, Premier Dental Products Co) and the study involved 10 subjects who met the inclusion and exclusion criteria. Each subject wore the tray with gel six different times on separate days. Evaluation of remaining amount of hydrogen peroxide was calculated by the method stated in US Pharmacopoeia. The study results indicate that the mean percentage of hydrogen peroxide recovered for 5, 10, 20, 30, 45 and 60 minutes was 61, 56, 49, 44, 38 and 32, respectively. The amount of hydrogen peroxide in the saliva sample after one hour was 0.42 mg. Excluding the first 10 minutes, the kinetics of hydrogen peroxide in the tray and teeth sample was exponential.

SUMMARY:
Diverse reports have described how various types of adhesive systems cause disastrous pulp necrosis, chronic severe inflammation or failure to stimulate any pulp reactions. This article reports on the effects of five common adhesive systems and how they compare in terms of pulp injury as measured by odontoblast survival or dentin regeneration and reactionary dentin formation. One hundred and thirty Class V pulp, non-exposed cavities were prepared in non-human primate teeth and were restored with five different adhesive systems. After a period of time between 3 and 172 days, the teeth were extracted, fixed, processed and examined histomorphometrically. Bacterial microleakage was detected with McKays stain and inflammation was categorized according to the International Organization for Standardization (ISO) criteria. The number of odontoblasts and the area of reactionary dentin were measured. Pulp reactions of all adhesive systems were generally minimal, although some systems permitted bacterial microleakage in 33% of restorations, and some other systems were associated with pulp inflammation in 22% of restorations. These observations suggest that adhesive systems provide acceptable biocompatibility, however, there is strong potential for improvement.

SUMMARY:
Various glass ionomer cements (GICs) and resin-modified GICs are widely used as tooth-colored restorative materials. However, their potential effects on pulp tissues are not fully understood. In this study, the authors compared the toxicity of nine types of GICs on cultured human dental pulp cells. Exposure of pulp cells to GICs for five days led to differential growth inhibition as analyzed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Exposure of pulp cells to ProTec CEM, Fuji II LC, Compoglass and GC Lining cement for five days decreased the cell numbers to 11%, 12%, 19% and 25%, respectively, of the control. Exposure of pulp cells to Fuji IX, GIC FX and Fuji II SC also decreased cell numbers by 62%, 33% and 24%, respectively. By contrast, Hy-Bond and Fuji I showed only mild suppression on the growth of pulp cells, with 12% and 16% decreased cell numbers. Morphologically, marked retraction and rounding of pulp cells were noted following exposure to GC Lining cement; in addition, cell surface blebbing was noted following exposure to Compoglass, Fuji II LC and ProTec CEM. Exposure of the pulp cells to Fuji II SC and Fuji IX, however, led to decreases in the cell density, with no obvious morphological changes. These results indicate that resin-modified GICs, such as Compoglass, Fuji II LC, ProTec CEM and GC Lining cements, are more toxic to pulp cells than conventional GICs. It is not recommended that resin-modified GICs be directly applied onto dental pulp cells. However, additional in vivo studies are needed to evaluate the potential toxicities of these resin-modified GICs during clinical operative procedures.

SUMMARY:
This study quantified and compared the thermal emission of different light curing units (LCU). Three LED (Elipar Freelight [3M]; GC e-light [GC]; Coolblu [Dentalsystems.com]) and three halogen (Max [Dentsply-Caulk]; Elipar Trilight [3M]; Astralis 10 [Ivoclar-Vivadent]) lights were selected for the study. Thermal emission of the LCUs, when used in various curing modes, was assessed using a K-type thermocouple and a digital thermometer at distances of 3 mm and 6 mm compared to the conventional halogen LCU (Max). The temperature profiles and mean maximum temperature change (n=7) generated by each LCU were obtained. Data was subjected to ANOVA/Scheffe’s post-hoc test and Independent Samples t-test at significance level 0.05. At 3 mm, temperature rise observed with LED lights ranged from 4.1°C to 12.9°C, while halogen lights ranged from 17.4°C to 46.4°C. At 6 mm, temperature rise ranged from 2.4°C to 7.5°C and 12.7°C to 25.5°C for LED and halogen lights, respectively. Thermal emission of LED lights was significantly lower than halogen lights. Significant differences in temperature rise were observed between different curing modes for the same light and between different LED/halogen lights.

SUMMARY:
This study evaluated the microleakage of a flowable polyacid-modified resin composite used as a fissure sealant on air-abraded teeth in comparison to a resin-based fluoride sealant. Sixty extracted human third molars were divided into six subgroups (n=10) under two main groups (fissure sealant materials). The occlusal surfaces of the teeth were air-abraded at 80 psi using 50 µm particles of aluminum oxide for 30 seconds, followed by rinsing and drying. Delton FS+ (Dentsply International) and Dyract Flow (Dentsply DeTrey) were applied to the teeth in subgroups following application of: a) an acid etching and bonding agent, b) bonding agent alone or c) air-abrasion alone, respectively. Acid etching (Delton EZ Etch, Dentsply International) and bonding agent application (Prime & Bond NT, Dentsply DeTrey) were done according to the manufacturers’ instructions. The teeth were thermocycled for 500 cycles between 5°C and 55°C with dwell time of 15 seconds. Basic fuchsin (0.5%) staining followed by buccolingual sectioning was performed. Microleakage was evaluated at 20x optical magnification. Kruskal–Wallis test was used to make comparisons among six subgroups. Pairwise comparisons were done with the Mann–Whitney U test with the level of significance set as a=0.05.

Dyract Flow application as a fissure sealant on air-abraded permanent teeth in combination with acid etching and/or bonding agent provided microleakage results comparable to Delton FS+. Results also showed that the use of air abrasion, alone, resulted in significantly higher microleakage scores.

SUMMARY:
This study evaluated the physiological remineralization of artificially demineralized dentin beneath glass ionomer cements with and without bacterial contamination. The artificially demineralized dentin was produced on 84mineralized dentin was also analyzed using Electron Probe Microanalysis. For the samples, the mean nanohardness of the three-day samples was significantly lower than the 360-day samples (p<0.05). Although there was no significant difference in the mean nanohardness within all the bacterially-contaminated groups through the experimental periods (p>0.05), the mean nanohardness of the bacterial-contaminated samples were significantly lower than the non-bacteria-contaminated samples (p<0.05). From the EPMA results, fluoride release from both cements to the bottom of the artificially demineralized dentin was detected within three days. Although Ca density was sparse within this demineralized dentin lesion, for the Fuji IX sample, a high Mg density within this lesion was detected at 360 days.

SUMMARY:
This study assessed the in vitro influence of surface sealing on the surface roughness of a posterior resin composite before and after toothbrushing. Thirty specimens (13 mm diameter x 1 mm high) were fabricated from Filtek-P60 resin composite and randomly assigned to three groups (n=10): a non-sealed control and two groups sealed with one of the tested materials—a surface-penetrating sealant (Protect-it!-PI) and a one bottle adhesive system (Single Bond-SB). The samples were subjected to a surface roughness reading to determine the initial roughness, then submitted to simulated toothbrushing with 35,600 cycles for 100 minutes. Specimens were then cleaned and a post-abrasion surface roughness reading accomplished. Means (µm), recorded before (B) and after (A) toothbrushing, and standard deviations were: Control—(B): 0.032 (±0.005), (A): 0.054 (±0.005); PI—(B): 0.034 (±0.005), (A): 0.060 (±0.034); SB (B): 0.031 (±0.004), (A): 0.047 (±0.007). Data were tabulated and submitted to two-way ANOVA. No statistically significant difference was observed when the control and experimental groups were compared. However, a significant difference (p<0.05) was found between the measurements performed before and after toothbrushing. Based on these results, it may be concluded that using either a surface penetrating sealant or a one bottle adhesive system did not provide the optimization of superficial integrity. The use of a dentifrice and toothbrush resulted in significant alterations to the surface smoothness of the resin composite.

SUMMARY:
The difficulty related to achieving a balance between wet and dry dentin makes the dentin bonding technique extremely sensitive. This study evaluated the effect of rewetting dried dentin with two commercial desensitizing agents (Protect and HurriSeal) on the dentin shear bond strength of three total-etch dentin bonding agents (Syntac Single-Component, OptiBond Solo Plus and Prime & Bond NT) and compared both to applying these same bonding agents to moist dentin and dry dentin. Each bonding agent was paired with an appropriate resin composite from the same manufacturer (Table 1). Recently extracted, formalin-treated caries-free human molars were used. The occlusal surface of each tooth was ground to create a flat dentin surface. Then, each tooth was mounted in acrylic. Twelve groups (n=15) were prepared: 1) Syntac Single-Component with Heliomolar resin composite (SSC/H) to moist dentin; 2) SSC/H to dry dentin; 3) SSC/H to dried dentin rewet with Protect; 4) SSC/H to dried dentin rewet with HurriSeal; 5) OptiBond Solo Plus with Point 4 resin composite (OBS+/P4) to moist dentin; 6) OBS+/P4 to dry dentin; 7) OBS+/P4 to dried dentin rewet with Protect; 8) OBS+/P4 to dried dentin rewet with HurriSeal; 9) Prime & Bond NT with TPH Spectrum resin composite (PBNT/TPH) to moist dentin; 10) PBNT/TPH to dry dentin; 11) PBNT/THP to dried dentin rewet with Protect and 12) PBNT/TPH to dried dentin rewet with HurriSeal. Groups 1, 5 and 9 were placed according to manufacturers’ instructions (moist dentin) as control groups. All the other groups received a 15-second air blast after etching and prior to applying the one bottle adhesive or desensitizer and one bottle adhesive. Resin composite cylinders [4 mm in diameter and 2 mm in height] were then placed. The specimens were stored in distilled water at 37°C for 24 hours prior to thermocycling 2,500 times (at 8°C and 48°C). Shear bond strengths (SBSs) were measured one week after fabrication by using a circular knife-edge and crosshead speeds of 0.5 mm/minute. Failure modes of debonded specimens were determined under a stereomicroscope (30x). Failed specimens with the low and high shear bond strengths in each group were evaluated under a low vacuum Scanning Electron Microscope (SEM-LV). One-way ANOVA and Tukey’s tests were used to compare the different conditions for each bonding system. In the Syntac Single-Component bonding agent groups, there was no significant difference in shear bond strength between the control (15.73 MPa), dry (18.11 MPa) and HurriSeal (16.18 MPa) specimens. Protect specimens showed significantly lower shear bond strength (6.39 MPa). In the OptiBond Solo Plus bonding agent groups, there was no significant difference between the control (20.79 MPa) and the HurriSeal (21.29 MPa) groups, and both groups had significantly greater bonds than the dry (14.13MPa) and Protect (9.57 MPa) groups. In the Prime & Bond NT bonding agent groups, the shear bond strength of the HurriSeal group (20.73 MPa) was significantly higher than the other groups: control (8.05 MPa), dry (5.73 MPa) and Protect (5.45 MPa).

SUMMARY:
Polymerization shrinkage causes microleakage of resin composite restorations. New materials and operative techniques should be developed in order to reduce polymerization shrinkage. This research studied the effects of cooled composite inserts and room-temperature composite inserts in the sealing ability of resin composite restorations placed at intraoral temperatures. Forty-eight extracted human molars (providing a total of 155 sections) were kept at intraoral temperatures, and Class V cavities were restored with an ormocer-based resin composite (Admira, Voco). Three restorative techniques were used: conventional bulk insertion (Group I or control group) (n=53 sections), room-temperature resin composite inserts (Group II) (n=52) and cooled resin composite inserts (Group III) (n=50). Microleakage and penetrating microleakage were studied under the microscope. Cooled composite inserts reduce microleakage at the gingival margins with respect to Groups I (p=0.002) and II (p=0.014). When small-size cooled composite inserts were used, the sealing ability at the gingival margins of Class V composite restorations was improved with respect to the bulk insertion technique and the room-temperature composite inserts technique.

SUMMARY:
Although resin composite restorations may undergo relatively extreme temperature changes in the oral cavity, little is known about the effects of temperature on their adhesion to tooth structure. This study evaluated the effect of temperature on shear bond strength to dentin of three commercial resin dentin adhesives through testing of matured specimens over the 20° to 55°C temperature range. A significant difference (p<0.05) was observed between 20°C and 55°C for all the materials, and for one of the materials, a significant difference was also observed between 20°C and 37°C.

SUMMARY:
Predicting the polymerization throughout resin-based composite (RBC) has been reduced to a set of variables involving irradiance of the light source, exposure duration and RBC transmission properties, together with an energy-conversion relationship (ECR) derived from Fourier Transform Infrared Spectroscopic analysis (FTIR) of a single shade of photo-polymerized RBC. The ECR describes the localized energy density required to achieve a desired conversion independent of shade. Using this ECR, conversion was predicted and experimentally verified throughout different opacities of RBC based on knowledge of their transmission properties and the incident radiant energy density (irradiance times exposure time). Also, using RBC transmission properties, a critical scrape-back energy of approximately 32 mJcm-2 was determined from cylindrical samples of photo-polymerized RBC in which the poorly polymerized material was removed. This value correlates to approximately 22% conversion. The critical scrape-back energy was then used to predict scrape-back lengths obtained from samples polymerized at various energy densities. These results confirm the logarithmic relationship between depth of cure and energy of exposure and the reciprocal relationship between irradiance and time of exposure.

SUMMARY:
This in vitro study evaluated the influence of curing tip distance on the Knoop Hardness Number (KHN) of a resin composite when using three different light curing units: (1) a halogen light (XL 1500 curing unit–3M), (2) a “softstart-polymerization” (Elipar Trilight curing in an exponential mode-ESPE) and (3) a PAC (Apolo 95E curing unit-DMD). The resin composite, Filtek Z250 (3M), was cured by these curing units at three light-tip distances from the resin composite: 0 mm, 6 mm and 12 mm. The resin composite specimens were flattened to their middle portion and submitted to 18 KHN measurements per specimen. The results showed that for the Elipar Trilight unit, the hardness of the resin composite decreased as the light tip distance increased. The XL 1500 unit presented a significant decrease in hardness as the depth of cure of the resin composite increased. Apolo 95E caused a decrease in the resin composite hardness values when the depth of cure and light tip distance increased.

SUMMARY:
Improvements in healthcare and health awareness have lengthened life spans and decreased edentulism, while at the same time presenting significant challenges to the dental community in the form of root caries. The incidence of root caries is dramatically high in spite of the vast amount of preventive tools available to patients and dentists (Cochran & Matis, 2000). Relative to coronal caries, root caries is not as easily diagnosed and treated. Diagnosis, access and isolation for restorative material placement can be extremely difficult, especially in the posterior regions of the mouth. When using the traditional Class II approach to restoring proximal root caries, a significant amount of sound tooth structure may have to be removed.

Glass ionomers (glass ionomer cements and resin-modified glass ionomers) are biocompatible restorative materials that chemically bond to tooth structure while serving as rechargeable fluoride delivery devices (Williams, Billington & Pearson, 2002; Creanor & others, 1995; Forsten, 1995). Recent advances in glass ionomer materials have improved not only the physical properties but also their ease of use. This paper presents an expedient clinical application for applying encapsulated glass ionomer cement when restoring proximal root decay in the presence of the contiguous tooth.

SUMMARY:
This study investigated the clinical efficacy of a bonded resin composite restoration with and without cuspal coverage for the treatment of painful, cracked teeth. Patients in a private dental practice who presented with complaints were selected. Inclusion criteria were sensitivity to cold, biting and a clinically-visible crack after removal of the existing restoration. All 40 teeth were restored with a three-step total etch system (Phosphoric acid/Clearfil SA primer/PhotoBond), 20 with cuspal coverage and 20 without. Patients were interviewed at one week, five weeks and six months regarding the presence of pain. In addition, the teeth were clinically examined after six months to reveal any sensitivity. At one week, patients reported that 12 teeth (30%) were free of pain and 28 teeth (70%) still had symptoms. At five weeks, patients reported that 25 teeth (62.5%) were free of pain and 13 teeth (32.5%) still had symptoms. Two teeth (5%) needed endodontic treatment after two and five weeks. At six months, patients reported that 30 teeth (75%) were functioning without any complaints. Upon clinical examination, only 20 teeth (50%) were free of symptoms.

No statistically significant difference between the results of the teeth treated with and without cuspal coverage could be shown (Fischer’s exact test at p<0.05).

SUMMARY:
This clinical study compared the effectiveness of bleaching non-vital teeth with an open pulp chamber during bleaching using 10% carbamide peroxide compared to the modified walking bleach technique and extracoronal bleaching. Sixty discolored, non-vital teeth were treated. They were divided into three groups. Each group was treated with one of the bleaching materials and methods: extracoronally using 10% carbamide peroxide for two weeks as negative control (Group A), intracoronally using sodium perborate mixed with 3% hydrogen peroxide (modified walking bleach technique) (Rotstein, Mor & Friedman, 1993) for four weeks (Group B) and intracoronally and extracoronally using 10% carbamide peroxide for two weeks (Group C) (Liebenberg, 1997). Tooth color was measured at baseline, (BL), immediately post-bleaching (IP) and six months post-bleaching (SP) with a colorimeter (Castor, Sigma, Germany) using a tooth-positioning jig. The color was determined according to the CIELAB system, which records lightness as L* and chromaticity coordinates as a* and b*. The difference in L* and b* among the three groups was significant between BL and IP examination. The post-bleaching, whitening effect in Group C was significantly better, but after six months, in Group C, it was as effective as in Group B.

SUMMARY:
A recent study showed that orange-red fluorescence in carious dentin could be used to detect residual caries (Lennon & others, 2002). This study compared the ability of a new fluorescence-aided caries excavation technique (FACE) with the conventional method. Forty extracted teeth with occlusal dentin caries were selected. The teeth were bisected longitudinally through the center of the lesion. Lesion depth and width were measured and the teeth were divided into two groups of 20, each with the same average lesion size. The tooth halves were reassembled and fixed by embedding the roots in acrylic resin. Access cavities were prepared using a high-speed handpiece and diamond fissure bur. In the FACE group, violet light (370–420 nm) was fed into the fiber optics of a slow-speed handpiece, so that it illuminated the operating field. The cavity was observed through a 530-nm highpass filter and orange-red fluorescing areas were removed. In the conventional group, a sharp probe was used to detect soft dentin, which was removed. One-half of each tooth was stained for bacteria using Ethidium Bromide and examined using Confocal Laser Scanning Microscopy (CLSM). Bacteria were present in significantly (p=0.037) fewer FACE samples (3) compared to conventional samples (9). It can be concluded that the new method is more effective than conventional caries excavation.

SUMMARY:
This study evaluated the dentinal composition and Knoop hardness measurements of the cavity floor following the removal of carious dentin by the Carisolv chemo-mechanical caries removal system, in vitro. The carious dentin of 25 extracted human teeth was removed by using Carisolv for one minute with instruments and excavation that was performed until the gel was clear. Caries removal with a sharp explorer was verified according to the color and hardness of the lesion, then, by means of DIAGNOdent. Atomic analysis of treated cavities was performed by energy dispersive x-ray spectroscopy (SEM-EDX) and the Knoop hardness number (KHN) of the cavity floor was determined. Surface characteristics were observed by the scanning electron microscope (SEM). Adjacent sound dentin was used as a control reference. No significant differences were found between the quantities of calcium content (Ca weight %), phosphorus content (P weight %) and the Ca/P weight ratio of Carisolv cavities with that of the adjacent, sound dentin (p<0.01). KHN of the Carisolv cavity floor was almost similar to that of the adjacent sound dentin. SEM analysis revealed an extremely rough or irregular surface, and there remained a minimal debris-like smear layer; most of the dentinal tubules were opened. The results indicated that Carisolv does not produce any adverse side effects on dentinal compositions of the treated cavities. The possibility of remaining residual softened dentin was also minimal in this study.

SUMMARY:
The application and polymerization of composite or polyacid-modified resin composites in thin layers (increment technique) for filling cavities might partially compensate for the stress associated with polymerization shrinkage. In this study, the effect of this technique on the marginal integrity of Class V polyacid-modified composite restorations was investigated.

In 30 extracted premolars, extended Class V cavities were prepared with the apical margin in root dentin and the coronal margin in enamel. They were then subjected to different treatments (10 teeth in each case): a) placement and polymerization of a thin resin composite layer (Dyract-Dyract PSA) in the coronal part of the cavity (plus one increment for the residual part) (Group 1), b) a thin layer at the apical part of the cavity (plus one increment for the residual part) (Group 2) and c) restoration of the entire cavity with one increment (bulk technique) (Group 3). Following three days’ storage in water, the teeth were subjected to cyclic thermal loading (4°C <-> 55°C, 2,000 cycles).

The percentages of defective bonding detected along the total length of the restoration margin were assessed before and after thermocycling by scanning electron microscopy. Following loading and thermocycling, no significant differences were found at the restoration-enamel interface. Fewer gaps were found at the restoration-dentin interface in Group 1 (18.7 ± 25.7%) and Group 2 (20.5 ± 22.8%) compared to the reference Group 3 (42.2 ± 30.6%) (Mann-Whitney U test: p<0.05).

Moreover, there were no significant differences between the two increment groups (1 and 2). In a significantly larger number of cases, a completely intact dentin restoration margin was detected when a coronal increment (Group 1) (44.4%) was used instead of the bulk technique (Group 3) (13.6%) (Chi square test: p<0.05).

These results indicate that gap formation can be significantly minimized by using an increment technique to restore extended Class V cavities with polyacid-modified composite materials.

SUMMARY:
This study investigated the effectiveness of cure and post-gel shrinkage of three visible light-cured composite resins (In Ten-S [IT], Ivoclar Vivadent; Z100 [ZO], 3M-ESPE; Tetric Ceram [TC], Ivoclar Vivadent) when polymerized with a very high intensity (1296 ± 2 mW/cm2) halogen light (Astralis 10, Ivoclar Vivadent) for 10 seconds. Irradiation with a conventional (494 ± 3 mW/cm2) halogen light (Spectrum, Dentsply) for 40 seconds was used for comparison. The effectiveness of cure was assessed by computing the hardness gradient between the top and bottom surfaces of 2-mm composite specimens after curing. A strain-monitoring device was used to measure the linear polymerization shrinkage associated with the various composites and curing lights. A sample size of five was used for both experiments. Data was analyzed using ANOVA/Scheffe’s post-hoc and Independent Samples t-tests at significance level 0.05. Results showed that the effect of the curing method on the effectiveness of cure and shrinkage was material-dependent. Polymerization of IT and TC with Spectrum for 40 seconds resulted in significantly more effective cure than polymerization with Astralis for 10 seconds. Polymerization of ZO with Spectrum for 40 seconds resulted in significantly more shrinkage than polymerization with Astralis for 10 seconds. In view of the substantial time saving, using high intensity lights may be a viable method to polymerize composites.

SUMMARY:
This in vitro study evaluated the cytotoxic effects of a restorative resin composite applied to an immortalized odontoblast-cell line (MDPC-23). Seventy-two round resin discs (2-mm thick and 4 mm in diameter) were light-cured for 20 or 40 seconds and rinsed, or not, with PBS and culture medium. The resin discs were divided into four experimental groups: Group 1: Z-100/20 seconds; Group 2: Z-100/20 seconds/rinsed; Group 3: Z-100/40 seconds; Group 4: Z-100/40 seconds/rinsed. Circular filter paper was used as a control material (Group 5). The round resin discs and filter papers were placed in the bottom of wells of four 24-well dishes (18 wells for each experimental and control group). MDPC-23 cells (30,000 cells/cm2) were plated in the wells and allowed to incubate for 72 hours. The zone of inhibition around the resin discs was measured under inverted light microscopy; the MTT assay was carried out for mitochondrial respiration and cell morphology was measured under SEM. The scores obtained from inhibition zone and MTT assay were analyzed with the Kruskal-Wallis followed by Dunnett tests. In Groups 1, 2, 3 and 4, the thickness of the inhibition zone was 1,593 ± 12.82 µm, 403 ± 15.49 µm, 1,516 ± 9.81 µm and 313 ± 13.56 µm, respectively. There was statistically significant difference among the experimental and control groups at the 0.05 level of significance. The MTT assay demonstrated that the resin discs of the experimental groups 1, 2, 3 and 4 reduced the cell metabolism by 83%, 40.1%, 75.5% and 24.5%. Only between the Groups 2 and 4 was there no statistically significant difference for mitochondrial respiration. Close to the resin discs, the MDPC-23 cells exhibited rounded shapes, with only a few cellular processes keeping the cells attached to the substrate or, even disruption of plasma membrane. Adjacent to the inhibition zone, the cultured cells exhibited multiple fine cellular processes on the cytoplasmic membrane organized in epithelioid nodules, similar to the morphology observed to the control group. Based on the results, the authors may conclude that the Z-100 resin composite light cured for 20 seconds was more cytopathic to MDPC-23 cells than Z-100 light cured for 40 seconds. The cytotoxic effects of the resin discs decreased after rinsing them with PBS and culture medium. This was confirmed by MTT assay and upon evaluation of the inhibition zone, which was narrower following rinsing of the resin discs.

SUMMARY:
This study compared the effectiveness of cure of two LED (light-emitting diodes) lights (Elipar FreeLight [FL], 3M-ESPE; GC e-Light [EL], GC) to conventional (Max [MX], Dentsply-Caulk [control]), high intensity (Elipar TriLight [TL], 3M-ESPE) and very high intensity (Astralis 10 [AS], Ivoclar Vivadent) halogen lights. The 10 light-curing regimens investigated were: FL1 400 mW/cm2 [40 seconds], FL2 0-400 mW/cm2 [12 seconds] Æ 400 mW/cm2 [28 seconds], EL1 750 mW/cm2 [10 pulses x 2 seconds], EL2 350 mW/cm2 [40 seconds], EL3 600 mW/cm2 [20 seconds], EL4 0-600 mW/cm2 [20 seconds] Æ 600 mW/cm2 [20 seconds], TL1 800 mW/cm2 [40 seconds], TL2 100-800 mW/cm2 [15 seconds] Æ 800 mW/cm2 [25 seconds], AS1 1200 mW/cm2 [10 seconds], MX 400 mW/cm2 [40 seconds].

Effectiveness of cure with the different modes was determined by measuring the top and bottom surface hardness (KHN) of 2-mm thick composite (Z100, [3M-ESPE]) specimens using a digital microhardness tester (n=5, load=500 g; dwell time=15 seconds).

Results were analyzed using one-way ANOVA/Scheffe’s post-hoc test and Independent Samples t-test (p<0.05). At the top surface, the mean KHN observed with LED lights ranged from 55.42 ± 1.47 to 68.54 ± 1.46, while that of halogen lights was 62.64 ± 1.87 to 73.14 ± 0.97. At the bottom surface, the mean KHN observed with LED and halogen lights ranged from 46.90 ± 1.73 to 66.46 ± 1.18 and 62.26 ± 1.93 to 70.50 ± 0.87, respectively. Significant differences in top and bottom KHN values were observed between different curing regimens for the same light, and between LED and halogen lights. Although curing with most modes of EL resulted in significantly lower top and bottom KHN values than the control, no significant difference was observed for the different modes of FL. Hence, the effectiveness of composite cure with LED LCUs is product dependent.

SUMMARY:
This study evaluated the influence of collagen removal and the use of a low-viscosity liner on the marginal quality of composite restorations for the total-etch system, Prime & Bond 2.1 (PB) and the self-etching primer system, Clearfil SE Bond (CSEB), in high C-factor cavities with margins in dentin. High C-factor cavities were made on dentin exposed from ground labial surfaces of 100 bovine lower incisors, randomly assigned to 10 treatment groups and restored with composite Z 250, placed in bulk. In Group 1 (PB), control group, PB was applied according to the manufacturer’s directions; in Group 2 (PB/PLF), an intermediate layer of low-viscosity composite Protect Liner F (PLF) was applied on the bonding resin surface; in Group 3 (PB/SH) following acid-etching, the surfaces were treated with 10% sodium hypochlorite (SH) for one minute and in Group 4 (PB/SH/PLF), the same procedure was conducted as for Group 3, plus an intermediate layer of PLF was applied as for Group 2. In Group 5 (CSEB), the control group, CSEB was applied according to the manufacturer’s directions; in Group 6 (CSEB/PLF), an intermediate layer of PLF was applied; in Group 7 (SH/CSEB), the cavity surface was pre-treated with SH; in Group 8 (SH/CSEB/PLF), SH pre-treatment was conducted as for Group 7, then an intermediate layer of PLF was applied; in Group 9 (CSEB/SH), after CSEB-primer application, the surface was treated with SH, followed by CSEB-adhesive application and in Group 10 (CSEB/SH/PLF), the same was conducted as for Group 9, then an intermediate layer of PLF was applied. The specimens were stored at 37°C for 24 hours, polished, molded and replicas were obtained in epoxy resin. The replicas were gold-sputter coated and observed by SEM (300x) for marginal quality classification. The Kruskal-Wallis non-parametrical multi-comparison Test (p<0.05) was used to obtain statistical analysis of the data. Results demonstrated that both adhesive systems in the control groups presented low marginal quality and a high variability. The use of an intermediate layer of PLF significantly improved the marginal quality with the CSEB system but had no effect with the PB system. Collagen depletion with SH enhanced marginal quality for the PB system and did not influence the CSEB system results.

SUMMARY:
The difficulty with comparing data obtained from different research centers calls for the standardization of laboratory procedures. This in vitro study compared the shear bond strength (SBS) of two adhesive systems—a self-etching system, Etch&Prime 3.0 and a one-bottle total-etch system, Single Bond—using two methods of load application (orthodontic edge wire loop and knife-edge blade). The hypothesis of substrate influence on the results obtained for both tests was also investigated. Twenty-four recently extracted human teeth were embedded in PVC tubes using acrylic resin and divided into two groups (n=12). A proximal surface of each tooth was wet-ground flat to expose dentin. Etch&Prime 3.0 and Single Bond adhesive systems were applied according to the manufacturers’ instructions, and cone-shaped restorations were then built using Z100 resin composite. After storage in distilled water at 37°C for 24 hours, the specimens were submitted to SBS testing using an orthodontic edge wire loop. The same teeth were again embedded in PVC tubes using acrylic resin and the other proximal surface was wet-ground flat to expose dentin. The specimens were prepared as explained above, and after storage in distilled water under the same previous conditions, they were submitted to SBS testing using a knife-edge blade. Two-way ANOVA and Tukey’s tests were performed to determine any statistically significant differences among testing conditions. Results indicated that SBS values obtained for Etch&Prime 3.0 were significantly lower than Single Bond for both methods of load application (p<0.001). Regarding the load application method, statistically significant higher values (p<0.01) were obtained for Etch&Prime 3.0 when the knife-edge blade was used, whereas, no significant difference was observed between the two methods for Single Bond. There was a significant correlation between the bond strength values obtained on the same tooth (p<0.05). SEM examination found that Etch&Prime 3.0 demonstrated narrower tags than Single Bond. Moreover, the peritubular dentin was not adequately decalcified when Etch&Prime 3.0 was used.

SUMMARY:
Many fluoride-releasing dental materials are being sold on the basis of their cariostatic properties. However, the amount fluoride release of these materials is still uncertain. This study investigated the fluoride release and uptake characteristics of four flowable resin composites (Heliomolar Flow, Tetric Flow, Wave, Perma Flo), one flowable compomer (Dyract flow), one conventional glass ionomer cement mixed with two different powder/liquid ratios (ChemFlex Syringeable and ChemFlex Condensable), one packable resin composite (SureFil), one ion-releasing composite (Ariston pHc) and one resin-modified glass ionomer cement (Vitremer). Seven discs (6-mm diameter and 1.5-mm height) were prepared for each material. Each disc was immersed in 3.5 ml of deionized water within a plastic vial and stored at 37°C. The deionized water was changed every 24 hours and the release of fluoride was measured for 30 days. At the end of this period, the samples were recharged with 2 ml of 1.23% acidulated phosphate fluoride (APF) gel for four minutes. Then, all samples were reassessed for an additional 10 days. The fluoride release of all samples was measured with a specific fluoride electrode and an ionanalyzer. Statistical analyses were conducted using two-way repeated measure ANOVA and Duncan’s multiple range tests. For all tested materials, the greatest fluoride release was observed after the first day of the study (p<0.01) but gradually diminished with time. During the test period, Tetric Flow released the lowest amount of fluoride; however, no statistically significant difference was found from Wave and Heliomolar Flow (p>0.05). Ariston pHc released the highest amount of fluoride, followed by ChemFlex Syringeable, Vitremer and ChemFlex Condensable. There were statistically significant differences among these materials (p<0.05). Fluoride release of all materials were significantly increased after the first day following refluoridation and Ariston pHc released the greatest among all materials (p<0.01). At the end of two days of refluoridation, the fluoride release rate for each material dropped quickly and stabilized within three days.

SUMMARY:
This research quantitatively evaluated the marginal adaptation of pit and fissure sealants. The occlusal surfaces of 48 intact, caries-free human molars were cleaned with an air-abrasion unit. The teeth were then randomly divided into eight groups of six teeth each according to the type of enamel conditioning, sealant material applied and curing unit used. After applying either 40% phosphoric acid gel (K-etch, Kuraray Co) or a self-etching primer adhesive system (Clearfil SE Bond, Kuraray Co), sealant materials of two viscosities were applied (Teethmate F-1 and Protect-Liner-F, Kuraray Co) and cured with halogen (Optilux 500, Demetron) or plasma arc (Apollo-95E, Dental & Medical Diagnostic Systems, Ltd) curing units. The marginal adaptation of the pit and fissure sealant restorations was evaluated by using a computer-assisted quantitative margin analysis in a scanning electron microscope (SEM) on epoxy replicas before and after thermal and mechanical stressing of the teeth. The results were statistically analyzed with one-way analysis of variance (ANOVA) at a confidence level of 95% (p=0.05). A post-hoc Tukey HSD-test was used for multiple pairwise comparisons between groups. The null hypothesis was that there was no statistically significant difference between the groups that were tested in this study.

The statistically significant differences between groups were more pronounced after loading. In most cases, the self-etching adhesive system (SE Bond) proved as effective as phosphoric acid etching (K-etch). The low viscosity sealant material (Teethmate F-1), in most cases, exhibited better marginal adaptation than the high viscosity material (Protect-Liner F). The high viscosity material performed equally well only when used in combination with the self-etching primer adhesive system as an intermediate layer. The halogen curing unit (Optilux 500) led to better marginal adaptation than the plasma arc curing unit (Apollo 95E), especially after thermal and mechanical stressing.

SUMMARY:
The authors hypothesize that the arrestment and remineralization of these lesions could be improved if secondary caries could be detected and monitored at earlier stages. Traditional diagnostic techniques detect secondary caries when it is relatively advanced and when significant tissue has been lost. This in vitro study evaluated the Quantitative Light-induced Fluorescence (QLF) system for detecting and monitoring demineralization surrounding tooth-colored restorations. This investigation was divided into three studies. The first study evaluated QLF for the detection and measurement of chemically induced lesions surrounding resin composite restorations. The second study evaluated QLF for the detection of demineralization around different tooth-colored restorations (glass ionomer, resin composite, compomer and smart material) created in a microbial caries model. Finally, the third study tested whether QLF was effective at detecting early wall lesions adjacent to resin composite restorations. Data from Study 1 demonstrated the potential for QLF to detect very early secondary caries and to distinguish between the different stages of early demineralization. Study 2 confirmed the potential for QLF to detect early secondary caries created by cariogenic bacteria and concluded that the four types of materials differed in their ability to prevent secondary caries in this model, with the glass ionomer being the most effective and the non-fluoride releasing composite performing the worst, which allowed for the development of larger lesions. The results of Study 3 suggest a potential application of the QLF system to detect early wall lesions. Data from this investigation strongly suggest that QLF is a potentially viable technology to detect and monitor early secondary caries.

SUMMARY:
This study evaluated the “in vitro” shear bond strength of two materials to bovine enamel when used as porcelain laminate veneer bonding systems. The authors used the dual-cured resin cement Variolink II (Vivadent) and the light-cured flowable composite Natural-Flow (DFL). Porcelain cylinders were bonded to bovine enamel following manufacturers’ directions. After 24 hours of storage in distilled water and thermocycling, the specimens were tested on a universal testing machine to determine the shear bond strengths. Mean strengths found in Groups 1 (resin cement) and 2 (flowable composite) were not statistically different (p≤ 0.05). The authors concluded that the shear bond strength of Natural-Flow is not different from Variolink II and that flowable composites can be a suitable alternative when used as porcelain laminate veneer bonding systems.

SUMMARY:
This in vitro study verifies whether there are differences between bonding to hypermineralized dentin and normal dentin and if longer acid etching can improve the bond strength to this modified substrate without damaging the bond to normal dentin. Forty-two extracted human molars with chronic occlusal caries were transversally cut with a diamond saw under refrigeration. The occlusal surfaces were ground until the carious lesion was removed, exposing the sclerotic dentin in the center and polished to 600/grid. A 35% phosphoric acid (3M) was applied for 15 seconds in 15 specimens. SingleBond (3M) adhesive system was applied and a hybrid resin composite (Filtek Z250, 3M) was inserted in four 1-mm increments and light-cured. The remaining 15 molars were prepared in the same manner, but with an acid etching time of 30 seconds. After 24 hours in water, the specimens were cut in two perpendicular directions to obtain a cross section of approximately 0.7 mm2 (n=25). A visual examination was conducted to select sticks between the two groups: sclerotic dentin (G15S or G30S) and normal dentin (G15N or G30N). Sticks without 100% sclerotic dentin (translucent area) or those with normal areas were not tested. Two-way ANOVA computed the µ-TBS data taking into consideration dentin type and acid etching time. The dentin Knoop hardness number (KHN) of the sticks was verified. A t-test compared the KHN data between sclerotic and normal dentin. Twelve additional molars (n=6) were prepared to observe the interface under a SEM. The mean (±SD) microtensile bond strengths (µ-TBS) were: G15S=56.4(±14.9), G15N=69.7(±17.2), G30S=63.2(±15.6) and G30N=67.7(±13.3). Two-way ANOVA showed higher µ-TBS to normal dentin than sclerotic dentin. Duncan’s Post Hoc showed G15N had higher mean µ-TBS than G15S. Other comparisons were not significantly different. The t-test showed statistically higher microhardness in sclerotic dentin than in normal dentin (p<0.0001). The hybrid layer (HL) formation was observed in all specimens without gap formation in any region. In sclerotic dentin (G15S), the HL was very thin, with minimal resin tags in the dentinal tubules and, when present, they were shorter. Doubling the etching time (G30S) resulted in more resin tags with an HL formation on peritubular dentin. The HL on normal dentin was thicker when it was acid etched for 30 seconds (G30N). Numerous resin tags were present with both etching times. The results suggest that the higher mineral amount in sclerotic dentin makes it difficult to bond to this substrate, resulting in a lower µ-TBS. However, doubling the etching time resulted in µ-TBS similar to normal dentin.

SUMMARY:
This study evaluated the cytotoxicity of four single component dentin bonding agents: Syntac Single Component, Prime & Bond 2.1, Single Bond and One Up Bond F. The test materials were applied on dentin discs of dentin barrier models in the same way as in the clinical procedures recommended by each manufacturer. Cell viability of L 929 after exposure with the bonding agents was determined by MTT assay. The results revealed that cell survival of the first three bonding agents was 60%, while the fourth was an impressive 93%. This study showed that a total-etching bonding system is more cytotoxic than a self-etching bonding system.

SUMMARY:
This study compared the interfacial integrity of Class II ceramic inlay restorations and direct resin composite restorations. The influence of a flowable resin composite liner was also evaluated. Class II DO cavities were prepared in 40 recently extracted mandibular molars and assigned to four treatment groups. Group A: direct composite restoration; Group B: Cerec inlays fabricated and cemented with a resin cement; Group C: adhesive lining with a flowable resin composite used prior to resin composite restoration; Group D: lining with a flowable resin composite prior to cementation of Cerec inlays. After finishing, polishing and thermocycling (4°C and 60°C x 500), the samples were cross-sectioned in a mesio-distal direction along the center of the fillings or inlays. The cross-sectioned surface was polished, and the adhesive interfaces between resin and enamel or dentin were observed under a scanning laser measurement microscope.

Ceramic inlay restorations showed no interfacial gaps in enamel, but direct resin composite restorations showed a significantly higher incidence of gaps at the interface or cracks in the interfacial enamel (p=0.0002). No differences were found in the resin–dentin interfaces for both the inlay and direct resin composite restorations. The use of a flowable resin com-posite as an adhesive liner produced a significantly greater gap-free resin-dentin interface in Cerec inlay and direct resin composite restorations (p=0.0233 & 0.0009), but it did not reduce gap formation at the resin-enamel interface.

SUMMARY:
This in vitro study compared three different methods to evaluate detectable levels of microleakage in Class II restorations placed with five commercially available packable resin composites: Alert, Glacier, Pyramid, Solitaire 2 and SureFil. A flowable resin composite, Flow-It, was used to line all packable composites. The hybrid resin composite Z100 was also included. The adhesive system used with all groups was Scotchbond MultiPurpose Plus. Standard Class II cavities were prepared on the mesial (enamel margins) and distal (dentin margins) sides of the teeth with no communication between them.

Based on a power analysis, 180 permanent human molars were randomly assign to each of six groups with 30 specimens per group. All restorative materials were placed following manufacturers’ recommendations. Following restoration and thermocycling, the specimens were stored at room temperature in solutions of 45Ca, methylene blue and rhodamine B, sequentially. Microleakage was ordinal scored as 1 (no penetration), 2 (penetration up to one-third of the cervical floor), 3 (penetration beyond one-third of the cervical floor to the axial wall) and 4 (penetration along the axial wall) by two independent evaluators. Analysis of the occlusal surfaces was also accomplished following the same scheme.

In this study, tracers/dyes were evaluated for differences in penetration using generalized estimating equation methodology applied to cumulative logistic regression models. The results showed that Rhodamine B detected more microleakage than 45Ca or methylene blue, and 45Ca generally detected more microleakage than methylene blue.

INTRODUCTION:
As a speaker at the February 2003 Academy of Operative Dentistry meeting, I was asked to wrap-up the meeting and try to “Put It All Together.” After considerable thought, I decided to attempt this huge task by telling my story of 30 years in dentistry, particularly regarding posterior direct and indirect restorations. Through personal experience and the refereed literature, I related what I had seen and experienced in the clinical and corporate setting. The following is a condensed, written version of that lecture.

INTRODUCTION:
The widespread use of Ca (OH)2, alone, is a debatable topic. The existing references do not conclusively link dentin bridge formation under calcium hydroxide to the healing process. Bridge formation can occur under different materials and using Ca (OH)2 is not necessarily a requirement for healing (Schroder, 1985; Cox, 1987). The disadvantage of calcium hydroxide is its tendency to dissolve under the restoration within one-to-two years (Cox & Suzuki, 1994). Also, since dentin bridges formed under this material contain tunnels in 50% of the cases, microleakage through these openings may lead to pulpal necrosis (Cox & others, 1985). One of the major factors leading to pulp healing is the suppression of bacterial activity (Matsuo & others, 1996) and hemorrhage control. In order to create and maintain the hermetic seal, the sealing material must be used in a bacterial-free environment, while pulpal bleeding must be completely stopped.

SUMMARY:
Occasionally, a clinician encounters a deep root caries lesion at the gingival cavosurface margin of a Class II cavity. This area is difficult to restore properly if the cavosurface is close to or right at the bone level. Often, even the gingival extension molar MOD matrix band is inadequate to seal off the subgingival cavosurface margin. Innovative methods are frequently proposed to tackle the challenges of concavity at the gingival cavosurface margin of a prepared cavity (Ireland, 1985; Khera & Swift, 1989; Woodmansey, 1998; Chan 2001). Other proposed techniques deal with severely broken down teeth (Knight 1996; Esquivel & Welsch, 1999). However, no method was proposed to deal with the deep root caries lesion at the gingival cavosurface margin of a Class II cavity.

This paper describes a technique for adaptation of the matrix band in cases where the gingival cavosurface margin extends subgingivally. An open sandwich restoration was prescribed. In such a case, the gingival area is first restored with a resin-modified glass ionomer material, then amalgam condensed on top of the cured glass ionomer layer.

SUMMARY:
While a one-year report had been previously published, this study was undertaken to evaluate the clinical performance and appearance of a resin-modified glass ionomer and a resin composite over two years. Thirty-seven pairs of restorations of FujI II LC and Z 250/Single Bond were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. Restorations were clinically evaluated at baseline, 6, 12, 18 and 24 months using modified Ryge/USPHS criteria. No statistically significant difference (p=0.13) was observed in the overall performance of the materials. Retention was 96% for the resin-modified glass ionomer and 81% for the resin composite, with no additional restorations of either mate-rial lost after one year. As previously reported, retention of the Z 250 restorations at six months was below the minimum specified in the ADA Acceptance Program for Dentin and Enamel Adhesives. The resin composite restorations generally had a better appearance, with a 100% alpha rating in color match, versus 85% for the resin-modified glass ionomer.

SUMMARY:
This study evaluated the effect of the elastic modulus and margin configuration on the clinical performance of resin-based composite restorations in Class V non-carious defects. One hundred and five cervical non-carious defects on buccal surfaces of canines and premolars were included in this study. Defects were randomly divided into three Groups and restored according to the following techniques: Group 1—no enamel bevel was placed and the defect was restored with a microfilled resin-based composite (Durafill VS); Group 2—the enamel margin was beveled and the defect restored as in Group 1; Group 3—the enamel margin was beveled and the defect was restored with a flowable resin-based composite (Natural Flow). Each group comprised 35 lesions. A total-etch, one-bottle adhesive (One-Step) was used in all groups. Retention rate, pre- and post-operative sensitivity, marginal discoloration and secondary caries were determined over a three-year period and the data were analyzed statistically.

At six months post-insertion, the restorations placed with beveled enamel margins resulted in 100% retention regardless of the composite used compared to a 66% retention of the non-beveled margins. At two and three years, no significant difference in retention rate was found among the three groups. Post-operative sensitivity, marginal discoloration and secondary caries were not affected by enamel beveling and restorative material.

Beveled enamel margins resulted in significantly better clinical retention in the first six months only. Enamel beveling and composite viscosity appeared to not significantly affect the clinical performance of Class V non-retentive composite restorations after three years.

SUMMARY:
This half-mouth design, two-week treatment phase, combined with an 11-week evaluation double-blinded randomized clinical trial was conducted to compare two in-office bleaching products, StarBrite (35% hydrogen peroxide) with Opalescence Xtra Boost (38% hydrogen peroxide), for degree of color change of teeth, any relapse effect (darkening) associated with discontinued use and gingival irritation and tooth sensitivity associated with use. The degree of color change and relapse was evaluated by using a colorimeter, shade guide and color slide photographs. Participants self-evaluated their gingival irritation and tooth sensitivity. They recorded daily the level of gingival irritation and tooth sensitivity experienced during the first three weeks of the study.

The results of this study showed no statistical difference between products during active treatment periods and any follow-up visits using the three-color evaluation methods. Color relapse began after the bleaching treatments were finished and continued until the fifth week, after which no further significant changes appeared. Also, there was no statistical difference in gingival irritation and tooth sensitivity between the products.

SUMMARY:
Dentin hypersensitivity is a transient condition that often resolves with the natural sclerotic obturation of dentin tubules. A method of rapidly forming calcium phosphate compounds within these tubules can mimic sclerosis and lead to rapid reduction in hypersensitivity. Amorphous calcium phosphates (ACP) can be formed in situ by the sequential application of calcium and phosphate solutions. In this clinical study, 30 patients with reported dentin hypersensitivity were randomly assigned to parallel treatment or placebo groups. In the experimental treatment group, ACP was formed by topical application of a 1.5 mol/L aqueous solution of CaCl2 followed by topical application of 1.0 mol/L aqueous K3PO4. The placebo group was treated with a topical application of 1.0 mol/L aqueous solution of KCl followed by topical application of distilled water. Treatments were repeated at the 7-day and 28-day recall appointments. Response to air and tactile stimuli were measured immediately before treatment using a visual analog scale initially on day 1, then on days 7, 28 and 180. The results showed that both the experimental and placebo treatments resulted in a reduction in hypersensitivity at 180 days. However, the ACP treatment group showed a much more rapid reduction in hypersensitivity over time. The change in sensitivity was much more apparent using the air stimulus than the tactile stimulus. These results show that topical placement of ACP can rapidly reduce dentin hypersensitivity.

SUMMARY:
This study compared the cuspal fracture resistance of posterior teeth restored with four different adhesive restorations. Fifty sound, maxillary human premolars were randomly divided into a control group and four experimental groups with 10 teeth in each. Specimens in the first group were intact teeth that were tested as unprepared. The remaining four groups received mesio-oclusodistal cavity preparations and were restored with a hybrid composite (Filtek Z250), a packable composite (Filtek P60), an ormocer (Definite) and an amalgam (SDI Permite) with an amalgam bonding agent (Amalgam Bond Plus). All groups were stored in water at 37°C for 15 days and thermocycled 1000 times between 5°-55°C. The specimens were preloaded five times in compression to 10 kg using two metal rods that contacted only the teeth on the cuspal inclines. The teeth were then loaded occlusally in an Instron Universal Testing Machine until fracture occurred. The means of force required to fracture the teeth in each of the five groups was analyzed using one-way ANOVA and Tukey Test.

The difference between the mean cuspal fracture resistance of the unprepared control teeth and those restored with amalgam groups was found to be statistically significant (p<0.05). No significant differences in resistance to cuspal fracture were found among the restoration groups, the unprepared control group and those teeth restored with hybrid composite, packable composite and ormocer groups (p>0.05).

SUMMARY:
This study determined the radiopacity of 21 commercially available direct esthetic restorative materials with reference to an aluminum step wedge and an equivalent thickness of enamel and dentin. A total of 168 samples measuring 6 mm in diameter and 1 mm in thickness, with eight samples of each material, were prepared from restorative materials. Enamel and dentin samples 1-mm thick were also prepared by longitudinally sectioning eight extracted human permanent molars using a microslicing machine. The optical densities of each restorative material, along with one tooth section and an aluminum step wedge were measured from radiographic images using a transmission photodensitometer. The optical density values of the specimens were used to determine the aluminum thickness equivalent values. The data were analyzed with one-way analysis of variance (ANOVA) and Duncan’s multiple range tests. The results showed statistically significant differences among materials. Tetric Ceram had the greatest radiopacity value and was higher than enamel. All materials except for the microfilled resin composite Filtek A 110 had radiopacity values greater than dentin and possessed sufficient radiopacity to meet ISO 4049 standard. Significant differences were found among materials of the same composition when compared to enamel.

SUMMARY:
Fiber posts are widely used in the restoration of endodontically treated teeth. Scientific evidence demonstrates that the mechanical performance of teeth restored with fiber posts in combination with resin luting cements is improved with respect to metallic post restorations. The post is cemented inside the root canal using low mod-ulus elastic polymer resins. In this study, the mechanical resistance of four different post-cement systems was assessed by means of a micro-mechanical pull-out test assisted by a simulation using the finite element methodology. This in vitro test is specifically designed to accurately characterize the post-cement interface. The results show no significant difference among the adhesion properties of the various types of post-cement systems used.

SUMMARY:
This study investigated the effects of bur cutting surface roughness and bonding systems on dentin permeability. A conventional straight edged bur, cross-cut serrated bur and an extensively serrated bur were utilized with two different bonding systems. Null hypothesis was that increased surface roughness does not decrease the permeability of dentin sealing after application of bonding agents. This study incorporated a fluid flow model for measuring dentin permeability. Seventy caries-free extracted molars were used and sectioned 2 mm apical to the cemento-enamel junction (CEJ). The pulp tissue was removed and the chamber cleaned using 37% phosphoric acid followed by 1:1 sodium hypochlorite solution. The specimens were mounted to plexiglass plates using cyanoacrylate cement. A flow system was established through the pulp chamber and gravity pressurized phosphate buffered saline (PBS) was forced into the chamber and the “closed system” permeability measured. Burs were used to prepare flat surfaces in dentin, and after etching with phos- phoric acid, the “open tubule” permeability was determined. After applying the dentin bonding agents, fluid flow from the pulp chamber into dentin was again measured. The percentage of reduction in permeability following bonding agent application was then calculated. A two-way ANOVA found a significant (p<0.05) decrease in bonded dentin permeability in specimens prepared using the cross-cut serrated and extensively serrated bur as compared to the conventional straight-edged bur. No significant differences were detected between bonding systems and no combination of surface topography or bonding agent completely sealed the surface.

SUMMARY:
This study evaluated the effects of food-simulating liquids on the shear punch strength of two composites (Tetric Ceram [TC], Vivadent; Esthet X [EX], Dentsply), a conventional (Compoglass [CG], Vivadent) and a posterior polyacid-modified (Dyract Posterior [DP], Dentsply) composite. Thirty-two specimens (10-mm in diameter and 1.6-mm thick) of each material were made, randomly divided into four groups of eight and conditioned for one week as follows—Group 1 (control): air at 37°C; Group 2: distilled water at 37°C; Group 3: 75% ethanol-water solution at 37°C and Group 4: heptane at 37°C. After conditioning, the specimens were restrained within the test apparatus and subjected to shear punch strength testing using a 3.2 mm diameter punch at a crosshead speed of 0.5 mm/minute. The shear punch strength of the specimens was computed and the data was subjected to ANOVA/Scheffe’s tests at significance level 0.05. The effect of food-simulating liquids on shear strength was found to be material dependent. All materials with the exception of EX were significantly weakened by ethanol solution. For DP, a significant increase in strength was observed after conditioning in water. EX was significantly stronger than TC and DY after conditioning in air, water and ethanol solution. The shear punch strength of EX and CG was significantly higher than DY after conditioning in heptane.

SUMMARY:
This study determined the effect of water storage on flexural strength (FS) and compressive strength (CS) of 12 luting cements from different material classes. In addition, the influence of the curing method on the mechanical properties was investigated. The materials examined were two zinc phosphate cements (Harvard cement and Fleck’s zinc cement), two glass ionomer cements (Fuji I and Ketac-Cem), three resin-modified glass ionomer cements (Fuji Plus, Fuji Cem and RelyX Luting), four resin cements (RelyX ARC, Panavia F, Variolink II and Compolute) and one self-adhesive universal resin cement (RelyX Unicem). The samples were prepared and tested according to ISO specifications. Specimens for FS and CS were loaded to fracture at a constant crosshead speed of 1 mm/minute. The mechanical properties were measured after the materials were stored in distilled water at a temperature of 37.0 ± 1.0°C for 24 hours and 150 days after mixing. In a one-way ANOVA, multiple mean value comparisons using Duncan’s multiple comparison tests were performed. Resin cements had the highest flexural and compressive strengths, followed by self-adhesive universal resin cement. These materials were statistically stronger than resin-modified glass ionomer cements, glass ionomer cements and zinc phosphate cements.

SUMMARY:
This study evaluated the regional tensile bond strength of a dual-cure resin composite core material to root canal dentin using photo and dual-cure adhesives and different modes of polymerization. Nineteen extracted premolars were decoronated and their root canals prepared to a depth of 8 mm and a width of 1.4 mm using Para Post drills. For the microtensile bond strength (µTBS) test, 15 roots were randomly divided into five groups and their canal walls treated with a dual-cure self-etching primer (Clearfil Liner Bond 2V Primer, Kuraray Medical Co, Japan). Adhesive resin (Clearfil Liner Bond 2V Bond A) was applied to two of the groups and light cured for 20 seconds. A dual-cure adhesive resin (Clearfil Liner Bond 2V Bond A+B, Kuraray Medical Co, Japan) was applied to the remaining three groups, one of which was light cured. The post spaces of all the groups were filled with a dual-cure resin com-posite (DC Core) and three were light cured for 60 seconds from a coronal direction. Chemical-cure resin composite was placed on the outer surfaces of the roots, which were then stored in water for 24 hours. They were serially sliced perpendicular to the bonded interface into eight 0.6 mm-thick slabs, then transversely sectioned into beams approximately 8 x 0.6 x 0.6 mm for the µTBS test. All of the failure modes were observed under SEM and analyzed using the Kruskal-Wallis Rank test. For Knoop hardness testing, four specimens were prepared in a similar manner, two were light-cured and the other two chemically-cured. The specimens were longitudinally sectioned into two pieces, and three indentations were made at 100 µm intervals from a coronal to an apical direction in the eight halves. Data were divided into two groups (coronal/apical halves of post space) and analyzed using two-way ANOVA and Scheffe’s test (p<0.05). For each curing strategy, there were no significant differences in µTBS and Knoop hardness between the coronal and apical regions (p>0.05). Light exposure of both the adhesive resin and resin composite resulted in significantly higher µTBS than chemical-cure alone (p<0.05). Light exposure also significantly increased Knoop hardness at both the coronal and apical regions (p<0.05). When the bonding resin and dual-cure resin composite were chemically-cured, failures occurred cohesively within the resin. Photo-initiated polymerization of the adhesive resin and dual-cure resin composite was necessary to achieve good bonding to root canal dentin, which was not dependent upon region.

SUMMARY:
This in vitro study evaluated the effect of the initial polishing period through 30 minutes, 3 hours, 12 hours, 24 hours and 1 week after setting on the gap formation around Class V restorations. Three resin-modified glass ionomers, one compomer, one conventional glass ionomer and one microfilled composite were used as controls.

When specimens of the two types of glass ionomers and a microfilled composite were polished immediately after the setting procedure, this study showed 100-140 gaps around the X-section of the restorations. In contrast, only 10-40 gaps around the Class V restoration were observed when the specimens were polished after 12 hours of storage. Significant differences were observed between polishing immediately and polishing after 12 hours of storage in the two glass ionomer restorative materials. The compomer did not show this pattern. No significant differences were observed among the six polishing periods of the sum number of gaps at the cavity-restoration interfaces. The tendency of Silux Plus was similar to the two types of glass ionomer materials; namely, when the specimen was polished and inspected after storage in water for 24 hours or one week, the authors observed almost 30 gaps around the restorative cavities.

SUMMARY:
This in vitro study tested the following null hypotheses: (1) surface finishing treatments do not significantly affect the biaxial flexure strength and microhardness of resin-based composites (RBC) and (2) storage media do not significantly affect these physical properties. Discs (81 RBC and 81 UR; 3M/ESPE) were prepared using a circular polyethylene mold (2.4-mm thick x 16.7 mm in diameter) that was polymerized through a Mylar strip and divided into three surface finishing treatment groups: 1 µm aluminum oxide slurry; 15 µm diamond and a Mylar strip. Randomly selected controls for each finishing group were stored at room temperature in individual vials. Test specimens were immersed in water, stored at 37°C for two days and transferred for an additional seven days to one of three aqueous storage media at 37°C: coffee (pH 5.1), cola (pH 2.4) or red wine (pH 3.7). Post immersion (nine days total), the specimens were tested for biaxial flexure strength (BFS) and Vicker’s microhardness (VHN). ANOVA and Tukey’s HSD test were used for statistical analysis. ANOVA results indicated that surface finishing treatments had a significant effect on the biaxial flexure strength and microhardness of the RBC and the UR specimens. BFS results for RBC specimens were AL>DD>ML (p<0.0001) and VHN results were AL, DD>ML (p<0.0001). Storage in wine medium reduced the VHN of UR specimens significantly. Both alternative hypotheses were accepted. In addition, the Mylar finishing group, because of the resin-rich surface layer, yielded the lowest mean values of BFS and VHN.

SUMMARY:
This study evaluated the interaction of five clinical application techniques and the shear bond strength of four DBAs (OptiBond FL, Clearfil SE Bond, PQ1 and Prime & Bond NT). A hybrid resin composite (Herculite XRV restorative resin) was attached to human dentin surfaces using five application techniques: Group A—adhesive spread with a 3M brush for 30 seconds, followed by compressed air 0.5 cm from the surface for one second to remove the excess adhesive. Group B—adhesive spread with a 3M brush for 30 seconds, followed by compressed air 0.5 cm from the surface for three seconds to remove the excess adhesive. Group C—adhesive spread with 3M brush for 30 seconds, excess adhesive removed with a clean brush, two strokes side by side, no compressed air. Group D—adhesive spread with a Micro-applicator brush for 30 seconds followed by compressed air 0.5 cm from the surface for one second to remove the excess adhesive. Group E—adhesive spread with a Micro-applicator brush for 30 seconds, the excess adhesive removed with a clean brush, two strokes side by side and no compressed air. The specimens were stored in distilled water at 37°C for 24 hours, followed by thermocycling between 5°C and 55°C for 1,000 cycles. The shear bond strengths were determined on a universal testing machine operating with a crosshead speed of 5 mm/minute. The fracture sites were examined by 20x stereo microscope to determine the type of failure that occurred during the debonding procedure. Bond strength data were compared with analysis of variance at a significance level of p<0.05. Post hoc comparisons of means were performed with t-tests with p-values adjusted for multiple comparisons. This in vitro study concluded that there was an interaction between the application technique and bonding agent tested. All DBAs utilized the one-second compressed air technique, which yielded the highest bond strengths.

SUMMARY:
This in vitro study evaluated the marginal adaptation of bonded inlays of lucite-reinforced glass ceramic (Empress) to dentin as influenced by different bonding systems and by luting resin composites (LRCs) with different curing modes. Forty-eight Empress inlays etched with 5% hydrofluoric acid and treated with a silane-coupling agent (Monobond-S) were bonded to two-surface Class II cavities. Two total-etch bonding systems (OptiBond FL, Nexus) and one bonding system with selective enamel etching and a self-conditioning dentin primer (ART Bond) were included in the study. ART Bond was tested with and without the pre-curing of a first layer of adhesive resin selectively applied to the cervical cavity floor (selective double-bond technique). Each bonding system was used in combination with a light-cured resin composite (Prodigy) and a dual-cured LRC (Nexus or Vita Cerec Duo Cement). Marginal integrity was evaluated before and after thermocycling (TC) in a scanning electron microscope (SEM). Dye penetration tests were performed after TC was completed. The median percentages of continuous margin in dentin ranged from 80% to 100% before TC and from 53.5% to 96.1 % after TC. After TC, the influence of the bonding system was more pronounced than that of the LRC. In combination with the LC resin composite, ART Bond with pre-curing was significantly higher and the Nexus bonding system had significantly lower proportions of continuous margin than all the other bonding systems investigated. Swelling of the adhesive along the gingival margins was frequently found with the Nexus bonding system and with ART Bond without pre-curing. Microleakage was detected with all bonding system/LRC combinations, with somewhat lower rates in specimens completed using the selective double-bond technique. With the exception of the Nexus bonding system, post-TC marginal integrity was not influenced by the curing mode of the LRC (LC vs DC). In conclusion, the marginal quality of dentin bonded ceramic inlays can be improved by proper selection of the bonding system/LRC combination. The results of this study indicate the use of the Nexus luting system as directed without substitution.

SUMMARY:
This study investigated the bonding of current resin adhesives to the region approximating the dentin-enamel junction (DEJ), where the etch pattern to enamel or dentin may be different. Three kinds of tooth substrates were chosen for testing: enamel, dentin and the DEJ region. A self-etching primer system (Clearfil SE Bond) and two total-etch wet bonding systems (Single Bond and One-Step) were used. Each tooth region was bonded with one of the adhesive systems, and a resin composite and was subjected to a micro-shear bond test. In addition, morphological observations were performed on debonded specimens and etched surfaces using confocal laser scanning microscopy (CLSM). CLSM observations showed that the DEJ region was etched more deeply by phosphoric acid gel than enamel or dentin, suggesting that the action of acid etch seemed to be more intense on the DEJ. However, no statistically significant differences of shear bond strength values were observed between the DEJ region and enamel or dentin, or the adhesive systems used (p>0.05). Bonding to the DEJ is potentially as good as that to enamel or dentin.

SUMMARY:
This study compared the dentin bond strength of a self-etching primer/adhesive system with dentin surface pH with or without bleaching and observed the morphological changes in bleached dentin treated with a self-etching primer. Dentin disks were prepared from the coronal-labial region of 32 human anterior teeth. The pulpal surfaces of the dentin disks were polished with 600-grit SiC paper under running water. The dentin surfaces on all specimens were bleached with a mixture of 30% hydrogen peroxide and sodium perborate in 100% humidity at 37°C for one week. The bleaching agent was then rinsed off with water for 5, 15 or 30 seconds. All specimens were stored in water at 37°C. Half of the five-second rinsing specimens were stored in water for an additional week. Dentin surface pH with or without bleaching was examined using a pH-imaging microscope (SCHEM-100). A self-etching primer/adhesive system (Clearfil SE Bond) was applied to bleached or unbleached dentin according to the manufacturer’s instructions. After 24-hour water storage, the bonded specimens were prepared for microtensile testing. Microtensile bond strength (µTBS) to dentin was measured using a universal-testing machine (EZ test, Shimadzu, Japan) at a crosshead speed of 1.0 mm/minute. Data were analyzed by one-way ANOVA and Scheffe’s test (a=0.05). The pH values of the dentin surfaces of the 5 and 15 second rinsing groups were significantly higher than the control group (p<0.05), while the 30-second rinsing and one-week water storage groups had similar surface pH values to the control group (p<0.05). The µTBS of 5, 15 and 30 second rinsing specimens after bleaching were significantly lower than the control specimens (p<0.05). However, after one-week of water storage, the µTBS returned to the control group. The application of a bleaching agent increased the pH value of the dentin surface and decreased the bond strength of the self-etching primer/ adhesive system. One-week water storage after bleaching recovered the surface pH and the µTBS to dentin.

SUMMARY:
A pH-imaging microscope was tested on carious teeth to examine the acid-base characteristics of active and arrested carious dentinal lesions and compared with an assessment of mineral loss in carious affected lesions using an x-ray analytical microscope. Extracted human molars, 22 active and 83 arrested carious teeth, were sliced vertically to maximize the presence of visible carious lesions. The pH change on the dentin surface was measured with a pH-imaging microscope, and the mineral loss was measured with an x-ray analytical microscope. The pH value of intact dentin and active and arrested carious dentinal lesions showed 7.0 (n=105), 5.8 (n=22) and 6.6 (n=83), respectively (analyzed by Kruskal-Wallis). The mineral loss was distinguishable in active dentinal lesions (4.92 times as much as intact dentin), while arrested lesions showed a slight mineral loss (2.19 times as much as intact dentin). The changes in pH value and mineral loss were significantly correlated (Pearson’s correlation coefficients r=-0.8024) in active carious dentin lesions and weakly correlated (r=-0.1480) in arrested carious dentin lesions. Changes in tooth substance with the progression of the active carious process were reflected in a reduction in pH value and an increase in the amount of mineral loss.

SUMMARY:
To evaluate the effects of two home-use bleaching gels (Nite-White and Contrast PM) on the surface roughness of one high-viscosity glass ionomer cement (Fuji IX GP), four polyacid-modified resin-based composites (Dyract AP, F2000, Élan and Compoglass F), two resin-modified glass-ionomer cements (Vitremer and Fuji II LC), a microfilled fluoride-releasing resin-based composite (Tetric) and a microfilled non-fluoridated resin-based composite (Valux) were used as controls. The null hypotheses tested were: (1) the use of bleaching gels would not result in surface roughness values different from those obtained at baseline; (2) differences in the amount of carbamide peroxide present in the gels would not influence surface roughness. Thirty specimen disks (the first 10 used for controls and the balance divided randomly into two groups) were made for each material according to the manufacturers’ instructions. Finishing and polishing of the test and control specimens was performed after 24 hours using a sequential series of three (medium, fine and superfine) Sof-Lex disks, keeping the restoration surface wet. For every sequence, 10 strokes were made in one direction using a low-speed handpiece. Ultrasonic cleaning of the polished specimens was performed for two minutes in distilled water to remove any surface debris. Prior to bleaching treatment, the specimens were stored in 37°C deionized water for 24 hours. The specimens were exposoughness for F2000, Dyract AP, Élan, Valux and Tetric, while Fuji IX, Fuji II LC, Vitremer and Compoglass F displayed decreased surface roughness values, suggesting that the effects of the gels appear to be material-dependent. Although Contrast PM contains 5% more carbamide peroxide as the active ingredient, the second null hypothesis was rejected for Fuji IX, Vitremer, Dyract AP, Compoglass F, Élan and Valux.

SUMMARY:
Dentin bonded with one-step self-etch adhesives does not couple well to chemically-cured composites despite the presence of ternary catalysts in some systems. To determine whether additional factors are responsible for the poor coupling of dentin bonded with these adhesives, the authors used a one-step self-adhesive in which the ternary catalyst is incorporated separately in the brush applicator for activating the adhesive. The activated adhesive was bonded to dentin or pre-polymerized composites. For microtensile bond strength evaluation, a dual-cured hybrid composite was used for coupling to the bonded substrates and activated using: (1) the light-cured mode (LC), (2) delayed light-activation (DL) and (3) the chemical-cured mode (CC). In addition, the composite polymerized in the CC mode was coupled to the two substrates bonded with (4) additional experimental adhesive versions without the ternary catalyst and (5) without the ternary catalyst and tertiary amine. Silver tracer penetration into bonded interfaces was examined using TEM by replacing the dual-cured composite with a light-cured or a chemically-cured microfilled composite. In the CC mode, the composites coupled poorly to both substrates bonded with the unactivated adhesive (5). The use of activated adhesives allowed for good coupling of the composites polymerized in all curing modes to bonded composite, but only in the LC mode to bonded dentin. Water-filled channels in the form of water trees and water blisters were present in the adhesive layer under all composite-curing modes in bonded dentin. These features were completely absent in the bonded composites, showing that the source of the water was from dentin. Water blisters were also observed along the adhesive-composite interfaces in bonded dentin when the coupling composites were polymerized using the CC or DL modes.

SUMMARY:
This study compares volumetric changes and rates of shrinkage during different stages of polymerization of dental resin composites and compomers exposed to the same total energy by using two different combinations of power density and exposure duration. A hybrid composite and its equivalent flowable and a compomer and its equivalent flowable were exposed using a halogen curing unit set at 400 mW/cm2 for 40 seconds and 800 mW/cm2 for 20 seconds: delivering 16 J/cm2 in both cases. Volumetric changes were recorded every 0.5 seconds using a mercury dilatometer. Ten replications per test condition were performed and the data were subjected to ANOVA. Statistically significant differences in shrinkage values and rates among different power densities were determined by means of paired t-tests at a 95% confidence level. Significantly more shrinkage (p<0.05) was found for the higher filled materials, Z250 and Dyract AP, when higher power density was used. However, no significant differences were found between their flowable counterparts when exposed to various power densities. Of the four materials, only Dyract AP exhibited no significant difference in shrinkage rate when various power densities were used. All the other materials exhibited significantly higher rates (p<0.05) at the higher power density.

SUMMARY:
This study determined the three-body abrasive wear resistance of two packable composites (P-60; Solitaire 2), an ion-releasing composite (Ariston AT), a hybrid composite (Tetric Ceram) and an ormocer (Admira). The study also looked at the correlation between wear resistance and hardness of the composites. Three-body wear testing was performed using an ACTA wear machine with 15 N contact force using millet seed as the third body. Wear depth (µm) was measured by profilometry after 200,000 cycles. The hardness test was performed using a digital microhardness tester (load: 500 g; dwell time: 15 seconds). The data were analyzed by using Kruskal Wallis (p<0.05). There were statistically significant differences among the three body abrasive wear of the composites. The ranking from least to most were as follows: Filtek P-60< Solitaire 2 < Ariston AT < Tetric Ceram < Admira. Filtek P-60 showed the highest microhardness value. No other significant differences in hardness were observed among the different resin composites (P-60>AristonAT=Tetric Ceram= Solitaire 2= Admira).

The results of this study indicate that there are significant differences in the wear resistance of the resin composites. The correlation between hardness and wear was significant with a correlation coefficient of r:–0.91. A significant negative correlation exists between hardness and three-body wear of resin composites.

SUMMARY:
This study investigated the polymerization shrinkage of restorative materials and microleakage in the proximal box of Class II restorations. Twenty caries free extracted human molars were prepared on the mesial and distal, making 40 slot cavities. Groups (n=10) were classified as: Group 1: Single bond/Filtek Z-250; Group 2: Single Bond/Filtek Flow/Filtek Z-250; Group 3: Admira Bond/Admira; Group 4: Ariston Liner/Ariston. Dentin bonding systems and resin composites were applied according to the manufacturer’s instructions. The specimens were stored in distilled water for one week at 37°C, thermocycled (5°-55°C x 2000), stained with 50% aqueous silver nitrate, immersed in a diluted developer solution (24 hours), rinsed and sectioned in two pieces with a low speed saw (Isomet). Dye penetration (Score 0-4) was determined separately at the occlusal enamel margin and cementoenamel junction. The volumetric polymerization shrinkage of materials was determined with the apparatus of Watts and Cash (Watts & Cash, 1991) for 300 seconds. Polymerization shrinkage results were as follows: Filtek Flow (3.5%±0.1) > Admira (2.1%±0.1) = Ariston AT (2.3%±0.1) > Filtek Z-250 (1.8%±0.1) (One-way Anova, post hoc Bonferroni test at p=0.05 level). No statistical difference was found at the enamel margins for any of the materials (Score 0-1). At the cemento-enamel junction, all test groups showed significantly higher microleakage when compared to the enamel margins (Kruskal-Wallis test, Mann-Whitney U). Dye penetration results at dentin were as follows: Filtek Flow + Filtek Z-250= Admira < Ariston AT=Filtek Z-250.

It was concluded that enamel showed no high dye penetration scores and microleakage was not influenced by the material. Microleakage at dentin could not be eliminated with any adhesive restoration. The ormocer and bonding-flowable-hybrid composite restorations showed less microleakage than the ion-releasing and hybrid composites lined only with bonding agent at the cementoenamel junction in Class II cavities.

SUMMARY:
This in vitro study evaluated the marginal leakage of two resin composites light cured in four different polymerization modes. Standardized Class V cavities were prepared on the buccal enamel surface of 80 sound, freshly extracted inferior bovine incisors. The teeth were randomly divided into eight experimental groups: two resin composites (Z250 Charisma) and four polymerization modes (conventional–680 mW/cm2/30 seconds; soft start–380mW/cm2/10 seconds + 680 mW/cm2/20 seconds; plasma arc curing– 1480mW/cm2–3 seconds; combined– 380mW/cm2– 10 seconds + 1480mW/cm2—3 seconds). All specimens were thermocycled (1,000 cycles at 5°C and 55°C) with a dwell time of one minute at each temperature and immersed in a 2% methylene blue solution for more than 12 hours. The specimens were then washed and prepared for spectrophotometric analysis to quantify the dye concentration. Soft start and combined polymerization modes presented better results and were statistically different from conventional and plasma arc curing polymerization methods for both resin composites. There were no statistical differences between the two resin composites.

SUMMARY:
In light of the current trend towards “minimal invasive” dentistry, diverse cavity preparation techniques have been introduced as an alternative or addition to common bur instrumentation. This study investigated whether diamond sonoabrasion (SonicSys Micro, Kavo), air abrasion (Prep Start, Danville) and Er:YAG laser irradiation (Fidelis) produce surfaces at enamel/dentin that are equally receptive to bonding as traditional mid-grit diamond-bur (Komet) and 600-grit SiC-paper prepared surfaces, of which the latter two served as controls. An etch&rinse adhesive (OptiBond FL, Kerr) applied with and without prior acid-etching and a self-etch adhesive (Clearfil SE, Kuraray) were employed to bond the restorative composite (Z100, 3M ESPE) to the diversely prepared enamel and dentin surfaces. The microtensile bond strength (µTBS) was determined after 24 hours of storage in water at 37°C. The results indicated that the manner of preparation of enamel and dentin prior to bonding procedures significantly influenced the bonding effectiveness of both the etch&rinse and the self-etch adhesive. Using an etch&rinse adhesive, separate acid-etching of air-abraded and Er:YAG-irradiated enamel and dentin surfaces remains mandatory. Bonding to diamond-sonoabraded and air-abraded enamel and dentin was, in general, not different from bonding to conventional diamond-bur prepared surfaces, whereas, bonding to Er:YAG-irradiated enamel and dentin surfaces in general resulted in a significantly lower bonding effectiveness compared to bonding to diamond-bur prepared surfaces.

SUMMARY:
It has been suggested that patients should accept the use of the air abrasion technique over the conventional handpiece due to the reduced need for anesthesia. Technologies for both air abrasion and the conventional rotary handpiece have, in recent decades, seen major improvements, but there are no recent scientific publications that evaluate the patient’s preference for these two technologies when performing a cavity preparation. This study determined the patient’s preference for air abrasion or the rotary handpiece for removing occlusal fissure carious lesions in mandibular premolars. Ten healthy subjects 18 years of age or older were recruited from the General Dentistry Clinic of the University of Rochester Eastman Dental Center, with fissure caries at a DEJ depth of similar size (determined by radiographs and clinical examination) in any two mandibular premolars in opposite quadrants. Within each subject, the two methods of caries removal were randomly assigned. In one premolar, air abrasion was used for cavity preparation, and in the other premolar, a conventional rotary handpiece was used. At each visit prior to treatment, the patients were instructed to complete the Emotional Status (ES) questionnaire (SUNY University at Buffalo Craniofacial Pain Clinic) to assess differences in their emotional status between appointments. At each appointment, when the restorative treatment was completed, patients were instructed to rate their pain on the Visual Analogue Scale (VAS). A technique preference questionnaire was given after the second appointment. The subjects rated the perception of pain as significantly lower (p<0.05) when using air abrasion (6.0 mm versus 29.6 mm). All of the patients preferred air abrasion over conventional rotary handpieces. None of the patients required anesthesia and there was no indication that the emotional status influenced the result. Air abrasion was the preferred method of cavity preparation when removing fissural caries in mandibular premolars and most subjects did not experience any pain when air abrasion was used.

SUMMARY:
This study tested recently recommended cut-off limits for the laser fluorescence based device DIAGNOdent (KaVo) for detection of occlusal caries. Two hundred and forty-eight permanent molars from 94 patients (mean age 19.2 years) of a general dental practice were included. After professional tooth cleaning, the teeth were examined visually and by the laser fluorescence method. The extent of occlusal lesions (gold standard) was determined after minimal operative intervention. Upon fissure opening, 24 teeth had enamel caries and 224 teeth revealed dentin caries, of which 58 and 166, respectively, were up to or beyond half the dentin. The optimal cut-off limits based on the highest k-values (0.51 and 0.54) were >18 for superficial dentinal caries (D3) and >37 for deep dentinal caries (D4). The comparison with DIAGNOdent cut-offs given by the manufacturer (n=4) and those based on clinical trials with in vivo validation (n=4) and in vitro studies with histological validation (n=3) revealed a considerable variation in performance. Recommended cut-offs between 17 and 21 for superficial dentin lesions were in the same order of magnitude (0.48–0.51). On the D4 level, only the manufacturer’s cut-off of >34 achieved the best performance (0.51). According to the highest k-values and the area under the ROC curves (D3: Az=0.903; D4: Az=0.830), the agreement between the extent of validated caries and laser fluorescence value is still unsatisfactory.

SUMMARY:
Post-operative sensitivity (POS) may be observed in recently placed posterior composites. Evidence-based guidelines for the management of posterior composites with POS have yet to be determined. This study examined a retrospective analysis of the findings of a unique multi-center clinical trial to investigate the five-year risk of failure of posterior composites with POS and to determine the factors likely to have an important impact on the prognosis of the restorations. Longitudinal five-year data from the multi-center trial of Occlusin were analyzed. Data pertaining to a total of 1,101 restorations were included in the study. The failure rate at five years was calculated by meanwith POS were found to have been more likely to have failed at five years than the restorations of Occlusin without POS, with odds ratios ranging from 1.73 (95% CI: 1.04, 2.87) to 1.97 (95% CI: 1.36, 2.85). Distributions of patient age and cavity size were significantly different for successful and failed restorations (chi-square test, p<0.05). Logistic regression indicated that cavity size was the only factor likely to have influenced the prognosis of the restorations with POS (p=0.041, odds ratio 3.21, 95% CI 1.05: 9.70). Restorations with POS in large cavities were more likely to have failed by five years than restorations in small cavities. It was concluded that the restorations with Occlusin included in the Occlusin trial program were more likely to have failed at five years if POS occurred within one month of placement. Cavity size has been shown to have been an important factor in the prognosis of Occlusin trial restorations with POS.

SUMMARY:
This study evaluated the marginal adaptation of four different inlay indirect restorative systems: feldspathic ceramic (Duceram LFC–Degussa) and three laboratory-processed resin composites (Solidex–Shofu; Targis-Ivoclar; Artglass-Heraeus Kulzer). Sixty mesial-occlusal-distal (MOD) standard cavities were prepared in mandibular molars and divided randomly. Polyvinylsiloxane impressions were made and the restorations were prepared following the manufacturer’s instructions. Marginal adaptation evaluation was accomplished using an image collector computer system with a digital gauging appliance at four points on the occlusal, proximal and gingival regions with 250x magnification. Among all the materials, the marginal discrepancy recorded on the gingival margins was statistically larger than that recorded on the proximal and occlusal regions. Duceram LFC showed greater marginal discrepancy than Solidex, Artglass and Targis, which showed no statistically significant differences among them.

SUMMARY:
Forty third molars were sectioned parallel to the occlusal surface in order to expose superficial and deep dentin. Exposed surfaces were ground flat with 500-grit sandpaper. Contact angle measurements were performed to assess wettability using the ADSA-CD technique. Specimens were divided into two groups. Group 1 was the control group (no contamination). Group 2 served as the test group. Dentin surfaces were covered with a provisional eugenol-containing material (IRM) and were placed into a humidor at 37°C for one week. The provisional material was removed. Wettability measurements of the two groups were made with water on ground dentin, with water and resin on etched dentin. Data were statistically analyzed by ANOVA, Student-Newman-Keuls multiple comparison and Student t-tests. Eugenol contamination did not affect the dentin wetting. Acid etching significantly diminished contact angle values. Dentin wetting was greater on deep dentin than on superficial dentin.

SUMMARY:
This study evaluated the microtensile bond strength (µTBS) of ethanol/water- and acetone-based, one-bottle adhesive systems to enamel (E) and dentin (D) in the presence (P) or absence (A) of their respective solvents. Thirty-two freshly extracted third molars were flattened with 600-grit SiC paper and restored with Single Bond (SB) or Prime&Bond 2.1 (PB) according to the manufacturers’ instructions and after full solvent elimination. The molars were divided into eight test groups (n=4): G1-SB-E-P, G2-SB-E-A, G3-PB-E-P, G4-PB-E-A, G5-SB-D-P, G6-SB-D-A, G7-PB-D-P and G8-PB-D-A. After applying the adhesive resins, composite crowns of approximately 8 mm were built up with TPH Spectrum composite. After 24-hour water storage, the specimens were serially sectioned bucco-lingually to obtain 0.8-mm slabs that were trimmed to an hourglass shape, approximately 0.8 mm2 at the bonded interface. The specimens were tested in tension using a universal testing machine (0.5 mm/minute). The results were statistically analyzed by ANOVA and Tukey tests. The frequency of fracture mode was compared using the Kruskal-Wallis test. There were no statistically significant differences in mean bond strength among the groups restored with or without solvent for enamel. However, the results were significantly different for the dentin groups (MPa): G5–26.2 ± 8.6a; G7–23.6 ± 11.3ab; G6–12.8 ± 2.1bc; G8–6.2 ± 3.1c. SEM examination indicated that the dentin group failure modes were significantly different from the enamel groups. The results suggest that the presence of organic solvents does not influence µTBS to enamel. However, µTBS to dentin was significantly affected by the absence of solvents in the adhesive system.

SUMMARY:
This study compared the effectiveness of cure of two LED (light-emitting diodes) lights (Elipar FreeLight [FL], 3M-ESPE and GC e-Light [EL], GC) to conventional (Max [MX] (control), Dentsply-Caulk), high intensity (Elipar TriLight [TL], 3M-ESPE) and very high intensity (Astralis 10 [AS], Ivoclar Vivadent) halogen lights at varying cavity depths. Ten light curing regimens were investigated. They include: FL1-400 mW/cm2 [40 seconds], FL2–0-400 mW/cm2 [12 seconds] Õ 400 mW/cm2 [28 seconds], EL1-750 mW/cm2 [10 pulses x 2 seconds], EL2-350 mW/cm2 [40 seconds], EL3-600 mW/cm2 [20 seconds], EL4–0-600 mW/cm2 [20 seconds] Õ 600 mW/cm2 [20 seconds], TL1-800 mW/cm2 [40 seconds], TL2–100-800 mW/cm2 [15 seconds] Õ 800 mW/cm2 [25 seconds], AS1-1200 mW/cm2 [10 seconds], MX–400 mW/cm2 [40 seconds]. The effectiveness of cure of the different modes was determined by measuring the top and bottom surface hardness (KHN) of 2-mm, 3-mm and 4-mm thick composite (Z100, [3M-ESPE]) specimens using a digital microhardness tester (n=5, load=500 g; dwell time=15 seconds). Results were analyzed using ANOVA/Scheffe’s post-hoc test and Independent Samples t-Test (p<0.05). For all lights, effectiveness of cure was found to decrease with increased cavity depths. The mean hardness ratio for all curing lights at a depth of 2 mm was found to be greater than 0.80 (the accepted minimum standard). At 3 mm, all halogen lights produced a hardness ratio greater than 0.80 but some LED light regimens did not; and at a depth of 4 mm, the mean hardness ratio observed with all curing lights was less than 0.80. Significant differences in top and bottom KHN values were observed among different curing regimens for the same light and between LED and halogen lights. While curing with most modes of EL resulted in significantly lower top and bottom KHN values than the control (MX) at all depths, the standard mode of FL resulted in significantly higher top and bottom KHN at a depth of 3 mm and 4 mm. The depth of composite cure with LED LCUs was, therefore, product and mode dependent.

SUMMARY:
This study evaluated the effects of four cavity pre-treatments on the microleakage of a fifth generation adhesive system and accompanying resin composite.

Sixty human molars were randomly selected for cavity pre-treatment for the following material groups: Ultra-Etch 35% phosphoric acid gel, Ultra-Etch AB 35% phosphoric acid gel with cetylpyridinium chloride antimicrobial agent, Ultra-Etch 35% phosphoric acid gel followed by Concepsis chlorhexidine gluconate antimicrobial solution, Ultra-Etch 35% phosphoric acid gel followed by Consepsis Scrub chlorhexidine gluconate antimicrobial slurry and no etchant and/or cavity pre-treatment. Circular preparations were cut on the facial or lingual surface of each tooth and treated with the appropriate etchant/cavity disinfectant. PQ1 self-priming adhesive was placed in the preparations followed by Vitalescence resin composite. The molars were thermocycled, sealed with nail varnish, placed in 5% methylene blue dye and sectioned. Leakage was assessed by dye penetration at the occlusal and gingival surface positions of the specimen blocks using a binocular microscope.

The Consepsis Scrub and no pre-treatment groups revealed significantly greater leakage than the other groups treated with antimicrobial disinfectants or etchants. No significant differences were shown in the two etchant groups that were compared, Ultra-Etch and Ultra-Etch AB. Significantly greater leakage was not exhibited by the same materials at the occlusal vs gingival surface positions.

SUMMARY:
This study determined the influence of curing lights and modes on composite resistance to chemical degradation by various food-simulating liquids. Two different types of curing light (Halogen [H]-Elipar Trilight, 3M-ESPE; LED [L]–Freelight, 3M-ESPE) and two curing modes (standard [S]; exponential [E]) were evaluated in the study. Forty-five composite (Z100 [3M-ESPE]) specimens were made for each light-curing mode combination (HS, HE, LS and LE). The specimens were randomly divided into five groups of nine and exposed to the following food-simulating liquids (FSL) for one week at 37°C: distilled water, 50% aqueous ethanol solution, heptane and citric acid. Specimens stored in air were used as control. After the one week conditioning period, hardness testing was conducted with a digital microhardness tester (load = 500 gf; dwell time = 15 seconds). Mean hardness (HK)/hardness deterioration (DHK) were subsequently computed and data was subjected to analysis using ANOVA/Scheffe’s test (p<0.05). The resistance of composite to chemical degradation by FSL was light/curing mode dependent. Significant differences in HK and DHK were observed among the four curing techniques after conditioning in some FSL and air. After conditioning in water and citric acid, specimens polymerized with HE underwent significantly more softening compared to specimens polymerized with HS, LS and LE.

SUMMARY:
This study investigated the effect of surface treatment and cement maturation on the bond strength of resin-modified glass ionomer cements (RMGICs) to dentin. Forty-two freshly extracted premolars were embedded and horizontally sectioned at a level 2 mm from the central fossa to obtain a flat dentin surface. The premolars were randomly divided into three groups of 14 teeth and treated as follows: Group 1 (control)–no surface treatment, Group 2–conditioned with 20% polyacrylic acid for 10 seconds and Group 3–etched with 37% phosphoric acid for 15 seconds. RMGIC (Fuji II LC, GC) columns (3 mm diameter; 2 mm high) were applied to the dentin surface and shear bond testing was carried out after one week (n=7) and one month (n=7) storage in distilled water at 37°C using an Instron Universal testing machine with a cross-head speed of 0.6 mm/minute. The failure mode was examined at 40x magnification and scored with imaging software. The results were analyzed using ANOVA/Scheffe’s post-hoc test and Kruskal-Wallis/Mann-Whitney test at a significance level of 0.05. The effect of surface treatment on shear bond strength to dentin was time dependent. Mean strengths ranged from 3.16 to 5.81 MPa at one week and 5.00 to 14.95 MPa at one month. Although no significant difference in strengths was observed among the groups at one week, significant differences (Group 2 > Group 1 > Group 3) were detected at one month. At one month, conditioned and untreated specimens exhibited significantly less adhesive failure than etched specimens.

SUMMARY:
This study evaluated the effects of two finishing techniques and pumice polishing on the surface roughness of eight different provisional materials. Provisional materials included polymethylmethacrylate-based Alike, Snap, Trim and Jet and composite-based provisional materials Temphase, Protemp 3 Garant, Luxatemp and Integrity. Baseline surface roughness was measured by a profilometer, then the provisional materials were finished using extra fine acrylic burs or medium abrasive disks. The surface roughness of each sample was measured following finishing using a profilometer as previously stated. Each surface was then polished with pumice and the surface roughness was measured again. The data were analyzed using repeated measures of ANOVA and Bonferroni pairwise comparisons (a=0.05). The results indicated that with composite provisional materials, the unfinished surfaces are smoother than with bur or abrasive-disk finished surfaces. Pumice application did not smooth the surface finish for all materials. The different types of provisional materials required different finishing techniques to produce the smoothest finishes.

SUMMARY:
This study investigated the effect of commercially available mouthrinses on the microhardness and wear of composite (Esthet-X, Dentsply) and compomer (Dyract Posterior, Dentsply) restoratives. Fifty-four hardness and 36 wear specimens of each material were fabricated and stored in distilled water at 37°C for two weeks. The specimens were then randomly divided into six equal groups and exposed to the following solutions for 24 hours at 37°C: distilled water [WC] (control); Listerine Original [AP] (alcohol-containing essential oil/phenolic compound mouthrinse); Colgate Chloropharm [AC] (alcohol-containing chlorhexidine mouthrinse); Oral B Tooth & Gum Care [AF] (alcohol-containing fluoride mouthrinse); Oral B Tooth & Gum Care Alcohol Free [OF] (alcohol free fluoride mouthrinse) and Oral B Sensitive [PF] (phosphoric acid containing fluoride mouthrinse). After conditioning, the specimens were subjected to hardness testing using a digital microhardness tester (load=500 gf; dwell time=15 seconds) and wear testing with a reciprocal compression-sliding system (contact stress=20 MPa). Wear depth was measured every 1,000 cycles up to 10,000 cycles using profilom-etry. Data was analyzed using ANOVA/Scheffe’s test at significance level 0.05. Dyract was significantly softened by AP, while Esthet-X was significantly softened by AC and AP. The wear resistance of Dyract was significantly reduced after exposure to PF, while the wear resistance of Esthet-X was significantly reduced by AC. The effect of mouthrinses on hardness and wear was material dependent.

SUMMARY:
This study tested the null hypothesis that there is no difference between two-step and one-step self-etch adhesives in their compatibility with these composites. The microtensile bond strengths (µTBS) of two two-step systems (Clearfil SE Bond, Kuraray and Tyrian SPE/One-Step Plus, BISCO) were compared with two one-step systems (Xeno III, Dentsply DeTrey and Brush&Bond, Parkell) for their coupling to a dual-cured composite. Silver tracer penetration of the four adhesives bonded to a light-cured or a chemical-cured composite was examined using TEM. Significant differences in µTBSs between composite curing modes were seen only in the one-step adhesives. For one-step self-etch adhesives bonded to the chemical-cured composite, TEM revealed signs of frank composite uncoupling along the adhesive-composite interface, which may be attributed to the adverse chemical interaction between the acidic adhesive and the composite. In addition, “water trees” that represent channels of increased permeability with the polymerized adhesive layer were also observed in the one-step adhesives. Both features were absent along the resin-dentin interfaces when chemical-cured composites were coupled to the two-step self-etch adhesives.

SUMMARY:
Types of sealants were categorized into three groups: classical sealant, flowable composite and flowable compomer. The molars were thermocycled in water (5,000 cycles between 5˚C and 55˚C), then stained with 5% methylene blue for 24 hours. Each tooth was then sectioned longitudinally at three sites. Fissure type, microleakage and penetration ability of the sealants was evaluated with a computer-linked light microscope (25x magnification). Formation of resin tags at the enamel-sealant interfaces was examined using SEM. Variables thought to influence performance of the sealants were analyzed by multiple regression analyses. Classical sealants showed significantly lower microleakage than flowable composites and flowable compomers. Conventional etching with phosphoric acid was critical for sealant success. Agitating the etchant could improve the quality of sealing by decreasing microleakage significantly. In addition, the fissure types had a significant effect on the penetration ability of sealants.

SUMMARY:
This study evaluated the effects of various restorative materials (Ariston pHc; Dyract; Vitremer; Tetric Ceram; Compoglass F, F2000; Hytac and Ketac Molar) on initial secondary caries formation in situ. Eighty-eight enamel slabs from sound human molars were sterilized (ethylene dioxide) and embedded in epoxy resin. Standardized tooth preparations were filled with the various restorative materials according to manufacturers’ recommendations. One specimen from each group was inserted into one of two buccal aspects of an intraoral appliance worn by 11 volunteers for four weeks, day and night. Oral hygiene was performed without additional fluoride application. During meals and oral hygiene procedures, the appliances were stored in sucrose solution (10%). After in situ exposure, the samples were prepared for microradiographic assessment. Mineral content and lesion depth were evaluated by a dedicated software package (TMR 1.24). Lesion depth and mineral loss of the carious lesions close to Ariston pHc was significantly lower when compared to distant parts of the same lesions (p<0.05; t-test, Bonferroni-Holm correction). All other materials containing fluoride showed no caries protective effect on surrounding enamel (p>0.05; t-test, Bonferroni-Holm correction). A hydroxyl-, calcium- and fluoride-containing restorative material hampers demineralization next to the restoration, whereas, fluoride release of various fluoride-containing restorative materials does not affect demineralization of adjacent enamel in situ.

SUMMARY:
This study evaluated the microleakage of Class V cavities restored with three different types of flowable resin restorative material and compared the effects of using their respective manufacturer's dentin adhesive or a different brand.

Class V cavities with the occlusal margin in enamel and the gingival margin in dentin on the buccal and lingual surfaces of 48 non-carious human molars. The teeth were randomly assigned to three equal groups of 16. The first eight teeth in each group were restored with one of the flowable restorative materials (Filtek Flow, Dyract Flow, Admira Flow) using the manufacturer’s recommended dentin adhesive (Single Bond, Prime & Bond NT, Admira Bond), and the remaining eight molars were restored using a different brand of dentin adhesive (Gluma Comfort Bond). The samples were thermocycled 200 times (5°C-55°C) with a one-minute dopy. There was no statistically significant difference at the occlusal margins for either restoration used with its respective dentin adhesive. At the gingival margins, there was a significant difference among all groups. Flowable ormocer (Admira Flow/Admira Bond) displayed the least leakage at the gingival margins. When these flowable restoratives were used with a different brand of dentin adhesive, statistically significant differences were observed both on enamel and dentin. None of the restoratives tested fully prevented leakage at the gingival margins.

No significant differences in microleakage were observed among the restorative materials used with respect to the manufacturer’s dentin adhesive or a different brand except for Admira Flow restorative at the gingival margins. The gingival margins had significantly more microleakage than the occlusal margins (p<0.05) except in the Admira Flow group, where microleakage at the occlusal and gingival margins was almost equal.

SUMMARY:
This study determined whether surface roughness of the internal walls of a Class V resin composite preparation, using a carbide bur, a medium-grit diamond bur and a fine-grit diamond bur, affected the degree of microleakage of the restoration. The facial and lingual surfaces of 45 non-carious extracted human molars provided 90 samples for evaluation. The specimen surfaces were assigned randomly in equal numbers to one of three groups (n=30). Conservative Class V composite preparations were made using one of three different burs: a 330-carbide bur, a 330 fine-grit diamond bur or a 330 medium-grit diamond bur (Brasseler USA). After acid etching, PQ1 (Ultradent Products Inc) primer/bonding resin and Vitalescence (Ultradent Products Inc) were applied and cured following the manufacturers’ instructions. After minor finishing, the apices of all root surfaces were sealed with Vitrebond (3M), and the unprepared external surfaces were sealed with nail polish to within 1 mm of the restoration margins. The specimens were stored in distilled water at room temperature for 24 hours, then subjected to 1,200 thermocycles at 5°C and 55°C with a 30-second dwell time. After cycling, the teeth were immersed in a 5% solution of methylene blue dye for 12 hours. The molars were invested in clear acrylic casting resin, labeled, then sectioned once vertically approximately midway through the facial and lingual surfaces using a diamond coated saw blade. Microleakage was evaluated using a 10x microscope for the enamel and cementum surfaces and blindly scored by two independent examiners. In all cases, regardless of the examiner, at both the enamel and the dentin margins, the analysis revealed no statistically significant differences in microleakage across bur types. Further results show that dentin margins leaked significantly more than enamel margins for all bur types.

SUMMARY:
This study investigated the effects of three intracoronal bleaching techniques on the color and microhardness changes of human dentin and compared them to a control group. Twenty-four dentin slabs were derived from extracted maxillary anterior teeth and evenly distributed among four groups. The pulpal surface of each dentin slab was treated with one of the following bleaching techniques: thermocatalytic treatment with 30% hydrogen peroxide, walking bleaching with 2% sodium perborate and a combination treatment that uses both methods. In the control group, the specimens were treated with distilled water. All specimens were subjected to repeated treatment with fresh bleaching pastes on days 0, 7, 14 and 21. During the experimental period, all specimens were placed in individual vials maintained at 37°C and 100% humidity. CIELab color parameters and microhardness (VHN) were evaluated prior to the experiments and seven days after each treatment. All bleaching treatments effectively increased L* values and decreased b* values of dentin. Thermocatalytic bleaching significantly reduced dentin hardness to half its original value after four treatment cycles; whereas, treatment with either walking bleaching or the combined technique did not significantly affect dentin hardness. Because the combination treatment had shown great bleaching efficacy, it can serve as an alternative approach for severely stained teeth.

SUMMARY:
This study quantified microleakage in restorations made with three packable resin composites–Solitaire, SureFil and P60; one hybrid resin composite–Z250 and an amalgam–Dispersalloy, with or without the thermocycling process. Sixty sound, freshly extracted human molars were sectioned mesiodistally, creating buccal and lingual blocks. One hundred blocks with the flattest surface were selected. Cylindrical cavities with a diameter of 1.85±0.05 mm and a depth of 1.5 mm were prepared with a special diamond bur. The blocks were randomly assigned to 10 test groups (n=10): five restorative materials and two thermal stress groups (thermocycled groups at 3,000 cycles at 5°C and 55°C with a dwell time of one minute at each temperature, or non-thermocycled). After the thermocycling test, the samples were immersed in 2% methylene blue for 12 hours. The samples were ground and the powder prepared for analysis in an absorbance spectrophotometer. All the results were statistically analyzed by the Kruskal-Wallis test and the Mann Whitney test. For the non-thermocycled groups, the means (µg/ml) of microleakage were: Amalgam–4.279 (a); Solitaire–4.148 (ab); Z250–3.418 (abc); P60–3.184 (bc); SureFil–2.890 (c). For the thermocycled groups, the means were: Amalgam–7.572 (a); Solitaire–5.471 (a); Z250–4.330 (ab); P60–3.418 (bc) and SureFil–2.779 (c). Thermocycling analysis showed no significant differences between the thermocycled and non-thermocycled groups for each material tested. It was concluded that no test material prevented microleakage. Only SureFil and P60 showed leakage means significantly lower than amalgam, with SureFil showing lower leakage than Solitaire. P60 only showed lower leakage than Solitaire in the thermocycled groups and Z250 showed results similar to the others materials.

SUMMARY:
Contamination of etched enamel with repair bond agents during repair of dental restorations may interfere with the bonding of composite to enamel. This study examined the bond strength of adhesive filling materials to etched bovine enamel after pre-treatment with the repair systems Monobond S, Silibond and Co-Jet. The materials Tetric Ceram, Dyract and Definite and their corresponding bonding agents (Syntac Single Comp, Prime & Bond NT, Etch and Prime) were tested in combination with the repair systems. One hundred and thirty-five enamel specimens were etched (37% phosphoric acid, 60 seconds) and equally distributed among three groups (A-C). In Group A, the repair materials were applied on etched enamel followed by applying the composite materials without using their respective bonding material. In Group B, the composite materials were placed on etched enamel after applying the repair materials and bonding agents. In control Group C, the composite materials and bonding agents were applied on etched enamel without using the repair systems. In each sub-group, every composite material was applied on 15 specimens. Samples were stored in artificial saliva for 14 days and thermocycled 1,000 times (5°C/55°C). The shear bond strength of the samples was then determined in a universal testing machine (ISO 10477). Applying Monobond or Silibond followed by the use of its respective bonding agents resulted in a bond strength that was not statistically different from the controls for all filling materials (Group C). The three composites that used Monobond and Silibond without applying the corresponding bonding agent resulted in bond strengths that were significantly lower than the controls. Utilizing the Co-Jet-System drastically reduced the bond strength of composites on etched enamel.

Contamination of etched enamel with the repairing bonding agents Monobond and Silibond does not interfere with bond strength if the application of Monobond and Silibond is followed by using its corresponding bonding system of the composites tested.

SUMMARY:
Polishing composite restorations at recall prophylaxis may affect their surface roughness. This investigation evaluated the effect of prophy paste on the surface roughness of a microfilled (Filtek A110) and a microhybrid (Filtek Z250) resin composite before and after simulated toothbrushing. Twenty, two-sided samples of both materials were fabricated in acrylic molds against a Mylar strip (baseline). Three roughness readings were recorded for each surface using a Surfanalyzer 5400 to determine the mean roughness. The samples were finished and polished with the Sof-Lex disk system and the surface roughness (Ra) was re-measured. Samples were randomly assigned and five surfaces for each material were polished with Nupro coarse, medium, fine or Clinpro prophy paste and the surface roughness measured again. All surfaces were brushed 60,000 times at 1.5Hz using a 2N brush-head force (Manly V-8 cross-brushing machine) in a 50:50 (w/w) slurry of toothpaste and water. The surface roughness was measured followed by the application of prophy paste as previously described and this final roughness recorded. Data were analyzed using repeated measures two-factor ANOVA with TUKEY HSD pairwise comparison as appropriate (a=0.05). No significant difference in surface roughness was determined between the microfilled and microhybrid materials at baseline or disk treatment, yet significant differences were observed following brushing and/or prophy paste application. In conclusion, although baseline and disk treated surfaces were not significantly different in microfilled versus microhybrid composites, subsequent prophy paste application and/or simulated toothbrushing caused significant differences.

SUMMARY:
This study evaluated the surface quality of four composite materials after polishing with six different polishing techniques.

Eighty specimens were made using three packable composites (Definite/Degussa, SureFil/ Dentsply and Solitaire/Heraeus-Kulzer) and one hybrid composite (Herculite XRV/Kerr). Five specimens of each material were polished using flexible Sof-Lex discs. The remaining 75 specimens of each composite were prepared using three finishing protocols: a single 30 µm diamond (n=25), two finishing diamonds (30/20 µm; n=25) and a 30 µm diamond followed by a tungsten carbide finishing bur (n=25). Final polishing of each of the three finishing groups was accomplished with SuperBuff, Diafix-oral, OneGloss, Astropol and HaWe Composite Polishers (n=5, each). Surface roughness was evaluated quantitatively by laser-stylus profilometry. Average roughness (Ra) was calculated; statistical analysis of the data was performed with two-way ANOVA and Scheffé post-hoc tests. The polished surfaces were examined qualitatively by SEM.

The results showed significant effects on surface roughness from the different composites (p=0.011) and polishing systems (p<0.001). After polishing, the Solitaire surfaces (Ra=0.72 µm) were smoother than Definite (Ra=0.87 µm) and SureFil (Ra=0.89 µm) and significantly smoother than Herculite (Ra=0.92 µm; p=0.011). Three of the polishing methods (SuperBuff, Diafix-oral and Astropol) achieved lower Ra-values than Sof-Lex discs. The polishing quality of the one-step systems SuperBuff and Diafix-oral was strongly affected by the initial finishing protocol.

SUMMARY:
Many studies have shown a considerable reduction in enamel bond strength of resin composite restorations when the bonding procedure is carried out immediately after bleaching. These studies claim that a certain waiting period is needed prior to restoration to reach the original bond strength values prior to bleaching. This study determined the effect of anti-oxidant applications on the bond strength values of resin composites to bleached dentin. Ninety human teeth extracted for orthodontic purposes were used in this study. The labial surface of each tooth was ground and flattened until dentin appeared. The polished surfaces were subjected to nine different treatments: 1) bleaching with gel (35% Rembrandt Virtuoso); 2) bleaching with gel + 10% sodium ascorbate (SA); 3) bleaching with gel + 10% butylhydroxyanisole (BHA); 4) bleaching with sol (35% hydrogen peroxide); 5) bleaching with sol + 10% sodium ascorbate; 6) bleaching with sol + 10% BHA; 7) bleaching with gel + immersed in artificial saliva for seven days; 8) bleaching with sol + immersed in artificial saliva for seven days; 9) no treatment. After bonding application, the resin composite in standard dimensions was applied to all specimens. The teeth were stored in distilled water at 37°C for 24 hours and a universal testing machine determined their resistance to shear bond strength. The data was evaluated using ANOVA and Duncan tests. Bond strength in the bleached dentin group significantly decreased compared to the control group. On the other hand, the antioxidant treatment had a reversal effect on the bond strength to dentin. After the bleaching treatment, the 10% sodium ascorbate application was effective in reversing bond strength. In the samples where antioxidant was applied after the bleaching process, bonding strength in dentin tissue was at the same level as those teeth kept in artificial saliva for seven days.

SUMMARY:
Wear resistance has been a problem for the posterior application of resin composites. This study evaluated and compared the wear characteristics of two conventional and two packable composites. Opposing enamel wear was also measured. One traditional hybrid composite– Herculite XR (HXR), one micro-filled composite–Heliomolar (HM) and two packable composites–Filtek P60 (P60) and Surefil (SF) were formed into disks (n=10) and used as substrates for the wear test. Enamel was harvested from extracted human third molars and machined into cusps with a 5-mm spherical radius (n=40). The Oregon Health Sciences University oral wear simulator was used to evaluate abrasive wear and attrition of the composite materials and wear of the opposing enamel. The resulting enamel wear facets were measured and recorded in mm2 using optical scanning methods and a computer graphics program. Abrasion and attrition of the composite substrates were measured using a profilometer. Both sets of data were subjected to ANOVA and multiple comparison tests to determine significant differences. After wear testing, scanning electron micrographs were made using representative composite samples from each group. The packable composites showed significantly less attrition and abrasive wear (p<0.001) than the conventional controls. The microfilled composite HM resulted in significantly lower enamel wear (p<0.001) than the materials HXR and P60 but was not significantly different from the packable composite SF at the a=0.05 level. The results of this in-vitro study suggest that packable composites may have improved wear resistance over some conventional composites. Clinical studies are needed to evaluate packable composites over time.