Chronological List of Articles

SUMMARY:
The objectives of this study include establishing a method for quantitative measurement of marginal change in ceramic inlays and clarifying their marginal disintegration in vivo. An accurate CCD optical laser scanner system was used for morphological measurement of the marginal change of ceramic inlays. The accuracy of the CCD measurement was assessed by comparing it with microscopic measurement. Replicas of 15 premolars restored with Class II ceramic inlays at the time of placement and eight years after restoration were used for morphological measurement by means of the CCD laser scanner system. Occlusal surfaces of the restored teeth were scanned and cross-sections of marginal areas were computed with software. Marginal change was defined as the area enclosed by two profiles obtained by superimposing two cross-sections of the same location at two different times and expressing the maximum depth and mean area of the area enclosed. The accuracy of this method of measurement was 4.3 ± 3.2 µm in distance and 2.0 ± 0.6% in area. Quantitative marginal changes for the eight-year period were 10 x 10 µm in depth and 50 x 103 µm2 in area at the functional cusp area and 7 x 10 µm in depth and 28 x 103 µm2 in area at the non-functional cusp area. Marginal disintegration at the functional cusp area was significantly greater than at the non-functional cusp area (Wilcoxon signed-ranks test, p<0.05). This study constitutes a quantitative measurement of in vivo deterioration in marginal adaptation of ceramic inlays and indicates that occlusal force may accelerate marginal disintegration.

SUMMARY:
This study evaluated the depth of cure associated with commercial LEDs (light-emitting diodes) (Elipar FreeLight [FL], 3M-ESPE; GC e-Light [EL], GC), high intensity (Elipar TriLight [TL], 3M-ESPE) and very high intensity (Astralis 10 [AS], Ivoclar Vivadent) Quartz Tungsten Halogen (QTH) curing lights. Depth of cure of the various lights/curing modes were compared to a conventional QTH light (Max [Mx], Dentsply-Caulk). Ten exposure regimens were investigated: FL1 - 400 mW/cm2 [40 seconds]; FL2 – 0-400 mW/cm2 [12 seconds] € 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] € 600 mW/cm2 [20 seconds]; TL1 - 800 mW/cm2 [40 seconds]; TL2 – 100- 800 mW/cm2 [15 seconds] € 800 mW/cm2 [25 seconds]; AS1 - 1200 mW/cm2 [10 seconds]; MX – 400 mW/cm2 [40 seconds]. Depth of cure was determined by penetration, scraping and microhardness techniques. The results were analyzed using one-way ANOVA/Scheffe’s post-hoc test and Pearson’s correlation at significance level 0.05 and 0.01, respectively. All light curing regimens met the ISO depth of cure requirement of 1.5 mm with the exception of EL1-EL3 with the microhardness technique. Curing with most modes of EL resulted in significantly lower depths of cure than the control [MX]. No significant difference in depth of cure was observed among the control and the two modes of FL. Curing with TL1 resulted in significantly greater depth of cure compared to MX with all testing techniques. No significant difference in depth of cure was observed between the control and AS1 for all testing techniques except for the penetration technique. The depth of composite cure is light unit and exposure mode dependent. Scraping and penetration techniques were found to correlate well but tend to overestimate depth of cure compared to microhardness.

SUMMARY:
Since fluoride (F-) and aluminum (Al3+) present anticariogenic properties and F- release from ionomeric materials depends on the media used in the evaluation, this study tested the hypothesis whether release of Al3+ also depends on the testing media. The simultaneous release of F- and Al3+ was assessed over 15 days in three media: (i) distilled and deionized water (H2O), (ii) artificial saliva (AS) and (iii) solutions simulating a cariogenic challenge (pH-cycling in demineral-izing and remineralizing solutions, De-Re-). Six cylindrical samples of each tested material (Ketac-Fil, Vitremer, Fuji Ortho LC and F 2000) were prepared and suspended individually in 1.0 mL of each solution. All solutions were changed daily. F- and Al3+ were determined by ion-selective electrode and atomic absorption, respectively. ANOVA showed statistical significance for the interaction of material, time, media (p<0.05), either for F- or Al3+ release. The resin-modified glass ionomer Vitremer released the highest amount of F- and Al3+ in De-Re- solutions compared to the other materials (p<0.05); differences among the materials in H2O and AS were statistically consistent. The data suggest that the media used to evaluate the simultaneous release of F- and Al3+ should be taken into account when the anticariogenic potential of different dental materials is assessed.

SUMMARY:
This study evaluated the pulpal response and in-vivo microleakage of a flowable composite bonded with a self-etching adhesive and compared the results with a glass ionomer cement and amalgam. Cervical cavities were prepared in monkey teeth. The teeth were randomly divided into three groups. A self-etching primer system (Imperva FluoroBond, Shofu) was applied to the teeth in one of the experimental groups, and the cavities were filled with a flowable composite (SI-BF-2001-LF, Shofu). In the other groups, a glass ionomer cement (Fuji II, GC) or amalgam (Dispersalloy, Johnson & Johnson) filled the cavity. The teeth were then extracted after 3, 30 and 90 days, fixed in 10% buffered formalin solution and prepared according to routine histological techniques. Five micrometer sections were stained with hematoxylin and eosin or Brown and Brenn gram stain for bacterial observation. No serious inflammatory reaction of the pulp, such as necrosis or abscess formation, was observed in any of the experimental groups. Slight inflammatory cell infiltration was the main initial reaction, while deposition of reparative dentin was the major long-term reaction in all groups. No bacterial penetration along the cavity walls was detected in the flowable composite or glass ionomer cement except for one case at 30 days in the glass ionomer cement. The flowable composite bonded with self-etching adhesive showed an acceptable biological compatibility to monkey pulp. The in vivo sealing ability of the flowable composite in combination with the self-etching adhesive was considered comparable to glass ionomer cement. Amalgam restorations without adhesive liners showed slight bacterial penetration along the cavity wall.

SUMMARY:
This study evaluated and compared the fracture toughness of compomers and composites. Three compomer (Compoglass F [CG], Vivadent; F2000 [FT], 3M-ESPE; Dyract Posterior [DP], Dentsply) and three composite (Tetric Ceram [TC], Vivadent; Z250 [ZT], 3M-ESPE; Esthet X [EX], Dentsply) restoratives were selected for the study. Single-edged notched specimens (25 x 2 x 2 mm) were fabricated according to manufacturers’ instructions and conditioned in distilled water at 37°C for one week prior to testing. Seven specimens were made for each material. The specimens were loaded to failure using an Instron microtester with a crosshead speed of 0.5 mm/minute. Data were subjected to ANOVA/Scheffe’s test and Independent Samples T-test at significance level 0.05. The mean fracture toughness (KIC) ranged from 0.97 to 1.23 MPam1/2 for compomers and 1.75 to 1.92 MPam1/2 for composites. The fracture toughness of compomers was significantly lower than their composite counterparts. No significant difference in KIC values was observed among the different composites. When the compomers were compared, FT had significantly higher fracture toughness than DP and CG. In view of their poorer resistance to crack propagation, compomers are not recommended for use in stress-bearing areas.

SUMMARY:
The tested hypotheses of this study were that dentin enamel bonding agents (DBAs) proposed for compomers create a hybrid layer (HL) that seals the margins of Class V restorations and HL is free from voids or gaps on both enamel and dentin margins. For purposes of this study, Class V restorations (n=70) were made in vitro at the CEJ in extracted third molars. Different systems (bonding agent + compomer) were selected. After finishing with discs, each margin was polished with diamond polishing paste for one minute, treated with a 2.5% NaOCl gel for 10 seconds and washed with deionized water to remove polishing debris and non-infiltrated collagen. All restorations were immersed in dye solution for 24 hours, then inspected along the margins. SEM analysis was used to evaluate the morphology of the marginal HL and microleakage tests to eval-uate their ability to seal the margins of restorations. Marginal leakage was observed along the dentin and enamel margin. A thin marginal HL (0.5-1.2 µm) was detected only along the dentin margin of several bonding systems but not along the enamel margin. Porosities and gaps were detected along margins when no HL was observed. The results demonstrated that the tested bonding agents for compomers produced a thin marginal hybrid layer, especially along the dentin margin. Microleakage had a relationship with the morphology (gap, porosities and thickness) of this hybrid smear layer. In conclusion, the DBAs tested specifically developed for compomers did not ensure an intimate interfacial adaptation, because microleakage was detected along the enamel and dentin interfaces and the marginal hybrid layer was only partially homogeneous.

SUMMARY:
This study evaluated the influence of mechanical and thermal cycling on microleakage at the cervical margins of proximal slot restorations and shear bond strength on flat dentin surfaces.

Microleakage Evaluation: One hundred and twenty slot cavity restorations were performed on bovine incisors. The restorations were randomly divided into four groups (n=30): control (no thermal and mechanical load cycling), thermal cycling (2,000 cycles, 5°C-55°C), mechanical load cycling (50,000–80N) and thermal and load cycling (2,000 5°C-55°C/50,000–80N). The specimens were sealed with acid resistant varnish, leaving a 1-mm window around the cervical margin interface. To detect marginal leakage, a 2% methylene blue buffered solution was used for four hours. The specimens were sectioned longitudinally and qualitatively evaluated by stereomicroscopy (45x) following a ranked score for the dentin cervical margin. The data were analyzed by Kruskal–Wallis test (a=0.05).

Shear Bond Strength Evaluation (SBS): Eighty bovine incisors were embedded and polished to obtain a flat standard surface on dentin. The surfaces were restored with Single Bond adhesive system and a resin composite subsequently inserted in a bipartite Teflon matrix. The specimens were randomly divided into the four groups (n=20) described above for microleakage. Shear bond strengths were measured in a universal testing machine with a crosshead speed of 0.5 mm/minute. The data were analyzed by one way ANOVA test (a=0.05). No statistically significant influence of thermocycling, mechanical load cycling or the combination was observed for both microleakage and shear bond strength.

SUMMARY:
In this in vitro study, the resistance to fracture of occlusal enamel supported by a bonded tooth-colored restorative material was compared to unsupported enamel and enamel supported by sound dentin. Eighty extracted human lower molars were sorted into five groups of 16 teeth each. Lingual cusps were removed. In Groups 2-5, dentin was removed from the facial cusps, leaving a shell of enamel. In Group 1, dentin was not removed. Group 2 remained unrestored. The groups in which a restorative material was inserted to replace missing dentin were as follows: Group 3–bonded resin composite (Scotchbond MP/Filtek Z250 [A2] in capsules, 3M); Group 4–resin-modified glass-ionomer (Fuji II LC [A2] in capsules, GC); Group 5–conventional glass ionomer (Fuji IX [A2] in capsules, GC). Specimens were thermocycled (1500 cycles, 6°–60°C, dwell 30 seconds), then mounted in die stone with lingual inclines of facial cusps approximately horizontal. The cusp ridges of the lingual inclines were flattened slightly using a horizontally mounted separating disk. Specimens were loaded evenly on flattened inclines in an Instron with a flat rectangular rod at a crosshead speed of 5 mm/minute.

Data analysis was with one-way ANOVA and Student-Newman-Keul’s test (F=50.30, p<0.0001). The bonded restorations provided significantly less enamel support than natural dentin and significantly more than when the enamel was left without support by dentin or a restorative material. There was no difference in support provided by the three restorative materials.

SUMMARY:
This in vitro study investigated cervical microleakage of proximal resin composite restorations placed with three application and polymerization techniques. Uniform mesio-occlusal-distal (MOD) preparations featuring cervical margins above (mesial) and below (distal) the CEJ suitable for restoration with resin composite were copy milled into 33 recently extracted permanent molars. The teeth were divided randomly into three groups of 11 teeth and restored using a conventional incremental technique (Group A) and two novel curing devices (Groups B and C). After 24 hours, a dye penetration test was used to assess microleakage. Conventional placement in preparations with cervical margins in enamel had significantly lower interfacial leakage scores than those recorded for placement in preparations with margins in cementum regardless of the technique used to place the restorative material. Use of the two novel curing devices conferred no advantage in reducing microleakage irrespective of where preparation margins were placed.

SUMMARY:
This in vitro study evaluated the effect of various surface treatments of prefabricated posts of titanium alloy (ParaPost XH), glass fiber (ParaPost Fiber White) and zirconia (Cerapost) on the bonding of two resin cements: ParaPost Cement and Panavia F by a diametral tensile strength (DTS) test. The posts received surface treatments in three categories: 1) roughening by sand-blasting and hydrofluoric acid etching; 2) application of primer by coating with Alloy Primer, Metalprimer II and Silane and 3) a combination treatment in the form of roughening (sand-blasting or etching) supplemented by the application of a primer or in the form of the Cojet system. After surface treatment, the post was embedded in a cylinder of resin cement (diameter = 4.0 mm, height = 4.0 mm). The surface-treated post was centered in the resin cement-filled mold with the aid of fixation apparatus. Fifteen minutes from the start of mixing the resin cement, the specimen was freed from the mold and stored in water at 37°C for seven days. Following water storage, the specimen was wet-ground to a final length of approximately 3 mm. The DTS of specimens was determined in a Universal Testing Machine. The bonding of resin cement to titanium alloy posts was increased by several surface treatments of the post. However, coating with primers as sole treatment had no effect on bonding. With the DTS method applied, none of the surface treatments had an effect on the bonding to glass fiber posts. The bonding of both resin cements to zirconia posts was improved by Cojet treatment, while sandblasting, followed by silane application, improved bonding of Panavia F.

SUMMARY:
This study evaluated the influence of air abrasive treatment of dentin surfaces on the tensile bond strength between dentin and two different composite-adhesive-systems (Scotchbond Multi-Purpose/Z100 and OptiBond FL/Herculite XR). The crowns of 200 maxillary central incisors were embedded in resin and then ground to expose a dentin surface 5 mm in diameter. The surfaces were etched or abraded by using a KCP 1000 device with different treatment conditions. Adhesive systems were applied according to the manufacturer’s instructions and composite cylinders were bonded to the conditioned dentinal surface using a split mold. Tensile bond strength values and failure modes were then determined. Tensile bond strength values of the acid-etched dentin-composite-interface were significantly higher than for the interface between air-abraded dentin and composite, independent of the composite-adhesive-system used. The light microscopic evaluation showed mainly adhesive and combined adhesive-cohesive fractures. Significantly more adhesive fractures could be observed between abraded dentin and composite than between etched dentin and composite.

SUMMARY:
The newly developed self-etching, self-priming all-in-one adhesives are appealing to clinicians because they are simple and efficient to use. These single-application bonding systems contain chemically active compounds that can alter pulpal blood circulation when applied to deep dentin surfaces. Since adequate microcirculation and oxygenation are the basic requirements for tissue survival, the aim of this study was to investigate the immediate vascular effect of a new self-etching adhesive, Prompt L-Pop/composite and compomer version/(test group).

The technique of vitalmicroscopy was used to record the changes in vessel diameter of the first lower incisor of 20 (10-10 in each group) male Sprague-Dawley rats (weighing 315 ± 74/SE/g) prior to, and at 5, 15, 30 and 60 minutes after the investigated materials were applied to dentin. The application of saline served as the untreated control.

The systemic arterial pressure remained unchanged throughout the experiments both in the control (110 ± 8 mmHg) and in test animals (114 ± 4 mmHg). In control rats, the diameter of the vessels was stable during the experiment. In the presence of Prompt L-Pop, the diameters decreased significantly during the experimental period (5 minutes: -11.15 ± 5.03%; 15 minutes: -14.66 ± 7.71%; 30 minutes: -13.35 ± 5.79%; 60 minutes: -11.82 ± 5.63% p<0.05 in each cases). In this group, stasis developed in pulpal circulation was 1 out of 10 rats.

The results from the rat model used in this study suggest that Prompt L-Pop may result in compromised pulpal microcirculation.

SUMMARY:
Many studies have evaluated the surface characteristics of finishing and polishing instruments on different restorative materials using two- and three-dimensional models based on mechanical and optical techniques. However, only limited data are available regarding the problem of marginal destruction. Instruments causing detectable surface alterations such as scratches or grooves may also cause marginal damage. This study aimed to correlate the smooth-surface polishing efficacy of different instruments with their potential for destructive effects on restoration margins and enamel finish lines. An index was created that will help to evaluate future polishing instruments and select suitable ones for different clinical situations.

A planar inlay system with a 100 µm wide defined gap was simulated in vitro. Pre-fabricated ceramic (n=40) and composite blocks (n=40) were connected to bovine enamel without luting material. After standardized pre-polishing, mean surface roughness and marginal quality were assessed using a profilometer and scanning electron microscopy (SEM). Enamel and restorative surfaces were colored, and subsequently prepared using one of 10 different finishing and polishing instruments. Four specimens per instrument and material were evaluated, resulting in eight interfaces for each test group. Surface roughness (Ra) and marginal quality (expressed as the percentage fracture-free margin) were measured and compared statistically using unpaired t-tests and two-way ANOVA, respectively. The level of significance was set at 0.05.

Eight-micrometer diamond burs and 40-fluted tungsten carbide finishers produced smoother surfaces and less finishing-line destructions than the other instruments under evaluation. The index values developed will prove helpful in evaluating and selecting appropriate instruments.

SUMMARY:
This study investigated the surface finish of resin-modified (Fuji II LC, GC) and highly viscous (Fuji IX GP Fast, GC) glass ionomer cements after treatment with three one-step finishing/polishing systems (One-Gloss [OG], Shofu; Pogo [PG], Dentsply; Sof-Lex Brush [SB], 3M-ESPE). The surface roughness obtained was compared to that using a matrix strip [MS], a two-step rubber abrasive (CompoSite [CS], Shofu) and a graded abrasive disk (Super Snap [SS], Shofu) system. Eight specimens (3-mm long x 3-mm wide x 2-mm deep) of each material were made for the various treatment groups. With the exception of the MS group, all groups were roughened with 320 grit grinding paper using a lapping device prior to finishing/polishing with the different systems. The mean surface roughness (µm) was measured with a profilometer. Data was subjected to ANOVA/Scheffe’s tests at significance level 0.05. Mean Ra ranged from 0.13 to 1.04 µm for Fuji II LC and 0.14 to 0.81 for Fuji IX GP. For both materials, the smoothest surface was obtained with MS and the roughest with OG. Depending on the materials, the surface finish produced by PG and SB was superior or comparable to that obtained with CS and SS. The effectiveness of one-step systems, when used to finish/polish resin-modified and highly viscous glass ionomer cements, is product dependent.

SUMMARY:
This study compared the cure and pulp-cell cytotoxicity of composites polymerized with light-emitting diode (LED) and halogen-based light curing units. A mini-filled resin composite (Tetric Ceram, Vivadent), two LED (E-light [EL], GC and Freelight [FL], 3M-ESPE), a conventional halogen (Max [MX], Dentsply) and a high-intensity halogen light (Astralis 10 [AS], Vivadent) were evaluated. Cure associated with the different lights was determined by measuring the top and bottom surface hardness (KHN; n = 5) of 2-mm thick specimens using a digital microhardness tester (load = 500 gf; dwell time = 15 seconds). Pulp-cell cytotoxicity was assessed using a direct contact method involving incisor tooth slices dissected from 28-day old Wistar rats maintained in Dulbecco’s Modified Eagle’s Medium (DMEM) and 1% agarose. The bottom surfaces of the cured composite specimens (7-mm diameter and 2-mm deep) were placed in contact with the openings of each tooth slice. After incubation in 5% CO2 atmosphere at 37°C for 48 hours, the tooth slices were fixed, demineralized and processed for histological examination. Pulp fibroblasts and odontoblasts were counted histomorphometrically at 400x magnification within a 1500 µm2 area using a computerized micro-imaging system. Eighteen readings were obtained for each curing light. Data was subjected to ANOVA/Scheffe’s test and Pearson’s correlation at significance level 0.05 and 0.01, respectively. At the top surfaces, the cure with AS was significantly greater than the other curing lights, with MX and FL being significantly greater than EL. At the bottom surfaces, MX, AS and FL had significantly better cure than EL. Specimens cured with MX were less cytotoxic than those polymerized with other curing lights. Specimens cured with AS and EL were significantly less cytotoxic than FL. Composite cure and cytotoxicity associated with LED lights is device dependent. Composite cure was not correlated to pulp-cell cytotoxicity. The response of pulpal fibroblasts to unreacted/leached components of composites differs somewhat from odontoblasts.

SUMMARY:
This study compared the surface finish of eight different types of aesthetic restorative materials. The materials included resin-modified (Fuji II LC [FL], GC) and highly viscous (Fuji IX GP Fast [FN], GC) glass ionomer cements, a compomer (F2000 [FT], 3M-ESPE), minifilled (Z100 [ZO], 3M-ESPE) and microfilled (A110 [AO], 3M-ESPE) composites and materials based on recently introduced ormocer (Admira [AM], Voco), nanomer (Filtek Supreme Translucent [FST], 3M-ESPE) and nanocluster technology (Filtek Supreme [FS], 3M-ESPE). Sixteen specimens (3-mm long x 3-mm wide x 2-mm deep) of each material were divided into two equal groups. Specimens in Group 1 received no further treatment after polymerization against a matrix strip, while the specimens in Group 2 were roughened with 320 grit grinding paper using a lapping device and were finished/polished with a graded abrasive disk system (Super-Snap, Shofu). The mean roughness (Ra, µm) of materials was determined using a surface profilometry. Data was analyzed by ANOVA/Scheffe’s test at significance level 0.05. Mean Ra values ranged from 0.04 to 0.16 µm for Group 1 specimens and 0.15 to 0.68 µm for Group 2 specimens. Results of statistical analysis were as follows: Group 1—FS, FST, FL, FN, AM > FT, AO, ZO; Group 2—FN, FT, FL > AO, FS, ZO, AM, FST (> indicates significantly greater Ra values). For the finished/polished composite materials, Ra values observed for AM and FST were significantly lower than for AO and FS. The surface finish of glass ionomers and compomer was significantly poorer than composites. Composite materials based on ormocer and nanomer technology were significantly smoother than those based on microfillers and nanoclusters.

SUMMARY:
A universal energy-conversion relationship (ECRu) predictive of conversion of a resin-based composite (RBC) polymerized with any light source has been described. This relationship was derived from an energy conversion relationship for RBC polymerized with a tungsten-halogen lamp and the lamp’s efficiency relative to a hypothetical standard lamp. The ECRu was then used to predict conversion throughout RBC polymerized with an LED lamp using the lamp’s relative efficiency compared to the standard lamp. The universal energy scale has also been described as predictive of scrape-back lengths for this RBC family when polymerized with any light source. Despite a 31% greater relative efficiency, scrape-back lengths from RBC polymerized using the LED lamp were predicted to be only 6% greater than those polymerized with the tungsten-halogen lamp when RBC is polymerized on an equal energy basis. This result was experimentally verified.

SUMMARY:
Resin posts are used more often than metal posts, as they are esthetically compatible and less damaging to remaining tooth structure. Many resin post systems are available, where a light transmitting post is used to build up the composite in layers. An easier and economical alternative method, a custom-made resin post, is described.

SUMMARY:
This study evaluated the clinical performance of ceramic inlays and onlays made with two systems: sintered (Duceram, Dentsply-Degussa)—D and pressable (IPS Empress, Ivoclar-Vivadent)—IPS after two years. Eighty-six restorations, 44 IPS and 42 D, were cemented into the mouths of 35 patients. Twenty-seven premolars and 59 molars received Class II preparations totaling 33 onlays and 53 inlays. All restorations were cemented with dual-cured resin cement (Variolink II, Ivoclar-Vivadent) and Syntac Classic adhesive under rubber dam. The evaluations were conducted by two independent investigators at the baseline and after one and two years using the modified USPHS criteria. Additionally, radiographs and slides were made. After two years, 100% of the restorations were assessed and all the restorations were considered clinically excellent or acceptable. Among the analyzed criteria, the following received Bravo ratings: marginal discoloration—IPS (31.82%), D (23.81%); marginal integrity—IPS (18.18%), D (11.9%), color match—IPS (4.55%), D (9.52%) and surface texture—IPS (2.27%); D (14.29%). No “Charlie” or “Delta” scores were attributed to the restorations. The results were subjected to the Fisher and McNemar Statistical Tests. No significant differences were noticed between the two ceramic materials. Among the analyzed criteria, only marginal discoloration presented an increased percentage of “Bravo” scores that increased with time for both ceramic materials. Compared with the baseline data, the difference was statistically significant (p<0.05). No difference was found between inlay and onlay restorations or between restorations placed in premolars or molars. In conclusion, these two types of ceramic materials demonstrated excellent clinical performance after two years.

SUMMARY:
This study evaluated occlusal margins and surfaces of composite and ceramic inlays after finishing and polishing in vivo.

Eighty Class II cavities surrounded by enamel were prepared by two experienced dentists. Forty cavities were restored with indirect micro-hybrid composite inlays (Tetric), the balance were treated with heat-pressed glass ceramic inlays (IPS Empress). Using a rubber dam, the inlays were inserted adhesively with a dual curing composite of high viscosity (Variolink Ultra). Finishing was performed with the sequence of a 30 µm and 20 µm diamond (finishing method FM 1) or a 30 µm diamond followed by a tungsten carbide finishing bur (FM 2). The composite inlays were divided into four groups of 10 that were finished and polished according to the following protocol: (A) FM 2/Diafix-oral, (B) FM 2/MPS gel, (C) FM 1/Diafix-oral, (D) FM 1/MPS gel. Ten ceramic inlays each were treated as follows: (E) FM 2/MPS gel, (F) FM 1/MPS gel, (G) FM 2/ Diamond polisher, (H) FM 1/Ceramiste silicon polishers. After polishing, replicas of the restorations were fabricated. The replicas were examined by SEM with respect to margin quality (portion of continuous margins, overhangs, submargination and marginal imperfections). Further-more, surface properties were evaluated qualitatively, which included assessing roundness of the contours in three grades (smooth rounding, few edged contours or predominantly edged contours) and evaluation of the surface roughness (smooth and homogeneous surface, minor roughness or severe roughness).

Quantitative analysis of the occlusal composite and ceramic inlay margins showed that 52.2% - 84.6% were rated as continuous, 0% - 14.0% were characterized by overhangs and 0.7% - 10.8% by submargination. A portion of 4.9% - 18.1% margins revealed imperfections. The amount of marginal gap formation was negligible. Composite and ceramic inlays showed a similar behavior with respect to marginal quality after finishing and polishing. Overall, there were no significant differences among the four methods applied to composite and the four methods used on ceramic inlays with respect to margin quality. The use of a 30 µm diamond followed by a tungsten carbide bur on composite and ceramic inlays resulted in a significantly larger portion of continuous margins compared to finishing with two diamonds (p=0.049).

Qualitative evaluation of composite and ceramic inlays revealed that 50% - 80% of the occlusal surfaces were characterized by few edged contours and 10% - 50% by smooth rounding. With respect to roughness, smooth surfaces prevailed both on composite (67.5% - 80.0%) and ceramic inlays (64.5% - 77.3%). Overall, no significant differences were detectable between the methods for finishing and polishing composite inlays and the methods applied to ceramic restorations with respect to roundness of contours and surface roughness.

SUMMARY:
This study measured the nanohardness and elastic modulus of carious and sound primary canine dentin and compared the values obtained under the lesion and in sound regions of incisal, center and cervical areas, and outer, middle and inner layers. Six extracted or exfoliated primary canines (three with dentin caries on both proximal surfaces and three sound teeth) were mesio-distally sectioned parallel to the long axis of the tooth and polished. The hardness (H), plastic hardness (PH) and Young’s modulus (Y) were measured by a nano-indentation tester. Ten indentations at intervals of 10 µm on all regions, areas and layers were made using a load of 1 gf for one second. All indentations were observed using a microscope attached to the tester. All data were statistically analyzed using ANOVA and Scheffe’s test at p<0.05. For sound teeth, the H, PH and Y values of the inner layer were significantly lower than the outer and middle layers in all areas. The H, PH and Y values of the cervical area were significantly lower than the incisal area in almost all of the outer, middle and inner layers. For carious teeth, the H, PH and Y values of the inner layer were significantly lower than the outer and middle layers in the center area. For the center area, the H, PH and Y values under the lesion were significantly lower than sound teeth in the outer and middle layers. Dentin under the lesion, near the pulp and cervical areas showed significantly lower nanohardness and elasticity.

SUMMARY:
To evaluate the effect of thermal and mechanical cycles on dentin bond strength to cervical margins of Class II restorations, 80 box-type Class II cavities were prepared on the surfaces of bovine incisors. The cavities were restored with Single Bond (3M-ESPE) and Z-250 composite (3M-ESPE) according to manufacturer’s instructions. The incisors were divided into four groups: G1- Control, G2- Thermal cycling (2,000 cycles, 5°C -55°C), G3- Mechanical cycling (100,000 cycles; 50N) and G4- Thermal and mechanical cycling (2,000 cycles 5°C-55°C/100,000 cycles; 50N). The restorations were sectioned perpendicular to the cervical bonded interface into 0.7 ± 0.2 mm-thick slabs. The slabs were further trimmed at the interface to 1.4 ± 0.2 mm with a fine diamond bur to produce a cross-sectional surface area of 1 mm2. All specimens were then subjected to microtensile bond testing. Means and standard deviations were expressed in MPa. The bond strength data were analyzed by one-way ANOVA and Fisher’s PLSD test (p<0.05). Fracture mode analysis was performed using SEM. Bond strengths were significantly lower when thermal and mechanical cycling were performed [G4-2.41 (8.57)] when compared to the other groups [G1-28.15 (14.03); G2-27.60 (10.14); G3- 27.59 (8.67)]. No differences were observed among Groups 1, 2 and 3. Interfacial fracture of the control (G1) and thermocycling (G2) groups mainly occurred between the deepest portion of the adhesive resin and the top layer of the demineralized dentin (Interphase). Mixed failure was predominant and increased when mechanical cycling was applied (G3 and G4).

SUMMARY:
Volumetric polymerization shrinkage of three resin composites (Suprafil, Z100 and Filtek P60) was determined using four light curing methods: method 1: continuous output with conventional intensity light; method 2: continuous output with higher intensity light; method 3: ramp output and method 4: pulse-delay output. Five disc-shaped specimens were prepared from each material for each curing method. Specimen weight was determined with an analytical electronic hydrostatic balance in air and in water before and after curing. Specific gravity values were then determined. Volumetric polymerization shrinkage was calculated using mathemat-ical formulas. Mean volumetric polymerization shrinkage ranged from 1.882 (.015)% to 2.169 (.028)%. ANOVA indicated significant differences among the materials (p<.05). Light curing methods had no effect on volumetric polymerization shrinkage except for Z-100, where method 2 resulted in significantly higher shrinkage than methods 1 and 4. Suprafil shrunk significantly less than the other two materials in all curing methods.

SUMMARY:
Ninety Class II cavities with cervical margins 1 mm below the CEJ were prepared in 45 extracted human premolars. The teeth were randomly divided into three groups (n=15). In each group, one side of each tooth was restored incremen-tally with respective composites–SureFil, Filtek P60 and Tetric Ceram; whereas, on the other side, flowable materials–Dyract Flow, Filtek Flow or Tetric Flow–were placed respectively as a 1-mm thick gingival increment before resin composite restoration. The restored teeth were stored for one week in distilled water at 37°C, thermocycled between 5°C and 55°C and immersed in 0.5% basic fuchsin for 24 hours. Dye penetration was evaluated using a stereomicroscope at 10x magnification. The data were analyzed statistically by Kruskal-Wallis analysis of variance and Mann-Whitney U-tests. The effect of flowable increments on reducing the gingival microleakage was found to be statistically significant for all restorative materials tested (p<0.05).

SUMMARY:
This study evaluated the micro-shear bond strength of two commercially available resin bonding systems (Single Bond, 3M, USA and SE Bond, Kuraray, Japan) to human enamel. One hundred and twenty enamel sections were prepared from extracted non-carious human molars by cutting with a slowly rotating blade. The enamel surfaces were polished with #280-grift SiC paper under running water. These surfaces were randomly divided into two groups and treated with either Single Bond or Clearfil SE Bond according to manufacturers’ instructions. After the bonding procedures, a micro tygon tubing with an internal diameter approximately 0.7 mm and 0.5 mm in height was placed on the enamel surface and Clearfil AP-X resin filled the tube. After the resin was photo-irradiated, the tygon tube was removed. The specimens were further divided into 12 groups according to storage time. All specimens were stored in isotonic sodium chloride solution at 37°C. The bond strength was then measured by means of micro-shear bond testing at one day, one week, one month, three months, six months and one year. After testing, the fractured surfaces and interfaces were observed using scanning electron microscopy (SEM). The data was analyzed by two-way ANOVA and Fisher’s PLSD tests at 95% level of confidence. The result was that both factors (storage time and material) affected bond strength and there was a statistically significant interaction between them. In general, bond strength decreased with time for both materials. The highest bond strengths were achieved at one day with SE Bond and Single Bond. For Single Bond, from one month to one year, the bond strength dramatically decreased. For SE Bond, the decrease in bond strength was gradual. After one-year storage, the bond strength drastically decreased and this value was not significantly different from the results of the one-year storage of Single Bond.

SUMMARY:
This in vitro study evaluated the microtensile bond strengths of sound versus caries-affected dentin using a self-etching adhesive system, Clearfil SE Bond, with or without additional acid pre-conditioning.

Extracted human mandibular molars with occlusal caries extending halfway through the dentin were used. In the first group, the teeth were bonded with the self-etching adhesive Clearfil SE Bond according to the manufacturer’s instructions. In the second group, prepared dentin surfaces were etched with 37% phosphoric acid prior to applying the same self-etching adhesive. After the bonding procedure, all specimens were built up with composite resin and stored in water for 24 hours. The teeth were serially sectioned vertically into 0.7-mm slabs and trimmed into an hourglass shape for measuring microtensile bond strength. Each specimen was attached to a Bencor device and stressed in tension at a crosshead speed of 1 mm/minute. Statistical analysis was performed using two-way ANOVA and the Tukey HSD test (p<0.05).

The microtensile bond strengths of Clearfil SE Bond to sound dentin (32.9) were significantly higher than to caries-affected dentin (15.9). In the second group where acid etching was performed prior to applying Clearfil SE Bond, there were no statistically significant differences between the microtensile bond strengths of sound (19.2) and caries-affected dentin (16.3). While bond strengths to sound dentin were decreased by using additional acid etching prior to applying Clearfil SE Bond, this procedure revealed no statistically significant differences in bond strengths for the caries-affected dentin.

SUMMARY:
This study compared the post-gel contraction of two “low-shrinkage” composites (InTen-S [IS], Ivoclar-Vivadent; Aelite LS [AL], BISCO Inc) and an ormocer (Admira [AM], Voco) to two conventional mini-filled composites (Renew [RN], BISCO; Z100 [ZO], 3M ESPE). A strain-monitoring device and test configuration were used to measure the linear polymerization shrinkage associated with the various composites (A2 shade) during and up to 60 minutes post light polymerization. Each specimen was irradiated for 40 seconds using a halogen curing light (Max, Dentsply-Caulk) with an intensity of 401 mW/cm2. Five specimens were made for each composite. Data was analyzed using one-way ANOVA/Scheffe’s post-hoc test at significance level 0.05. The linear percentage shrinkage immediately after light polymerization and at 60 minutes post light polymerization ranged from 0.10 ± 0.02 to 0.40 ± 0.02% and 0.22 ± 0.02 to 0.60 ± 0.05%, respectively. Post-gel shrinkage ranking of the materials was as follows: immediately after light polymerization – IS < AL < AM < ZO < RN and at 60 minutes post light polymerization – IS < AL = AM < ZO < RN. The shrinkage associated with IS, AL and AM was significantly lower than for ZO and RN immediately after light polymerization and at 1, 10, 30 and 60 minutes post light polymerization. The post-gel polymerization shrinkage of IS, AL and AM was significantly lower than conventional mini-filled composites.

SUMMARY:
This study evaluated the influence of different bleaching procedures on the fracture toughness and microhardness of enamel. The labial aspects of 72 bovine incisors were prepared for microhardness determination. At baseline, Knoop hardness (KH) determination was conducted on each specimen. Moreover, the fracture toughness (FT) of enamel was assessed using Vickers hardness indentations with a load of 9.8 N. The length of both indentations and enamel cracks were recorded and used for calculation of FT. The samples were divided among six (A-F) groups (n=12) and sectioned, resulting in a control and an experimental half. The samples were stored in artificial saliva for 10 days. The experimental halves were removed from the saliva and subjected to bleaching according to manufacturers’ instructions (A: Opalescence Xtra, B: Opalescence Quick, C: Rapid White, D: Whitestrips, E: Opalescence 10%, F: Opalescence PF 15%). Bleaching with C-F was conducted daily (C: twice per day for 10 minutes, D: twice per day for 30 minutes, E: 8 hours, F: 4 hours), systems A-B were applied on the first and fifth day (A: twice for 10 minutes, B: 1 hour). Finally, Knoop hardness and FT were assessed and statistically compared to baseline values using Wilcoxon-tests (p<0.05). KH and FT of the controls remained stable during storage in saliva. All bleaching regimens resulted in a statistically significant percentage loss of KH (mean + standard error of means): A: 17.3±2.8%, B: 8.6±3.3%; C: 83.5±0.61%, D: 29.0±1.9%, E: 9.0±2.9%, F: 5.4±2.2%. The percentage changes (mean + standard error of means) of FT in the experimental specimens were as follows: A: 3.9±9.5%, B: 0.1±4.7%; D: -8.2±7.1%, E:-18.9±4.7%, F: -12.0±4.7%. Due to severe surface softening, FT could not be determined for the samples in Group C. Applying Opalescence 10% resulted in a significant reduction in FT compared to baseline. In the remaining groups, changes in FT were not statistically significant. Bleaching with the tested materials resulted in 1) reduction of surface microhardness and 2) a decrease in fracture toughness (depending on the bleaching system applied).

SUMMARY:
Purpose: To evaluate the bond strength of a total-etching, self-priming system (Single Bond) and a self-etching system (Clearfil SE Bond) to deciduous and permanent human dentin. Methods and Materials: Buccal dentin discs were prepared with a diamond disc from permanent first premolars, permanent third molars and deciduous second molars. The flat dentin surfaces were obtained by polishing with wet 600 grit silicon carbide papers. The specimens of each group were further divided into two groups for bonding to either Single Bond or Clearfil SE Bond. After 24 hours, the micro-shear bond strength testing was executed on a universal-testing machine. Statistical analysis was performed at a=0.05. Results: No significant differences in bond strength were found between materials. However, deciduous dentin demonstrated significantly lower bond strengths than permanent premolar dentin when Single Bond was applied (p<0.05). Conclusion: The difference in bonding substrate (permanent or deciduous dentin) had a significant effect on bond strength when the total-etching, self-priming system was applied.

SUMMARY:
Proper finishing of restorations is desirable not only for aesthetic considerations but also for oral health. The primary goal of finishing is to obtain a restoration that has good contour, occlusion, healthy embrasure forms and a smooth surface. This study investigated: 1) analyzing the surface roughness of three resin composites finished and polished with a new one-step and two conventional multi-step polishing systems and 2) evaluating the effectiveness of one-step polishing system and surface morphology using scanning electron microscope analysis (SEM).

Specimens (n=72) measuring 8-mm in diameter x 2-mm in thickness were fabricated in a plexiglass mold covered with a Mylar strip using three esthetic resin composites. After polymerization, six specimens per resin composite received no finishing treatment and served as a control. Fifty-four specimens were randomly polished with Sof-Lex discs, Enhance disc with polishing paste or PoGo for 30 seconds after being ground wet with a 1200 grit silicon carbide paper. The average surface roughness of each polished specimen was determined with a profilometer (Surtronic 4). The data were analyzed using repeated measures ANOVA and Scheffe’s post-hoc test of multiple comparisons (p≤0.01). Representative samples of the mentioned finishing procedures were selected and examined using a scanning electron microscope (SEM).

There was no surface roughness in all resin composites tested against Mylar strip. The results showed no difference between the surfaces of Clearfil ST and Esthet-X polished with PoGo and the Mylar group (p≥0.01). Among all the polishing systems tested, PoGo exhibited the smoothest finish for all resin composites. The combination of Enhance and Prisma Gloss polishing paste exhibited the highest roughness values for Filtek A110 and Clearfil ST; however, it gave the same Ra values as PoGo for Esthet-X (p≤0.01).

SEM analysis of Esthet-X samples confirmed the profilometer’s results. The surfaces of the Clearfil ST discs polished with PoGo resemble that of Mylar, while Enhance and Sof-Lex exposed and dislodged the filler particles. PoGo scratched in some places Filtek A110’s surface, while Enhance produced mostly a Mylar-like surface with dislodged fillers in some places.

SUMMARY:
The objectives of this study include comparing the cement thickness and microleakage of Class II ceramic inlays built with three ceramic systems and verifying whether there was a correlation between those two variables. The ceramic systems used include: 1) Heat-pressed (IPS-Empress); 2) CAD-CAM (CEREC 2) and 3) Sintered (Colorlogic). Standardized MOD Class II inlay cavities with one proximal box extending below and the other extending above the cement-enamel junction (CEJ) were prepared in 30 extracted human molars and randomly assigned to three groups. The ceramic inlays were constructed according to manufacturer’s instructions and cemented using a dual-cure resin cement (Variolink II). All teeth were mechanically cycled (100,000 cycles, 78N) and thermocycled (700 cycles, 5°C-55°C). After immersion in silver nitrate, the inlays were sectioned mesial-distally and evaluated with an optical microscope (40x). The cement thickness obtained by the Colorlogic system (enamel: 113 ± 25 µm; dentin: 118 ± 23 µm) was significantly higher than that obtained by CEREC (enamel: 78 ± 14 µm; dentin: 87 ± 13 µm) and Empress (enamel: 65 ± 15 µm; dentin: 89 ± 14 µm). Regarding dye penetration, there was no statistical difference among the three ceramic systems in enamel. At the dentin margins, the Colorlogic system resulted in a significantly higher penetration depth compared to CEREC and Empress, which had similar average values. No correlation was found between cement thickness and microleakage either in enamel or dentin for any of the ceramic systems.

SUMMARY:
This study evaluated in vitro and in situ the potential adverse effects of 10% carbamide peroxide on human enamel using microhardness, calcium loss and surface morphology analysis. Twenty-four enamel slices (4 mm2) were obtained from recently extracted premolars. The specimens were polished under water-cooling down to 1,200-grade sandpaper. After initial microhardness readings (100g), the specimens were randomly divided into two groups for in situ and in vitro conditions. The specimens were covered with 10% carbamide peroxide for eight hours. After removing the bleaching gel, the in vitro specimens were stored in deionized water and the in situ specimens, included in an intra-oral appliance, were placed in the oral cavity of four volunteers. These cycling sequences took place for 14 days. Upon conclusion of the bleaching treatment, new microhardness readings were performed on all specimens. Calcium dosage was assessed from the bleaching gel collected after initial exposure on day one, then from gel collected between days two and seven and gel collected between day eight and 14 using an atomic absorption spectrophotometer. Surface mor-phology was observed from two non-treated control specimens and two specimens of each experimental bleached group under SEM evaluation. Statistical analysis (ANOVA and Tukey tests) disclosed that specimens bleached in situ showed similar microhardness to unbleached specimens and had statistically higher (p<0.01) hardness than in vitro bleached specimens. The loss of calcium in the in vitro situation at 14 days was 2.5 times higher than the in situ condition. SEM micrographs demonstrated that surface alterations were more pronounced in the in vitro condition. The adverse effects of carbamide peroxide on enamel were evident in specimens bleached in vitro but were not seen in situ. The presence of saliva could prevent the demineralizing effect of bleaching gel in situ.

SUMMARY:
Anterior crown fractures are a common form of injury that mainly affects children and adolescents. The position of maxillary incisors and their eruptive pattern carries a significant risk for trauma. In the pre-adhesive era, fractured teeth needed to be restored either with pin-retained inlays or cast restorations that sacrificed healthy tooth structure and were a challenge for clinicians to match with adjacent teeth. The development of adhesive dentistry has allowed dentists to use the patient’s own fragment to restore the fractured tooth. Since then, several successful case reports that use a variety of techniques and materials to reattach fractured teeth have been published. This article presents a comprehensive literature review on techniques and materials used to restore uncomplicated dental trauma.

SUMMARY:
Studies have suggested that fracture resistance of undermined enamel increases when supported by a layer of bonded composite. Composite to reinforce enamel must have a secure foundation in dentin and/or enamel that is supported by dentin to perform optimally.

A restorative technique is presented using resin composite material to support and reinforce undermined enamel that lacks dentinal support in traditional amalgam restorations. This technique is intended to conserve unsupported enamel cavity walls and weakened cusps in extensive Class I and II preparations.

SUMMARY:
This study compared the post-operative results of cementing full crowns (all metal or PFM) with either a conventional (Fuji I, GC; n=102) or a resin modified GI luting cement (Rely X, 3M/ESPE; n=107). Methods: Ten private practitioners fabricated 209 crowns using standardized preparation/luting criteria and randomly assigned cements. Patients self-reported temperature and biting sensitivity, on a 0-10 scale at 24 hours, one week, one month and three months post-cementation. Data were analyzed using t-tests, confirmatory Mann-Whitney tests and Pearson correlations, with a significance level of p≤0.05. Results: Of all patients, 50.7% reported any sensitivity at any time period. Mean sensitivity for all patients on the 10-point scale was 0.52 for temperature and 0.23 for biting. Cements did not differ in cold or biting sensitivity at any time. There were many significant (though low) correlations between the sensitivity measures and age (inverse relationship) and dentin area of preparation (direct). The practice-based format provided a viable alternative to performing clinical research.

SUMMARY:
This retrospective longitudinal study compared the long-term survival rate of repaired versus replaced amalgam restorations and recemented crowns and gold castings versus non-recemented similar restorations. Private general dental practitioners treated adult subjects at three city practices. No significant survival differences were found between the repaired and replaced amalgams at five years, although the repaired amalgams showed higher failure rates by 10 years (p=0.37). However, there were significantly higher failures by five years for recemented crowns (p<0.001) and recemented gold castings (p=0.01) when compared with the initially cemented restorations. After 10 years, the repaired amalgams had survival rates of approximately 37 ± 15 (SEr) percent, recemented crowns 28 ± 15 (SEr) percent and recemented gold castings 42 ± 17 (SEr) percent.

SUMMARY:
A 24-month clinical study was carried out to evaluate and compare the retention rate, marginal integrity and caries preventing effects of a polyacid-modified resin composite based fissure sealant, Dyract Seal, to that of a resin based fluoride fissure sealant, Delton FS+. Fifty-three patients (27 female and 26 male), 7 to 10 years old, were included in the study. At baseline, a total of 192 permanent first molars were sealed with either fissure sealant (n=96, each), using invasive technique. The sealed teeth were evaluated at post-operative 3, 6, 12 and 24 months with respect to evaluation parameters. The data were analyzed with the Chi-Square tests where a=0.05. There were no statistically significant differences between fissure sealants as regards to retention and prevention of caries for all periods of the evaluation (p>0.05). However, regarding marginal integrity of the sealants, Delton FS+ gave significantly better results than Dyract Seal for the 3-, 6- and 12-month evaluations, respectively (p<0.05). In conclusion, the use of Dyract Seal on permanent molars with invasive technique was found to be clinically comparable to Delton FS+ for the 24-month evaluation period.

SUMMARY:
This clinical study compared the performance of complex amalgam restorations retained with self-threading pins or bonded with a filled, 4-META-based resin. Sixty amalgam restorations (28 pin-retained and 32 bonded), each replacing at least one cusp, were placed. Self-threading stainless steel pins (Coltene-Whaledent) were used in the pin-retained group. A filled, 4-META-based bonding resin (Amalgambond Plus with HPA powder) was used in the bonded group. For both groups, any retention form remaining after removal of an old restoration was left in place but not enhanced. At six years, 11 restorations had failed; eight of which were pin-retained and three bonded. Using Fisher’s exact test to compare the groups at six years, there was no significant difference in failure rate, marginal adaptation, marginal discoloration, secondary caries, tooth sensitivity or tooth vitality. At six years, there was no difference in the performance of pin-retained amalgam restorations and bonded amalgam restorations.

SUMMARY:
This study investigated the wear resistance of recently introduced nanofill (Filtek Supreme [FS], 3M-ESPE) and ormocer (Admira [AM], Voco) composites and compared their wear characteristics to microfill (Filtek A110 [AO], 3M-ESPE]), minifill (Esthet X [EX], Dentsply; Filtek Z250 [ZT], 3M-ESPE) and polyacid-modified (Dyract AP [DY], Dentsply) composites. Six specimens were made for each material. The specimens were conditioned for one week in distilled water at 37°C and subjected to wear testing at 20 MPa contact stress against SS304 counter-bodies using reciprocal compression-sliding wear instrumentation. Distilled water was used as lubricant. Wear depth (µm) was measured using profilometry every 5,000 cycles up to 20,000 cycles. The results were analyzed using ANOVA/Scheffe’s test (p<0.05). Wear of the materials was cycle and fatigue dependent. Although no significance in wear was observed between materials after 5,000 cycles of wear testing, significant differences were observed at 10,000 cycles and greater. After 20,000 cycles of wear testing, ranking was as follows: ZT > DY > AM > AO > FS > EX. Wear ranged from 39.90 µm for EX to 113.32 µm for ZT. The wear resistance of ZT and DY was significantly lower than AO, FS and EX. In addition, ZT experienced significantly more wear than AM. Under the conditions of this in-vitro study, the wear resistance of nanofill and ormocer composites was comparable or superior to polyacid-modified, microfill and minifill composites.

SUMMARY:
This study investigated the surface texture of composite (Z100, 3M ESPE) and compomer (F2000, 3M ESPE) restoratives after treatment with different one-step finishing/polishing systems (One-Gloss [OG], Shofu; PoGo [PG], Dentsply; Sof-Lex Brush [SB], 3M ESPE). The surface roughness obtained was compared to that using a matrix strip [MS], a two-step rubber abrasive (CompoSite [CS], Shofu) and a graded abrasive disk (Super Snap [SS], Shofu) system. Eight specimens (3-mm long x 3-mm wide x 2-mm deep) of each material were made according to manufacturer’s instructions. With exception of the MS group, all groups were roughened with 320 grit grinding paper using a lapping device prior to finishing/polishing with the different systems. The mean surface roughness (µm) was measured with a profilometer. Data was subjected to ANOVA/Scheffe’s tests and independent samples t-test at significance level 0.05. Mean Ra ranged from 0.22 to 0.32 µm for Z100 and 0.45 to 0.68 for F2000. For both materials, the smoothest surfaces were obtained with MS. The roughest surfaces were observed after treatment with SS and OG for Z100 and F2000, respectively. The effectiveness of the finishing/polishing systems was material dependent. The surface finish produced by PG and SB was superior or comparable to that obtained with CS, SS and OG.

SUMMARY:
This study tested the hypothesis that commercially available caries dyes stain non-carious human coronal dentin in freshly extracted teeth. Multiple sections were cut from 10 non-carious and two control carious teeth using a water-cooled saw. Each section was stained with one of five caries dyes. The location of staining, if any, was noted and the staining intensity was scored on a four-point scale. One of the sections from each tooth was subsequently decalcified and processed for observation under a light microscope using four histologic staining techniques to evaluate morphology, collagen distribution and bacterial content. The association between the stain intensity scores on the undecalcified sections and the five dyes was evaluated using the Kruskal-Wallis One-Way ANOVA by Ranks test. Outer carious dentin in the control specimens stained intensely with each of the five dyes. In the undecalcified, non-carious sections, all had at least one area of staining. However, this staining could be differentiated from the intensity of dye staining in the carious controls, except in two instances. The association between stain inten-sity scores and the five dyes was not statistically significant. In the histologic sections, numerous bacteria were seen within the dentinal tubules of carious lesions of the two control specimens; however, no bacteria were found in any of the sections from non-carious specimens. Histologically, no differences were observed in the morphology or staining pattern within mantle or circumpulpal dentin in areas stained with caries dye, and in only one unique instance within the main body of the dentin. These results suggest that the five dyes evaluated in this study can stain non-carious dentin, however, this stain can be differentiated from the staining of outer carious dentin in vitro.

SUMMARY:
This study evaluated the characteristics of two kinds of recently developed light-curing unit; plasma arc and blue light emitting diodes (LED), in comparison with a conventional tungsten-halogen light-curing unit. The light intensity and spectral distribution of light from these light- curing units, the temperature rise of the bovine enamel surface and the depth of cure of composites exposed to each unit were investigated.

The light intensity and depth of cure were determined according to ISO standards. The spectral distributions of emitted light were measured using a spectro-radiometer. The temperature increase induced by irradiation was measured by using a thermocouple.

Generally, light intensities in the range 400-515 nm emitted from the plasma arc were greater than those from other types. Light in the UV-A region was emitted from some plasma arc units. The required irradiation times were six to nine seconds for the plasma arc units and 40 to 60 seconds for the LED units to create a depth of cure equal to that produced by the tungsten-halogen light with 20 seconds of irradiation. The temperature increased by increasing the irradiation time for every light-curing unit. The temperature increases were 15°C to 60°C for plasma arc units, around 15°C for a conventional halogen unit and under 10°C for LED units.

Both the plasma arc and LED units required longer irradiation times than those recommended by their respective manufacturers. Clinicians should be aware of potential thermal rise and UV-A hazard when using plasma arc units.

SUMMARY:
This study evaluated the effect of fractured or sectioned fragments on the fracture strength recovery of four techniques used for reattachment and resin composite buildups. Ninety-one sound, permanent lower central incisors were used. Half the teeth were fractured in the incisal-proximal edge; the other half had the incisal-proximal edge sectioned by a diamond saw. Teeth from each half were randomly divided into five techniques: 1) bonded only; 2) chamfer; 3) over-contour; 4) internal dentinal groove and 5) resin composite buildup. An adhesive system and dual cure resin cement were employed for the reattachment. Restored teeth were subjected to load in a specific point on the buccal surface. Based on the fracture strength of sound teeth, a fracture strength recovery was calculated for each tooth. A one-way ANOVA and Tukey’s test (a=0.05) were used to evaluate differences between the techniques for each method of obtaining fragments. The fracture strength recovery of similar techniques was evaluated by a Student t-test (a=0.05). No differences could be detected among reattachment techniques when fragments were obtained by sectioning. In groups where the fragments were fractured, Techniques 3 and 4 showed the highest fracture strength recovery. The resin composite buildup provided fracture strength recovery similar to intact teeth regardless the way fragments were obtained.

SUMMARY:
This in vitro study aimed to investigate the influence of flowable composite lining with different thicknesses on the marginal quality and internal porosity of Class II composite restorations. Thirty-two intact molars, each prepared with two box-only Class II cavities, were randomly divided into four groups: Group 1, P60 filling alone; Group 2, ultrathin flowable composite lining/co-cured with overlaying composite; Group 3, thin lining/pre-cured and Group 4, thick lining/pre-cured. The teeth were then thermocycled for 1500 cycles (between 5°C and 60°C) and dye immersed for 24 hours. Exterior surface replicas of these restorations were fabricated before and after thermocycling and examined by SEM to evaluate percentages of the five mar-ginal patterns. Data was statistically evaluated using one-way ANOVA test. The teeth were subsequently sectioned longitudinally. The interface microleakage of cervical margin was measured as to the extent of dye penetration. Internal voids were separately recorded in the cervical interface and the cervical and occlusal halves of the restorations. Mann-Whitney test was applied to analyze the interface microleakage and internal voids. Results revealed that replicas of Group 4 presented the highest percentage of marginal openings both before and after thermocycling in SEM examination. Group 2 exhibited superior marginal quality in interface microleakage evaluation compared to the other groups, while Group 4 exhibited the worst. The pre-cured groups (Group 3 and 4) showed significant reduction in interface and cervical voids. Despite the reduction in interface voids, a thick lining may impair the marginal sealing, especially after thermocycling. It was concluded that a minimally thin flowable composite lining improved cavity adaptation and marginal sealing.

SUMMARY:
Manufacturers of mild self-etch adhesives advocate the adjunctive use of phosphoric acid etching when bonding to unground enamel. This study tested the null hypothesis that there is no difference between the recently introduced, more aggressive self-etch adhesives and a total-etch adhesive in bonding to unground enamel. The ultrastructure and microtensile bond strengths (µTBS) of Xeno III (Dentsply) and Simplicity (Apex Dental Materials), bonded to unground enamel, were examined after thermocycling. Clearfil SE Bond (Kuraray), a mild self-etch adhesive, was used as the negative control, and One-Step (BISCO), a total-etch adhesive bonded to phosphoric acid-etched unground enamel, was used as the positive control. Differences in the thickness of enamel hybrid layers were observed and the aggressiveness of apatite dissolution in the four adhesives.

SUMMARY:
This study compared the post-gel shrinkage of two LED (light-emitting diodes) lights (Elipar FreeLight [FL], 3M ESPE; GC e-Light [EL], GC), a high intensity (Elipar TriLight [TL], 3M ESPE) and a very high intensity (Astralis 10 [AS], Ivoclar Vivadent) halogen light to a conventional (Max [MX] (control), Dentsply-Caulk) halogen light. Ten light curing regimens were investigated. These included continuous (FL1, EL2, MX, TL1 and AS1), soft-start (FL2, EL4, TL2), pulse activation (EL1) and turbo (EL3) modes. A strain-monitoring device and test configuration was used to measure the linear polymerization shrinkage of a composite restorative (Z100, [3M ESPE]) during and post-light polymerization up to 60 minutes when cured with the different modes. Five specimens were made for each cure mode. Results were analyzed using ANOVA/Scheffe’s post-hoc test and independent sample t-tests at significance level 0.05. Shrinkage associated with the various modes of EL was significantly lower than MX immediately after light polymerization and at one-minute post-light polymerization. No significant difference between MX and the various lights/cure modes was observed at 10, 30 and 60-minutes post-light polymerization. At all time intervals, post-gel shrinkage associated with continuous light curing mode was significantly higher than the soft-start light curing mode for FL and TL.

SUMMARY:
This study evaluated the temperature rise in two different adhesive (Clearfil SE Bond [CSEB] and EBS-Multi [EBSM]) and composite systems (Clearfil AP-X [CAPX,] Pertac II [PII]) by the same manufacturer when illuminated by four different light sources: Light-emitting diode (LED), Plasma arc curing (PAC), high intensity quartz tungsten halogen (HQTH) and quartz tungsten halogen (QTH). Forty dentin disks were prepared from extracted premolars. These dentin disks were placed in apparatus developed to measure temperature rise. Temperature rise during photopolymerization of adhesive resin and resin composite was then measured. The mean values of temperature increases for adhesive and resin composites did not differ significantly (p=0.769). The highest temperature rise was observed during photopolymerization of EBSM with PAC (5.16°C) and HQTH (4.28°C), respectively. Temperature rise values produced by QTH (1.27°C – 2.83°C for adhesive resin; 1.86°C – 2.85°C for resin composite) for both adhesive and resin composites were significantly lower than those induced by PAC and HQTH (p<0.05). However, these values were significantly higher than those produced by LED (1.16°C – 2.08°C for adhesive resin; 1.13°C – 2.59°C for resin composite). Light sources with high energy output (PAC and HQTH) caused significantly higher temperature rise than sources with low energy output (QTH and LED). However, in this study, no temperature rises beneath 1-mm dentin disk exceed the critical 5.6°C value for pulpal health.

SUMMARY:
This study investigated the effects of dentin surface characteristics on bond strengths between resin and dentin. The shear bond strengths mediated by two dentin adhesive systems (Clearfil SE Bond and OptiBond Solo Plus) were evaluated. For each material, flat dentin surfaces prepared from human upper premolars were allocated to eight groups according to three characterizations; dentin location (occlusal or cervical), dentin depth (superficial or deep) and dentinal tubule orientation (perpendicular or parallel). A 0.75-mm diameter area of dentin was bonded according to each manufacturer’s instructions before placing 0.5-mm high resin composite. The bonds were stressed in shear at a crosshead speed of 1 mm/minute. The mean bond strengths were compared using ANOVA and independent t-test. No statistically significant differences were found in shear bond strengths based on dentin location. Clearfil SE Bond presented higher bond strengths to deep dentin specimens bonded perpendicular to the tubules compared to those that were bonded parallel to the tubules. Whereas, the opposite results were found for deep dentin specimens bonded with OptiBond Solo Plus. In the case of superficial dentin, there were no differences between the two materials when bond strengths were compared among the different orientations of tubule. The results indicated that shear bond strengths may be affected by dentin depth, orientation of the tubule and the bonding material used, but not by location of the dentin.

SUMMARY:
All indirect restorative techniques involving cast metals, ceramics or resin-based materials are expensive compared to directly placed restorations. A restorative technique is presented that combines the esthetic properties of directly bonded resin-based composite material and the wide range of indications for dental amalgam in stress-bearing areas.

SUMMARY:
As operative dentists, we are constantly challenged with ways to creatively restore a carious dentition. This has held true for dentistry since its inception. Today, with the advent of fluoride, it is common knowledge that the caries rate has been reduced. However, it is still not abolished. We still have the responsibility to restore teeth in order to maintain form and function.

SUMMARY:
The increased use of all-ceramic crowns and inlays has identified the need for a fit checking material that is more suitable for these types of restorations. The conventional materials are white and provide very little contrast when used with all-ceramic restorations. This makes finding areas of internal binding and interference difficult to identify. A simple technique is proposed to change the color of the existing material to make it easier to identify areas that need adjustments.

SUMMARY:
The provision of restorative dentistry in the esthetic zone requires more than an understanding of current restorative materials. With the increased emphasis on facial and dental esthetics, the restorative dentist must also understand and manage the perio-restorative interface.

SUMMARY:
This combination technique provides an atraumatic approach for the management of a difficult, deep, proximal-cervical Class V lesion with a resin-modified glass ionomer restorative material.

SUMMARY:
This device helps to reduce aluminum oxide powder in the air when sandblasting during intra-oral procedures, simulating laboratory units.

SUMMARY:
This study evaluated the histological changes in dental pulp after nightguard vital bleaching with 10% carbamide peroxide gel. Fifteen patients between 12 and 26 years of age with caries-free first premolars scheduled for orthodontic extraction were treated with 10% Opalescence (Ultradent Products, Inc). Tooth #5 had four days of bleaching, tooth #12 was treated for two weeks, tooth #21 was bleached for two weeks followed by two weeks without treatment and tooth #28, serving as the control, was without treatment. All teeth were extracted at the same time. Immediately after extraction, 4 mm of the most apical portion of the root was sectioned off and each specimen was placed in a vial containing 10% neutral buffered formalin. The samples were prepared for histological evaluation at the Scandinavian Institute of Dental Materials (NIOM) and microscopically examined independently at both NIOM and Indiana University School of Dentistry (IUSD). Pulp reactions were semi-quantitatively graded as none, slight, moderate and severe. Slight pulpal changes were detected in 16 of the 45 bleached teeth. Neither moderate nor severe reactions were observed. The findings indicate that the slight histological changes sometimes observed after bleaching tend to resolve within two weeks post-treatment. Statistical differences existed only between the untreated control and the four-day (p=0.0109) and two-week (p=0.0045) treatment groups.

The findings from this study demonstrated that nightguard vital bleaching procedures using 10% carbamide peroxide might cause initial mild, localized pulp reactions. However, the minor histological changes observed did not affect the overall health of the pulp tissue and were reversible within two weeks post-treatment. Therefore, two weeks of treatment with 10% carbamide peroxide used for nightguard vital bleaching is considered safe for dental pulp.

SUMMARY:
This study examined the hypothesis that experimental primer containing the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB), which was previously reported to show bactericidal effects in vitro, inhibits bacteria in cavities under in vivo conditions. The number of bacteria resulting from applying primer solution to cavities in dog teeth infected with Streptococcus mutans was determined. The infected cavities were also restored using primer and the pulp response was histopathologically examined after 7, 30 and 75 days. No bacteria were recovered after applying the experimental primer, although the bactericidal effects of the proprietary primer were insignificant. Restoration with the experimental primer resulted in little or no pulpal inflammation for all periods; whereas, mild to moderate inflammatory response was observed when using proprietary primer. These results indicate that the experimental primer containing MDPB could exhibit in vivo antibacterial effects, suggesting its possible clinical benefit.

SUMMARY:
A three-year randomized, controlled prospective study evaluated the clinical performance of two three-step etch & rinse adhesives (OptiBond FL, Kerr: O-FL; PermaQuick, Ultradent: PMQ) in Class V cervical erosion–abrasion lesions. The latter adhesive was also tested with two restorative composites with contrasting stiffness in order to evaluate the effect composite stiffness might have on the clinical longevity of cervical restorations. A total of 150 lesions were randomly restored in pairs of the three adhesive/composite combinations (PMQ combined with Amelogen Hybrid: PMQ/A-Hy, Ultradent; PMQ combined with Amelogen Microfill: PMQ/A-Mi, Ultradent; O-FL combined with Prodigy: O-FL/Pro, Kerr) per patient and evaluated at baseline, after six months, one year, two years and three years of clinical service. After three years, the retention rate was 100% for O-FL/Pro and 98% for both PMQ/A-Hy and PMQ/A-Mi, thereby, satisfying the “full acceptance” guidelines specified by the American Dental Association. A pairwise comparison showed no significant difference in adhesive performance between restorations made using the microfilled and hybrid composite for any evaluation criteria (p>0.05).

SUMMARY:
This study quantitatively and morphologically analyzed and clarified the longitudinal marginal changes of ceramic inlays and determined the mechanism for those changes. Epoxy replicas of 15 Class II ceramic inlays in permanent premolars prepared at baseline, 6, 12, 24, 48, 72 and 96 months after placement were selected. A CCD optical laser scanner was employed to measure quantitative changes in the occlusal surfaces of restored teeth. Longitudinal cross-sections of marginal areas of a ceramic inlay were com-puted, and two profiles of the same location obtained at different periods were superimposed using software. The area enclosed by the two profiles obtained at different periods was defined as the quantitative marginal change, and both the area and maximum depth in the area enclosed were calculated with picture analysis software. The marginal deterioration pattern was analyzed by drawing a longitudinal curve of quantitative change for each restoration. Morphological observation was carried out by scanning electron microscopy at magnifications from 20x to 75x. Quantitative measurement and morphological observation identified a sequential three-stage pattern of marginal deterioration; initial rapid progress of wear of resin composite cement in the first stage, followed by a second stage without any remarkable visible change, then rapid progression of microfractures of ceramics and/or enamel in the third stage. Boundaries between the first and second stage were found in the six and 21-month period, and those between the second and third stage at 72 months. It was concluded that longitudinal marginal deterioration of fired ceramic inlays progressed in a sequential three-stage pattern.

SUMMARY:
Whereas replacement of failed restorations is the major treatment for adults in dental practice, repair is an important alternative with the potential to save tooth structure and increase the longevity of restorations at a lower cost. This in vitro study recorded the choices of treatment for the same set of teeth with defective Class II amalgam restorations by students and faculty at two dental schools (University of Manchester, UK and University of Florida, USA). Treatment options (monitor, refurbish, repair and replace) and reason(s) for the choice of treatment for 24 marked amalgam restorations were selected.

Overall, participants more frequently chose replacement of restorations; whereas, repair was the least favored option. The reasons cited the most to replace restorations were secondary caries including unsightly appearance, partially lost restoration and tooth fracture; for repair, the major reasons included loss of part of the restoration and marginal ditching; and for refurbishment, the major reasons included poor anatomic form and marginal ditching. There was a significant difference between the students and faculties at the two sites in their choice of treatment (p<0.0001; Chi-square test). The treatment decision to “monitor” the restorations was more frequent for the Manchester site than the Florida site. Conversely, the combined treatment decisions to “refurbish, repair and replace” were more frequently chosen in Florida than in Manchester.

SUMMARY:
This study evaluated the effects of home bleaching agents on the surface roughness of composite restoratives. Two home bleaching gels (10% and 15% carbamide peroxide, Opalescence) and five different tooth-colored restorative materials from the same manufacturer (3M-ESPE) were selected. They included microfill (Filtek A110 [FO]), flowable (Filtek Flow [FF]), polyacid-acid modified (F2000 [FT]) and minifill (Z100 [ZO]; Filtek Z250 [ZT]) composites. Thirty-six specimens of each material were fabricated, randomly divided into three groups (n=12) and treated as follows: Group 1—Stored in distilled water, Group 2—Bleached with 10% carbamide peroxide (CP) eight hours/day; Group 3—Bleached with 15% CP eight hours/day. All treatment was conducted at 37°C and fresh gel applied and rinsed off daily for eight weeks. For the bleached groups, the specimens were stored in distilled water at 37°C during the hiatus periods. All the specimens were subjected to roughness testing (Ra) at weeks 0, 1, 2, 4, 6 and 8 using a profilometer. The results were analyzed using general linear model with Scheffe’s post-hoc tests at significance level 0.05. The results showed that the effect of bleaching on surface roughness was material and time dependent. ZT was not affected by bleaching treatment, while FT was significantly roughened after one week of bleaching with 15% CP compared to the control group. FO, FF and ZO were not significantly roughened until eight weeks of bleaching. Repolishing or replacement of tooth-colored restorations may be required after bleaching procedures.

SUMMARY:
Posts and cores are used to restore endodontically treated teeth that have substantial loss of the coronal tooth structure. This in vitro study was designed to determine the mechanical properties of prefabricated titanium posts following attachment of their metal cores by molten casting (cast-on). Prefabricated tapered titanium posts (ER post-restoring system, Komet, Lemgo, Germany) in three diameter sizes (ISO 50, 90, 110) (n=9) were cast over with the metal cores of three different alloys (Au-Ag-Pt, Au-Pt-Pd, Co-Cr-Mo). Also, posts of each size were precision fit into the central core channels of the different cast metal cores to serve as control specimens. The 0.2% yield strengths (R0.2) of all specimens were tested on a universal testing machine. Statistical analyses of the results were carried out with an analysis of variance (ANOVA, one-way, two-way) and Bonferroni-Dunn’s multiple comparisons post-hoc analysis for test groups (a=0.05). There was a significant decrease in yield strength (p<0.05) as a result of casting the various metals over the different post sizes, considered to be due to the detrimental thickening and porosity formation of the titanium surface oxide layer. Twenty-one percent, 51% and 33% reduction in yield strength, respectively, was obtained for the ISO 50, ISO 90 and ISO 110 cast-on groups relative to controls (p<0.05). Statistically significant differences in various core alloys were found only for the Au-Ag-Pt alloy compared to the Co-Cr-Mo alloy (post size ISO 50) and the Au-Pt-Pd alloy compared to the Co-Cr-Mo alloy (post size ISO 110) (p>0.05). Prefabricated titanium posts with metal cores cast over them showed inferior mechanical properties compared to precision-fit posts. These results indicate greater strength of the titanium posts when their cast cores were attached mechanically rather than by the molten casting method.

SUMMARY:
This study investigated the influence of curing lights and modes on the cross-link density of dental composites. Four LED/halogen curing lights (LED–Elipar Freelight [FL], 3M-ESPE and GC e-light [EL], GC; high intensity halogen–Elipar Trilight [TL], 3M-ESPE; very high intensity halogen–Astralis 10 [AS], Ivoclar Vivadent) were selected for this study. Pulse (EL1), continuous (FL1, EL2, TL1), turbo (EL3, AS) and soft-start (FL2, EL4, TL2) curing modes of the various lights were examined. A conventional, continuous cure halogen light (Max [MX], Dentsply-Caulk) was used for comparison. Six composite (Z100, 3M-ESPE) specimens were made for each light-curing mode combination. After polymerization, the specimens were stored in air at 37°C for 24 hours and subjected to hardness testing using a digital microhardness tester (load=500g; dwell time=15 seconds). The specimens were then placed in 75% ethanol-water solution at 37°C for 24 hours and post-conditioning hardness was determined. Mean hardness (HK)/change in hardness (DHK) was computed and the data subjected to analysis using one-way ANOVA/Scheffe’s test and Independent Samples t-test (p<0.05). Softening upon storage in ethanol (DHK) was used as a relative indication of cross-link density. Specimens polymerized with AS, TL2 and all modes of both LED lights were significantly more susceptible to softening in ethanol than specimens cured with MX. No significant difference in cross-link density was observed among the various modes of EL and FL. For TL, curing with continuous mode resulted in specimens with significantly higher cross-link density than curing with the soft-start mode.

SUMMARY:
Simple changes to bonding techniques can improve resin-dentin bond strengths. This study evaluated the effect of multiple consecutive coatings of adhesive resin on dentin by measuring both microtensile bond strength and nanoleakage following exposure to ammoniacal silver nitrate. Resin-dentin bonded specimens were prepared using two total-etch adhesives (OptiBond Solo Plus/Kerr or Single Bond/3M ESPE). During bonding, resin application and air evaporation were done 1, 2, 3, 4, 6 or 8 times on acid-etched, moist dentin surfaces. Mean microtensile bond strengths were evaluated by two-way ANOVA and Fisher’s PLSD test (p<0.05; n=16 for each group). Additionally, nanoleakage of silver nitrate was evaluated by transmission electron microscopy (TEM). The results indicated that bond strengths increased with each coating up to four coats. Nanoleakage decreased with each coat, becoming very small after four or more coats. This adhesive application method can be easily applied to clinical practice, thereby improving the quality of resin-dentin bonds.

SUMMARY:
This study compared the shear bond strength (SBS) to enamel of five self-etching primer/adhesive systems and one total-etch, one-bottle adhesive system. Sixty freshly extracted bovine incisors were mounted, polished to 600-grit and randomly assigned to six groups (n=10): Adper Prompt Self-Etch (AD), OptiBond Solo Plus Self-Etch (OP), AdheSE (AS), Tyrian (TY) and Clearfil SE Bond (SE) as self-etching systems; and Single Bond (SB) as a total-etch system (control). The respective hybrid composite was applied in a #5 gelatin capsule and light-cured. After 500 thermal cycles (5°C-55°C), the specimens were loaded in shear using an Instron at 5 mm/minute. Mean bond strengths were analyzed with one-way ANOVA, followed by a Duncan’s post-hoc test (p 0.05). SBS (mean ± SD) were: AD=13.0(±2.5); OP=5.6(±2.3); AS=12.6(±3.7); TY=7.6(±2.6); SE=17.6(±4.5) and SB=17.9(±4.4). ANOVA showed a significant difference at p<0.0001. Duncan’s post-hoc test ranked this difference in three homogeneous subsets. Only SE showed similar enamel SBS compared to the total-etch system tested (SB). AD and AS were ranked in the intermediary Duncan’s subset, while TY and OP resulted in the lowest SBS. SBS to enamel with self-etching primers may depend on its specific composition.

SUMMARY:
This study quantitatively assessed the amount of microleakage on Class V cavities prepared by Er:YAG laser and high-speed handpiece, varying the surface treatment and restoring with a resin-modified glass ionomer cement. Fifty cavities were prepared using either an Er:YAG laser device or a carbide bur at high speed. The surface treatment was performed as follows: Er:YAG laser irradiation (G1); 40% polyacrylic acid (G2); laser + acid (G3); finishing with low speed + laser + acid (G4); conventional bur preparation + acid (G5–control). The samples were restored with Fuji II LC, thermocycled, isolated and immersed in a 50% AgNO3 solution. The restorations were serially sectioned and the extent of dye penetration was measured in millimeters using specific computer software. Data were analyzed by two-way ANOVA and Tukey test. The lowest degree of microleakage was observed for G5, which was statistically similar (p>0.05) to G4 but different (p<0.05) from all the other experiental groups. Lesser microleakage was observed at the occlusal margins than at the cervical margins (p<0.05). It may be concluded that the use of Er:YAG laser for cavity preparation and surface treatment negatively affected the marginal sealing of resin-modified glass ionomer restorations.

SUMMARY:
This study evaluated the influence of salivary contamination during dentin bonding procedures on shear bond strength and investigated the effect of contaminant-removing treatments on the recovery of bond strength for two dentin bonding agents.

One hundred and ten human molars were embedded in cylindrical molds with self-curing acrylic resin. The occlusal dentin surface was exposed by wet grinding with #800 silicon carbide abrasive paper. The teeth were divided into five groups for One-step (OS) (BISCO, Inc) and six groups for Clearfil SE Bond (SE) (Kuraray Co, Ltd, Osaka, Japan). For One-step, the grinding surface was treated with 32% phosphoric acid; BAC (BISCO Inc) and divided into five groups: OS control group (uncontaminated), OS I (salivary contamination, blot dried), OS II (salivary contamination, completely dried), OS III (salivary contamination, wash and blot dried) and OS IV (salivary contamination, re-etching for 10 seconds, wash and blot dried). For SE bond, the following surface treatments were done: SE control group (primer applied to the fresh dentin surface), SE I (after salivary contamination, primer applied), SE II (primer, salivary contamination, dried), SE III (primer, salivary contamination, wash and dried), SE IV (after procedure of SE II, re-application of primer) and SE V (after procedure of SE III, re-application of primer).

Each bonding agent was applied and light cured for 10 seconds. Clearfil AP-X (Kuraray Co, Ltd) composite was packed into the Ultradent mount jig mold and light cured for 40 seconds. The bonded specimens were stored for 24 hours in a 37°C waterbath. The shear bond strengths were measured using an Instron testing machine (Model 4202, Instron Corp).

The data for each group were subjected to one-way ANOVA followed by the Newman-Keuls test to make comparisons among the groups.

The results were as follows:

• In the One-step groups, the OS II group showed statistically significant lower shear bond strength than the OS control, I, III and IV (p<0.05).

• In the Clearfil SE Bond groups, the SE II and SE III groups had decreased shear bond strength compared with the control and SE I, SE IV and SE V groups (p<0.05).

In conclusion, when using One-step total etch adhesive and when the etched surface is contaminated by saliva, blotting the surface and applying the primer can recover the bond strength. Complete drying of the salivary contaminated surface should be avoided. In the Clearfil SE Bond groups, the re-priming treatment (SE IV and SE V) resulted in the recovery of shear bond strength in the specimens contaminated after priming.

SUMMARY:
This study investigated the influence of curing lights and modes on the elution of leachable components from dental composites. Four LED/halogen curing lights (LED–Elipar Freelight [FL], 3M-ESPE and GC e-light [EL], GC; high intensity halogen–Elipar Trilight [TL], 3M-ESPE; very high intensity halogen–Astralis 10 [AS], Ivoclar Vivadent) were selected for this study. Pulse (EL1), continuous (FL1, EL2, TL1), turbo (EL3, AS) and soft-start (FL2, EL4, TL2) curing modes of the various lights were examined. A conventional continuous cure halogen light (Max [MX], Dentsply-Caulk) was used for comparison. Three composite (Z100, 3M-ESPE) specimens (6.5 mm in diameter and 1-mm thick) were made for each curing light-mode combination. After polymerization, the specimens were stored in air at 37°C for 24 hours and incubated in acetonitrile at 37°C for 24 hours. BisGMA and TEGDMA extracts were isolated by high performance liquid chromatog-raphy (HPLC). Data were subjected to analysis using one-way ANOVA/Scheffe’s post-hoc test and Independent Samples t-test at significance level 0.05. The total monomer (BisGMA and TEGDMA) eluted ranged from 8.75 to 27.97 ppm for FL1 and AS, respectively. Significantly more unreacted monomers were leached from composites cured with all modes of EL and AS when compared to MX. No significant difference in the total monomer eluted was observed between the two modes of FL/TL and MX. Although composites cured with EL2 released significantly less monomer than EL1, 3 and 4, no significant difference in the total monomer eluted was observed between the continuous and soft-start modes of FL and TL. The elution of leachable components from composites appears to be curing light specific rather than light source (LED or halogen) and curing mode specific.

SUMMARY:
This study determined the caries-protective effects of two different dentin bonding systems (Syntac, Scotchbond) on sound and irradiated root surfaces in vitro. The root surfaces of 30 freshly extracted caries-free human molars were used. The teeth were bisected in the mesio-distal direction and all lingual halves of the teeth were irradiated. The irradiation dose of 60 Gy was fractionally applied over six weeks (2 Gy/day, 5d/wk). All halves were then coated with acid-resistant nail varnish, exposing two rectangular windows 6 mm2 each on the dentinal root surface. One window served as an untreated control, while the other was treated with one of the above mentioned dentin adhesive systems. The specimens were randomly distributed among the four experimental groups as follow: Group A: Syntac, non-irradiated; Group AR: Syntac, irradiated; Group B: Scotchbond, non-irradiated; Group BR: Scotchbond, irradiated. Subsequently, all specimens were demineralized for 14 days with acidified gel (HEC, pH 4.8, 37°C). From each window, two dentinal slabs were cut. The slabs were ground to a thickness of 80 µm and submerged in water. The depth of the lesions was determined using a polarized light microscope. The non-irradiated control specimens showed lesions with an average depth of 63 µm (+/-10,2 µm). In the case of the irradiated control specimen, the lesion depth was not significantly different. In all experimental groups, the lesion depth was significantly reduced compared to the control groups. Statistical analysis revealed no significant differences between the irradiated and non-irradiated specimens. It can be concluded that demineralization of the root surface can be hampered by application of the dentin adhesive systems tested. In this study, no differences between irradiated and sound root surfaces could be detected.

SUMMARY:
This study evaluated the effects of various cavity configurations on the bond strength, microleakage, flexural strength and elastic modulus of a hybrid (Clearfil AP-X) and a microhybrid (Esthet-X) composite restorative. After the specimens were made with C-factors of less than 1, 2.4 and 3.4, flexural strength and elastic modulus were evaluated in three-point bending using a mechanical testing machine. Fragments of the fractured specimens were selected randomly and the fracture surfaces were examined in SEM. To evaluate the microtensile bond strength and microleakage of composite restorations in bovine cavities, C-factors (ratio of bonded to non-bonded cavity surface) were controlled as 1.0, 2.3, 3.0 and 3.7. All specimens were stored in distilled water at 37°C for 24 hours and tested in a universal testing machine (EZ Test, Shimadzu, Japan). For the microleakage test, teeth with restorations were stained with silver nitrate and examined by two examiners under a stereomicroscope at 40x magnification.

The hybrid composite showed higher mechanical properties than the microhybrid composite. The flexural strength and elastic modulus of both composites decreased when polymerized under greater constraint, that is, with increasing C-factor. Mean microtensile bond strength to dentin was also decreased with increasing C-factor for both types of composites. Microleakage scores for the hybrid composite restorations were generally higher than the microhybrid composite.

SUMMARY:
Since the importance of luting cement on secondary caries in enamel and dentin is unknown, an in situ crossover study was conducted in three phases over 21 days using a fluoride-containing toothpaste. One hundred and twenty-six metallic restorations were cemented into the dentinoenamel junction of slabs of human teeth with zinc phosphate (ZP), resin-modified glass ionomer (GI) or resinous cement (RC). The slabs were inserted onto flanges of the removable partial acrylic dentures of 14 volunteers and covered with gauze to enhance dental plaque accumulation. The volunteers used fluoride toothpaste (1.100 µg F/g, w/w). After 21 days, the biofilm that formed on the slabs was collected for biochemical and microbiological analyses, and the demineralization in enamel-dentin around the restorations was evaluated. The fluoride concentration of biofilm in the GI group was higher (p<0.05) than the ZP and RC groups. Also, the concentration of Zinc in biofilm formed on the slabs cemented with ZP was higher (p<0.05) than the other groups. However, the effect of the luting material on enamel or dentin demineralization was not statistically significant (p>0.05). The data suggest that when fluoride toothpaste is used, the anticariogenic property of the luting cement may not be relevant to the reduction of secondary caries.

SUMMARY:
This study evaluated the clinical performance of a polyacid-modified resin composite, Dyract AP (De Trey/Dentsply), under different conditioning methods in primary teeth. Eighty-one box-shaped cavity preparations (three restorations per patient) on the mesial or distal surfaces of primary first or second molars were prepared in 27 patients. The cavity preparations were either non pre-treated or pre-treated with 36% phosphoric acid or NRC (De Trey/Dentsply). The teeth were restored with Prime & Bond NT (De Trey/Dentsply) and Dyract AP. The restorations were evaluated at baseline and 6, 12 and 18-month recalls according to the modified Ryge criteria by two calibrated operators. The data obtained from the clinical assessment of all restorations were subjected to statistical analysis by chi-square-tests at a 0.05 level of significance. The ratings of each criteria were compared among each evaluation period between treatment groups. Statistical analysis revealed no significant difference among each evaluation period between groups in regard to color match, marginal discoloration, marginal adaptation, secondary caries, surface texture, anatomic form and retention.

SUMMARY:
The anti-cariogenic properties of three fluoride-releasing materials on root surfaces were evaluated using two different caries models. Standardized cavities were prepared in dentin specimens and restored with either glass-ionomer, resin-modified glass-ionomer, polyacid-modified resin composite or resin composite material. Two groups of 56 specimens were demineralized using a microbial caries model for three days, while another 56 specimens were demineralized using a chemical demineralization model for three days. Lesions around the restorations were measured with a confocal laser-scanning microscope. Glass ionomers demonstrated significant anti-cariogenic properties when exposed to the chemical model. However, no significant anti-cariogenic properties were observed with the microbial caries model. In conclusion, the fluoride releasing materials showed different anti-cariogenic properties in root surfaces under the different caries models, suggesting that caution should be exercised when trying to extrapolate the results of in vitro studies to the clinical situation.

SUMMARY:
This study determined the influence of interchanging adhesive resins and self-etching primers on the mechanical properties of adhesive resins. Four commercially available two-step self-etching primer systems were used. To measure microtensile strength, 0.5-mm thick dumbbell-shaped slabs of each combination of adhesive resin and self-etching primer were prepared. After 24 hours storage in 37°C distilled water, these specimens were subjected to microtensile testing at a crosshead speed of 1.0 mm/minute. Fourier transformation infrared spectroscopy was used to determine the degree of conversion. The percentage of residual double bonds, including pendant and monomeric double bonds, was calculated by comparing the obtained ratio against uncured adhesive resin. The degree of conversion of the adhesive resins was obtained by subtracting the %C=C from 100%. Two-way ANOVAs, followed by Tukey tests, were done. The microtensile strengths and degree of conversion varied with different combinations of self-etching primer and adhesive resin. Numerically, the highest microtensile strengths were obtained when the primer/adhesive resin combinations from the same manufacturer were used. When the different combinations of self-etching primers and adhesive resins were mixed, the microtensile strength and degree of conversion of the adhesive resins tended to decrease for some combinations. Within the limitations of this study, which was far removed from clinical situations, the role of the self-etching primers on the mechanical properties of adhesive resins should be considered to create an authentic resin-dentin interface.

SUMMARY:
This study evaluated the immunohistochemical labeling pattern of dentin collagen fibrils within hybrid layers created by different bonding systems using high resolution SEM.

Four different adhesive materials, including self-etching and total-etching systems, were examined: Prime & Bond NT, OptiBond SOLO Plus, Single Bond and Clearfil Protect Bond. All materials were applied to the dentin of extracted human third molars. After cutting the bonded specimens transversely, an anti-collagen type I antibody was incubated on the surface of the dentin-adhesive interface and gold-conjugated secondary antibody was applied to reveal collagen labeling under high resolution SEM.

The hybrid layers showed a significant number of collagen fibrils embedded in the resin matrix. The presence of exposed dentin collagen fibrils, as determined by positive labeling with an anti-type I collagen monoclonal antibody, is considered an indication of the presence of incompletely embedded fibrils and, thus, the quality of dentin matrix hybridization. The hybrid layers produced by total-etching systems showed higher labeling compared to those produced by the self-etching system. Positive collagen labeling was also found along the resin tags produced by total-etching adhesive systems.

SUMMARY:
This study investigated the effects of aging on the hardness and modulus of two composites (Tetric Ceram [TC], Vivadent; Esthet X [EX], Dentsply), a conventional (Compoglass [CG], Vivadent) and a posterior compomer (Dyract Posterior [DP], Dentsply) using a depth-sensing microindentation approach. Seven specimens (3-mm wide x 3-mm long x 2-mm deep) of each material were made and conditioned in distilled water at 37°C. Hardness and modulus of the materials were determined at seven and 30 days using depth-sensing microindentation testing with the Instron MicroTester. Hardness was determined by dividing the peak load over the maximum projected contact area while effective modulus was calculated by analysis of the loading/unloading P-h curves and the analytical model according to Oliver and Pharr (1992). Results were analyzed using one-way ANOVA/Scheffe’s post-hoc test and Independent Samples t-test at significance level 0.05. Mean Vickers Hardness (HV) ranged from 46.60 to 58.67 and 44.44 to 59.41 at seven and 30 days, respectively. Mean indentation modulus ranged from 9.57 to 9.95 and 9.19 to 10.03 for the same time periods. At both time periods, EX was significantly harder than all the other materials and HV values for TC were significantly greater than CG. No significant difference in hardness and modulus was observed between seven and 30 days for all materials with the exception of CG. For the latter, a significant decrease in mechanical properties was detected over time.

SUMMARY:
Resin composites are considered susceptible to environmental conditions that might affect bond strength. This study investigated the influence of relative humidity and temperature on the dentin bond strength of newly developed one-application adhesive systems. Bonding systems employed in this study were five commercial one-application adhesive systems. Labial surfaces of bovine incisors were ground wet on 600-grit SiC paper. The teeth were transferred to a controlled temperature and humidity chamber and the specimens were prepared in six different environmental conditions, A) 25 ± 0.5°C, 50 ± 5% RH, B) 25 ± 0.5°C, 80 ± 5% RH, C) 25 ± 0.5°C, 95 ± 5% RH, D) 37 ± 0.5°C, 50 ± 5% RH, E) 37 ± 0.5°C, 80 ± 5% RH, F) 37 ± 0.5°C, 95 ± 5% RH. The dentin surfaces were treated according to each manufacturer’s instructions. Resin composites of each bonding system were condensed into a mold and light irradiated. After storage in 37°C water for 24 hours, 10 specimens per group were tested in a shear mode in a testing machine at a crosshead speed of 1.0 mm/minute. Statistical analysis was carried out with one-way ANOVA followed by Duncan’s multiple range tests at a p-value of 0.05. The dentin bond strengths of one-application adhesive systems decreased with increasing RH. These data suggest that the relative high humidity in the oral environment needs consideration in developing clinical procedures for management of these one-application adhesive systems.

SUMMARY:
The influence of three different cavity preparations on the marginal integrity of partial ceramic crowns (PCC) luted with four different luting systems was investigated in this in vitro study. PCC preparations were performed in 144 extracted human molars using one of the following preparation designs (n=48/preparation): A–Coverage of functional cusps/butt joint preparation; B–horizontal reduction of functional cusps and C–complete reduction of functional cusps/butt joint preparation. Non-functional cusps were not covered; mesial and distal proximal boxes were extended 1 mm below the cemento-enamel-junction. PCC were fabricated from Vita Mark II ceramic (Vita) with a Cerec 3 Unit (Sirona) and adhesively luted to the cavities using the following luting systems: (VL) Variolink II/Excite (Vivadent), (PA) Panavia F/ED Primer (Kuraray), (DY) Dyract/Prime & Bond NT (DeTrey/Dentsply) and (FU) Fuji Plus/GC Cavity Conditioner (GC). Samples were simultaneously exposed to thermocycling and mechanical loading (TC: 5000x8-55°C, 30 seconds/cycle; ML: 500000x72.5N, 1.6Hz). Marginal adaptation was assessed by evaluating dye penetration on multiple sections by relating the actual penetration distance to the maximal length of the corresponding cavity wall (100%). Ceramic- and tooth-luting material interfaces were evaluated separately. The data were statistically analyzed with the Mann Whitney U-test and Wilcoxon Rank Sum test.

In general, no significant differences could be found between preparations A, B and C. The combination of preparation C and luting material PA showed a tendency for the lowest dye penetration values, especially within dentin (30%). Significant differences could be determined between luting materials: Composite luting materials PA (0%) and VL (1%) revealed less dye penetration than the compomer DY (6%) and resin-modified glass ionomer cement (RMGIC) FU (26%); use of RMGIC caused fractures of the restorations. The dentin/luting material interface showed the highest penetration values, ranging from 17% to 100%.

In conclusion, with adhesively bonded partial ceramic crowns, the choice of luting material proved to be more relevant than preparation design under the limitations of this study. Margins below the cemento-enamel junction reveal significant loss of adhesion in spite of subsequent application of adhesive luting techniques. RMGIC cannot be recommended as a luting material for feldspathic PCC.

SUMMARY:
This study determined the degree of conversion of two LED (light-emitting diodes) (Elipar FreeLight [FL], 3M ESPE; GC e-Light [EL], GC), a high intensity (Elipar TriLight [TL], 3M ESPE) and a very high intensity (Astralis 10 [AS], Ivoclar Vivadent) halogen light. The degree of conversion of these lights was compared to a conventional halogen light (Max [MX] (control), Dentsply-Caulk). Ten different light curing regimens, including pulse (EL1), continuous (FL1, EL2, TL1), turbo (EL3, AS1) and soft-start (FL2, EL4, TL2) modes of various lights were also investigated. Composite specimens of dimensions 3 x 3 x 2 mm were cured with the 10 different light curing regimens investigated. Micro-Raman spectroscopy was used to determine the degree of conversion at the top and bottom surfaces of a composite restorative (Z100, [3M ESPE]) at 60 minutes post-light polymerization. Five specimens were made for each cure mode. The results were analyzed using ANOVA/Scheffe’s post-hoc test and Independent Samples t-tests at significance level 0.05. The degree of conversion ranged from 55.98 ± 2.50 to 59.00 ± 2.76% for the top surface and 51.90 ± 3.36 to 57.28 ± 1.56% for the bottom surface. No significant difference in degree of conversion was observed for the 10 light curing regimens when compared to MX (control). The curing efficiency of LED lights was comparable to halogen lights regardless of curing modes.

SUMMARY:
This study compared the demineralization inhibition properties of fluoride releasing tooth-colored restorative materials. Materials evaluated included a giomer (Reactmer, Shofu [RM]), a conventional glass ionomer (Fuji II, GC [FJ]), a resin modified glass ionomer (Fuji II LC, GC [FL]) and a compomer (Dyract AP, Dentsply [DY]). A non-fluoride releasing composite (Spectrum TPH, Dentsply [SP]) was used for comparison. Class V preparations on buccal and palatal/lingual were made at the CEJ of 75 freshly extracted molars. The teeth were randomly divided into five groups of 15 and restored with the various materials. The occlusal half of each restoration was in enamel, while the gingival half was in dentin. The restored teeth were stored in distilled water at 37°C for two weeks and subjected to artificial caries challenge (18 hours demineralization [pH 5.0] followed by six hours of remineralization [pH 7.0]) for three days. Sections of 130 ± 20 µm were examined with a polarized light microscope, and outer lesion depth [OLD] and wall area [WA] lesion/inhibition measurements were made using image analysis software. All data were subjected to statistical analyses at 0.05 significance level. For the various materials, OLD ranged from 54.55 to 65.86 µm and 124.68 to 145.97 µm in enamel and dentin, respectively. WA ranged from -2356.13 to 1398.20 µm2 and -3011.73 to 5095.80 µm2 (positive values indicate wall inhibition, negative values indicate wall lesion) in enamel and dentin, respectively. Results of ANOVA/Scheffe’s post-hoc test (p<0.05) were as follows: Enamel OLD—no significant difference between materials; Dentin OLD—SP > FJ, FL & RM; Enamel WA inhibition—FJ, FL & RM > DY & SP and Dentin WA inhibition—FJ > FL > RM > DY > SP. The demineralization inhibition effect of giomers, conventional and resin-modified glass ionomer cements appear to be more evident at the margins of restorations.

SUMMARY:
This study determined the effect of pH on the surface texture of commonly used posterior glass-ionomer based/containing restorative materials. The materials evaluated included a compomer (Dyract AP), a giomer (Beautifil) and two highly viscous glass ionomer cements (Fuji IX and Ketac Molar). A resin composite (Esthet-X) was used for comparison. Forty-two specimens (3-mm wide x 3-mm long x 2-mm deep) were made for each material. The specimens were divided into six groups and conditioned in the following solutions at 37°C for one week: Citric acid (pH 2, 3, 4, 5 and 6) and distilled water (pH 7). After conditioning, the surface roughness (Ra, µm) of each specimen was measured using a surface profilometer (Surftest, Mitutoyo Corp, Tokyo, Japan). Data was analyzed using one-way ANOVA and Scheffe’s test at a significance level of 0.05. The effects of pH on the surface texture of glass-ionomer based/containing restoratives were material dependent. Ra values ranged from 0.02 µm to 0.15 µm and 0.03 µm to 4.40 µm for pH 7 and 2, respectively. With the exception of the composite, the surface roughness of all materials evaluated was significantly affected by acids of low pH. The surface texture of highly viscous glass ionomer cements deteriorated significantly when conditioned in solutions of low pH, which makes them more susceptible to clinical failure.

SUMMARY:
This study evaluated the influence of (1) different dentin treatments and (2) storage time on dentin shear bond strengths. Two hundred and twenty-five bovine incisors were collected, ground to expose a flat dentin surface and randomly divided into three groups according to dentin surface treatment: (1) Total etch + Single Bond; (2) Total etch + collagen depletion with 10% NaOCl + Single Bond and (3) No etch + experimental self-etching adhesive. Composite was applied to the treated surfaces using a 3 x 5-mm cylindrical Teflon matrix and was light-cured. Each group was further stratified in five subgroups according to storage time in water at 37°C: 1 day, 7 days, 30 days, 6 months and 12 months. Shear bond strengths (SBS) were determined and expressed in MPa. Data was analyzed for statistical significance with two-way ANOVA and Tukey’s test (p=0.05). No interaction was observed between surface treatment and storage time. Storage time did not significantly affect bond strengths. Statistically significant differences were observed among the different surface treatments. Single Bond applied after total-etch presented higher mean SBS when compared to the other surface treatment methods. Collagen removal negatively influenced SBS, and the experimental self-etching adhesive presented intermediate values.

SUMMARY:
This paper reports on the results of a retrospective observational study that sought to determine both the longevity and effects of surface treatments of gold palatal veneers used to restore tooth surface loss. Details of all gold palatal veneers fabricated from Mattident 60 were sourced from hospital records spanning 11 years and 9 months. The case notes of each individual were accessed and, for each restoration, a note was made of the date and method of cementation, together with the period of patient follow-up. When patients continued their routine check-ups, the records were scrutinized closely for evidence of restoration failure. This yielded a data set of 151 palatal gold veneer cementations for which the surface treatments and/or cementing media were known. Survival analysis by the Kaplan-Meier method of alumina blasted veneers revealed median survival times of 4,663 days when cemented with Panavia 21 and 687 days if cemented with Aquacem. Veneers that were alumina blasted, oxidized and cemented with Panavia 21 had a survival probability of 1.0. A Logrank test revealed highly statistically significant differences between the survival curves (p<0.0001). It was concluded that: (1) Alumina blasting the fit surface of a gold veneer prior to cementation with Panavia 21 resulted in a significantly more durable restoration compared to alumina blasting and cementation with Aquacem and no etching of tooth substance. (2) Due to low MST cementing, gold palatal veneers with a conventional glass polyalkenoate cement are not recommended. (3) Pre-treatment of gold palatal veneers by alumina blasting and oxidation prior to cementing with Panavia 21 appears to improve the chances of obtaining a dependable restoration. A greater number of restorations would be required to statistically test this trend.

SUMMARY:
The natural history of posterior teeth treated with a four or more surface amalgam restoration (LA) or a large amalgam restoration and a full-coverage crown (LAC) were compared over five- and 10-year periods. Subsequent treatment information was used to construct Treatment Outcome Trees (TOT), which described treatment that the teeth received after placement of LA and LAC restorations. Data were collected for all treatments provided to patients who received a four or five surface LA in 1987 or 1988 at the University of Iowa, College of Dentistry (UICD). The probability that these teeth would receive subsequent treatment and the type of subsequent treatment were placed into a TOT.

In general, a higher percent of teeth with an LA received subsequent treatment and were more likely to receive major treatment (root canals, extractions, crowns) five years post placement than teeth with an LAC. Between five and 10 years, this trend continued, with the percentage of teeth with an LA receiving subsequent treatment increasing more (48% to 64%) than teeth with an LAC (12% to 22%). Regardless of the initial restoration type (LA/LAC), women were less likely to receive subsequent treatment and major treatment compared to men. The use of a TOT was found to be an effective observational approach for evaluating the natural history of teeth with alternative restorative treatment.

SUMMARY:
Bleaching offers a non-interventive way of improving the appearance of sound, yet discolored anterior teeth. Until recently, the whitening agent was applied using a tray, but now other methods of delivering whitening agents, such as those using brush applicators, are available. This study investigated the tooth whitening efficacy of two novel, self-applied tooth whitening systems containing either 18% (Group 1) or 16.4% (Group 2) carbamide peroxide. Ninety-five subjects, ranging in age from 18 to 70 with anterior teeth A3 or darker, were recruited and randomly allocated to a group. The subjects were instructed to apply the formulation to all maxillary anterior teeth after brushing in the morning and evening. At baseline, two weeks and six months the upper six anterior teeth of the subjects were measured using the Vita shade guide tab system. In addition, the gingival health of the labial surfaces of the upper six anterior teeth was assessed using the Loee and Silness Gingival index (Loee & Silness, 1963) at baseline and at two weeks. The mean (SD) reduction in shade guide scores was 4.1 (2.4) shade guide tabs for subjects in Group 1, compared to 3.7 (2.6) shades for those in Group 2. This difference was not statistically significant (p=0.5). During the course of study, the gingivitis scores reduced from a mean (SD) of 0.91 (0.62) at baseline to 0.44 (0.55) at final examination (48% reduction). At the six-month recall, the mean (SD) reduction in shade guide scores was 2.3 (2.7) shade guide tabs for subjects in Group 1, compared to 2.5 (2.5) shades for those in Group 2. The different concentrations tested were found to be equally effective in improving the whiteness of upper anterior teeth by approximately four shades over a two-week period and the majority of the whitening benefit (c.60%) was sustained at six-month recall.

SUMMARY:
This study compared the efficacy of using conventional low-power density QTH (LQTH) units, high-power density QTH (HQTH) units, argon (Ar) laser and Plasma arc curing (PAC) units for curing dual-cured resin cements and restorative resin composites under a pre-cured resin composite overlay.

The microhardness of the two types of restorative resins (Z100 and Tetric Ceram) and a dual-cured resin cement (Variolink II) were measured after they were light cured for 60 seconds in a 2 mm Teflon mold. The recorded microhardness was determined to be the optimum microhardness (OM).

Either one of the two types of restorative resins (Z100, Tetric Ceram) or the dual cured resin cement (Variolink II) were placed under a 1.5-mm thick and 8 mm diameter pre-cured Targis (Vivadent/Ivoclar AG, Schaan, Liechtenstein) overlay. The specimens that were prepared for each material were divided into four groups depending upon the curing units used (HQTH, PAC, Laser or LQTH) and were further subdivided into subgroups according to light curing time. The curing times used were 30, 60, 90 and 120 seconds for HQTH; 12, 24, 36 and 48 seconds for the PAC unit; 15, 30, 45 and 60 for the Laser and 60, 120 or 180 seconds for the LQTH unit. Fifteen specimens were assigned to each subgroup. The microhardness of the upper and lower composite surfaces under the Targis overlay were measured using an Optidur Vickers hardness-measuring instrument (Göttfert Feinwerktechnik GmbH, Buchen, Germany). In each material, for each group, a three-way ANOVA with Tukey was used at the 0.05 level of significance to compare the microhardnesses of the upper and lower composite surfaces and the previously measured OM of the material. From the OM of each material, 80% OM was calculated and the time required for the microhardness of the upper and lower surface of the specimen to reach 100% and 80% of OM was determined.

In Z100 and Tetric Ceram, when the composites were light cured for 120 seconds using the HQTH lamp, microhardnesses of the upper and lower surfaces reached OM. When they were cured with the PAC unit, only 48 seconds was needed for the upper and lower surfaces to reach OM. When they were cured using the laser, the lower surface did not reach OM in any of the groups. When the specimens were cured using the LQTH lamp, 180 seconds of curing was needed for Z100 to reach OM, whereas Tetric Ceram did not reach OM. In Z100, 60, 12, 30 and 60 seconds were needed in HQTH, PAC, Laser and LQTH, respectively, for the specimens to reach 80% OM. Tetric Ceram was needed 60, 24, 45 and 180 seconds to reach 80% OM.

In the Variolink II specimen, microhardness of the upper and lower surfaces did not reach OM even though they were light cured with the HQTH lamp for 120 seconds. When they were cured with the PAC unit, 48 seconds was insufficient for them to reach OM. When they were cured with laser for 45 and 60 seconds, microhardness reached OM on the upper surface but not on the lower surface. However, when they were cured using the LQTH lamp, microhardness did not reach OM on the upper and lower surfaces even though the curing time was extended to three minutes. In Variolink II, 120, 36, 45 and >180 seconds were needed in HQTH, PAC, Laser and LQTH, respectively, for the specimens to reach 80% OM.

In conclusion, the PAC system is the most effective curing system to cure the restorative composite and dual cured resin cement under the 1.5 mm Targis overlay, followed by the laser, HQTH and LQTH units. In addition, the restorative composites cured more efficiently than the dual-cured resin cements.

SUMMARY:
Fluoride varnish applications were applied to two hybrid resin composite materials, Z-100 (3M Dental Products, St Paul, MN, USA) and Esthet-X (Dentsply Caulk, Milford, DE, USA), shades A1 and A2 and a glass ionomer, GC Fuji IX GP Fast (GC Corporation, Tokyo, Japan), shade A2, to evaluate color stability. Specimens (12.6-mm dia x 2.3 mm) were prepared using a polyethylene frame, light-cured and polished through a 1-µm alumina finish. After the initial baseline color measurements, the discs were suspended in Fusayama artificial saliva (FAS) solution at 37˚C for 48 hours. Post immersion, the specimens were divided into five groups (n=15 each). The following fluoride varnishes were applied to four groups of test specimens: Duraphat (Colgate Oral Pharmaceutical, Inc, Canton MA, USA), Cavity Shield (OMNII Oral Pharmaceuticals, West Palm Beach, FL, USA), Duraflor (Pharmascience Inc, Montreal, Canada) and Fluor Protector (Vivadent, Ivoclar North America, Amherst, NY, USA). The varnish was allowed to dry for five minutes before immersion. The control group was not coated with varnish, although the specimens were immersed in FAS. All specimens were incubated in newly prepared FAS at 37˚C for 24 hours, cleaned with an electric toothbrush and the process repeated using newly prepared FAS. CIE L*a*b* color measurements were recorded five times: at baseline, after 48 hours FAS immersion, after cleaning the first and second fluoride varnish applications and after the final brushing using a commercial toothpaste (Crest). A Minolta CR-300 tristimulus colorimeter with an 8-mm aperture (Ramsey, NJ, USA) was used to record color measurements with the daylight (D65) setting. Calculations were performed for using CIE parameters DE*, DL*, Da*, Db*. Analysis of variance (ANOVA) and post-hoc test (Fisher’s PLSD) were used for statistical analysis. After immersion in saliva, the tested glass ionomer (Fuji IX) produced the most significant color changes (DE*=1.19 and DL*=-1.03), indicating the effect of the color change was due to absorption. After fluoride varnish applications, Duraphat varnish produced significant changes in all tested materials and shades, resulting in color changes with DE greater than (>) 1 but less than (<) 3. These color changes are considered visually perceptible, yet have been reported in dental literature as clinically acceptable. Fluoride varnishes can be used without adversely affecting the color of restorative materials.

SUMMARY:
Knoop microhardness and the degree of conversion of three packable composites (SureFil, Alert and Solitaire), a microfil composite (Heliomolar), a microhybrid composite (Herculite) and an indirect laboratory-processed composite (Belleglass) were evaluated as a function of distance from the irradiated surface. Cylindrical specimens (5.0 mm [diameter] x 6.0 mm [length]) of each material were visible light cured for 60 seconds in black-backed Teflon molds and sectioned. Knoop microhardness values were then obtained at 0-, 2- and 4-mm using a 50-gram load and 20 second dwell time. Degree of conversion was determined using Fourier Transform Infrared Spectroscopy. ANOVA (p<0.001) and Tukey Multiple Comparison Test (p<0.05) showed the indirect laboratory-processed composite Belleglass exhibited the highest mean values for both hardness and degree of conversion. Alert exhibited significantly greater hardness than SureFil and Solitaire at 0-mm depth. SureFil had significantly greater hardness than Alert at 4-mm depth. The degree of conversion of SureFil packable composite at 4-mm depth was significantly higher than any of the other direct composites tested.

SUMMARY:
The nature of the hybrid layer (HL) following chemical treatment has not been resolved. The effects of chemical treatments and polishing on HL morphology and composition were investigated using micro-Raman spectroscopy and SEM. Polished and unpolished SingleBond adhesive/dentin (a/d) interfaces from the same tooth were randomly selected for one of the following treatments: a) 5N HCl followed by 5%NaOCl; b) 5%NaOCl; c) 5%NaOCl and sonication; d) 5%NaOCl followed by 5N HCl. The results indicated that the HCl-NaOCl treatment could obscure the “true” HL in the unpolished a/d interfaces that were actually porous. The composition and morphology of the polished interface specimens were largely unchanged by the above treatments. Descriptions of HL quality are commonly based on the acid reactivity of polished specimens. The results of this study indicate that polishing dramatically alters the native composition, increasing its acid-resistance, and thus, this procedure could lead to false conclusions about HL quality.

SUMMARY:
Cuspal deflection produced by polymerization shrinkage was measured after using different composite restoration techniques. This study included 30 healthy premolars embedded in acrylic resin connected to a system that simu-lated intrapulpal pressure. A small ball was attached to each cuspal vertex as a reference point for intercuspal distance measurements. A large mesio-occlusal cavity was cut in each premolar. All premolars were treated with the same adhesive (ScotchBond) and composite (Tetric Ceram). The teeth were randomly distributed among three study groups: Group 1, filled with two horizontal increments; Group 2, filled with two horizontal increments, the first up to half the cavity height and light cured using a transparent plastic cone (Cerana), and the second filling the remainder of the cavity and Group 3, filled in the same way as Group 2, except that the first increment only filled one-third of the cavity height. The intercuspal distance was measured before beginning the restoration and immediately after polymerization of the first and second increments. Under the experimental conditions used, none of the filling techniques utilized avoided the cuspal deflection phenomenon. Polymerization of the final increment, which binds occlusal enamel in the buccal-lingual plane, was the main cause of cuspal deflection and produced a statistically significant reduction in intercuspal distance vs the baseline measurement in the three study groups. The global deflection ranged from 4 µm to 6 µm, depending on the filling technique used, although the differences among techniques did not reach statistical significance (p<0.05).

SUMMARY:
Objectives: To investigate the surface roughness changes of newer esthetic dental restorative materials with aging and acid erosion in a simulated oral environment. Methods: The materials included two viscous conventional glass ionomer cements originally marketed for the ART approach, one resin-modified glass ionomer cement and two resin composites. Ten specimens for each material were prepared according to the manufacturers’ instructions, then each specimen was immersed in 2 ml of buffered artificial saliva at 37°C for three weeks. For each material, five specimens (Group B) were then coated with 1.23% acidulated phosphate fluoride (APF) gel for four minutes, rinsed and immersed again in artificial saliva for another three weeks. Gel was not applied to the Group A specimens. For each material, the surface roughness of an additional three fresh specimens and those from Groups A and B were evaluated using a profilometer and SEM. Results: The resin composites showed the least effects of acidic corrosion on their surface texture. The viscous glass ionomer cements showed the greatest changes, with significantly increased surface roughness p<0.001). Conclusions: The immersion of two newer viscous GICs in a buffered artificial saliva and the single application of APF gel resulted in significantly rougher surfaces over a relatively short six-week period.

SUMMARY:
This study investigated the water sorption and solubility of two light-cured resin composites (Filtek P60 and Solitaire 2), one compomer (Compoglass F), one ormocer (Admira) and the associated bonding agents (Scotchbond 1 [Scotchbond 1 = Scotchbond Single Bond in USA], Gluma One Bond, Excite and Admira Bond, respectively) and of a RMGIC (Fuji II LC). Five disks of each product type were subjected to water sorption and solubility tests based on ISO 4049 requirements. The data were subjected to Kruskal-Wallis and non-parametric multiple-comparison tests using ranked sums at 95% confidence interval. Fuji II LC showed the highest water sorption (167.5 µg/mm-3). Fuji II LC and Compoglass F had higher solubility values (8.3 and 10.0 µg/mm-3, respectively) than the other materials. Bonding agents have very high water sorption and solubility values (between 77.4 and 355.4 µg/mm-3 and between 75.9 and 144.9 µg/mm-3, respectively) compared to the restorative materials. Gluma One Bond and Admira Bond showed lower sorption and solubility than Excite and Scotchbond 1.

SUMMARY:
This study compared the radiopacity of 41 resin-based materials using conventional dental x-ray film (Ultraspeed-D) and a digital system (Digora) based on storage phosphor plate technology.

For the film-based technique, optical density measurements were carried out using an X-Rite densitometer. Al equivalents (mm) were calculated as described in the literature using a calibration curve of Optical Density versus the thickness of aluminum. Regarding the digital system after exposures of 0.16 and 0.32 seconds, the images were exported to an image processing software (NIH Image Engineering). An approach similar to that used for optical density was used to generate a calibration curve for gray pixel values.

Linear correlations were found between the percentage of fillers by weight and x-ray film radiopacity and the Digora system, and the same coefficient of estimation was recorded (r=0.60; p≤0.05). A linear correlation was also observed between the conventional x-ray film technique and the Digora system (r=0.93; p≤0.05). Using two different exposure times did not affect the radiopacity.

Considerable differences were found among materials of the same category. Flowable resin composites were more radiopaque than dentin, while microfine composites were “radiolucent.” Most of the available resin-based materials were more radiopaque than enamel. The radiopacity of resin composites depended on their fillers (percentage and type). Using elements with low atomic numbers (Si) resulted in radiolucent materials, while adding elements with high molecular numbers (Ba, Y, Yb), resulted in radiopaque resin composites.

Despite the numerous benefits offered by the digital imaging system (low irradiation dose, instant image, image manipulation), the conventional x-ray film technique seems to be more accurate for radiopacity measurements.

SUMMARY:
The effect of a polyalkenoic acid conditioner pre-treatment on the bond strength of a glass-ionomer adhesive to tooth substrates with or without smear layer was evaluated. Smear-layer covered and smear-layer free dentin and enamel surfaces were prepared from 24 extracted human molars. Resin composite was bonded to the surfaces using FujiBond LC with or without a polyalkenoic acid conditioner and subjected to microtensile bond strength (µTBS) testing. Failure modes were determined using scanning electron microscopy. For dentin, smear-layer coverage and conditioner treatment did not reveal significant differences in µTBS, which ranged from 20 to 29 MPa. For enamel, smear-layer coverage did not significantly affect µTBS, whereas, the use of conditioner significantly improved µTBS, reaching the same µTBS-values as when bonded to dentin. Regarding failure mode, most dentin specimens failed mixed adhesive cohesively. For enamel, adhesive failures mostly occurred when no conditioner was used, though mixed failures were predominant when the specimens were conditioned beforehand. Bonding of the glass ionomer adhesive to dentin can be achieved without the separate use of a polyalkenoic acid conditioner, even with the interposition of a smear layer. However, instrumented and non-instrumented enamel requires separate conditioning to provide sufficient micro-mechanical retention.

SUMMARY:
Adhesive bonding to dentin can fail if the dentin is too wet during application of the bonding resin. This study compared the in vitro 24-hour microtensile bond strength of teeth restored at four different priming times at the gingival cavity wall of Class II resin composite restorations. After IRB approval, six pairs of extracted third molars (yielding 12 teeth) received a proximal Class II prep/restoration in each tooth. Each pair was from the same patient. Four treatment groups were randomly assigned for each pair. The treatment groups were: TM–primer applied and dried according to manufacturer’s directions; T30–primer allowed to dry for an additional 30 seconds; T60–primer dried for an additional 60 seconds; T120–primer dried for an additional 120 seconds. The teeth were restored with 3M ESPE Scotchbond Multi-Purpose Dental Adhesive and 3M ESPE Z100 Restorative. Manufacturers’ directions were followed except for the additional primer dwelling times. The teeth were sectioned to obtain rectangular specimens with a surface area of approximately 0.5 mm2. Samples were tested on the Instron at 1.0 mm/minute until failure. The results in megapaschals were TM (n=15) 25.5 ± 12.2; T30 (n=14) 22.7 ± 13.6; T60 (n=15) 28.1 ± 14.7; T120 (n=20) 27.7 ± 15.2. Samples that debonded during the preparation phase and could not be tested from each group were TM=5, T30=6, T60=5, T120=1. A one-way ANOVA found no statistically significant difference between groups. Ninety percent of the samples broke through the adhesive layer as observed under the scanning electron microscope at 2000x. A chi square analysis found no difference in the number of debonds between groups. Increasing the primer drying time did not increase the microtensile bond strength of adhesive bonded to the dentin gingival wall.

SUMMARY:
Knoop microhardness (KHN) and degree of conversion (DC) values were obtained from the bottom and top surfaces of 1-, 2- and 3-mm thick samples of three types of resin composite: an anterior microfill, an anterior hybrid and a posterior hybrid, all having differing filler size and loading but similar shade (A2) and basic monomeric content. Sample infrared spectra were obtained using attenuated total reflectance (ATR) in a Fourier transform infrared (FTIR) spectrometer. The samples were exposed using a 40-second exposure to a quartz-tungsten-halogen light source with an irradiance of ≈ 560 mW/cm2. They were stored for 24 hours in complete darkness at 37°C and 100% humidity prior to obtaining cured spectra and KHN readings. KHN and DC values were obtained from the same sample specimen made at similar surface depths, but separate groups were made for obtaining top and bottom values. Cure and hardness data were analyzed with one- and two-way ANOVAs followed by the Tukey-Kramer post-hoc test. Linear regression was also applied. Statistical testing was performed at a pre-set 0.05 level of significance. KHN and DC were significantly different according to composite type and depth (p=0.0001), with an interaction effect (p=0.0022). KHN, DC and corresponding bottom/top surface (B/T) ratios decreased with depth. Regression revealed a linear relationship between DC and KHN for each composite type, with no r2 less than 0.96. When B/T ratios were correlated, a B/T-KHN ratio of 0.80 corresponded to a narrow range of B/T-DC ratios (between 88 to 91%) for the three composites tested. When combining results from composite types, linear regression of B/T-DC and B/T-KHN produced a very predictable relationship (r2=0.959), for which a B/T-KHN ratio of 0.80 corresponded to a B/T-DC ratio of 0.90. As a measure of completeness of conversion, B/T-KHN was approximately 2.5 times more sensitive than the B/T-DC ratio. In SUMMARY:, while KHN cannot be used to directly compare conversion of the different composites tested, the use of B/T ratios for both hardness and conversion resulted in a linear relationship independent of filler size or loading.

SUMMARY:
Objective: To evaluate a total-etch three-step adhesive system’s resin-dentin interfacial ultrastructure and microtensile dentin bond strength (µTBS) after multi-year storage in water.

Methods: Resin composite crowns were formed on 600 grit SiC flattened extracted human molars using a total-etch three-step adhesive system (Optibond FL, Kerr) and a hybrid resin com-posite (Prodigy, Kerr). µTBS specimens were fabricated and placed in water with 0.5% chloramine T at 37˚C until respective static load to failure testing at one-month, six-months and five-year storage. Failure modes were determined by scanning electron microscopy. The interfacial ultrastructure of the resin-dentin interface was analyzed by transmission electron microscopy (TEM) at 48-hours and 44-months storage. µTBS was modeled with Weibull distribution for survival analysis and failure curve distributions were analyzed by the Wald chi-square statistic for significant differences at a=0.05.

Results: The characteristic tensile strength (so) at one-month, six-months and five-year storage was 52.63, 14.77 and 23.57 Mpa, with a Weibull modulus of 3.04, 1.56 and 1.28, respectively. Failure distributions for all groups were significantly different (p<0.0001) with one-month > five-year > six-months. TEM interfacial morphology demonstrated hydrolytic degradation of hybrid layer components at 44-months storage.

Significance: The decrease in tensile strength and changes in ultrastructure may be caused by water sorption and resultant hydrolytic degradation of the adhesive joint.

SUMMARY:
This in vitro study evaluated the influence of two flowable resin composites on marginal microleakage and internal voids in Class II composite restorations with the margins below the cementoenamel junction (CEJ). Class II cavities randomly divided into four groups: Group I–Filtek with Filtek Flow lining; Group II–Filtek; Group III–Tetric Ceram with Tetric Flow lining; Group IV–Tetric Ceram. After thermocycling tests (5-60 x 1500) and dye soaking, the teeth were sectioned in a mesiodistal direction along their longitudinal axis. Gingival-marginal microleakage and internal voids in three separate portions of the restoration (interface, cervical and occlusal voids) were observed with a microscope. Statistical analyses indicated that the use of flowable resin composites (Groups I and III) provided a reduction in marginal microleakage and a reduction in some parts of the internal voids or total voids (p<0.05). The condensable material (Filtek) in combination with the flowable liner showed fewer voids (interface, occlusal, total) than the hybrid resin (Tetric) (p<0.05). There was a correlation between the number of internal voids or total voids and the marginal microleakage (p<0.05). It was concluded that a composite lining in a Class II resin composite with margins below the cementoenamel junction may reduce marginal microleakage and voids in the interface and the total number of voids in the restoration.