Aim:The purpose of the present randomized clinical trial was to evaluate the color change, rebound effect and sensitivity of at-home bleaching with 15% carbamide peroxide and power bleaching using 38% hydrogen peroxide.Materials and Methods:For bleaching techniques, 20 subjects were randomized in a split mouth design (at-home and power bleaching): In maxillary and mandibular anterior teeth (n = 20). Color was recorded before bleaching, immediately after bleaching, at 2 weeks, 1, 3 and 6 month intervals. Tooth sensitivity was recorded using the visual analog scale. The Mann-Whitney test was used to compare both groups regarding bleaching effectiveness (ΔE1), rebound effect (ΔE2) and color difference between the rebounded tooth color and unbleached teeth (ΔE3) while the Wilcoxon compared ΔE within each group. Distribution of sensitivity was evaluated using the Chi-square test (α =0.05).Results:There was no significant difference between groups regarding ΔE1 and ΔE3 (P > 0.05). Even though, ΔE2 showed no significant difference between groups after bleaching as well as at 2 week, 1 month and 3 month follow-up periods (P > 0.05). Although, significant difference was found in ΔE2 (P < 0.05 Mann-Whitney) between two methods after 6 months and a high degree of rebound effect was obtained with power bleaching. Within each group, there was no significant difference between ΔE1 and ΔE3 (P < 0.05 Wilcoxon). The distribution of sensitivity was identical with both techniques (P > 0.05).Conclusion:Bleaching techniques resulted in identical tooth whitening and post-operative sensitivity using both techniques, but faster color regression was found with power bleaching even though color regression to the baseline of the teeth in both groups was the same after 6 months.

The sandwich technique results in more microleakage than classically bonded composite resin restorations. SUMMARYObjectives: The aim of the present study was to evaluate the effect of four different sandwich techniques on gingival microleakage of Class II direct composite resin restorations. Materials and Methods: Fifty sound human premolars were selected and randomly divided into five groups (n=10). Class II box only cavities were prepared in one of the proximal surfaces of each tooth with a gingival margin located approximately 0.5 mm below the cemento-enamel junction. Group A (control) was restored incrementally with composite resin (Tetric Ceram). Groups B, C, D, and E were restored with the sandwich technique using a compomer (Compoglass F), flowable composite resin (Tetric Flow), self-cure composite resin (Degufill SC), or resin modified glass ionomer (Fuji II LC), respectively. After thermal-load cycling, the specimens were immersed in 0.5% basic fuschin for 24 hours. Dye penetration (10 À1 mm) was detected using a sectioning technique. Data were analyzed with repeated measurements and Duncan test at a=0.05.Results: The least amount of microleakage was detected in the incremental group (1.28 6

BackgroundTo evaluate the clinical performance of direct composite restorations using the snowplow technique with up to 4 years of follow-up.Material and MethodsIn this retrospective study, 101 class II composite restorations which were placed in permanent molars (n = 19) and premolars (n = 82) in 85 patients by the snowplow technique, were evaluated according to the modified USPHS criteria. A Kaplan-Meier analysis with a 95% confidence level was used to calculate the survival probability.ResultsOf the 101 teeth examined, tooth failure was identified in 8 teeth due to secondary caries (3%), marginal gap (2%), marginal discoloration (1%) and restoration breakdown (2%) which required replacement of the whole restoration. Sixteen teeth achieved a Bravo score and just needed to be repaired. The results of the Kaplan-Meier analysis regarding overall survival estimates of composite-treated teeth using the snowplow technique at 1-, 2-, 3- and 4- year follow-ups were 99%, 96.2%, 89.6% and 79% respectively. The median survival times of composite restorations using the snowplow technique were 46.49 ± 11.47 month.ConclusionsThis retrospective study showed that application of a flowable composite as a liner using the snowplow technique does not improve the clinical survival of posterior composite restorations. Key words:Snowplow, composite restoration, success rate.

Heroin addiction changed the effective salivary factors and therefore could negatively contribute to oral health. These factors were not return to the normal range after 1 month of MMT. Physicians should be informed about focusing on oral health in patients under MMT.

AimThe aim of the present study was to determine the shear bond strength of self-adhesive resin cements to enamel and dentin with and without surface treatments, and compare them with conventional resin cement as the control group.MethodsIn this experimental study, buccal and lingual surface of the thirty sound human premolars were polished in order to obtain a flat surface of enamel (E) in buccal, and dentin (D) in lingual. Sixty feldspathic ceramic blocks (2×3×3 mm) were prepared and randomly divided into six groups (n=10). Each block was cemented to the prepared surface (30 enamel and 30 dentin surface) according to different protocol: E1 and D1; RelyX ARC as control group, E2, D2; RelyX Unicem, E3, D3; acid etching +RelyX Unicem. The specimens were termocycled and subjected to shear forces by a universal testing machine at a cross head speed of 0.5 mm/min. The mode of fracture were evaluated by stereomicroscope. Data were analyzed with descriptive statistical methods using SPSS version 15. One-way ANOVA, and post hoc Tukey tests were used to compare bond strengths between the groups with different adhesives at α=0.05.ResultsStatistical analysis showed no significant differences within the enamel subgroups, but there were significant differences within the dentinal subgroups, and statistically significant differences were found between the groups D1and D3 (p=0.02). Comparison between similar enamel and dentinal subgroups showed that there was a significant difference just between the subgroups E3 and D3 (p=0.01).ConclusionElective etching of enamel did not lead to significant increase in the shear bond strength of RelyX Unicem in comparison to RelyX ARC. On the other hand, elective etching of dentin reduces the bond strength of RelyX Unicem with the dentin.