Cuspal deflection and marginal microleakage following the application of bulk-fill and conventional composite resins

Objectives: This study compared the cuspal deflection and marginal microleakage following the application of bulk-fill and conventional composite resins. Materials and Methods 70 sound premolars with MOD preparation were randomized into 5 groups (n = 14). In three groups, the cavities were restored with Tetric Ceram N, X-tra fil, and Opus bulk-fill composite resins. In the remaining two groups, the cavities were restored with P60 conventional composite with 2 mm (incremental technique) and 4 mm (bulk-fill technique) increments. Cuspal deflection was measured by a digital micrometer. After aging, marginal microleakage was assessed. Data were analyzed by repeated measures one-way and two-way ANOVA, and Tukey, Bonferroni, Kruskal-Wallis, Mann-Whitney, Friedman, Wilcoxon signed rank, and t tests. Results Cuspal deflection of bulk-fill composite groups was lower than that of conventional composite applied incrementally (P < 0.05), but it was not significantly different among the bulk-fill composite groups (P = 0.16). The microleakage scores was not significantly different among the bulk-fill composites, or between the bulk-fill and conventional incremental composite group (P > 0.05). Microleakage at the cervical cementum margin of proximal box was significantly higher than that at the cervical and occlusal enamel margins of proximal box (P = 0.001). Conclusion the cuspal deflection in bulk-fill composite restoration was lower than that in the conventional composite in incremental technique but marginal microleakage of bulk-fill and conventional composite resin restorations were comparable.