Effects Of Fiber Insertion And Sonic Energy On Microleakage Of Bulk Fill And Nanohybrid Composites In Deep Class II Cavities: A Stereomicroscopic Study

Introduction: Composite is material of choice for restoration for cavities in todays era. Fibers and sonic energy are newer technology incorporated into dental composites to reduce polymerization shrinkage and thus microleakage. Objectives: To evaluate effects of fiber insertion and sonic energy on gingival microleakage in class II composite restorations placed apical to the cementoenamel junction. Materials and Methods: Standardized class II cavities were prepared on extracted molars and randomly divided into four groups (n = 20 each): Group I, Filtek Z350; Group II, Filtek Z350 + Ribbond; Group III, Filtek Bulk fill; Group IV SonicFill BulkFill composite. All specimens were subjected to a thermocycling regime, immersed in 2% methylene blue dye for 24 h, sectioned longitudinally, and examined under a stereomicroscope to assess dye penetration on a six-point scale. The score data were subjected to statistical analysis, whereby the Kruskal–Wallis analysis of variance was used for multiple group comparisons and the Mann–Whitney test for groupwise comparisons at a significance level of P ≤ 0.05. Results: A statistically-significant decrease in microleakage was found when Ribbond fiber and Sonic energy was used: group 2 vs group 1 (P < 0.001), group 4 vs group 3 (P < 0.001). No significant difference in microleakage scores (p=0.530>0.01) in the Filtek Bulk fill composite (group 3) when compared to the nanohybrid composite (group 1) was found. Group 4 (Sonicfill Composite) showed the least mean microleakage score compare to all other groups. Conclusion: Sonic energy and polyethylene fiber inserts significantly reduces microleakage in class II composite restorations with gingival margins below the cemento-enamel junction.