Marginal Integrity of Different Bulk Fill Application Techniques

Objectives: The bulk fill resin based composite are claimed to offer clinical advantages as it offers a higher depth of cure 4mm or 5mm due to their high reactivity to light and at the same time shows a decline in internal stresses, and consequently leads to precise and accurate adaptation to the tooth substrate.
This study is aimed at evaluating marginal integrity of different application techniques of posterior bulkfill composite resin by using scanning electron microscope before & after thermocycling.
Methods: Using a calibrated diamond bur under water cooling high-speed handpiece, class II cavities were prepared with parallel walls in forty non-carious extracted upper premolars. The overall dimensions were standardized as follows: 4 mm wide & 4 mm deep at the occlusal box, 4 mm wide & 2 mm axial depth at the proximal box & 5mm occluso-cervical length. Divided into 4 groups, corresponding to the different bulk-fill application technique used (n = 10).
Test Group 1: 10 teeth were restored with sonicfill2 composite using sonic activation. Test Group 2: 10 teeth were restored with Tetric N Ceram bulk-fill composite utilizing the bulk fill technique. Test Group 3:10 teeth were restored with Surefill SDR flow bulk composite + Tetric N Ceram capping material. Control Group 4: 10 teeth were restored with Tetric N Ceram composite utilizing the conventional layering technique. After the restorative procedures, finishing & polishing, the cavity margins were evaluated before and after Thermocycling by scanning electron microscopy.
Results: The marginal integrity of each wall (the mean & the median values) before and after thermocycling in the four groups were statistically analyzed using Kruskal Wallis test and multiple pairwise comparisons using Bonferroni adjusted significance
Conclusions: Sonically activated bulkfill composite restorations have better marginal sealing in comparison with other bulkfill composites.