Comparing Proximal Box Marginal Adaptation in Restorations Using Bulk-Fill Composites

Objectives: Bulk filling could lead to marginal gaps due to the inability to adapt smaller composite increments to cavity walls. The objective was to determine the marginal adaptation of 11 different bulk-fill resin composites placed in the proximal box of a Class II preparation.
Methods: Ten pre-prepared, uniform, Class II preparations in plastic teeth were restored by each of the 11 bulk-fill composites according to manufacturers’ instructions. Restorations were then cured, stained, finished, and analyzed for voids along all proximal box margins. The incidents of voids were calculated using Image J software by measuring the total length of voids along the total length of each buccal (n=10), gingival (n=10) and lingual (n=10) margins of the proximal box. Total percentage of voids (n=30) was analyzed by analysis of variance. Means were compared using Fisher’s PLSD test at the 0.05 level of significance.
Results: Means and standard deviations are shown in the table. ANOVA showed significant differences (p<.0001) among composites. Fisher’s PLSD interval for comparisons of means was 0.1%. SonicFill 2 had the highest average percent voids at 18.6%, whereas BEAUTIFIL-Bulk Flowable had the least voids at 0.4%. Voids may be affected by the design of the tips and syringe and the viscosity of the composite.
Conclusions: In conservative Class II preparations, flowable composites (5 out of 11 materials tested) had overall better marginal adaptation than sculptable composites (6 out of 11 tested).