Cuspal Deflection and Marginal Gap of Class II MOD Using Preheating Bulk-Fill Composite with Different Application Techniques

Abstract

The novel bulk-fill composite to reduces time consumption and overcomes sensitive incremental techniques. Cuspal deflection and marginal gap are the common problems of composite material restoration. This in vitro study was conducted to evaluate the cuspal deflection and marginal gap of CL II MOD cavity restored with preheated One bulk-fill composite resin applied with different application techniques. Methodology: 48 upper 1st premolar teeth were prepared as CL II MOD cavities to be restored with One bulk-fill restorative composite resin without (Group A) or with preheating (Group B). Each group (n=24) was subdivided into three subgroups (n=8): A1 and B1 were restored in one increment, A2 and B2 were restored using two increments, and A3 and B3 were filled using a sublayer of a flowable composite resin. The intercuspal distance of the buccal and palatal cusps was recorded before preparation, after 5 minutes, and 24 hours from the restoration. The cuspal deflection (CD) was calculated by subtracting intercuspal distance after restorat ion (5 minutes or 24 hours) from before preparation for all subgroups. The marginal gaps were recorded from images by scanning electron microscopy (SEM) for both the proximal and gingival margins. The mean values of the data we re analyzed statistically using one-way ANOVA and paired t -test at p<0.05. Preheating of One bulk-fill resin did not pr oduce a significant effect on cuspal deflection compared with the control (p>0.05) however, the incremental layering of One bulk-fill composite recorded significantly lower cuspal deflection with or without preheating. While preheating of bulk-fill produced a significant decrease of both marginal gaps compared with the control subgroups (p≤0.05). Preheating One bulk-fill composite before cu ring did not influence the cuspal deflection while imp roved marginal adaptation in different application techni ques. The incremental technique significantly reduced cuspal deflection and marginal gap.