A Comparative in vitro Investigation on the Impact of Fiber Insertion on Cuspal Deflection of Maxillary Premolars Restored with Various Types of Bulk Fill Direct Composite Restorations

Abstract

Background: Polymerization shrinkage remains a significant disadvantage that makes the use of direct composite restorations difficult. Objective: To evaluate how well a fiber insert and multiple bulk-fill direct restorations worked on the cuspal deflection of MOD cavities in premolar teeth using a Dino-Lite digital microscope and computer software. Methods: In sixty fresh maxillary first premolars, large MOD cavities were created. Teeth were randomly divided into six groups of ten based on restorative materials. SonicFill®, Beautifil Bulk®, and Filtek® Bulk Fill posterior restoratives were used in groups A1, B1, and C1, whereas groups A2, B2, and C2 used the same bulk composite with E-glass fiber (UFM, Dentapreg). Under a digital microscope, the intercuspal distance between two reference points on the cusp tips was measured before preparation, after preparation, 15 minutes after finishing restorations, and one month following incubation. Results: There was a significant difference between the groups after 15 minutes of restoration, but no significant differences following cavity preparation or one month of incubation. CD values were considerably higher after 15 minutes of restoration in groups restored with bulk fill only. Beautifil Bulk Fill restorative resulted in greater cuspal deflection than the other groups. The CD values in each group were significantly higher 15 minutes after restoration compared to cavity preparation and a month of incubation. Conclusion: Using inserts, cuspal deflection in MOD cavities can be significantly minimized, and stress release usually occurs after water incubation.