COMPARATIVE EVALUATION OF FRACTURE RESISTANCE OF TWO ANTIBACTERIAL COMPOSITES AGAINST A COMMERCIAL COMPOSITE - AN IN VITRO STUDY

Introduction: Antibacterial composites are desirable since it decreases the incidence of secondary caries. The downfall of addition of antimicrobial fillers to a commercial composite is that they may hinder the mechanical properties of the parent material. This study was aimed to compare and evaluate the fracture resistance of modified composite by incorporation of 5wt% ZnO NPs & a novel antibacterial composite - Sri Chitra Thirunal Institute of Medical Science and Technology (SCTIMST) against a commercial composite.

Materials and Methods: The three study groups were determined: Group I: Commercial composite without incorporation of ZnO-NPs, Group II: Novel antibacterial composite (SCTIMST) containing Zn²⁺,Group III: Commercial composite + 5wt% ZnO- NPs. 10 cylindrical specimens (2 mm in diameter and 4 mm in height) were prepared using mold from each group of composite. Polymerization was carried out for 40s at the top and at the bottom before removal of specimen. The samples were stored in distilled water at 37°C for 24 h. Compressive strength was evaluated using a universal testing machine (INSTRON) at a cross-head speed of 0.5 mm/min.

Results: There was no significant difference(p >0.05)in mean compressive strength values between the study groups, statistically analyzedusing independent sample t test.

Conclusion: The addition of antibacterial nanoparticles to the commercial composite and the novel antibacterial composite (SCTIMST) did not affect the strength of the composite, rather, it had a reinforcing effect as compared to the control material on evaluation of the compressive strength.