Evaluation of Microleakage and Biocompatibility of Universal Adhesive Containing Titanium Dioxide Nanoparticles: A Comparative In Vitro Study

Background Objective: Although dental composites have undergone a high level of development in recent years, there are still difficulties including microleakage. The incorporation of nanoparticles (NPs) in dental materials can produce antibacterial effects, but the effect of TiO_2 NPs on microleakage has not yet been investigated. The present study aimed to determine the effect of TiO_2 NPs incorporation in the universal single bond and pretreatment with them on microleakage of clV cavities using both total-etch and self-etch approaches. Materials Methods: Standard clV cavities were prepared on the buccal surfaces of the sixty non- carious human molar teeth. The restoration of samples was carried out with 6 different methods and randomly divided into six groups of ten subjects. Microleakage in both gingival and occlusal margins was determined after placement in 2% basic fuschin solution for 24h. Biocompatibility of a universal single bond was evaluated by MTT assay. Results: In both occlusal and gingival margins in all groups, the application of TiO_2 NPs was better than no application. We observed the relatively low cytotoxic effect of TiO_2 NPs incorporated in the universal adhesive on NIH-3T3 cell viability. Conclusion: Regarding the limitations of the present investigation, using TiO_2 NPs with both total-etch and self-etch approaches to universal single bond may lead to a decrease in the microleakage of resin composite restorations.