Main approaches of biofilm formation in composite resins: a concise systematic review

Abstract

Introduction: Composite resins are widely used in clinical dental practice to restore the structure lost by caries and dental defects, achieving aesthetic and functional results. Failures in the photoactivation process can cause problems in the mechanical resistance to wear in regions of direct occlusal contact on the restorative material. This occurs due to the reduction in the degree of conversion of monomers into polymers, compromising the clinical performance of the composite resin. Polymerization shrinkage leads to microleakage of the restoration, leading to staining and the development of bacterial biofilms. Objective: It was to carry out a systematic review of the main scientific evidence of biofilm formation on composite resin veneers, identifying potential predictors, as well as proposals to mitigate this problem. Methods: The systematic review rules of the PRISMA Platform were followed. The search was carried out from December 2022 to March 2023 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases, using articles from 2015 to 2022. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed accordingly, according to the Cochrane instrument. Results and Conclusion: A total of 125 articles were found, 25 articles were evaluated and 20 were included and developed in this systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 10 studies with a high risk of bias and 70 studies that did not meet GRADE. It was concluded that the surface properties of resin-based composite materials, as well as surface treatments, can strongly affect bacterial adhesion and biofilm formation. In addition, scientific evidence highlights that cariogenic biofilm formation can alter the surface properties of materials, thus stimulating bacterial adhesion and biofilm formation. Photoactivation allows the curing and crosslinking of polymer chains, essential for the clinical longevity of the composite resin. Insufficient photoactivation culminates in marginal microleakage in restorations and biofilm accumulation on surfaces exposed to the oral environment.