S.mutans Biofilm Changes the surface of Composite Resins

Recent in vitro experiments indicate that resin composites support bacterial growth. Objectives: The purpose of our study was to investigate three-dimensional topographical changes of three commercial composite resins following biofilm accumulation. Methods: Light polymerized composite resin disks were prepared between two glass slides or between a glass slide and a Mylar strip. Triplicate specimens were brought in contact with S. mutans biofilm for 1 hour, 24 hrs, 1 week or 1 month. Surface degradation of the restorations was evaluated by root-mean-square (RMS) roughness analysis, using atomic force microscopy (AFM). Results: AFM images showed a significant increase in RMS roughness related to the time exposure of the composite resins to biofilm. The RMS roughness values grew from 7.428nm at 1 hour, 7.31nm at 24 hours to 18.713nm at 1 week and 40.869nm at 1 month.Conclusions: The results suggest that S. mutans biofilm accumulation affects the surface integrity of composite resin. This may have a meaningful effect on the longevity of such restorations.