Adherence of Streptococcus mutans to Nanoceramic and Nanohybrid Resin Composites: An In vitro Study

Streptococcus mutans (S. mutans) is one of the cariogenic microorganisms. The restorative materials which harbor a biofilm with high number of S. mutans can accelerate the occurrence of dental caries. The purpose of this study was to evaluate the adherence of S. mutans to nanoceramic and nanohybrid resin composites. Fifteen discs of each material (Nanohybrid resin composite, Nanoceramic resin composite) were prepared, polished, and sterilized in a gamma radiation chamber. Specimens were exposed to the S. mutans bacterial suspension (0.5 McFarland) and were incubated for 4 hours. Specimens were rinsed and sonicated in normal saline, 10 μl of the obtained suspension was cultured in a sterile blood agar medium. After 24 hours, the number of colony forming units of S. mutans was counted. A sterility test control was considered for each group of materials. The data was analyzed by Independent t test. The means and standard deviations of the logarithmic counts of the colonies on the surfaces of nanohybrid resin composites and nanoceramic resin composite were equal to 3.2±0.87 and 2.8±0.324 respectively. Ceram X Universal did not show any significant difference in the bacterial adhesion compared to Filtek Z350XT. Both composites showed similar behaviour in terms of S. mutans colonization in a simple biofilm formation model.