Streptococcus mutans Adhesion: A Controlled In vitro Investigation Using Bracket and Composite Material in Relation to Saliva pH

Abstract

The risk of caries is increased when Streptococcus mutans adheres to orthodontic equipment, which leads to the production of biofilms. The purpose of this research was to determine the in vitro effects of bracket material, composite type, and saliva pH on S. mutans adhesion. The following procedures were used to evaluate six different combinations of brackets and composites: plastic, metal, ceramic brackets with light-cure and self-cure composites, and artificial saliva with a pH of 5 and a pH of 7, respectively. Six samples were produced for each of the twelve groupings. Following the development of the pellicle, the samples were exposed to 1.5 × 10¹ CFU/mL of S. mutans and the number of colony-forming units (CFUs) was measured. With a significance level of 0.05, the data were examined using generalized estimating equations (GEEs). The results showed that at a pH of 5, the average CFU/mL for metal brackets was 59.10 ± 5.23, 93.11 ± 83.25, and for ceramic brackets it was 87.77 ± 35.61. Two kinds of composites were produced: 72.18 ± 67.92 for light-cure and 308.93 ± 75.19 for self-cure. A significant main impact of bracket material (P = 0.001) and an interaction between brackets and composites (P = 0.001) were seen when the two variables were combined, however GEE did not find any significant effects of either bracket material (P = 0.183) or composite type (P = 0.966) when examined separately. The averages for ceramic, metal, and plastic brackets at pH 7 were 816.38 ± 50.72, 393.32 ± 67.50, and 671.41 ± 83.25 CFU/mL, respectively. Light-cure and self-cure composites demonstrated 84.33 ± 78.94 and 243.22 ± 67.43 CFU/mL, respectively. According to GEE, there was no interaction (P = 0.234), a composite effect (P = 0.001), and a bracket effect (P = 0.095) that was not statistically significant. The results show that the saliva pH controls the material impacts on the adherence of S. mutans. Adhesion differences are driven by bracket-composite interactions in acidic circumstances, whereas the composite type predominates at neutral pH. The oral pH environment and material matching should be considered while selecting an appliance.