Impact of Polishing Methods on Surface Roughness and S. Mutans Adhesion in Composite Resins: An in Vitro Study

Abstract

Background This study aimed to evaluate the surface roughness and Streptococcus mutans adhesion on two different composite resin materials following the application of various polishing systems. Methods Eighty disk-shaped specimens (8 mm diameter, 2 mm thickness) were fabricated using nanohybrid (Charisma Topaz) and nanofilled (Tokuyama Estelite Asteria) composite resins (n = 40 each). Each material group was further divided into four groups (n = 10) according to the polishing system used: Mylar strip (control), Sof-Lex (TM), Clearfil (TM) Twist Dia, and Opti1Step (TM). After measuring the surface roughness, the sterilized samples were divided into two subgroups as, "artificial saliva-treated samples" and "non-treated samples." For each subgroup, solutions containing S. mutans were added, and the samples were incubated at 35-37 degrees C for 24 h. Determination of adhered bacteria on surfaces depended upon colony counts obtained after incubation, which was presented as CFU/mL. Statistical analyses included two-way ANOVA for surface roughness and three-way ANOVA with Tukey post hoc test for bacterial adhesion. Results SR values ranged from 0.07 +/- 0.01 mu m to 0.09 +/- 0.03 mu m across all groups, remaining well below the clinical threshold of 0.2 mu m, highlighting that the minor surface variations observed are unlikely to have clinical significance regarding plaque retention. (p > 0.05). S. mutans adhesion values ranged between 2.83 +/- 0.25 log CFU/mL and 3.57 +/- 0.32 log CFU/mL. No statistically significant differences were found between polishing methods or saliva conditions (p > 0.05). The three-way ANOVA revealed a statistically significant main effect of composite resin material on S. mutans adhesion (F = 29.895, p < 0.001, partial eta(2) = 0.322), indicating that bacterial colonization varied according to the resin material used. Conclusion While different polishing systems did not significantly affect surface roughness or bacterial adhesion, the composite resin type appears to play a crucial role in S. mutans colonization.