Influence of thickness, color, and polishing process of ethylene-vinyl-acetate sheets on surface roughness and microorganism adhesion.

BACKGROUND/AIM: The surface roughness of dental materials can make cleaning difficult, thus facilitating retention of food debris and accumulation of microorganisms. The aim of this study was to assess whether thickness, color, and the polishing process influence the surface roughness of ethylene-vinyl-acetate (EVA) sheets and the amount of microorganisms that adhere to them.

MATERIALS AND METHODS

A total of 180 samples of EVA (5 × 5 mm) were divided into 9 groups according to thickness (G1 = 2 mm; G2 = 3 mm; and G3 = 4 mm), color (G4 = black and G5 = white), and type of polishing (G6 = Scheu™; G7 = Scheu™ associated with hot-air burner; G8 = Erkodent™ and G9 = Erkodent™ associated with hot-air burner). Mean value of 3 roughness parameters was assessed: Ra, Rq, and Rz (one-way ANOVA test and Tukey's test, P < .05). Seven samples of each group (n = 63) were inoculated with saliva for 2 hours to promote microbial adhesion and count the number of colony-forming units (CFUs) (one-way ANOVA test, P < .05). Scanning electron microscopy (SEM) of microbial adhesion and the effects of the polishing process on the surface was assessed.

RESULTS

Only the polishing parameter presented less roughness (G2, G7 and G9; P < .05) as also observed on SEM. SEM characterized microbial adhesion but the CFU count was not statistically significant, independent of the assessed parameters.

CONCLUSION

The polishing systems, Scheu™ and Erkodent™ in association with a hot-air burner, were effective in decreasing the surface roughness without influencing the amount of adhered microorganisms.