The Effect of a Continuous Mechanical Polishing Protocol on Surface Roughness, Biofilm Adhesion, and Color Stability of Acrylic Resin Artificial Teeth.

PURPOSE

Acrylic resin properties are susceptible to change over the duration of use, thereby decreasing prosthesis longevity. To make the material less susceptible to the action of external agents such as stain-causing liquids and cleaning solutions, polishing procedures are recommended. A specific mechanical polishing procedure performed regularly was evaluated regarding the biofilm adhesion, surface roughness (Ra), color stability (ΔE), and mass changes in acrylic resin artificial teeth.

MATERIALS AND METHODS

Sixty artificial teeth divided into two groups (n = 30) were immersed in distilled water (WT) and coffee (CF). These groups were then subdivided (n = 10) according to the type of polishing procedure administered: no polishing, biweekly polishing (once every 2 weeks) (pol 1), or monthly polishing (once a month) (pol 2), using aluminum oxide paste and a felt polishing wheel attached to an electric motor at a speed of 3000 rpm. Properties were evaluated at baseline and after 4, 8, 12, and 24 months of simulated immersion. At the end, the adhesion of Candida albicans and Streptococcus mutans multispecies biofilm in all groups was assessed.

RESULTS

The CF group showed an increased Ra and weight, and a significantly greater ΔE compared to the WT group. The polishing procedure reduced Ra and minimized the stains caused by coffee, without losing mass, with the biweekly regime more effective than the monthly regime. Also, polishing reduced the adhesion of biofilm in the CF groups, again with the biweekly regime the most effective.

CONCLUSIONS

When performed regularly, the mechanical polishing procedure tested reduces the changes in artificial teeth subjected to immersion in coffee, with the biweekly frequency most effective regarding the properties evaluated.