Effect of polishing technique and brushing on surface roughness of acrylic resins.

ABSTRACT

PURPOSE: This study evaluated the abrasion resistance of acrylic resin to routine dental brushing procedures using different dentifrices after the resin surface had been chemically or mechanically polished. MATERIALS AND METHODS: Eighty specimens were prepared using heat-polymerizing (HP) and autopolymerizing (AP) acrylic resin, and immediately submitted to grinding with abrasive stones and disks. The specimens were divided into two groups the first group was mechanically polished (MP) using pumice slurry, and the second group was chemically polished (CP) using heated monomer. After polishing, the specimens were submitted to 30,000 brushing cycles. Surface roughness was measured after polishing and brushing procedures, using a Surfcorder SE 1700 rugosimeter. Data were statistically analyzed by ANOVA (alpha= 0.05). RESULTS: There were significant differences in surface roughness between polishing with MP and CP (p < 0.05). Significant differences in surface roughness were also found between brushing with MFP dentifrice and Tartar Control dentifrice (p < 0.05). CONCLUSION: MP produced smoother surfaces than CP, and surface roughness as a result of polishing technique was not influenced by acrylic resin type. Even though MP resulted in smoother surfaces initially, subjecting the acrylic resin to dentifrice brushing negated this advantage.