The Effect of Prophylactic Polishing Pastes and Toothbrushing on the Surface Roughness of Resin Composite Materials In Vitro

Polishing composite restorations at recall prophylaxis may affect their surface roughness. This investigation evaluated the effect of prophy paste on the surface roughness of a microfilled (Filtek A110) and a microhybrid (Filtek Z250) resin composite before and after simulated toothbrushing. Twenty, two-sided samples of both materials were fabricated in acrylic molds against a Mylar strip (baseline). Three roughness readings were recorded for each surface using a Surfanalyzer 5400 to determine the mean roughness. The samples were finished and polished with the Sof-Lex disk system and the surface roughness (R_a) was re-measured. Samples were randomly assigned and five surfaces for each material were polished with Nupro coarse, medium, fine or Clinpro prophy paste and the surface roughness measured again. All surfaces were brushed 60,000 times at 1.5Hz using a 2N brushhead force (Manly V-8 cross-brushing machine) in a 50:50 (w/w) slurry of toothpaste and water. The surface roughness was measured followed by the application of prophy paste as previously described and this final roughness recorded. Data were analyzed using repeated measures two-factor ANOVA with TUKEY HSD pairwise comparison as appropriate (α=0.05). No significant difference in surface roughness was determined between the microfilled and microhybrid materials at baseline or disk treatment, yet significant differences were observed following brushing and/or prophy paste application. In conclusion, although baseline and disk treated surfaces were not significantly different in microfilled versus microhybrid composites, subsequent prophy paste application and/or simulated toothbrushing caused significant differences.