Efeito dos diferentes tipos de polimento sobre a rugosidade de superfície de uma resina acrílica comercial quimicamente ativada: estudo in vitro

Abstract

Objective: evaluate in vitro the influence of polimerization and polishing techniques on acrylic resin chemically enabled, through the surface roughness (Ra). Materials and method: were made 40 samples of acrylic resins poli methylmethacrylate (PMMA) with dimensions of 10 x 10 x 2mm, and was separated in four groups: Finishing absence (FA); Polishing absence (PA); Chemical polishing (CP); Polishing with silicone rubbers + Brushes (MP). Every experimental group contain n=10. The specimens was evaluated in rugosimeter in three different points horizontally on the samples. After the first read, the proof bodies were submitted to artificial ageing submerged in distilled water on culture incubator for 60 days. After the ageing the specimens was evaluated again by the rugosimeter. Results: data were analyzed using descriptive statistics. For the initial surface roughness (Ra measured in µm) the samples showed that the group FA had the lower values of roughness, and the group PA the highest values of roughness, with average and standard deviation respectively between the samples of (Ra 0,17 ± 0,11) and (Ra 0,52 ± 0,10). Now after the ageing the group FA had the lowest averages and the group CP the highest values of roughness, therefore (Ra 0,38 ± 0,20) and (Ra 1,33 ± 0,32) respectively. The results showed numerical diferences when the samples was submitted to the finishing with drills, therefore, being necessary the polishing of the material. Conclusion: the chemically polymerizable acrylic resin presents a different behavior in relation to the surface roughness before the different methods of finishing and polishing.