Efeito de um protocolo de polimento mecânico contínuo na estabilidade de cor de uma resina acrílica para base de prótese dentária e dentes artificiais submetidos à fumaça de cigarro e ao café.

Abstract

The acrylic resin is widely used in the manufacture of dental prostheses. Despite its numerous advantages, it is subject to changes in itsproperties such as color over the period of use. The polishing of prosthetic surfaces is usually performed in a laboratory environment after they are polymerized, or by dentists during clinical visits. Studies evaluating the effects of continuous polishing on prosthetic materials are scarce in the literature. To evaluate in vitro the effect of a continuous mechanical polishing protocol on the color stainability of a denture base acrylic resin and acrylic resin artificial teeth after exposure to cigarette smoke and coffee immersion. For each material, 70 specimens were divided according to the following experimental groups (n=10): DW - immersion in distilled water (control); CS - only exposure to cigarette smoke; CS + Pol - exposure to cigarette smoke + polishing; CF - only immersion in coffee solution; CF + Pol; CFCS - exposure to cigarette smoke associated with coffee immersion; CFCS + Pol. The immersion in coffee was performed for 24 days, simulating 2 years of coffee consumption. The exposure to the smoke of 10 cigarettes daily for a period of 24 dayswas performed using a plastic device connected to a portable suction machine. The mechanical polishing was performed by using an aluminum oxide-based polishing paste and felt wheel coupled to a manual electric motor (3000 rpm), at simulated biweekly time intervals. The surface roughness and color stainability were evaluated by using a digital contact profilometer and a portable spectrophotometer, respectively, before (T0) and after 12 (T1) and 24 days (T2) of the experimental situations described. The data were analyzed by ANOVA-2-way. The Bonferroni test was used for post hoc analysis (α=.05). The highest impact on the association of coffee with cigarettes was observed for color stainability when compared to the isolated groups (CF, CS), generating the highest average values of ΔE00. Regarding color stability, the polishing significantly reduced the color change observed in most experimental conditions, in both materials, even concerning CFCS groups. The polishing protocol tested was able to control thecolor variationin both acrylic resin artificial teeth and denture base acrylic resin, caused by the contact with coffee and cigarette smoke, isolated or associated.