Avaliação do efeito da imersão em diferentes soluções de limpeza na dureza, rugosidade e estabilidade de cor de dentes artificiais de resina acrílica

Abstract

To be appropriate for use, chemicals for cleaning dentures should not affect the properties of artificial teeth. This study evaluated the effect of cleansers solutions (Sodium hypochlorite 0.5%, Chlorhexidine 0.12%, vinegar and alkaline peroxide) and a control (distilled water) on the Vickers hardness, surface roughness (Ra) and color stability of artificial acrylic resin teeth (Platinum TRI Bionew and 3G). To assess hardness and roughness, 80 maxillary central incisors was selected, which were included in PVC tubes and had planed their buccal surface with water sandpaper and polished with felt and alumina. 5 immersion groups were allocated (n = 8). We selected 50 maxillary lateral incisors for color stability, keeping them without prior finishing treatment. 5 immersion groups were allocated (n = 8). The bodies-specimens were immersed for 120 days in substances, with daily exchanges, simulating a daily cleaning during 12 months. The Vickers hardness and roughness (Ra) were measured at baseline (t = 0), 60 days (t = 60) and 120 days (t = 120) and the means were analyzed by Kruskal-Wallis and Mann-Whitney (p <0.05). The color was measured at baseline (t = 0) and 120 days (t = 120) and measurements were analyzed by Kruskal-Wallis and Student-Newman-Keuls tests. Results showed that for platinum TRI the roughness average increased from t = 0 to t = 60 in TA, TV and TP groups and significantly reduced only in the group TC. In the interval t = 120, non group showed difference compared with t = 60. There was a statistically significant reduction in hardness between t = 0 and t = 60 for all groups, including the control and T = 120 showed an increase in hardness for all groups, however, still maintaining statistically lower than the initial. In relation to color stability, no significant difference between the groups after 120 days. For groups of Bionew 3G, DV group showed a statistically significant increase in roughness and the DCL decreased, while the DA, DH and DP groups showed no difference. Regarding hardness, all groups decreased at t = 60, and the DH, DP and DV groups increased at t = 120, which did not happen with DA and DC. On color stability, there was no difference between the color of the materials after 120 days of treatment with water, hypochlorite, peroxide and chlorhexidine. However, vinegar had significant difference in all solutions. It was concluded that all the solutions decreased the hardness, changed the color and none affected the roughness, except vinegar and chlorhexidine.