Elaboração de um protocolo de esterilização de espécimes de resina acrílica em micro-ondas.

Abstract

Aims: The purpose of this work was to establish sterilization parameters with microwave irradiation for acrylic resin specimens, without impairment of their main physico-mechanical properties. Materials and Methods: Microwave irradiation was carried out for 3 or 5 minutes associated with potencies of 450W or 650W with the specimens immersed in 250 mL of distilled water. In the first stage of this study, the specimens were submitted to monospecific biofilm formation of Staphylococcus aureus and Candida albicans, before being irradiated (n = 18). After irradiation, a thioglycollate sterilization test was performed with 14 days of incubation at 37 ° C, in order to check the turbidity of the medium. In the second stage, samples were tested for surface roughness (Ra, μm; n = 40) as well as Knoop microhardness (kg / mm2; n = 40) and dimensional stability (mm; n = 40) before and after the irradiation protocols. Statistical analyzes were performed under confidence interval of 95% ( = 0.05). Results: All irradiation parameters (450W / 650W for 3/5 minutes) were able to sterilize the samples exposed to S. aureus and C. albicans, except the protocol 450W/3 minutes. There were no statistically significant differences between the control group and the parameters tested (p> 0.05) for roughness and dimensional stability. Only the parameter 450W / 3 minutes did not cause significant statistical differences in microhardness values. Conclusion: The parameters 450W / 5 minutes and 650W / 3 and 5 minutes can be considered safe values for the elaboration of a sterilization protocol, however further studies, both mechanical and microbiological, are still necessary to consolidate these parameters.