Estudo in vitro da aplicação de plasma de argônio no controle de biofilme de Candida albicans em resina acrílica autopolimerizável

Abstract

Statement of the problem: Candida albicans biofilm control in removable prostheses has been problematic due to the absence of techniques that do not cause the recurrence of infection, microbial resistance and damages to the acrylic resin that compose its. Objective: To evaluate the effects of the application of argon plasma on acrylic resin surfaces as a pretreatment to inhibit the formation of C. albicans biofilm and also its direct antimicrobial action on C. albicans biofilm formed on the studied specimens Materials and Methods: The specimens were sterilized in ethylene oxide gas and submitted to in vitro biofilm growth, which occurred before or after the plasma application. The experimental treatment consisted of the application of argon plasma (99,998% purity, 5 liters per minute, power of 10 W). The specimens divided into groups (n=5): control group (C); pretreatment group; chlorhexidine group (CX); gas group (G); plasma 1 minute group (Pl 1 min) and plasma 2 minutes group (Pl 2 min). Then, after washing of the specimens and serial dilution of the obtained suspension, aliquots of 25μL of each dilution was prepared, with culture medium agar in petri plates, which were incubated for 48 hours at 37oC. The datas of pretreatment plasma groups was analyzed by unpaired T test, and the datas of antimicrobial effects of plasma was analyzed by Kruskal-Wallis and Dunn Test (α=0,05). Results: There was no statistically significant difference between the C (Control) and pretreatment groups (p=0,1566). When the control group (C), Pl 1min, gas group (G) and Cx group were compared, a significant difference was observed among them (p<0,0001). Plasma treatment groups (Pl 1min and Pl 2min), although without statistically significant difference among the times, significantly reduced amount of CFU/ml compared to group (C) and achieved similar results as chlorhexidine. Conclusions: The use of argon plasma as a pretreatment to inhibit biofilm adhesion of Candida albicans on acrylic resin surface was not effective. However, its direct antimicrobial action on the already formed Candida albicans biofilm was effective with results similar to chlorhexidine, considered the gold standard for disinfection.