Avaliação de métodos de desinfecção/esterilização e seus efeitos sobre a morfologia das pontas polidoras de resina composta

Abstract

The present study aimed to evaluate In situ five methods of disinfection for composite resin finishing points and the In vitro effects on their morphology. For microbiological evaluation 180 composite resin finishing points from three different trademarks (Optimize -TDV Dental, Pomerode, Santa Catarina), Pontas polidoras -DFL Indústria e Comércio SA, Rio de Janeiro; e Jiffy polishers-Ultradent Products, Inc.,South Jordan, UT, USA) were used for In situ finishing on composite resin restorations. The disinfection methods performed were autoclave, peracetic acid 2% for 5 minutes and for 60 minutes, 5.25% sodium hypochlorite for 5 minutes and 60 minutes, and no method of disinfection/sterilization (control group). Test specimens with 5 mm in diameter and 3 mm in height (76) were fabricated in photo-activated composite resin Amelogen (Ultradent Products, Inc.,South Jordan, UT, USA), for evaluation of the surface of points on SEM. These test specimens were finished with points with no previous use, points with one use, points with one disinfection/sterilization cycle and one use, and, finally, with points submitted to five disinfection/sterilization cycles and five uses. After that, these finishing points were evaluated in scanning electron microscopy in high vacuum. The microbiological results were statistically analysed using the Fisher’s test (p < 0.05). Of 180 points, 27.22% were contaminated after disinfection. There was no statistical difference in the microbial growth within the different trademarks of finishing points. The microbial growth was 100% in the control group, 0% in the autoclave, the 13.33% peracetic acid for 5 minutes in 3.33% peracetic acid, 36.66% in 5.35% sodium hypochlorite for 5 minutes and 10% in 5.25% sodium hypochlorite for 60 minutes. Furthermore, the points subjected to methods of disinfection and sterilization suffered morphological changes that could be observed by scanning electron microscopy. Microbiologically, the points that were submitted to the autoclave, the peracetic acid for 5 minutes, the peracetic acid for 60 minutes and 5.25% sodium hypochlorite for 60 minutes showed no statistical differences. All these methods of disinfection/sterilization were effective. The autoclave is the safer sterilization method and it is the one indicated by the manufacturers. Sodium hypochlorite 5, 25% for 5 minutes was the method of disinfection that showed the worst performance.