Adherence of Streptococus mutans to the surface of direct-use composites submitted to different polishing techniques

ABSTRACT

The purpose of this study was to evaluate the adherence of Streptococcus mutans to the surface of direct-use composites submitted to different polishing techniques. Cylindrical specimes were made of resins Filtek Z250®; Filtek A110®; Filtek P60® and Filtek Supreme®. The samples were grouped in accordance with the surface treatment poliester matrix (without polishing); brush technique (without polishing); Sof-Lex® disks; fine grain and extra-fine grain diamond points; carbide burs with 12 and 30 blades; diamond points associated with silicone points (Enhance® system); and multibladed burs associated with silicon points. In a sterile laminar flux apparatus the samles were disinfected and placed in Petri dishes where BHI sucrose broth was added and S. mutans ATCC 25175 was inoculated in a such a manner that the study surface was turned upwards (incubation at 35+ - 2°C). After 24 and 72 hours, three previously calibrated examiners used a stereomicroscope to classify the samples with regard to the presence and thickness of the pellicle and quantity of colonies. The data were statistically analyzed nonparametric tests of Mann Whitney and Student-New-man-Keuls (p<0,05). The microhybrid resin exhibited the same indexes of adherence when compared to both the microparticle and the nanoparticle, and lower adherence than packable composite.Among the polishing systems, the most effective were the multibladed burs and diamond points used before the silicon points. For the obtainment of a smooth surface by means of polishing, it is necessary to inhibit the impregnation of bacteria on the composite resin restorations.