Influência da barreira de proteção na capacidade de fotopolimerização de resinas bulk fill

Abstract

The objective of this laboratory research was to evaluate whether the protection barrier applied at the tip of the curing light interferes with the polymerization of bulk fill resins. Four bulk fill resins (2 of regular consistency and 2 of fluid consistency) were evaluated, in addition to a conventional resin (control group). The samples were prepared in prefabricated matrices, with a resin insertion hole measuring 6 mm in diameter x 2 mm in depth for the control group and 6 mm in diameter x 4 mm in depth for the bulk fill resins, following the photopolymerization indicated by the manufacturers. 300 specimens were made, divided into 5 groups (60 specimens for each resin) polymerized by 3 photopolymerization devices of different commercial brands. Within each group, 20 specimens were polymerized by each curing light (10 specimens using the protective barrier and 10 without its use). The specimens were submitted to the top and bottom Knoop microhardness test and the results were statistically analyzed by analysis of variance (ANOVA) with a significance level of 5%, verifying that in the 5 groups the base/top ratio was significantly lower when the protection barrier was used on the light-emitting tip of the curing light. Thus it is concluded that the higher base/top ratio is directly linked to the better performance of the curing light, indicating that in this study the disposable protective barrier negatively influenced the light curing of bulk fill resins.