Effect of Highly Filled Light-Cured Resin Sealant on Bracket Shear Bond Strength in Demineralization Conditions

Abstract

This study examined the effect of a highly filled light-cured sealant (HFLCS) on bracket shear bond strength and subsequent adhesive remnant index (ARI) following exposure to cariogenic challenge. Specimens were divided into two groups to receive conventional primer or HFLCS prior to orthodontic bracket bonding in a simulated oral environment. After curing bracket adhesive, specimens were separated into two storage solutions, either phosphate buffered saline or a demineralization solution (pH 4.1) for 96 hours. Brackets then underwent shear bond strength testing followed by ARI scoring. Enamel surfaces were visually examined for white spot lesion (WSL) severity using a WSL scoring index. HFLCS and exposure to demineralization conditions were not significant factors in shear bond strength or subsequent adhesive fracture pattern (ANOVA, p>.05). The majority of brackets were given an ARI score of 1, meaning that greater than 50% of the resin adhesive remained on the bracket. A significant difference (p<0.05) was detected in WSL scores between the HFLCS and conventional primer groups when exposed to demineralization conditions. With HFLCS, no specimen developed WSLs, while all specimens with conventional primer had either minor or severe WSL formation after cariogenic challenge. This investigation suggests that HFLCS did not have a protective effect on bracket bond strength in demineralization conditions, but HFLCS was effective in preventing enamel demineralization without compromising shear bond strength.