Influence of low viscosity resin infiltrant on the adhesion of orthodontic attachments.

INTRODUCTION: The search for materials and techniques that promote better adhesion to enamel previously affected by carious lesions has intensified in orthodontics, especially with the use of infiltrating resins and composites with different characteristics. OBJECTIVE: To evaluate the adhesion of orthodontic attachments made with different composites bonded to previously infiltrated enamel. METHODS: Ninety bovine lower incisors were randomly divided into 6 groups (n=15): 1 control Z350 (group C) and 5 experimental: Z350 (group Z), bulk fill - 3M (group FM), bulk fill flow - 3M (group FFM), bulk fill - FGM (group FF), bulk fill flow - FGM (FFF). Each group differed by the type of composite used to attachment. Only the experimental groups were subjected to cariogenic challenge followed by treatment with Icon, a low viscosity resinous infiltrant. After aging, orthodontic attachments were bonded to all specimens (n=90) and a mechanical shear bond strength test was performed with subsequent analysis of the adhesive remnant index (ARI). Data were analyzed using Jamovi software version 2.3 with a significance level of 5%. Descriptive statistics (means and standard deviations), normality test and ANOVA/Tukey for shear variables and Kruskal-Wallis test for ARI were performed. RESULTS: The control group required greater force to shear the attachment (100N ± 32.6; p= 0.016), while the group that used the Bulk Fill Flow FGM composite required less force (55.6N ± 22.5; p= 0.016). CONCLUSION: The presence of resin infiltrant influenced the adhesion of orthodontic attachments, made with different composites. However, it did not interfere with ARI.