Sodium Hypochlorite as Fluorotic Dentin Pretreatment of Two-Step Self-Etch Adhesive with Silver Nanoparticle: Atomic Force Microscope and Adhesive Microtensile Bond Strength Evaluation

Abstract

The objective of this work was to evaluate the effect of pretreatment with commercial sodium hypochlorite, 5.25%, with a self-etch adhesive (Optibond Versa) in its original formula and with the incorporation of silver nanoparticles (NaAg) on fluorotic dentin. 240 human molars were classified according to fluorosis severity with Thylstrup-Fejerskov Index (TFI) and subdivided into three study subgroups according to the adhesive technique: (1) self-etch (SE) control subgroup; (2) NaOCl/SE subgroup; (3) NaOCl/SE + NaAg subgroup. The nanostructural characteristics were observed by AFM, μTBS was tested, and hybrid layer formation was observed by SEM. One-way analyses of variance (ANOVA) and Tukey-Kramer post hoc tests were used. No statistically significant differences were found in roughness values in any of the subgroups and subgroups studied. Remnants of smear layer were detected in areas devoid of resin tags in SEM images of samples bonded with subgroup 2, in contrast to subgroup 3. No statistically significant difference between any of the results was found in μTBS and a greater number of adhesive failures were observed. The results show that the pretreatment technique of 5.25% NaOCl and the incorporation of NaAg to the self-adhesive system do not produce a surface more adequate for a better adhesion.