Evaluation of adhesive systems in primary dentin by nanoleakage: effects of aging

Abstract

Nanoleakage evaluation by silver uptake in permanent teeth provides good spatial resolution of submicron defects at the hybrid layer, which have not been tested in primary teeth. Objective:This study evaluated the nanoleakage at the dentin-adhesive interface in primary teeth by two methods, for three adhesive systems, immediately (IM) and six months (6M) after adhesive procedures. Material and methods: Crowns of primary molars were occlusal flat grounded and divided into three groups according to the adhesive system tested (n = 6-7). Scotchbond Multi-purpose/SMP, Single Bond/SB and Clearfil SE Bond/CSB adhesive systems were applied with a composite resin (Filtek Z-250). Crowns were sectioned so that 0.8 mm² sticks were obtained and subdivided depending on the time of evaluation: IM or 6M. They were immersed into silver nitrate solution and evaluated by SEM-EDS. Data (%) were analyzed by ANOVA (p < 0.05) and the scores by Kruskal-Wallis and U Mann-Whitney tests (p < 0.05). Results: There was no difference between groups regarding to the evaluation time (aging) percentage. In terms of scores, there was a significant difference for the adhesive variable: SMP and SB showed similar results with less leakage, while CSB demonstrated higher leakage. Conclusion: Nanoleakage was not influenced by aging, but noticeable difference was observed between total-etch and self-etching adhesives. Total-etch showed better performance.