Avaliação da resistência de união em dentina humana submetida a diferentes formas de armazenagem

Introduction and objective: Human teeth are frequently used in laboratory and research activities. The aim of this study was to evaluate the bond strength of human dentin subjected to different forms of storage. Material and methods: Fifteen intact third molars were selected and divided into three experimental groups (n = 5): 1) teeth sterilized by autoclave for 15 minutes (121°C) and frozen in distilled water for 60 days; 2) teeth immersed in 2% glutaraldehyde solution for 24 hours and frozen in distilled water for 60 days; 3) only frozen in distilled water for 60 days (control). Samples were prepared with a diamond disk under cooling until obtaining flat surfaces of middle dentin, which were exposed by wet abrasion with 600-grit SiC paper in order to create smear layer prior to hybridization. The conventional adhesive system Adper Single Bond 2 and the composite Filtek Z250 (3M Espe) were used according to manufacturer's instructions. Tygon tubing molds were placed on each sample and its internal volume was filled with the composite. After photoactivation, the molds were removed and the specimens were exposed and stored in distilled water at 37°C for 24 hours before microshear bond strength test. Results: The bond strength was calculated in MPa±SD, and data were statistically analyzed by Anova and Tukey test at 5% significance level. Data showed that the control group presented bond strength statistically higher than the other experimental groups. Conclusion: The autoclaving and immersion in glutaraldehyde solution reduced significantly the bond strength in human dentin when compared to frozen teeth in distilled water.