Immediate bonding properties of universal adhesives to dentine

Objectives: To evaluate the dentine microtensile bond strength (mu TBS), nanoleakage (NL), degree of conversion (DC) within the hybrid layer for etch-and-rinse and self-etch strategies of universal simplified adhesive systems. Methods: forty caries free extracted third molars were divided into 8 groups for mu TBS (n = 5), according to the adhesive and etching strategy: Clearfil SE Bond [CSE] and Adper Single Bond 2 [SB], as controls; Peak Universal Adhesive System, self-etch [PkSe] and etch-and-rinse [PkEr]; Scotchbond Universal Adhesive, self-etch [ScSe] and etch-and-rinse [ScEr]; All Bond Universal, self-etch [AlSe] and etch-and-rinse [AlEr]. After restorations were constructed, specimens were stored in water (37 degrees C/24 h) and then resin-dentine sticks were prepared (0.8 mm(2)). The sticks were tested under tension at 0.5 mm/min. Some sticks from each tooth group were used for DC determination by micro-Raman spectroscopy or nanoleakage evaluation (NL). The pH for each solution was evaluated using a pH metre. Data were analyzed with one-way ANOVA and Tukey's test (a = 0.05). Results: For mu TBS, only PkSe and PkEr were similar to the respective control groups (p > 0.05). AlSe showed the lowest mu TBS mean (p < 0.05). For NL, ScEr, ScSe, AlSe, and AlEr showed the lowest NL similar to control groups (p < 0.05). For DC, only ScSe showed lower DC than the other materials (p < 0.05). Conclusions: Performance of universal adhesives was shown to be material-dependent. The results indicate that this new category of universal adhesives used on dentine as either etch-and-rinse or self-etch strategies were inferior as regards at least one of the properties evaluated (mu TBS, NL and DC) in comparison with the control adhesives (CSE for self-etch and SB for etch-and-rinse). (C) 2013 Elsevier Ltd. All rights reserved.