Effect of aging on ¥ì-TBS to dentin of self-etching adhesives

Objectives: The purpose of this in vitro study was to compare the micro-tensile bond strength (m-TBS) of self-etching adhesives to dentine according to aging methods and periods. Methods: Thirty-six human molars within one month from extraction were used in this study. The dentin surfaces were ground flat on 500 grit SiC paper. One total-etching (Single Bond; SB), one self-etching primer (SE-Bond; SE) and two self-etching adhesives (Xeno-¥²; X¥² and Adper Prompt; AP) were applied according to the manufacturer's instructions on the dentine and followed by bonding composite resin (Z250). The samples were divided into three groups. Group 1 and 2 were stored in DW for 48 h and 1 week, respectively. For group 3, 5000 cycles of thermo-cycling at 5-55C were performed. After the aging, m-TBS test was performed at a cross-head speed of 1 mm/min. The results were analyzed by One-Way ANOVA at a significant level of 0.05 using SPSS program. Results: The m-TBS of SB were 45.25(5.68 (Gr 1)), 42.84(8.35 (Gr 2)), and 39.64(13.97 (Gr 3)) in Mpa (p > 0.05). For SE, the m-TBS were 33.7(9.72 (Gr 1)), 43.53(8.56 (Gr 2)) and 41.48(13.7 (Gr 3)). There was significant increase in Gr 2 and 3 in comparison to Gr 1 (p < 0.05) for SE. For AP, the m-TBS showed significant increase (17.24(3.8 (Gr 1)), 21.58(4.83 (Gr 2)) and 26.07(2.35 (Gr 3)) with aging processes (p < 0.05). X¥² also showed a tendency of increasing m-TBS, that is, 24.64(9.89 (Gr 1)), 26.3(11.91 (Gr 2)) and 28.11(9.22 (Gr 3)), but not significant (p > 0.05). Conclusion: The bond strength of the self etching primer and adhesive systems increased significantly with aging processes in contrast to the total etching adhesive. Supported by the KSEF through IBEC at SNU.