ISPUB.COM The Internet Journal of Dental Science Volume 6 Number 2 1 of 7 Micro-tensile bond strength of one-step adhesives to dentin K Abdelaziz, N Ayad Citation K Abdelaziz, N Ayad. Micro-tensile bond strength of one-step adhesives to dentin. The Internet Journal of Dental Science. 2008 Volume 6 Number 2. Abstract Purpose: To evaluate the micro-tensile bond strength of 2 one-step adhesive systems and a 1 two-step etch-and-rinse to dentin before and after thermal cycling. Materials and Methods: Occlusal surfaces of 30 extracted human molars were prepared using diamond tips to expose flat dentin surfaces. Two one-step, G-Bond (GB) and Adper Prompt L-Pop (APL), and 1 two-step, Excite (Ex), adhesive systems were applied to bond composite to the prepared dentin surfaces. The prepared specimens were sectioned for micro-tensile bond strength testing (µTBS). The de-bonding patterns of the fractured specimens were also analyzed. Results: The one-way ANOVA test indicated presence of differences between the bond strength of different adhesives to dentin before and after thermal cycling (ANOVA, p < 0.001). There was no statistical difference between the 2 one-step adhesives (Tukey's comparison, P > 0.05) before or after thermal cycling. This difference was not statistically significant (Tukey's comparison, P > 0.05) when the bond strength of unthermal-cycled G-bond was compared with the control (Excite) or the thermal-cycled G-bond was compared with the thermal-cycled (Excite). The admix (adhesive/cohesive) de-bonding was the dominant pattern of specimens' failure. Conclusion: The one-step adhesive APL does not perform worse regarding µTBS, (16.3 ± 2.7) than the newer one GB (18.4 ± 4.9). The µTBS of GB is also comparable to that of the control, Ex two-step adhesive (20.9 ± 2.4). Thermal cycling has no statistically significant deteriorating effect on the performed bond of different adhesives under investigation, APL-Th (13.1 ± 1.2), GB-Th (14.7 ± 2.4), Ex-Th (18.4 ± 1.7). INTRODUCTION Restoring teeth with minimal sacrifice of sound tooth structure currently forms the basis of restorative dentistry. Essential in achieving this goal is the adhesive that provides strong and durable bond to the remaining sound tooth tissues especially when shrinking materials such as resin composites are planned to be used. 1 , 2 The early successful adhesive systems have typically accomplished resin-dentin bonding in three steps respectively are the etching, priming, and application of bonding resin. 3 Using these systems, the quality of the created bond is greatly influenced by the duration of the etching process, and by the amount of dentin surface humidity following rinsing of the etching acid and prior to resin infiltration. 4 Therefore, most of the recent researches and developments in dentin adhesion are directed to simplify the bonding procedures and to eliminate all possible technical sensitivities by reducing the number of bonding steps. These developments have been started when the primer and bonding resins were combined together in one bottle. The self-etching primers were then released with the ability to etch and prime the dentin in one step. 4 , 5 The self-etching approach seemed promising as it reduces the chair-side time, and eliminates the critical and difficult standardization of the bonding steps. 6 The one-step self-etch adhesives were subsequently introduced simplifying the conditioning, priming, and bonding procedures just in a single step. However, the early types of these adhesive systems seemed to achieve lower bond strength values in comparison to the two-step systems. 7 , 8 Newer types of the one-step self-etching adhesive systems have recently been introduced to the market claiming to have higher bond strength via formation of an unusual very thin interaction layer. 9 , 10 A conflict was raised regarding the success of these