Estimation and comparison of tensile bond strengths at resin-dentin interface of total-etch and self-etch bonding systems

Abstract

Objective: To estimate and compare the Tensile Bond Strengths and to observe the resindentin interface of total-etch and self-etch bonding systems to dentin of primary and permanent molar teeth.
 Method: Thirty non-carious exfoliated primary human molars and thirty extracted permanent molars were randomly assigned to four groups according to adhesives used. The specimens were subjected to tensile bond strength (TBS) testing at a crosshead speed of 1 mm/min. Mean TBS was statistically analyzed with student ‘t’ test. Interfacial morphologies were analyzed by Scanning Electron Microscopy (SEM).
 Result: Etch-and-rinse adhesive Adper Single Bond 2 Total Etch® yielded high bond strength when applied to both primary and permanent dentine. For the one-step Adper Easy One® self-etching adhesive, the bond strength was relatively low regardless of the dentine type. SEM interfacial analysis revealed funnel shaped resin tags and a rough hybrid layer in specimens subjected to total etch system and cylindrical shaped and a smooth hybrid layer in specimens subjected to self etch system in both primary and permanent teeth. 
 Conclusion: The total-etch systems provide better adhesion to primary and permanent tooth dentine. The self etch systems though convenient to use, do not match the bond strengths of conventional total etch systems. Also, it can be concluded that both adhesives show weaker bond strengths to primary tooth dentin.