The effect of additional etching and curing mechanism of composite resin on the dentin bond strength

ABSTRACT

PURPOSE: The aim of this study was to evaluate the effects of additional acid etching and curing mechanism (light-curing or self-curing) of a composite resin on the dentin bond strength and compatibility of one-step self-etching adhesives. MATERIALS AND METHODS: Sixteen human permanent molars were randomly divided into eight groups according to the adhesives used (All-Bond Universal ABU, Clearfil S3 Bond CS3), additional acid etching (additional acid etching performed EO, no additional acid etching performed EX), and composite resins (Filtek Z-250 Z250, Clearfil FII New Bond CFNB). Group 1 ABU-EO-Z250, Group 2 ABU-EO-CFNB, Group 3 ABU-EX-Z250, Group 4 ABU-EX-CFNB, Group 5 CS3-EO-Z250, Group 6 CS3-EO-CFNB, Group 7 CS3-EX-Z250, Group 8 CS3-EX-CFNB. After bonding procedures, composite resins were built up on dentin surfaces. After 24-hour water storage, the teeth were sectioned to make 10 specimens for each group. The microtensile bond strength test was performed using a microtensile testing machine. The failure mode of the fractured specimens was examined by means of an optical microscope at x20 magnification. The data was analyzed using a one-way ANOVA and Scheffe's post-hoc test (alpha=.05). RESULTS: Additional etching groups showed significantly higher values than the no additional etching group when using All-Bond Universal. The light-cured composite resin groups showed significantly higher values than the self-cured composite resin groups in the Clearfil S3 Bond. CONCLUSION: The additional acid etching is beneficial for the dentin bond strength when using low acidic one-step self-etch adhesives, and low acidic one-step self-etch adhesives are compatible with self-cured composite resin. The acidity of the one-step self-etch adhesives is an influencing factor in terms of the dentin bonding strength and incompatibility with a self-cured composite resin.