Bond Durability of OptiBond XTR Self-Etch Adhesive System

OptiBond XTR (Kerr), a new 2-component light-curable self-etching adhesive system, was recently developed with improved bond strength to dentin/enamel and enhanced bond compatibility with all self-cured/dual-cured resin cements or composites.   Objective: To study the bond durability of OptiBond XTR self-etch adhesive system to dentin and un-cut enamel substrates.  Methods: Dentin substrates were polished with 600 grit SiC paper and bovine enamel substrates were pumice-cleaned prior to bonding.  OptiBond XTR adhesive system was applied according to manufacturer's instructions and a bonding jig (Ultradent) with a cylindrical mold (D=2.38mm) was securely placed on adhesive-covered substrate surface.  Herculite XRV (A2 shade, Kerr) was then condensed into the jig and light cured.  The shear bond strength was tested after the bonded specimens (n=6) were: (i) stored in de-ionized water (37°C) for 24 hours (initial); (iii) stored in de-ionized water (37°C) for 1 week; (iii) stored in de-ionized water (37°C) for 1 month; and (iv) stored in de-ionized water (37°C) for 24 hours and then thermocycled for 5,000 cycles (5/55°C).  Results:  ANOVA analysis revealed that there were no statistical differences (p > 0.05) among the bond strengths after 24-hour storage, 1-week storage, 1-month storage, and thermocycling. 

                *Means with the same letter are not statistically different at p > 0.05.

Conclusion:  The bond strength of OptiBond XTR self-etch adhesive system to both dentin and un-cut enamel substrates is quite stable and is not negatively affected by thermocycling and increased storage time in de-ionized water.