Indirect Bond Strength to Dentin of Various Adhesive/Cement Combinations

Objectives: To evaluate indirect shear bond strength (SBS) to dentin of Optibond eXTRa Universal/NX3 (Kerr) and Optibond eXTRa Universal/Maxcem Elite (Kerr) adhesive/cement combinations along with several commercial adhesive/cement combinations (listed in the table).
Methods: Dentin substrates were polished with 600 grit SiC paper prior to bonding. Each adhesive was applied per its manufacturer's instructions. After light curing, a bonding jig (Ultradent) with a cylindrical mold (D=2.38mm) was securely placed on adhesive-covered substrate. The cement from the same manufacturer as the adhesive was condensed into the mold, and self-cured for one hour at 37°C (~90% humidity). The bonded specimens (n=6) were then stored in deionized water at 37°C for 24 hours before being subjected to shear force on an Instron mechanical tester following ISO29022:2013. Statistical analysis was performed using One-way ANOVA and Tukey’s method for pair-wise comparison to determine significant differences among groups (p<0.05).
Results: The results are summarized in the table below. The SBS of Optibond eXTRa Universal and OptiBond XTR paired with either NX3 or Maxcem Elite are not statistically different (p>0.05) from each other, but are significantly higher (p<0.05) that those of other adhesive/cement combinations.
Conclusions: Conclusions: Both Optibond eXTRa Universal and OptiBond XTR when paired with either NX3 or Maxcem Elite yielded higher SBS than other adhesive/cement combinations, suggesting excellent bond compatibility of two Optibond adhesives with either NX3 or Maxcem Elite resin cement.