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 self-cured/dual-cured resin cements or composites. Objective: To measure and compare the dentin & un-cut enamel bond strength of OptiBond XTR with a 2-component self-etch adhesive system Clearfil SE Bond (Kuraray) and several total-etch adhesive systems: OptiBond Solo Plus (Kerr), Single Bond Plus (3M ESPE), and OptiBond FL (Kerr). Methods: Dentin substrates were polished with 600 grit SiC paper and bovine enamel substrates were pumice-cleaned prior to bonding. Each adhesive 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. Herculite XRV (A2 shade, Kerr) was condensed into the jig and light cured. The bonded specimens (n=6) were then stored in de-ionized water at 37ºC for 24 hours before being subjected to shear force on an Instron mechanical tester. Results: ANOVA analysis revealed that the dentin bond strength of OptiBond XTR is significantly (p < 0.05) higher than those of Clearfil SE Bond and Single Bond Plus. The enamel bond strength of OptiBond XTR is not statistically different (p > 0.05) from those of total-etch adhesive systems, but is significantly (p < 0.05) higher than that of Clearfil SE Bond.
Adhesive Systems | Type | Shear Bond Strength (MPa) | |
|
| Dentin | Un-cut Enamel |
OptiBond XTR | Self-etch | 38.1±5.7a* | 31.8±3.2A |
Clearfil SE Bond | Self-etch | 20.3±2.4b | 25.7±3.5B |
OptiBond Solo Plus | Total-etch | 31.3±2.7a | 30.8±1.9A,B |
Single Bond Plus | Total-etch | 21.9±3.6b | 29.6±4.2A,B |
OptiBond FL | Total-etch | 32.2±4.9a | 29.4±1.5A,B |
*Means with different letters are statistically different at p < 0.05.
Conclusion: The dentin/enamel bond strengths of OptiBond XTR are comparable or higher than those of total-etch adhesive systems tested in this study, but significantly higher than those of Clearfil SE Bond.