Micro-tensile bond strength to bovine sclerotic dentine: influence of surface treatment.

OBJECTIVE

The objective of this study was to evaluate the influence of the surface treatment and acid conditioning (AC) time of bovine sclerotic dentine on the micro-tensile bond strength (micro-TBS) to an etch and rinse adhesive system.

MATERIALS AND METHOD

Thirty-six bovine incisors were divided into six groups (n=6): G1 sound dentine submitted to AC for 15s; G2-G6 sclerotic dentine: G2-AC for 15s; G3-AC for 30s; G4-EDTA and AC for 15s; G5-diamond bur and AC for 15s; G6-diamond paste and AC for 15s. An adhesive system was applied to the treated dentine surfaces followed by a hybrid composite inserted in increments and light cured. After 24h storage in water at 37 degrees C, the specimens were perpendicularly cut with a low-speed diamond saw to obtain beams (0.8 mm x 0.8 mm cross-sectional dimensions) for micro-TBS testing. Data was compared by ANOVA followed by Tukey's test (p<or=0.05).

RESULTS

The mean micro-TBS was G1: 18.87+/-5.36 MPa; G2: 12.94+/-2.09 MPa; G3: 11.73+/-0.64 MPa; G4: 11.14+/-1.50 MPa; G5: 22.75+/-4.10 MPa; G6: 22.48+/-2.71 MPa. G1, G5 and G6 presented similar bond strengths significantly higher than those of all other groups.

CONCLUSION

The surface treatment of sclerotic dentine significantly influenced the bond strength to an adhesive system. Mechanical treatment, either using a diamond bur or a diamond paste was able to improve bonding to bovine sclerotic dentine, reaching values similar to bonding to sound dentine.