Do enamel microabrasion and casein phosphopeptide-amorphous calcium phosphate affect shear bond strength of orthodontic brackets bonded to a demineralized enamel surface?

OBJECTIVE

To evaluate and compare the effects of enamel microabrasion, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and their combination on the shear bond strength (SBS) of orthodontic brackets bonded to demineralized enamel surface.

MATERIALS AND METHODS

One hundred human first premolar teeth were randomly allocated to one of five groups. Group I was considered as the control of other groups. For the remaining groups, demineralization was performed via solutions. In group II, brackets were directly bonded to the demineralized enamel surface. CPP-ACP was applied in group III, microabrasion was performed in group IV, and both microabrasion and CPP-ACP application were performed in group V. The specimens were tested for SBS. Bond failures were scored according to the Adhesive Remnant Index (ARI). Analysis of variance and Tukey tests were used to compare the SBS of the groups. ARI scores of the groups were evaluated with a G-test. The statistical significance was set at P <. 05 level.

RESULTS

Statistically significant difference was found among the five investigated groups (F  =  111.870; P < .001). The SBS of groups II and IV were significantly lower than the other groups. No statistically significant difference was found among groups I (control; mean 24.1 ± 4.1 MPa), III (mean 22.0 ± 3.6 MPa), and V (mean 24.3 ± 1.9 MPa). Microabrasion and combination with CPP-ACP showed higher SBS compared to the control group. The differences between ARI scores of the groups were statistically significant (P < .001).

CONCLUSION

CPP-ACP pretreatment, microabrasion of the enamel, and the combination of these two methods improve the bonding to demineralized enamel.