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

To compare the effects of fluoride and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) containing topical agents on shear bond strength (SBS) and fracture mode of orthodontic brackets bonded to demineralized enamel.

Eighty freshly extracted human premolar teeth were randomly divided into four equal groups. The first group was the control, and no pretreatment was performed on this group. In the remaining three groups, demineralization process was performed and teeth were stored in artificial saliva. In group II, bonding was performed after demineralization. Pretreatment with fluoride and CPP-ACP gels was performed in groups III and IV, respectively. Brackets were bonded using a conventional system. The SBS of these brackets was measured and recorded in MPa. Adhesive remnant index (ARI) scores were determined after the brackets failed. Data were analyzed with analysis of variance (ANOVA), Tukey, and G-tests at the P < .05 level.

ANOVA comparison of four groups revealed statistically significant differences. No significant differences were found between control and CPP-ACP-treated groups. However, lower SBS values were recorded for group II (6.6 ± 3.9 MPa) and group III (17.1 ± 2.9 MPa). ARI scores were significantly different among the four groups (P < .001). No enamel detachment was found in the control group, and enamel detachment measured 75% for group II.

Fluoride and CPP-ACP gel applications showed higher debonding forces compared to bonding in untreated demineralized samples. CPP-ACP pretreatment resulted in comparable SBS values compared with the control group.