This work is licensed under Creative Commons Attribution–NonCommercial International License
(CC BY-NC 4.0).
Background: Dental fluorosis alters enamel microstructure through increased porosity, subsurface
hypomineralization, and irregular prism formation, resulting in compromised etching patterns and reduced shear
bond strength (SBS) during orthodontic bonding. Casein phosphopeptide–amorphous calcium phosphate (CPPACP) has demonstrated remineralization potential, but its effect on bonding to fluorosed enamel remains
insufficiently explored.
Aim: To evaluate the effect of CPP-ACP pretreatment on the shear bond strength of orthodontic brackets bonded to
fluorosed enamel and to assess the mode of bond failure using the Adhesive Remnant Index (ARI).
Materials and Methods: Thirty-eight premolars with moderate fluorosis (TFI 4–5) were confirmed using laserinduced fluorescence and TFI scoring, then randomly allocated into two groups (n = 19):Group I: Control (no
pretreatment).
Group II: Experimental (CPP-ACP applied twice daily for three weeks).
All samples underwent standardized bonding procedures, thermocycling, SBS testing using a universal testing
machine, and ARI evaluation. Data were analyzed using independent samples t-test and Chi-square test (p < 0.05).
Results:CPP-ACP significantly increased both maximum load and SBS compared with untreated fluorosed enamel
(p < 0.001). SBS improved from 14.8 ± 1.3 MPa in the control group to 23.2 ± 2.6 MPa in the treated group. ARI
scores also differed significantly between groups (p < 0.05), with the CPP-ACP group exhibiting higher
frequencies of ARI 2 and 3, indicating improved enamel–adhesive interface integrity.
Conclusion:CPP-ACP pretreatment substantially enhances the shear bond strength of orthodontic brackets bonded
to moderate fluorosis teeth, and it also modifies the failure pattern toward more favorable ARI scores. This
suggests that CPP-ACP may serve as an effective, noninvasive adjunct to improve bonding reliability in patients
with moderate dental fluorosis.