Comparing the Effect of Two Different Remineralizing Agents on Shear Bond Strength of Orthodontics Brackets

Objective: This study was conducted to evaluate shear bond strength of orthodontic brackets bonded to demineralized enamel, which in turn were pretreated with glass ionomer (Clinpro XT Varnish) modified with resin or resin infiltrate (Icon) of low-viscosity. Methods: A total of 45 human maxillary premolars were allocated into three groups (n = 15). In all groups, the buccal surfaces were subjected to the cariogenic challenge to initiate white spot lesions. In group I, the lesions were treated with resin infiltrate while, in Group II, the lesions were treated with Clinpro XT Varnish, in Group III the buccal surfaces were untreated which used as control. Transbond XT adhesive system was used and shear bond strength was tested by a universal testing machine. Samples were examined under scanning electron microscopy (SEM) after treatment of enamel surfaces. Statistical analysis was performed by ANOVA tests followed by post-hoc Tukey test. Results: The two tested groups showed significantly higher shear bond strength than the control group. SEM images revealed that cohesive failure mode and the combination bracket/adhesive interface respectively were more noticeable in group II (Clinpro XT) than in group I (Icon). Conclusion: Preconditioning of demineralized enamel with resin infiltrate (Icon) or Clinpro XT Varnish did not cause any impairment to the shear bond strength of the orthodontic brackets but rather caused its increase.