Soft adhesives may cause more iatrogenic damage than hard adhesives during cleanup following bracket removal.

Abstract

Objectives: To determine if adhesive remnants and enamel loss after debonding and cleanup with a finishing bur were affected by hardness properties of the adhesive resins.

Materials and methods: Stainless steel orthodontic brackets (American Orthodontics, Mini Master series) were bonded on facial surfaces of extracted premolars using a relatively soft bioactive resin (ACTIVA BioACTIVE-Restorative, Pulpdent) or harder traditional adhesive (Transbond XT, 3M; N = 20/group). Bracketed teeth underwent 5000 thermocycles before brackets were debonded. Debonding surfaces were examined qualitatively and categorized by three examiners. Remaining adhesive was removed with a carbide finishing bur. Teeth were scanned with an optical scanner before brackets were bonded (baseline), after debonding, and after cleanup. Surface changes (mean thickness or depth, affected surface area, and volume) were calculated quantitatively after aligning scans to the baseline. Differences between the two groups were analyzed statistically with Mann-Whitney U-test or pairwise comparison at a significance level of 0.05.

Results: Qualitative examination of debonded surfaces did not show a significant difference (P = .7949) in adhesive remnants between groups, which was confirmed by quantitative evaluation (P > .05). After cleanup, enamel loss was significantly higher in the softer bioactive resin group (mean depth = 91 ± 16 µm, area = 24.48 ± 9.88 mm2) than the harder traditional adhesive (mean depth = 66 ± 9 µm, area = 6.34 ± 4.41 mm2; P < .0001).

Conclusions: The likelihood of adhesive remnants after debonding a bracket bonded with the bioactive resin was similar to traditional adhesive. However, enamel loss from cleaning up with a finishing bur was higher for the softer bioactive resin.