Debonding forces of a bioactive material compared with those of resin-based and glass ionomer-based orthodontic adhesives

Introduction

This study investigated if a bioactive material used for bonding orthodontic brackets had bond strength comparable to a conventional resin-based adhesive in combination with the potential of reducing white spot lesions like a glass ionomer-based adhesive.

Methods

Brackets were bonded to 90 premolars, extracted for orthodontic purposes, with a bioactive, conventional resin-based, or glass ionomer material. Brackets were debonded by a shear force using a universal testing machine after 24 hours or after artificial aging (thermocycling) with or without subsequent acid challenge. Removal forces were compared among the 9 groups (n = 10/group). After debonding, adhesive remnants were indexed, and the demineralization around the brackets was measured. In addition, the diametral tensile strength of each material was determined.

Results

Materials (bioactive, conventional, and glass ionomer) had a significant effect on debonding forces (P <0.001; 2-way analysis of variance), whereas conditions (24-hour, aged, and aged + acid challenged) had no significant effect (P = 0.811). Bond strengths correlated positively with diametral tensile strengths (r = 0.67). The bioactive material generally had bond strengths comparable with those of the conventional adhesive and higher than those of the glass ionomer. Surface demineralization with the bioactive adhesive was similar when compared with that of the glass ionomer group and significantly lower than that of the conventional adhesive group (P <0.001). Significantly less adhesive remnant was left by the bioactive resin in the aged + acid-challenged group (P = 0.001).

Conclusions

Debonding forces for brackets bonded with the bioactive resin were comparable to those of a conventional orthodontic adhesive. In vitro, the bioactive resin showed the potential to reduce demineralization around the brackets, similar to glass ionomer cement.