Effects of three adhesion promoters on the shear bond strength of new and recycled orthodontic brackets—an in vitro study

Abstract

Introduction This study was done to determine the effect of 3 adhesion promoters: Ortho Solo™ (Ormco), ALL-BOND 2® (Bisco), and Enhance L.C. (Reliance) on the shear bond strength of new and recycled orthodontic brackets and the amount of remnant adhesive on the teeth after debonding and to verify whether Enhance L.C. is material specific as stated by the manufacturer. Materials and Method This in vitro study was carried out on 120 premolar teeth which were bonded to 0.018 Roth premolar brackets. These teeth were divided into 6 groups of 20 with 2 subgroups—new group and recycled group. Brackets were bonded according to manufacturer's instructions: 1) Transbond™ XT 2) Transbond™ XT+ALL-BOND 2® 3) Transbond™ XT + Ortho Solo™ 4) Transbond™ XT + Enhance L.C. 5) Light Bond™ 6) Light Bond™ + Enhance L.C. Bond strength was tested on a universal testing machine and remnant adhesive on the tooth surface was determined. Kruskal-Wallis test and Mann-Whitney test were carried out to know the significant difference between the groups. Chi-square test was used to determine significant differences in the Adhesive Remnant Index (ARI) scores between the scores. Weibull analysis was performed to know the percentage of bracket failures among the groups tested. Results There was no significant difference between the groups with respect to the median load (p<0.001). Higher mean load was recorded in Group Via (Light Bond™ + Enhance L.C.) and least in Group lb (recycled with Transbond™ XT). Chi-square test showed no significant association between the ARI scores and the different groups. Conclusion Recycling brackets with Ashpol electropolishing liquid can serve them as new brackets in terms of the clinically acceptable bond strength. It is preferable to use Enhance L.C. with Light Bond™ when greater bond strength is required with new brackets.