The effect of repeated bracket recycling on the shear bond strength of different orthodontic adhesives

Aim: The aim of this study was to evaluate the effect of two consecutive recycling procedures on the shear bond strength of different orthodontic adhesives.
Methods: Edgewise brackets were bonded to the buccal surfaces of 40 bovine incisors using the following bonding materials: Concise (group I), Transbond XT (group II), Smart Bond (group III) and Fuji Ortho (group IV). The teeth were stored in water at 37°C for 24 h, thermocycled between 5 and 55°C, and debonded using an Instron machine at a crosshead speed of 0.5 mm/min. In all groups, the bonded brackets were detached and rebonded after recycling by 50-μm particle aluminum oxide blasting. After the second recording of retentive strengths, the recycling procedure, the rebonding and the shear bond strength test were repeated. Data were analyzed statistically by ANOVA and Tukey’s test at 5% significance level.
Results: The results showed that repeated recycling did not interfere in retention of brackets, regardless of the adhesive used. The highest shear bond strength values were obtained after bonding with Transbond XT, independent of the recycling procedure.
Conclusion: Repeated bracket recycling using 50-μm aluminum oxide particle air abrasion did not affect the shear bond strength of metallic brackets bonded with different orthodontic adhesives.