Effect of thermal recycling of metal brackets on shear and tensile bond strength

Aim: The study was undertaken to measure the changes within the mesh pad associated with reconditioning process, measure the bond strength of new and reconditioned orthodontic brackets and correlate the changes in mesh strand diameter with changes in bond strength. Material and methods: 120 clinically normal premolar teeth extracted for orthodontic reasons, were divided equally for bonding with new and recycled brackets using a no-mix type of adhesive. The mesh strand diameters of new and reconditioned brackets were evaluated with a binocular light microscope. Recycling of brackets was done using Esmadent® bracket and band reconditioner. Results: The mesh strand diameter, tensile and shear bond strength of new and reconditioned brackets were evaluated statistically and the latter was found to show a significant reduction (p< 0.0001). However, the bond strength values of the reconditioned brackets were found to be well above the clinically required minimum. Conclusion: Reduction in mesh strand diameter, as a result of reconditioning process, does not correlate with the change in bond strength between initial and recycled bondings. Clinical significance: The bond strength of reconditioned brackets is adequate enough to resist the magnitude of forces generated in the mouth, throughout the duration of orthodontic treatment for successful treatment results.