An Evaluation of the Bond Strength of Recycled Orthodontic Bonded Brackets

Abstract

This investigation was designed to determine the effects of recycling orthodontic bonded attachments on bond strength. It was hypothesised that the reduction of the bracket mesh wire diameter as a result of electro-polishing may affect the bond at the mesh-resin interface.

Ten brackets with brazed mesh were bonded to extracted bicuspid teeth and after 24 hours the mesh-resin bond was tested to failure in tension. The brackets were recycled in an Esmadent bracket reconditioner and rebonded to 10 fresh teeth. The process was repeated until the brackets had been recycled six times each and the bond strength determined for a total of 70 teeth, with the following results.

1. The mean bond strengths for each group were not significantly different at the .05 probability level. 2. There was no significant correlation between the number of cycles and bond strength. 3. After the brackets had been recycled five times, there were areas of missing mesh around the periphery of same brackets.

It can be concluded that the primary factor limiting the number of times a bracket can be reused is the widening of the bracket slot, rather than the decrease in band strength.