Effect of various mesh designs on shear bond strength of new and recycled brackets –a comparative, invitro study

Abstract

Introduction: Various chemical and mechanical methods are used to enhance the retention of adhesive to the metal bases of the brackets.Inspite of several efforts,bracket failure is one of the commonest problems faced during treatment.Debonded brackets are generally recycled and reused.This study was designed to compare the shear bond strength(SBS)of five commonly available mesh designs and to determine which mesh design offers least reduction of SBS following recycling. Method: Sample consisted of 5 types of brackets with different mesh designs, bonded to 70 extracted human premolars.The SBS was checked using Instron universal testing machine.The brackets were recycled using sandblasting procedure and were rebonded on the sample teeth.Bond strength testing was again carried out using the same procedure. Results: Mean SBS of Discovery smart bracket with laser structured base was highest followed by 3M Unitek brackets.The brackets by American Orthodontics had lowest bond strength.After recycling with sandblasting procedure,an insignificant reduction in SBS was noticed in all five groups. Conclusion: Laser structured base design was superior to other bracket base designs.All five bracket types had optimal bond strength required for successful bonding both before and after recycling (>7.8 MPa).