Retentive Shear Strengths of Various Bonding Attachment Bases: An in vitro Study

Abstract

The increasing demand for a more esthetic metal bonded appliance has led to a reduction in the size of the brackets and their bases. The reduction of bracket size improves esthetics and produces a more easily cleansed appliance. This reduction results in less base surface area available for bonding with the concomitant clinical reality of increased debonding rates. Objectives: To compare the shear bond strength and to evaluate and compare the surface design characteristics (mesh type, mesh wire size) of different commercially available direct bonding metal brackets. Materials and methods: Maxillary first premolar brackets of six different manufacturing companies were bonded on freshly extracted human premolars preserved in artificial saliva, with the same adhesive and then debonded using a universal testing machine. The bracket bases were also examined under the scanning electron microscope (SEM). Results: The bond strength obtained with different commercially available bracket bases was stastically variable. The size of bracket bases influenced the shear bond strength values. The mesh size and its configuration also affect the bond strength. Conclusion: Gemini brackets provided the best bond strengths clinically, followed by Mini Diagonali, Nu-Edge, Mini Twin, Mini Diamond and the Sapphire brackets in decreasing order as measured using the Weibull analysis.