Dentistry

Abstract

Bond Strengths of Metal, Ceramic and Polymer Brackets in Combination with Different Enamel Preconditioning Methods

Lorenz M. Brauchli, Pascal Schönenberger, Judith Ball and Andrea Wichelhaus

Introduction: Adhesive technology is widely spread throughout the different specialities of dentistry. In orthodontics the bonding of brackets accounts for a significant percentage of time in practice routine. Bond strength is dependent on several factors such as enamel conditioning, adhesive technology and the material and construction of the bracket base. It was the intention of the present study to investigate the bond strength in relation to the above mentioned parameters.
Method: Four different brackets (metal, ceramic, polymer, fiber reinforced polymer) were evaluated for their bond strength during tensile testing with a universal testing machine using a conventional composite (Transbond MIP, XT) and in the case of the fiber reinforced bracket additionally a specially designed adhesive (Quick-Bond). Enamel conditioning was achieved with conventional etching, air-abrasion or a combination of both techniques. ARI (adhesive remnant index) scores were evaluated.
Results: There were significant differences between the types of enamel conditioning. All brackets showed significantly lower bonding forces when the enamel was prepared with air-abrasion alone. Metal brackets had the highest bonding strength and the fiber reinforced composite brackets with the conventional adhesive the lowest. The ARI scores showed good correlation to the bonding forces, with low bonding forces presenting as a detachment at the enamel-adhesive interface.
Conclusion: Air-abrasion alone showed significantly lower bonding forces than enamel conditioning with etching for all bracket types. This finding was independent of the bracket material, base design or adhesive system.