Evaluation of the shear bond strength of lingual brackets manufactured by three different processes using two different adhesive primers: An in vitro study

Abstract

Objective: To compare and evaluate the shear bond strength (SBS) of lingual brackets, manufactured by three different processes, that is, laser sintering, milling, and casting, bonded with two different adhesive primers. Materials and Methods: One hundred and twenty premolars were selected, and three types of lingual brackets were used, namely, STB (milling), 7 th Generation (casting), and lingualmatrix (laser sintering). Forty brackets per system were used half of which were sandblasted while the other half were used as available. Further, these were subdivided and bonded with Transbond XT primer and adhesive and 3M ESPE Primer and Transbond XT adhesive. Customization of STB and 7 th Generation was done by Torque Angulation Reference Guide, Lingualmatrix had bases customized by Computer-aided design/computer-aided manufacturing. SBS was tested with universal testing machine and evaluated for adhesive remnant index (ARI). Results: Statistical analysis showed that surface treatment, use of different primers, method of customization influenced the SBS, and ARI suggested that the fracture occurred between composite and bracket interface. Conclusion: Lingualmatrix bracket showed greater SBS as compared to STB and 7 th Generation, sandblasting increased SBS. 3M ESPE primer group showed increased SBS as that bonded with Transbond XT primer. The fracture was between the composite bracket interface.