The Influence of Orthodontic Bracket Base Design and Bonding System on Shear Bond Strength

The success of orthodontic therapy depends on the effective, continuous application of forces to teeth. Therefore, an essential element of the treatment is the adhesion between the bracket and enamel. The purpose of this study was to evaluate the influence of bracket base design and bonding system on shear bond strength. The study was conducted on eighty extracted premolars which were randomly divided into four groups of twenty teeth each, using two types of metal brackets (80-gauge mesh and anchor pylons base design) and two types of bonding systems (conventional and self-etching). The combination of bracket and bonding system resulted in four distinct configurations of bracket bonding, with each configuration tested on twenty teeth. Shear bond strength testing was performed using a Laryee Universal Testing Machine. The obtained values were statistically analyzed. Slightly higher shear bond strength values were recorded for brackets with anchor pylons bonded using the conventional bonding system (13.32 ± 4.20 N/mm²), whereas the lowest values were recorded for the same bracket base design bonded with the self-etching system (11.10 ± 4.50 N/mm²). Nevertheless, ANOVA test did not reveal statistically significant differences between the two bracket types or between the two bonding techniques in terms of shear bond strength and force values and no significant interaction effects were observed. Considering the obtained results, several additional factors must be taken into account when evaluating the shear bond strength of orthodontic brackets.