Abstract
Objectives: The fit between a bracket base and the tooth surface may affect the outcome of orthodontic treatment. The purpose of this study was to compare the fit of five commercially available brackets by evaluating the gap size between the bracket base and the buccal surface of the upper central incisor and first premolar. Methods: Six maxillary digital models, comprising twelve teeth (including six upper first premolars and six central incisors), were imported into the 3Shape Indirect Bonding software. Five commercially available brackets (A-E) were digitally bonded to the upper first premolars and central incisors. Five virtual slices were made per bracket, and gap measurements were taken at fifteen locations. A mixed-effects model and multiple comparisons with the best (MCB) analysis (p<0.05) were used to evaluate differences between brackets. Results: The gap was generally smaller for the central incisor than for the first premolar. Significant differences in mean and maximum gap sizes were found among the brackets. Central incisor brackets had larger gaps gingivally and distally, with brackets A and B having the largest gaps. First premolar brackets had the largest gaps occlusally and gingivally, with bracket E having the largest overall. The largest horizontal gap was observed mesially, regardless of bracket type. Conclusions: The shape and fit of the bracket base are critical when selecting commercial brackets, as larger gaps in certain locations may affect the expression of tip and torque, potentially affecting treatment outcomes. The findings of this digital simulation study need further validation through a clinical trial with large sample size.