Reproducibility of digital indirect bonding technique using three-dimensional (3D) models and 3D-printed transfer trays

Abstract

Objective: To evaluate the reproducibility of digital tray transfer fit on digital indirect bonding by analyzing the differences in bracket positions. Materials and Methods: Digital indirect bonding was performed by positioning brackets on digital models superimposed by tomography using Ortho Analyzer (3Shape) software. Thirty-three orthodontists performed indirect bonding on prototyped models of the same malocclusion using prototyped transfer trays for two types of brackets (MiniSprint Roth and BioQuick self-ligating). The models with brackets were scanned using an intraoral scanner (Trios, 3Shape). Superimpositions were made between the digital models obtained after indirect bonding and those from the original virtual setup. To analyze the differences in bracket positions, three planes were examined for each bracket: vertical, horizontal, and angulation. Three orthodontists repeated indirect bonding after 15 days, and Bland-Altman plots and intraclass correlation coefficients were used to evaluate inter- and intraevaluator reproducibility and reliability, respectively. Repeated-measures analysis of variance (ANOVA) was used to analyze the differences between bracket positions, and multivariate ANOVA was used to evaluate the influence of orthodontists’ experience on the results. Results: Differences between bracket positions were not statistically significant, except mesial-distal discrepancies in the BioQuick group (P ¼ .016). However, differences were not clinically significant (horizontal varied from 0.04 to 0.13 mm; angulation, 0.458 to 2.038). There was no significant influence of orthodontist experience and years of clinical practice on bracket positions (P ¼ .314 and P ¼ .158). The reproducibility among orthodontists was confirmed. Conclusions: The reproducibility of digital indirect bonding was confirmed in terms of bracket positions using three-dimensional printed transfer trays.