Applied Sciences, Vol. 16, Pages 285: Transfer Accuracy and Chairside Efficiency of Two Digital Indirect Bonding Techniques: An In Vitro Analysis

Applied Sciences doi: 10.3390/app16010285

Authors:
Maria Elena Grecolini
Alessandro Bruni
Cristiana Nocco
Mimmo Castellana
Andrea Abate
Enrico Spinas
Alessandro Ugolini
Valentina Lanteri

Background: Digital indirect bonding (IB) has emerged as a reliable approach to improving the precision and efficiency of orthodontic bracket placement. Methods: This in vitro study evaluated and compared the positional accuracy and efficiency of two digitally driven indirect bonding (IB) techniques—a rigid single-tooth transfer jig (Leone Jig System) and a flexible three-part transfer tray (IBT Flex Resin)—as well as conventional direct bonding. Ten sets of 3D-printed resin dental models were randomly allocated to the three bonding protocols. Bracket positions were virtually planned and analyzed by superimposing pre- and post-bonding STL models using landmark- and surface-based registration. Linear discrepancies were measured along the axial, sagittal, and vertical planes, and data were analyzed using repeated-measures ANOVA and Friedman tests (α = 0.05). Results: Both indirect bonding techniques showed significantly smaller deviations from the ideal virtual setup compared with direct bonding across all spatial planes (p < 0.001). Mean discrepancies were consistently below 0.3 mm for the indirect protocols, compared with values exceeding 0.4 mm for direct bonding. The rigid jig demonstrated the highest precision, particularly in the sagittal (0.18 ± 0.06 mm) and vertical (0.21 ± 0.07 mm) planes, while the flexible tray showed slightly higher deviations (approximately 0.25–0.30 ± 0.08–0.09 mm across planes). Chairside bonding time per full arch was reduced by more than 50% with both IB techniques, with the jig-based system being the most time-efficient. No significant interaction between bonding method and spatial plane was observed. Conclusions: Within the limitations of this in vitro study, digital indirect bonding—especially rigid, patient-specific jigs—demonstrated superior bracket placement accuracy and procedural efficiency compared with direct bonding.

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