Comparison of three-dimensional scan and conventional indirect bonding methods for bracket positioning accuracy: an in vitro study.

OBJECTIVES

To compare transfer accuracy between a three-dimensionally (3D) printed transfer jig and a conventional silicone tray in an in vitro setting using 3D linear measurements.

MATERIALS AND

METHODS

3D intraoral scans were obtained from four patients. Sixteen 3D-printed models (eight maxillary, eight mandibular) were prepared for each group. In Group 1, brackets were digitally positioned using 3Shape Ortho Analyzer software and transferred from working to posttransfer models using eight 3D-printed jigs. In Group 2, eight silicone trays were fabricated for bracket transfer. Working and posttransfer models were superimposed using Geomagic software, and divergence was summarized as the median and interquartile range. Tooth-level deviations between methods were compared using the Wilcoxon signed-rank test, stratified by arch and tooth type. Statistical significance was set at P < .05.

RESULTS

Although a statistically significant difference between methods was observed (P = .024), median deviations for both methods were within the American Board of Orthodontics clinically acceptable limit (≤0.5 mm). In the mandible, the 3D-printed jig group showed smaller positional deviations than the conventional method (P < .001). Conversely, in the maxilla, the conventional method showed smaller positional deviations (P = .003). Deviations occurred most often in the vertical and horizontal directions in the 3D-printed jig group and in the transverse and vertical directions in the conventional group.

CONCLUSIONS

The 3D-printed jig demonstrated greater accuracy in the mandible, while the conventional silicone tray was more accurate in the maxilla. However, the differences were not clinically significant, and both techniques achieved clinically acceptable bracket transfer accuracy.