Evaluation of the accuracy of a 3D-printed palatal auxiliary device for maxillary protraction after palatal expansion

This study aimed to evaluate the accuracy of a three-dimensional (3D)-printed palatal auxiliary device (PAD) compared to computer-aided design (CAD) reference data.

Thirty patients who underwent orthodontic treatment using a PAD for maxillary protraction after palatal expansion were included in this study. Two groups of 15 patients were analyzed to compare the accuracy of the two PAD designs. Accuracy and adaptation were assessed through two sets of measurements: 1) deviations between the printed PAD and its CAD reference to determine printing accuracy, and 2) deviations in PAD positioning when clinically applied, simulated on a printed model. Sixteen measurement points (anterior, posterior, left, and right) were evaluated across the x-, y-, and z-axes and t tests were performed for comparison.

The PAD-only measurements showed errors greater than 0.1 mm on all axes but within the marginal limits of 0.05 mm to 0.25 mm (P < 0.05). Similar results were observed with the PAD-adapted measurements. Significant differences were found across all axes in the PAD-only group and between the two designs. Tukey's post hoc analysis identified a specific ranking of errors in the combination-type PAD: left, anterior, posterior, and right. However, for PAD-adapted group, majority of comparisons showed no significant differences and those that did lacked consistency in pattern.

This study demonstrates that 3D-printed PADs maintain clinically acceptable accuracy and can be effectively integrated into existing intraoral devices. Although errors varied in certain areas, they did not significantly impact the final adaptation.