Accuracy Evaluation of Indirect Bonding Techniques for Clear Aligner Attachments Using 3D-Printed Models: An In Silico and Physical Model-Based Study

An inaccurate bonding procedure of the attachments related to clear aligner systems could influence the predictability of tooth movement The aim of this study was to compare the positioning reliability of horizontal and vertical orthodontic clear aligner attachments. Materials and Methods: A total of 70 horizontal and 70 vertical orthodontic clear aligner attachments were bonded to five upper and five lower experimental anatomically based acrylic resin models with 14 clinical crowns each. The experimental anatomically based acrylic resin models were randomly distributed to the following study groups: Group A—horizontal orthodontic clear aligner attachments (n = 70) (HORIZONTAL) and Group B—vertical orthodontic clear aligner attachments (n = 70) (VERTICAL). Afterward, the orthodontic clear aligner attachments were digitally planned using orthodontic planning software, and orthodontic templates were manufactured by thermoforming on 3D-printed models in trilayer glycol-modified polyethylene terephthalate. Both horizontal and vertical orthodontic clear aligner attachments were put through an intra-oral scan to obtain a postoperative digital image, and PAPver, PCPver, PMVver, AUver, Alver, PPMhor, PPDhor, PMVhor, AMhor and ADhor cephalometric parameters were analyzed using a t-test or a non-parametric Mann–Whitney–Wilcoxon test. Results: The results showed that all cephalometric parameters showed statistically significant differences (p < 0.05) between the accuracy of the indirect bonding technique for horizontal and vertical orthodontic clear aligner attachments, except for the PAPver (p = 0.6079) and PMVhor (p = 0.5001) cephalometric parameters. Conclusions: The vertical orthodontic clear aligner attachments are more accurate than the horizontal orthodontic clear aligner attachments through the indirect bonding technique.