Three-dimensional assessment of virtual bracket removal for orthodontic retainers: A prospective clinical study

Computer-aided design and manufacturing of orthodontic retainers from digitally debonded models can be used to facilitate same-day delivery. The purpose of this prospective clinical study was to validate a novel technique for virtual bracket removal (VBR) in-office, comparing the accuracy with 2 orthodontic laboratories that use VBR for retainer fabrication in the digital workflow.

The sample consisted of 40 intraoral scans of 20 patients. Four groups were compared. The scans without brackets were used as a control group. VBR was performed by 3 groups: In-office VBR (Software Meshmixer, version 3.5.474; Autodesk, San Rafael, Calif), Orthodent Laboratory (ODL; Buffalo, NY), and New England Orthodontic Laboratory (NEOLab; Andover, Mass). The virtually debonded models were superimposed onto the control models using surface-based registration. Regional 3-dimensional Euclidean distances between surface points of superimposed models were calculated for comparative analysis of surface changes after VBR using Vector Analysis Module (Canfield Scientific, Fairfield, NJ) software.

The accuracy of VBR using the Meshmixer did not differ significantly from the VBR protocols used by the 2 laboratories. However, there was a statistically significant difference between the 2 laboratories, with ODL showing lower accuracy than NEOLab. Although some differences were statistically significant, they were very small and not considered clinically relevant. There was also a statistically significant difference between the 3 tooth segments (incisors, canines/premolars, and first molars), with VBR of the first molars and second premolars showing the least accuracy.

The VBR techniques using the in-office Meshmixer, ODL, and NEOLab were considered accurate enough for the clinical use of orthodontic retainers fabricated from printed models.