Comparison of the quality of 3D digital setups created by Invisalign and an orthodontist

Aim:To compare the quality of the initial digital setups created by Invisalign (Align Technology, San Jose, CA, USA) and by an orthodontist. Methods:Twenty-six consecutively treated Invisalign patients were enrolled retrospectively in the study and their initial iTero (Align Technology) scans were collected. Initial malocclusion characteristics (vertical overlap, horizontal overlap, molar classification, canine classification, maxillary and mandibular crowding) were recorded. A digital setup was created for each patient using uDesign version 6.0 software (uLab Systems, San Mateo, CA, USA) and two groups were then formed: initial digital setups created by an Invisalign technician and digital setups created by an orthodontist. The quality of the setups was measured objectively for both groups using the American Board of Orthodontics Objective Grading System.
Results:With the exception of occlusal and interproximal contacts, there were significant differences in the scores for all the Objective Grading System categories between the setups created by the Invisalign technician and those created by the orthodontist. The total Objective Grading System score, alignment/rotation, marginal ridges, buccolingual inclination, horizontal overlap and occlusal relationships were all significantly lower (fewer point deductions) in the setups created by the orthodontist. Initial severity of horizontal overlap was correlated with a significant difference between the two groups’ horizontal overlap scores, and initial maxillary and mandibular crowding were correlated with a significant difference between the two groups’ marginal ridge scores.
Conclusions:Objective Grading System scores were significantly higher (more point deductions) for initial digital setups created by Invisalign compared to those created by the orthodontist in uDesign. For the Invisalign group, initial Objective Grading System scores for horizontal overlap and marginal ridges were significantly higher when the initial malocclusion presented with excessive horizontal overlap and maxillomandibular crowding, respectively. Keywords: American Board of Orthodontics Objective Grading System, Invisalign, digital orthodontics, digital setups