Accuracy of 3D Reconstructed Orthodontic Models

Abstract

Objective: To evaluate the accuracy of 3D reconstructed orthodontic models, derived by various digitization methods, as compared to conventional orthodontic plaster models. Materials and Methods: Twenty-five maxillary orthodontic plaster models were randomly selected from the Indiana University School of Dentistry Department of Orthodontics. Each plaster model was scanned with the Cadent iOC scanner and the digital data was used to print 3D reconstructed orthodontic models. The same 25 plaster models were duplicated using alginate and poured in plaster after two days. These duplicated plaster models were also scanned with the iOC scanner and 3D reconstructed. Next, the duplicate plaster models were sent to a lab, scanned with a 3Shape R700 scanner, and the digital data was 3D reconstructed. Digital calipers were used to obtain ten linear dimensional measurements on all plaster and 3D reconstructed models for comparisons. Equivalence testing was performed using 2 one-sided paired t-tests with a significance level of P <0.05. Results: Nine of the 10 linear measurements were statistically equivalent in all groups. Clinically insignificant, but statistically significant, measurement differences in maxillary central incisor height (P <0.05) were found on 3D reconstructed models derived from the 3Shape R700 desktop scanner. Conclusion: 3D reconstructed orthodontic models derived from alginate impressions, iOC scanners, and 3Shape R700 scanners are an accurate and reliable substitute for orthodontic plaster models.