The Accuracy of OrthoCAD Digital Models Compared to Plaster Models

Objective: To compare the three dimensional accuracy of OrthoCAD digital models to plaster models. Methods: Routine maxillary and mandibular alginate (Identic) impressions were taken on twenty-nine unidentified patients with varied malocclusions as part of their initial orthodontic records appointment. Alginate impressions were sent to OrthoCAD following the packaging guidelines. OrthoCAD returned both digital and plaster models after they were scanned and processed. Both the digital and plaster models were measured in the following three dimensions: anterior-posterior, transverse, and vertical. The digital models were measured using the OrthoCAD software. The plaster models were measured using a vernier caliper. A paired (t-test) was used to analyze the data. Results: No significant differences were found in the vertical dimension measurements. Only one transverse dimension measurement out of six was found to be statistically significant. All the anterior-posterior dimensions were found to be statistically significant. Conclusions: While a number of the measurements were found to be statistically significant, none of the measurements were clinically significant with the largest mean difference being only 0.253 mm. With the overall advantages of digital models, it is only a matter of time until they replace their plaster predecessors.