Reliability And Efficiency: Digital Versus Plaster Orthodontic Models

This study aims to evaluate the reliability and efficiency of measurements on digital orthodontic models in comparison to measurements on traditional plaster models. Fourteen sets of archived plaster models of permanent dentitions were randomly selected to assess overjet, overbite, mandibular canine width, maxillary first molar width and anterior crowding. First, the models were measured manually with an orthodontic caliper. Then, computer-based models were generated with a 3D scanner, where corresponding measurements were taken digitally using orthodontic analyzing software. The models were assessed by a single rater and repeated after one week. Furthermore, time required to complete the measurements was recorded. Intra-rater reliability was analyzed with intraclass correlation coefficient (ICC) for absolute agreement. Agreement between digital measurements was high (ICC 0.88-0.99), with mean differences of 0.02-0.20 mm. Manual measurements had similar agreement (ICC 0.84-0.99), with mean differences of 0.02-0.23. Comparing digital and manual measurements, agreement was somewhat lower, with a mean difference of 0.03-0.57 mm (ICC 0.73-0.98). Agreement was lowest for maxillary anterior crowding (ICC 0.73-0.88) for all comparisons. On average, digital measurements were 84 seconds faster than manual measurements. Both digital and manual measurements demonstrate high reliability, although digital measurements had slightly higher agreement and were less time-consuming. This supports the use of digital models in epidemiological studies, offering reliable data and efficient data collection and analysis.