Student learning of simple orthodontic model analysis using plaster and digital casts

Abstract

INTRODUCTION: Cast analysis plays an essential role in orthodontic diagnosis. Intraoral scanning to produce digital models is a relatively new but increasingly common practice in graduate orthodontic programs. It is unknown how incorporating digital models in post graduate orthodontic programs will influence student learning of model analysis. The purpose of this study was to investigate the possible differences in learning speed and accuracy of basic orthodontic model analysis using digital models or traditional plaster casts.

MATERIALS/METHODS: Two groups of senior dental students participated, one for each mode of cast analysis. A study moderator provided a 15-minute tutorial instructing participants on how to analyze the casts. A standardized scoring sheet was used for data collection. Each group was given five sets of orthodontic models to measure the following parameters: Right molar occlusion, overbite, overjet, arch length, required arch space, crowding, and incisor irregularity. The accuracy of the measurements as well as the time taken to complete all measurements on each model were recorded. Learning as measured by increasing accuracy or decreased time over the group of five casts was determined. Five orthodontic faculty served as the control group.

RESULTS: Twenty-five students analyzed plaster casts; forty students analyzed digital casts. Molar occlusion was judged as either correct or incorrect; means of the millimetric measurements of the other parameters were compared between groups using general linear modeling. The digital learning group had 15 measurements that were significantly different from the faculty mean; the plaster learning group had only 2 (p<0.05). Regarding molar occlusion, the plaster group was always more accurate. The time required for the measurements decreased in each group to a similar extent, with the greatest decrease between digital casts 1 and 2.

CONCLUSIONS: Senior dental students learned how to analyze plaster orthodontic models more accurately than digital casts. The time required for analysis decreased over 5 trials, but was not significantly different between the groups.