Introduction: With the limitations of plaster study models and the role of digital technology in Orthodontics, digital study models may become a viable replacement of conventional plaster study models. A number of companies worldwide now provide digital study models. ESM Digital Solutions are a new company providing this service based in the U.K. The aim of the study was to assess reliability of their technology as independent assessor.
Methods and Materials: 112 sets of study models with a range of malocclusions and crowding were selected. Various occlusal features were measured manually with digital callipers on the plaster models. The same measurements were performed on digital study models. Each method was carried out twice in order to check for intra-operator variability. The repeatability and reproducibility of the methods was assessed.
Results: 112 sets of plaster models and 111 sets of digital models were analysed. There were significant differences between the two methods, with the plaster measurements appearing more repeatable for 8 of 16 occlusal features measured. However these differences would not all be of clinical relevance. There were significant systematic errors for 12 of 16occlusal features, with the plaster measurements being significantly greater for 11 of these, indicating an element of shrinkage of the digital models.
Conclusions: The repeatability of digital models compared with plaster models is satisfactory and should be considered for use as an adjunct to clinical findings. Digital study models have a role for clinical use although cannot supersede current methods for scientific purposes.