Variations in orthodontic treatment planning decisions of Class II patients between virtual 3-dimensional models and traditional plaster study models

Introduction: Study models provide invaluable information in treatment planning. Digital models have proved to be an effective measurement tool, but their use in treatment planning has not been studied. Methods: Ten sets of records of Class II malocclusion subjects (dental study models, lateral cephalograms/tracings, panoramic radiographs, intraloral and extraoral photographs) were used for treatment planning by 20 orthodontists on 2 separate occasions. Digital models were used to evaluate the patients at 1 session and plaster models were used at the other session. Treatment recommendations were scored and compared for agreement. Eleven orthodontists served as the control group, looking at the records on 2 occasions with plaster models for agreement. Results: Good agreement was noted for surgery (P = 1.00, kappa = 0.549), extractions (P =.360, kappa = 0.570), and auxiliary appliances (P = 1.00, kappa = 0.539) for the digital/plaster group. Agreement in the plaster/plaster group for surgery (P = 1.00, kappa = 0.671), extractions (P = 1.00, kappa = 0.626), and auxiliary appliances (P =.791, kappa = 0.672) was also good. Overall proportions of agreement ranged between 0.777 and 0.870 for digital/plaster and 0.818 and 0.873 for plaster/plaster. Conclusions: There was no statistical difference in intrarater treatment-planning agreement for Class II malocclusions based on the use of digital models in place of traditional plaster models. Digital orthodontic study models (e-models) are a valid alternative to traditional plaster study models in treatment planning for Class II malocclusion patients.