Comparison of reliability and accuracy of the two different digital orthodontic modelling methods

The using of digital orthodontic models in diagnosis and treatment planning is becoming more prevailing with the ongoing developments of software technologies. While it?s been well evidenced that digital models obtained with conventional laser surface scanning method are accurate and reliable, direct measurements on plaster models have still been the golden standard?. Digital modelling based on direct scanning of impression material and bite waxes with CBCT (Cone beam computed tomography) is a relatively new method. The aim of this study is comparing the reliability and accuracy of the intra-arch and interarch measurements being made on the digital orthodontic models generated by two different techniques. Our study was made on the plaster and digital models of 50 patients who came to our clinic to get orthodontic treatment. Impressions were taken with PVS and one plaster and two digital models were obtained from every patient by the digital modelling companies (Orthomodel, Orthoproof) work with different methods. Intra-arch and interarch measurements and PAR (Peer Assessment Rating) index scores that we modified for this study were used on the models. The data was evaluated by analysing ICC (Intraclass correlation coefficient) and using one-way ANOVA test. Reliability was found very high considering repeated measurements by the researcher (ICC>0.90). When we compare the measurements that were made on the digital models generated by both methods with those on the plaster models that represent the golden standard?, there?s no statistically and clinically significant difference in any of the lineer measurements and scores (p>0.05). The reliability and the accuracy of the orthodontic measurements that were made on the digital models obtained with CBCT scanning process are not different from those derived from the conventional laser surface scanning method.