Evaluation of virtual models (3Shape Ortho System) in assessing accuracy and duration of model analyses based on the severity of crowding

Objective: The purpose of this study was to determine the accuracy and time taken to perform the space analysis (arch length discrepancy and Bolton's) based on the severity of crowding using new virtual model software (3Shape Ortho System, 3Shape A/S, Copenhagen) with that of conventional plaster models. Materials and methods: Models from 45 patients, divided into three groups based on the severity of crowding (group 1: <2.5 mm, group 2: 2.5-5 mm, and group 3: >5 mm) were included in this study. The mesiodistal width of each tooth from first molar to first molar was measured to the nearest 0.1 mm with digital calipers, and the arch length tooth mass discrepancy and Bolton's ratio were calculated for each model of every group. The total time required to perform the space analysis was recorded in seconds using a stopwatch. This process was repeated to record the digital measurements with the 3Shape Ortho System software. The difference between the two methods in all the three groups was calculated, and a paired t test was used to analyze the data. Results: The results showed no statistically significant difference between the mesiodistal width measurements, arch length discrepancy and Bolton's values in all the three groups. However, the total time required to perform the space analysis between the two methods revealed statistically significant differences, with digital models averaging more time in all the groups. Conclusion: Virtual models can be used as an alternative to routine plaster models in model analysis procedures, independent of severity of crowding.