Making three-dimensional Monsonʹs sphere using virtual dental models

Objectives nsonʹs sphere and curve of Wilson can be used as reference for prosthetic reconstructions or orthodontic treatments. This study aimed to generate and measure the three-dimensional (3-D) Monsonʹs sphere and curve of Wilson using virtual dental models and custom software. s ular dental casts from 79 young adults of Korean descent were scanned and rendered as virtual dental models using a 3-D digitizing scanner. 26 landmarks were digitized on the virtual dental models using a custom made software program. The Monsonʹs sphere was estimated by fitting a sphere to the cusp tips using a least-squares method. Two curves of Wilson were generated by finding the intersecting circle between the Monsonʹs sphere and two vertical planes orthogonal to a virtual occlusal plane. Non-parametric Mann–Whitney and Kruskal–Wallis tests were performed to test for difference between sex and in cusp number within tooth position. s an radius of Monsonʹs sphere was 110.89 ± 25.75 mm. There were significant differences between males and females in all measurements taken (p < 0.01), within 16.87–17.27 mm. Furthermore, morphological variation derived from variability in cusp number in the second premolar and second molar were not found to influence occlusal curvature (p > 0.05). sions tudy describes a best-fit algorithm for generating 3-D Monsonʹs sphere using occlusal curves quantified from virtual dental models. The radius of Monsonʹs sphere in Korean subjects was greater than the original four-inch value suggested by Monson. al significance nsonʹs sphere and curve of Wilson can be used as a reference for prosthetic reconstruction and orthodontic treatment. The data found in this study may be applied to improve dental treatment results.