fa Making three-dimensional Monson's sphere using virtual dental models ارتودنسی Orthodontics پژوهشي Research <p> <strong>Objectives </strong></p><p> The Monson's 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) Monson's sphere and curve of Wilson using virtual dental models and custom software. </p><p> <strong>Methods</strong> </p><p> Mandibular 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 Monson's 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 Monson's 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. </p><p> <strong>Results</strong></p><p>  The mean radius of Monson's sphere was 110.89±25.75mm. There were significant differences between males and females in all measurements taken (p<0.01), within 16.87–17.27mm. 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). </p><p> <strong>Conclusions</strong></p><p>  This study describes a best-fit algorithm for generating 3-D Monson's sphere using occlusal curves quantified from virtual dental models. The radius of Monson's sphere in Korean subjects was greater than the original four-inch value suggested by Monson. </p><p> <strong>Clinical significance</strong></p><p>  The Monson's 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. </p><hr><p></p><p> <strong>Source: </strong>Journal of Dentistry</p><p> <a href="http://www.jodjournal.com/article/S0300-5712(13)00021-3/abstract" target="_blank"><font color="#0000ff">Full Text</font></a></p> Monson\'s sphere, Curve of Wilson, Virtual models, Algorithm 0 0 http://idai.ir/browse.php?a_code=A-10-32-2137&slc_lang=fa&sid=1 Shin-Eun Nam 100319475328460010023 100319475328460010023 No Department of Oral Anatomy, Dental Research Institute and School of Dentistry, Seoul National University, 28-22 Yunkeun-Dong, Chongro-Ku, Seoul 110-749, Republic of Korea Young-Seok Park 100319475328460010024 100319475328460010024 No Department of Oral Anatomy, Dental Research Institute and School of Dentistry, Seoul National University, 28-22 Yunkeun-Dong, Chongro-Ku, Seoul 110-749, Republic of Korea WooCheol Lee 100319475328460010025 100319475328460010025 No Department of Conservative Dentistry, Dental Research Institute and School of Dentistry, Seoul National University, 28-22 Yunkeun-Dong, Chongro-Ku, Seoul 110-749, Republic of Korea Sug-Joon Ahn 100319475328460010026 100319475328460010026 No Department of Orthodontics, Dental Research Institute and School of Dentistry, Seoul National University, 28-22 Yunkeun-Dong, Chongro-Ku, Seoul 110-749, Republic of Korea Seung-Pyo Lee 100319475328460010027 100319475328460010027 Yes Department of Oral Anatomy, Dental Research Institute and School of Dentistry, Seoul National University, 28-22 Yunkeun-Dong, Chongro-Ku, Seoul 110-749, Republic of Korea