The relationship between the changes in three-dimensional facial morphology and mandibular movement after orthognathic surgery Dae-Seung Kim a, b , Kyung-Hoe Huh b, c , Sam-Sun Lee b, c , Min-Suk Heo b, c , Soon-Chul Choi b, c , Soon-Jung Hwang b, d, ** , Won-Jin Yi b, c, * a Interdisciplinary Program in Radiation Applied Life Science Major, College of Medicine, BK21, Seoul National University, Seoul, South Korea b Dental Research Institute, School of Dentistry, Seoul National University, Seoul, South Korea c Department of Oral and Maxillofacial Radiology, BK21, Seoul National University, Seoul, South Korea d Department of Oral and Maxillofacial Surgery, BK21, Seoul National University, Seoul, South Korea article info Article history: Paper received 10 August 2012 Accepted 3 January 2013 Keywords: Three-dimensional facial morphology changes Three-dimensional mandibular movement changes Orthognathic surgery Height of face Contralateral side morphological changes abstract Purpose: The purpose of this study was to investigate the relationship between changes in three- dimensional (3D) facial morphology and mandibular movement after orthognathic surgery. We hy- pothesized that facial morphology changes after orthognathic surgery exert effects on 3D mandibular movement. Materials and methods: We conducted a prospective follow-up study of patients who had undergone orthognathic surgical procedures. Three-dimensional facial morphological values were measured from facial CT images before and three months after orthognathic surgery. Three-dimensional maximum mandibular opening (MMO) values of four points (bilateral condylions, infradentale, and pogonion) were also measured using a mandibular movement tracking and simulation system. The predictor variables were changes in morphological parameters divided into two groups (deviated side (DS) or contralateral side (CS) groups), and the outcome variables were changes in the MMO at four points. Results: We evaluated 21 subjects who had undergone orthognathic surgical procedures. Alterations in the TFH (total facial height), LFH (lower facial height), CS MBL (mandibular body length), and DS RL (ramus length) were negatively correlated with changes in bilateral condylar movement. The UFH, DS MBL and CS ML (mandibular length) showed correlations with infradentale movement. The CS ML, DS ML, MBL, UFH, and SNB were correlated with pogonion movement. Conclusion: The height of the face is most likely to affect post-operative mandibular movement, and is negatively correlated with movement changes in the condyles, infradentale and pogonion. The changes in CS morphological parameters are more correlated with mandibular movement changes than the DS. The changes in CS MBL and bilateral RL were negatively correlated with condylar movement changes, while the bilateral MBL and CS ML were positively correlated with changes in infradentale and pogonion. Ó 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved. 1. Introduction Orthognathic surgery is widely performed to improve facial aesthetics and masticatory function, including mandibular move- ment, thus enhancing quality of life (Jan and Johanne, 2012). Some studies have examined the functional or morphological changes that can occur after orthognathic surgery, assessing parameters such as mechanical advantages, bite force, soft tissue, and range of mandibular movement (Kouta et al., 2012; Popat et al., 2012; Sforza et al., 2010; Song et al., 1997; Throckmorton and Ellis, 2001; Throckmorton et al., 2000, 1980; Verze et al., 2011; Yang et al., 2005; Zarrinkelk et al., 1996, 1995). Mandibular movement gen- erally decreases after orthognathic surgery (Aragon et al., 1985; Boyd et al., 1991; Storum and Bell, 1984; Ueki et al., 2008). On the other hand, in their long-term follow-up study, Pepersack and Chausse reported no decrease in maximum mouth opening (Pepersack and Chausse, 1978). Zimmer et al. (1992) reported dif- ferences in the patterns of changes in mandibular movement ac- cording to different orthognathic surgical procedures. Other studies * Corresponding author. Department of Oral and Maxillofacial Radiology, BK21, Seoul National University, Seoul, South Korea. Tel.: þ82 2 2072 3049; fax: þ82 2 744 3919. E-mail address: wjyi@snu.ac.kr (W.-J. Yi). ** Corresponding author. Department of Oral and Maxillofacial Surgery, BK21, Seoul National University, Seoul, South Korea. Contents lists available at SciVerse ScienceDirect Journal of Cranio-Maxillo-Facial Surgery journal homepage: www.jcmfs.com 1010-5182/$ e see front matter Ó 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jcms.2013.01.011 Journal of Cranio-Maxillo-Facial Surgery xxx (2013) 1e8 Please cite this article in press as: Kim D-S, et al., The relationship between the changes in three-dimensional facial morphology and mandibular movement after orthognathic surgery, Journal of Cranio-Maxillo-Facial Surgery (2013), http://dx.doi.org/10.1016/j.jcms.2013.01.011