Qianyang Xie1, Chi Yang2, Dongmei He3, Xieyi Cai1, Zhigui Ma1. 1. Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Key Laboratory of Stomatology, Shanghai 200011, China. 2. Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Key Laboratory of Stomatology, Shanghai 200011, China. Electronic address: yangchi63@hotmail.com. 3. Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Key Laboratory of Stomatology, Shanghai 200011, China. Electronic address: dongmeihe119@yahoo.com.
Abstract
PURPOSE: To investigate the prevalence of mandibular asymmetry (MA) within the symptomatic unilateral anterior disc displacement (ADD) patients, and analyze the influence TMJ factors of the MA severity. METHODS: Patients aged under 20 years old with symptomatic unilateral ADD and asymptomatic volunteers with normal disc-condyle relationship diagnosed by magnetic resonance imaging (MRI) were included in this study. Posteroanterior cephalometric radiographs were taken to measure MA. Condylar height, disc length and disc displacement were measured by MRI. The prevalence and severity of MA were compared between the ADD and the control groups. The correlation between the severity of MA with the amount of condylar height shortage, disc deformity and distance of disc displacement were also evaluated within the ADD group. RESULTS: There were 165 cases in the unilateral ADD group, and 156 cases in the control group. One hundred and nineteen cases had MA which accounted 72.12% (119/165) in the ADD group; while in the control group, only 25.64% (40/156) exhibited MA. The mean horizontal menton deviation and condylar height shortage in the unilateral ADD group were significantly larger than that in the control group (5.62 mm vs. 4.19 mm; 3.14 mm vs. 1.32 mm, p < 0.01). The severity of MA was significantly correlated with the amount of disc displacement, disc deformity and condylar height shortage (correlation coefficient: 0.80, 0.70, and 0.82). CONCLUSION: MA is much more common and severe in young unilateral ADD patients. The severity of MA is correlated with the height of condyle and the status of the disc.
PURPOSE: To investigate the prevalence of mandibular asymmetry (MA) within the symptomatic unilateral anterior disc displacement (ADD) patients, and analyze the influence TMJ factors of the MA severity. METHODS:Patients aged under 20 years old with symptomatic unilateral ADD and asymptomatic volunteers with normal disc-condyle relationship diagnosed by magnetic resonance imaging (MRI) were included in this study. Posteroanterior cephalometric radiographs were taken to measure MA. Condylar height, disc length and disc displacement were measured by MRI. The prevalence and severity of MA were compared between the ADD and the control groups. The correlation between the severity of MA with the amount of condylar height shortage, disc deformity and distance of disc displacement were also evaluated within the ADD group. RESULTS: There were 165 cases in the unilateral ADD group, and 156 cases in the control group. One hundred and nineteen cases had MA which accounted 72.12% (119/165) in the ADD group; while in the control group, only 25.64% (40/156) exhibited MA. The mean horizontal menton deviation and condylar height shortage in the unilateral ADD group were significantly larger than that in the control group (5.62 mm vs. 4.19 mm; 3.14 mm vs. 1.32 mm, p < 0.01). The severity of MA was significantly correlated with the amount of disc displacement, disc deformity and condylar height shortage (correlation coefficient: 0.80, 0.70, and 0.82). CONCLUSION: MA is much more common and severe in young unilateral ADD patients. The severity of MA is correlated with the height of condyle and the status of the disc.