Study on relationship between craniofacial morphology and condylar resorption due to TMD using helical CT

本研究旨在探讨髁突骨性改变与颅面形态的关系。29名受试者（平均年龄18.8岁）与髁突骨变化，从正畸患者谁经历了螺旋CT和MM评估可疑的TMJ内部紊乱和髁突骨变化，因为TMD症状。颅面形态进行了评估，侧位和额部头颅X线片。对于每名患者，将6个线性和5个角度测量值与日本标准的年龄和性别匹配人群进行比较。在双侧髁突骨改变组（双侧组）中，骨赘形成和侵蚀是常见的骨改变，并且存在于成人和青少年受试者中。单侧髁突骨质改变组（单侧组）以扁平化最常见，侵蚀仅见于19岁以下人群.双侧组中90.6%的患者出现颈盘移位，单侧组中76.9%的患者出现颈盘移位，双侧组中出现下颌后缩。单侧组的门顿均向髁突骨性改变的一侧移位。4.单侧组的咬合力分布不平衡，双侧组的咬合力较小，提示双侧组的成年人和青少年的髁突骨性改变可能是进行性的、不稳定的。结论：颞下颌关节紊乱病患者的髁突骨性改变可能与下颌骨的侧向移位和下颌骨后缩有关。

The present study was performed to investigate how condylar bony changes related to craniofacial morphology. Twenty-nine subjects (an average age of 18.8) with condylar bony changes were selected from orthodontic patients who had undergone both helical CT and MM to evaluate suspected TMJ internal derangement and condylar bony changes because of TMD symptoms. Craniofacial morphology was assessed with lateral and frontal cephalograms. For each patient, 6 linear and 5 angular measurements were compared with an age- and sex-matched population from the Japanese standard.1. In the bilateral condylar bony change group (bilateral group), osteophyte formation and erosion were the common bony change and were present in adult as well as juvenile subjects. In the unilateral condylar bony change group (unilateral group), flattening was the most common feature, erosion was only present in subjects below 19 years.2. Disk displacement without reduction was seen in 90.6% of the bilateral group, and in 76.9 % of the unilateral group.3, In the bilateral group, retrognathic mandible was shown. In the unilateral group, all subjects exhibited a lateral shift of the menton to the side with condylar bony changes.4.Imbalance distribution of occlusal force in the unilateral group and small occlusal force in the bilateral group was shown.These findings suggested that condylar bony changes might be progressive and unstable in adults of the bilateral group as well as juveniles of the both groups. It is concluded that condylar bony changes may be related to a lateral shift of the mandible and a retrognathic mandible in orthodontic patients with TMD symptoms.