Masticatory muscles thickness and its association with signs and symptoms of temporomandibular disorders

许多颞下颌疾病（TMD）患者的咀嚼功能和咬合力受损，但由于缺牙或口腔副功能活动，咀嚼肌对疲劳和萎缩的易感性尚不确定。在本研究中，我们将研究咬合支持对咀嚼肌的影响以及随后对颞下颌关节的影响。有TMD症状和体征的患者，不同的咬合支持对三颚肌横截面积的影响；用MRI检查咬肌、翼状内侧肌和翼状外侧肌。2440名年龄在20至80岁之间的受试者的头部磁共振图像可从波美拉尼亚健康研究（Ship-2和Ship-Trend）的人口队列中获得。使用免费软件Osirix在MRI上测量头部两侧的咬肌、内侧和外侧翼状肌的横截面积。我们的工作小组之前已经发布了一种根据法兰克福水平面标准化MRI图像方向的程序，以保证肌肉的正确可重复性测量。根据Eichner指数分类的咬合接触数据将从波美拉尼亚（Ship-2和Ship-Trend）健康研究的现有牙科检查数据中收集。本研究的目的是首先考虑咬合接触和口腔功能数据，探讨TMD体征和症状与定义的每种咀嚼肌厚度差异的关系。其次，调查这些假设的关联是否因性别而异。

Masticatory function and bite force are known to be impaired in many patients with temporomandibular disorders (TMD), but the susceptibility of their masticatory muscles to fatigue and atrophy because of missing teeth or oral para-functional activity is less certain.In this proposed study, the effects of occlusal support on the masticatory muscles and subsequently on the temporomandibular joint will be studied.The effects of different occlusal support that are present in patients with signs and symptoms of TMD on the cross- sectional area of three jaw muscles; the masseter, medial pterygoid and lateral pterygoid will be investigated using MRI. Magnetic resonance images of the head for 2440 subjects aged between 20 and 80 years are available from the population based cohort known as the study of health in Pomerania (Ship-2 and Ship-Trend). The cross- sectional area of the masseter, medial and lateral pterygoid muscles on both sides of the head will be measured on MRI using the freely available software Osirix. A procedure to standardize the orientation of the MRI images according to Frankfort Horizontal plane has been published by our working group before to guarantee correct reproducible measurements of the muscles.Data on the occlusal contact as classified by the Eichner index will be assembled from the available dental examination data of the study of health in Pomerania (Ship-2 and Ship-Trend)The aims of this study are first to investigate the relationship of TMD signs and symptoms to defined differences in each masticatory muscle thickness, taking occlusal contact and oral parafunctional data into consideration. Second, to investigate of whether these postulated associations differ by gender.