颞下颌关节三维动态磁共振成像研究及生物力学分析

目的通过在多层面二维动态MR成像上获取颞下颌关节组织的运动数据,构建颞下颌关节的三维动态模型,并进行初步生物力学分析。方法 MRI检查采用GE Signa 1.5T TwinSpeed超导型磁共振扫描仪。选取2例无症状男性志愿者行颞下颌关节MRI检查,将图像数据导入Mimics软件,构建颞下颌关节的三维模型,动态分析张口幅度和关节盘横径的量化关系。结果建立的颞下颌关节三维动态模型清晰显示三维动态盘髁关系及关节盘在动态过程中的形态变化;志愿者1张口/关节盘横径拟合直线为:y=-0.03x+14.44,相关系数R2=0.591,志愿者2相关拟合直线为:y=-0.061x+13.48,相关系数R2=0.306,志愿者张口位置与关节盘横径变化具有直线趋势,关节盘横径随着张口幅度的加大而呈现减小的趋势,颞下颌关节盘对于髁突的包绕程度与张口幅度呈反比。颞下颌关节盘纵径厚度在张口活动中后带外份及中带内份的变化幅度最大。结论通过颞下颌关节二维动态MR成像数据可构建三维动态模型立体动态地观察颞下颌关节运动,可直观、准确显示颞下颌关节盘髁关系,可作为颞下颌关节二维静态MR成像的有益补充,弥补常规MRI检查的局限。     

颞下颌关节骨骼肌肉系统三维有限元模型的构建

目的探讨基于影像学与解剖学构建颞下颌关节(temporomandibular joint,TMJ)骨骼肌肉系统三维有限元模型的可行性,为TMJ生物力学研究提供建模的新思路。方法采集第2代中国虚拟人男性第23号头颅CT图像、咀嚼肌及TMJ关节盘MRI图像,以DICOM格式导入Mimics软件进行三维重建,再通过Geomagic Studio软件配准模型、优化模型及构建关节软骨和关节囊,最后由ANSYS软件定义各组织的材料属性,建立TMJ骨骼肌肉系统的三维有限元模型。结果建立了一个包含关节盘、关节软骨、关节囊、上颌骨(包括颧骨及鼻骨)、下颌骨、颞骨(包括部分顶骨)、蝶骨、上牙列、下牙列、颞肌、咬肌、翼内肌、翼外肌、颞下颌韧带、蝶下颌韧带及茎突下颌韧带的TMJ骨骼肌肉系统的三维有限元模型。结论根据CT、MRI图像和解剖学,利用Mimics、Geomagic Studio及ANSYS可以精确、可行地构建TMJ骨骼肌肉系统的三维有限元模型。模型更加真实还原TMJ的生物力学环境,为TMJ生物力学研究提供新的建模方法,为临床上TMJ疾病的可视化治疗提供仿真平台。     

Clinical Signs and Subjective Symptoms of Temporomandibular Disorders in Instrumentalists

PurposeMost of the reports on instrumentalists'' experiences of temporomandibular disorders (TMD) have been reported not by clinical examinations but by subjective questionnaires. The aim of this study was to investigate the clinical signs and subjective symptoms of TMD in a large number of instrumentalists objectively.ResultsOverall, 453 participants (61.3%) reported having one or more symptoms of TMD. The most frequently reported symptom was a clicking or popping sound, followed by temporomandibular joint (TMJ) pain, muscle pain, crepitus, and mouth opening limitations. Compared with lower-string instrumentalists, a clicking or popping sound was about 1.8 and 2 times more frequent in woodwind and brass instrumentalists, respectively. TMJ pain was about 3.2, 2.8, and 3.2 times more frequent in upper-string, woodwind, and brass instrumentalists, respectively. Muscle pain was about 1.5 times more frequent in instrumentalists with an elevated arm position than in those with a neutral arm position. The most frequent diagnosis was myalgia or myofascial pain (MFP), followed by disc displacement with reduction. Myalgia or MFP was 4.6 times more frequent in those practicing for no less than 3.5 hours daily than in those practicing for less than 3.5 hours.ConclusionThe results indicate that playing instruments can play a contributory role in the development of TMD.     

工程化颞下颌关节盘组织的细胞源问题:现状与展望

目的是为学者探索适当的颞下颌关节盘组织工程种子细胞提供参考。目前颞下颌关节盘组织工程正处于起步阶段,而细胞来源是制约关节盘组织工程发展的主要因素之一,本文概述了关节盘细胞、软骨细胞、皮肤成纤维细胞、骨髓基质干细胞、脂肪干细胞和胚胎干细胞等6种细胞作为关节盘组织工程细胞源的可行性,以便寻找一种合适的细胞源。     

Role of magnetic resonance imaging in the clinical diagnosis of the temporomandibular joint

Temporomandibular joint (TMJ) abnormalities cannot be reliably assessed by a clinical examination. Magnetic resonance imaging (MRI) may depict joint abnormalities not seen with any other imaging method and thus is the best method to make a diagnostic assessment of the TMJ status. In patients with temporomandibular joint disorder (TMD) referred for diagnostic imaging the predominant TMJ finding is internal derangement related to disc displacement. This finding is significantly more frequent than in asymptomatic volunteers, and occurs in up to 80% of patients consecutively referred for TMJ imaging. Moreover, certain types of disc displacement seem to occur almost exclusively in TMD patients, namely complete disc displacements that do not reduce on mouth opening. Other intra-articular abnormalities may additionally be associated with the disc displacement, predominantly joint effusion (which means more fluid than seen in any asymptomatic volunteer) and mandibular condyle marrow abnormalities (which are not seen in volunteers). These conditions seem to be closely related. Nearly 15% of TMD patients consecutively referred for TMJ MRI will have joint effusion, of whom about 30% will show bone marrow abnormalities. In a surgically selected material of joints with histologically documented bone marrow abnormalities nearly 40% showed joint effusion. Disc displacement is mostly bilateral, but joint effusion seems to be unilateral or with a lesser amount of fluid in the contralateral joint. Abnormal bone marrow is also mostly unilateral. Many patients have unilateral pain or more pain on one side. In a regression analysis the self-reported in-patient TMJ pain side difference was positively dependent on TMJ effusion and condyle marrow abnormalities, but negatively dependent on cortical bone abnormalities. Of the joints with effusion only one fourth showed osteoarthritis. Thus, there seems to be a subgroup of TMD patients showing more severe intra-articular pathology than disc displacement alone, and mostly without osteoarthritis. It should, however, be emphasized that patients with TMJ effusion and/or abnormal bone marrow in the mandibular condyle seem to constitute only a minor portion (less than one fourth) of consecutive TMD patients referred for diagnostic TMJ imaging. The majority of patients have internal derangement related to disc displacement, but without accompanying joint abnormalities. In patients with rheumatoid arthritis and other arthritides TMJ involvement may mimick the more common TMDs. Using MRI it is possible, in most cases, to distinguish these patients from those without synovial proliferation.     

伴偏斜对下颌前突患者颞下颌关节应力分布的影响

目的探究伴偏斜对下颌前突患者颞下颌关节(temporomandibular joint,TMJ)应力分布的影响。方法在Mimics中建立4名下颌前突伴偏斜患者和4名下颌前突不伴偏斜患者的三维颌面部模型,在ABAQUS中赋予模型偏侧咬合(单侧磨牙咀嚼)的肌肉力与边界条件,分析偏侧咬合工况下患者TMJ的最大和最小主应力。结果偏侧咬合工况下,伴偏斜患者髁突的平均最大应力显著大于不伴偏斜患者(P<0.05),伴偏斜会使髁突处应力增加2~3倍,关节窝应力增加5~7倍,且伴偏斜患者中颞下颌关节紊乱综合征(temporomandibular disorder,TMD)患者同侧TMJ处的应力高于无TMD患者。结论伴偏斜会增大患者髁突和关节窝的应力,TMD会引起伴偏斜患者同侧TMJ的高应力。建议根据偏斜与否考虑下颌前突的治疗。     

Cytopathologic diagnosis on joint lavage fluid for patients with temporomandibular joint disorders

Temporomandibular joint (TMJ) disorders (TMD) are usually diagnosed based on the patient's clinical findings and the results of image investigations; however, understanding of the inflammatory process in TMJ is difficult. In addition, many of the TMJ disease types share common principal symptoms. Therefore, TMJ diseases in the early stage can be misdiagnosed with TMD. It is hypothesized that cytopathologic examination of the joint lavage fluids is useful in interpreting the TMD‐associated inflammatory process from a cellular aspect. The aim of this study was to assess the TMJ lavage fluid cytopathologically in TMD patients. Thirty‐nine patients, clinically diagnosed as TMD, were included in the present study. Clinical symptoms of the patients were recorded. Forty‐four samples of TMJ lavage fluid were collected and paraffin‐embedded cell sections were made by cell block tissue array method. Cytologic conditions in upper articular cavity of TMJ were cytopathologically diagnosed and were compared with the clinical symptoms of each patient. Cell components were detected in 22 of the 44 analyzed joint lavage fluids. There was a correlation between cytopathologic findings and clinical symptoms. Variety of cytopathology and inflammatory conditions in patients with similar clinical symptoms were also found. The results suggested that cytopathologic examination of the joint lavage fluids from TMD patients is helpful for gaining an understanding of the inner local conditions of TMJ at the cellular level. Diagn. Cytopathol. 2014;42:30–36. © 2013 Wiley Periodicals, Inc.     

Lubrication of the Temporomandibular Joint

Although tissue engineering of the temporomandibular joint (TMJ) structures is in its infancy, tissue engineering provides the revolutionary possibility for treatment of temporomandibular disorders (TMDs). Recently, several reviews have provided a summary of knowledge of TMJ structure and function at the biochemical, cellular, or mechanical level for tissue engineering of mandibular cartilage, bone and the TMJ disc. As the TMJ enables large relative movements, joint lubrication can be considered of great importance for an understanding of the dynamics of the TMJ. The tribological characteristics of the TMJ are essential for reconstruction and tissue engineering of the joint. The purpose of this review is to provide a summary of advances relevant to the tribological characteristics of the TMJ and to serve as a reference for future research in this field. This review consists of four parts. Part 1 is a brief review of the anatomy and function of the TMJ articular components. In Part 2, the biomechanical and biochemical factors associated with joint lubrication are described: the articular surface topology with microscopic surface roughness and the biomechanical loading during jaw movements. Part 3 includes lubrication theories and possible mechanisms for breakdown of joint lubrication. Finally, in Part 4, the requirement and possibility of tissue engineering for treatment of TMDs with degenerative changes as a future treatment regimen will be discussed in a tribological context.     

Prevalence and clinical signs of degenerative temporomandibular joint changes validated by magnetic resonance imaging in a non-patient group

The aim of this study is to investigate associations between degenerative bony changes of the temporomandibular joint (TMJ) evaluated by magnetic resonance imaging (MRI) and signs and symptoms of temporomandibular disorders (TMD) in a non-patient group. A total of 307 subjects (140 males and 167 females) were selected from the cross-sectional epidemiological study "Study of Health in Pomerania" (SHIP) for this evaluation. A clinical functional examination of the masticatory muscles and the TMJs was performed as well as an MRI examination of the TMJs. Another 77 subjects (25%) exhibited degenerative changes of one or both TMJs in the MRI. Clinical analysis revealed pain on palpation of the masticatory muscles in 113 subjects. Some 39 subjects had pain during palpation of the TMJs. There were significant associations between the MRI confirmed diagnosis of osteoarthrosis and some clinical signs (joint noises, joint palpation pain, reduced mouth opening) and symptoms (reported pain in the jaw and masticatory muscles) of TMD as well as further MRI diagnoses (disc displacement with and without reduction, fibrosis of the posterior ligament). Although there were some associations, clinical examination alone is not sufficient for diagnosing degenerative joint diseases. MRI is a necessary diagnostic adjunct for estimating the prevalence of TMD subgroups in non-patient populations.     

人体颞下颌关节盘后组织生物力学研究

确定了颞下关节盘后组织的生物力学性质,研究其功能机制。对取自８个新鲜关节标本的１３个盘后组织试件进行了软组织单向拉伸应力松驰和破坏实验,结合Ｆｕｎｇ ＹＣ拟线 粘弹性理论对实验结果进行了分析。结果表明：盘后组织的生理二相区在２０％－３０％应变范围内。     

Correlation of MRT imaging with real-time axiography of TMJ clicks

There is a series of tools useful for gathering diagnostic information on patients with temporomandibular joint disorders. Tracings of the joint movement (axiography) provide useful information about the motion of the joints. Since the availability of electronic axiographic tracers, the movement of the condyles can be resolved with high resolution both in space and in time. In order to obtain information about the anatomical relation of the joint surfaces and the disc, magnetic resonance tomography imaging (MRI) is routinely carried out. It is common practice to take MR images of the joints with the mouth closed and fully open. In order to correlate the MR images with the axiographic tracings, a series of images can provide much more information. In this study we examined patients with distinct temporomandibular joint (TMJ) clicks. In one case, the click occurs once a day, while in the other case the click happens every time the mouth is opened. In order to obtain information about both motion and anatomical relation of the TMJ at and around the position where the clicks occur, we recorded a series of MRI scans with the mouth gradually opened and before and after joint clicks. Real-time axiographic tracings during the click were taken with an optimized system where the polar moments were reduced as much as possible to follow the movement during the click. These tracings were correlated with the MRI scans to determine the exact internal conditions of the TMJ and the changes during the click. In particular cases, the additional information provided by this procedure can be useful in deciding whether and which therapeutic intervention is advisable.     

用于分析面形态与颞下颌关节生物力学关系的三维有限元模型的建立

目的为研究(牙合)面形态变化对颞下颌关节应力影响的规律,建立包括下颌牙列(牙合)面形态及双侧髁突的三维有限元模型.方法尸头1具,平行于眶耳平面作CT扫描,获取下颌骨几何参数;取石膏模型,以三维扫描仪对牙列(牙合)面扫描(精度0.5mm);将石膏模型参数与CT参数换算到同一坐标系下,在髁突上方设均厚类关节盘,关节盘顶及下颌角作约束设计,经划分网格生成有限元模型.结果建立了包括双侧髁突、类关节盘及下颌牙列在内的用于分析咬合与颞下颌关节关系的三维有限元模型.结论采用本方法可建立研究(牙合)面形态与颞下颌关节应力关系的三维有限元模型.     

颞下颌关节音分析的临床应用研究

目的：探讨以TMJ音分析作为TMJ损伤及病变临床诊断和病理研究方法的可行性。材料和方法：利用线性谱分析和非线性分形分析两种方法对健康人和TMD患者的TMJ音进行分析。结论：结果表明，两种方法均能正确识别健康人和TMD患者的TMJ音，但谱分析法仍需依靠医生的临床经验。     

碱性成纤维细胞生长因子对骨髓间充质干细胞向颞下颌关节盘细胞分化的影响

为观察碱性成纤维细胞生长因子(bFGF)对骨髓间充质干细胞(BMSCs)分化的影响,采用bFGF诱导山羊BMSCs,通过组织学、免疫组织化学和酶联免疫吸附实验(ELISA)等方法检测BMSCs产生的细胞外基质(ECM)包括Ⅰ型胶原和蛋白多糖的情况,初步评价BMSCs做为颞下颌关节(TMJ)盘组织工程种子细胞的可行性。结果表明:经bFGF诱导,BMSCs向成纤维细胞样细胞分化,能够合成糖胺聚糖(GAG)和I型胶原,因此认为BMSCs作为工程化关节盘种子细胞是可行的。     

上颌扩弓对颞下颌关节应力影响的有限元分析

目的 通过三维有限元法对比扩弓前和放置扩弓器时颞下颌关节(temporomandibular joint, TMJ)内部各组织应力分布情况。方法 根据1名上颌牙弓狭窄患者CBCT影像资料,构建扩弓前和包含扩弓器的TMJ三维有限元模型,对模型加载相同的肌力和边界约束,观察TMJ髁突、关节盘、关节窝的等效应力、最大主应力和最小主应力。结果 扩弓前TMJ等效应力主要分布在下颌支前缘、髁突前斜面、关节盘中间带和后带以及关节窝顶部。放置扩弓器时,TMJ应力分布特征与扩弓前基本一致,应力虽然明显增加,但应力分布区域更加均匀;髁突和关节盘应力向前、向外侧移动,髁突后斜面表现出更加均匀的最大主应力分布范围。结论 上颌扩弓器产生的矫形力能够使TMJ应力增加,诱导髁突发生组织改建,协调髁突和关节盘的关系。临床上对于牙弓狭窄的患者应该采用合适的手段进行扩弓矫治。     

关节盘移位对颞下颌关节内应力分布的影响

目的 通过对不同关节盘移位的数值模拟,探究各种移位情况下颞下颌关节（temporomandibular joint,TMJ）内各结构的应力分布规律。方法 依据CT图像,建立包含下颌骨、全牙列、关节盘和关节软骨的正常TMJ三维有限元模型;参考关节盘前、后、外、内移位的临床特征,建立对应的4个模型。关节盘与关节软骨间考虑接触,用缆索元模拟下颌韧带和关节盘附着,施加正中咬合荷载。结果 前移位将导致关节盘中带产生过高的压应力,达到3.23 MPa;后、内、外移位时关节盘的整体应力水平比前移位和正常TMJ高;各种移位都使关节结节后斜面的应力值大幅度增加,但对髁突关节面的影响却不大。结论 各种移位都将导致关节盘和关节结节后斜面产生过高的应力,且后、内、外移位更为危险,更容易造成关节结构和功能的损伤。     

Subchondral bone resorption in temporomandibular joint disorders

Several tissues are involved in temporomandibular joint (TMJ) health, including synovial fluid, the TMJ disc, articular cartilage, and subchondral bone. This article focuses upon bone resorption in temporomandibular joint disorders (TMD) and has the following objectives: (1) to provide a brief review of the current understanding of bone formation and bone resorption (bone remodeling); (2) to present selected case studies which illustrate the spectrum of bone resorption patterns in TMD patients of various ages; (3) to review previous reports in the literature describing loss of subchondral bone in TMD, and (4) to discuss the interaction between osteoporosis and TMD and the potential role for antiresorbing agents in TMD therapy.     

颞下颌关节骨性部分的测量和分析

本文观察测量并分析了颞下颌关节的形态结构,建立了能较客观反映该关节形态的15项指标的正常值。用3项特征指数,即关节窝指数、关节结节指数和髁突指数,能较好地反映该关节的几何形态,并表达其功能部位的相互关系,以及用频数分布曲线反映其分布规律。本文认为,男性的颞下颌关节显著大于女性,而左、右侧之间,有无咬(牙合)组之间的差别均不显著。本文结果可为该关节的临床研究、病变分析乃至人工颞下颌关节的设计,提供形态学依据。     

Comparison of conventional MRI and 3D reconstruction model for evaluation of temporomandibular joint

The aim of this work was to define the diagnostic value of a method for 3D reconstruction of MRI images for the assessment of temporomandibular joint. Sixty subjects, 42 diagnosed with unilateral temporomandibular disorders (TMD) with disc displacement and 18 without signs or symptoms of TMD (control group) were included. All subjects had both temporomandibular joints scanned by MRI. Three-dimensional imaging reconstructions of temporomandibular joint were generated by segmentation software, allowing visualization of the components of temporomandibular joint (articular disc, condyle and temporal bone) on arbitrary planes. Disc displacement was observed in 83% of 3D reconstruction and 81% of conventional MRI. The agreement between 3D diagnosis and MRI findings was significant and high. The present analysis suggested that 3D reconstruction is a useful and accurate method for the assessment of the temporomandibular joint in TMD ID.     

A mechanical evaluation of three decellularization methods in the design of a xenogeneic scaffold for tissue engineering the temporomandibular joint disc

Tissue-engineered temporomandibular joint (TMJ) discs offer a viable treatment option for patients with severe joint internal derangement. To date, only a handful of TMJ tissue engineering studies have been carried out and all have incorporated the use of synthetic scaffold materials. These current scaffolds have shown limited success in recapitulating morphological and functional aspects of the native disc tissue. The present study is the first to investigate the potential of a xenogeneic scaffold for use in tissue engineering the TMJ disc. The effects of decellularization agents on the disc's mechanical properties were assessed using three common decellularization protocols: Triton X-100, sodium dodecyl sulfate (SDS) and an acetone/ethanol solution. Decellularized scaffolds were subsequently characterized through cyclic mechanical testing at physiologically relevant frequencies to determine which chemical agent most accurately preserved the native tissue properties. Results have shown that porcine discs treated with SDS most closely matched the energy dissipation capabilities and resistance to deformation of the native tissue. Treatments using Triton X-100 caused the resultant tissue to become relatively softer with inferior energy dissipation capabilities, while treatment using acetone/ethanol led to a significantly stiffer and dehydrated material. These findings support the potential of a porcine-derived scaffold decellularized by SDS as a xenograft for TMJ disc reconstruction.