颞下颌关节盘前移位关节盘及盘后区超微结构变化的实验研究

目的通过建立关节盘前移位实验动物模型的方法,研究颞下颌关节盘前移位后关节盘及盘后区早期超微结构的变化。方法10只兔左侧关节经手术诱导为关节盘前移位模型,右侧为手术对照组;2只为正常对照组。术后24小时、1周、2周、3周、4周,麻醉下活体各切取2只手术组实验动物同一部位的关节盘和关节盘后区组织,制成透射电镜标本观察。结果关节盘组织中软骨样细胞逐渐增多,细胞周围的淡区逐渐变小并消失,胞浆中微丝增加,胶原纤维间排列紊乱数量减少,并见新生毛细血管及神经纤维,最后软骨样细胞转化为纤维母细胞和肌纤维母细胞。盘后区早期出现幼稚的软骨样细胞,有排列相对致密的胶原纤维,最后转化成类似于关节盘样组织。结论颞下颌关节盘前移位后,关节盘失去纤维软骨盘的特性转化为纤维结缔组织;盘后区则由疏松的结缔组织变成纤维软骨盘样组织。     

Histopathological study of human TMJ perforated discs with emphasis on synovial membrane response

Fifteen perforated TMJ discs from human cadavers were studied histologically to examine the synovial membranes and to compare the findings with previous experimental results in monkeys. There were four with perforations in the bilaminar zone (these four discs were displaced anteriorly), three in the medial third of the disc, and eight in the lateral third of the disc. Histopathologically, there was an increase in vascularity and strong methyl pyronine-positive cellularity around the margins of the perforations. A young, loose, collagenous tissue lined the lateral margins of the perforated discs. Increased fibrous tissue content of the synovial subintimal territorial matrix and osteochondroid metaplasia were also seen. Severe synovial hyperplasia was visible in all joint recesses, but was greatest within those associated with displaced discs. There was patchy distribution of acidic glycoproteins, especially in the lateral parts of the perforated discs. As in the animal studies, human TMJ disc perforation was associated with a vigorous synovial reaction that was seen to form lateral bridges along the margins.     

Disc-like changes and type II collagen mRNA expression in the bilaminar zone of rabbit temporomandibular joint following disc displacement]

OBJECTIVE: To study the adaptive alteration in bilaminar zone of rabbits' temporomandibular joint following disc displacement. METHODS: Twenty-six Japanese white rabbits were used in this study. Among these rabbits,6 were used as controls. The right discs of other 20 rabbits were displaced anteriorly by operation. Four of these rabbits were killedatn 1, 2, 4, 6 and 8 weeks respectively after surgery. The TMJS were studied by HE staining, Alcin bluen staining and in situ detection of type II collagen mRNA expression. RESULTS: There appeared cartilage metaplasia after one week following disc displacement. Typical chondrocytes could be found in the bilaminar zone. The new chondrocytes expressed type II collagen. CONCLUSIONS: The bilaminar zone of TMJ will be remodeled following disc displacement and become a disc-like tissue to function as a disc.     

Arthrotic changes and deviation in form of the temporomandibular joint--an autopsy study

An autopsy study was performed on 84 left human temporomandibular joints. Frequency and location of osteoarthrosis and deviation in form were registered in each joint component. Locations of disc perforations were registered with special emphasis on involvement of the bilaminar zone. The anatomical relationship between the deep masseter muscle and the TMJ capsule was investigated in part of the material. Deviation in form was most frequent in condyles (53%) compared with temporal components (40%) and discs (15%). The relative frequencies of the three joint components were opposite for osteoarthrosis; discs (32%), temporal components (26%) and condyles (21%). Higher frequency of arthrotic changes was found in edentulous specimens than in dentulous ones. Disc perforations were located within disc tissue except for one joint where it also included part of the bilaminar zone. No correlation between sex and arthrosis and/or deviation in form was found. Insertion of the posterior fibres of the deep masseter muscle into the anterior capsule was macroscopically observed in six of ten joints.     

Angiogenesis in the human temporomandibular joint studied by immunohistochemistry for CD34 antigen

The CD34 antigen is a sensitive marker of vascular endothelium and angiogenesis. Thus, we examined the expression of CD34 in 20 human temporomandibular joint (TMJ) samples with internal derangement and in 10 control specimens by an immunohistological technique using paraffin-embedded tissue and specific anti-human CD34 monoclonal antibody. In the control specimens, CD34 was observed sporadically within the TMJ discs. On the other hand, in the internal derangement specimens, CD34 was found frequently in the walls of blood capillaries within the TMJ discs. In the synovial membrane, CD34 was detected frequently in the walls of many blood capillaries in both the controls and the internal derangement specimens. Indeed, CD34 expression in internal derangement specimens was more intense than in control specimens. In the posterior loose connective tissue of the bilaminar zone, and in the anterior loose connective tissue between the upper and lower lamellae of the anterior capsular wall, CD34 was detected in abundance in the walls of blood capillaries both of the controls and the internal derangement specimens. Generally, CD34 was found rarely in the walls of large blood vessels. The presence of CD34 is suggested to be correlated with the process of angiogenesis induced by internal derangement of the TMJ.     

Expression of heat shock protein 27 (HSP27) in human temporomandibular joint discs of patients with internal derangement

Heat shock proteins (HSPs) are believed to represent a cellular stress response mechanism that protects intracellular proteins from damaging events. Some studies have demonstrated an enhanced expression of large-molecular-weight HSPs in diseased systematic joints. Small heat shock proteins, and among these HSP27, have been studied to a lesser extent. HSP27 has cytoprotective and biosynthetic functions within chondrocytes, and it is an estrogen-associated protein that is under hormonal modulation. To improve understanding at a molecular level of the pathophysiology of certain temporomandibular joint disorders, the authors carried out this immunohistochemical study to assess the presence of HSP27 in human TMJ discs. Twelve adult human TMJ discs (10 diseased and 2 healthy discs) and 5 TMJ fetal human discs were used in this study. Adult discs and TMJ tissues of human fetuses were fixed in 10% buffered formalin. Samples were then processed for histologic examination. Sections were immunohistochemically stained using the streptavidin-biotin detection method. No reaction product for HSP27 in the discs of fetuses was noted. HSP27 was weakly expressed in normal TMJ discs and highly up-regulated in discs of patients showing new vessel formation and chondroid metaplasia. Any correlation between gender and HSP27 was found in the sample, being the up-regulation of HSP27 related mostly to major histopathological changes. This different pattern of HSP27 immunostaining in human TMJ discs detected in the authors' specimens suggests that the expression of this small HSP is functionally modulated. In fact HSP27 up-regulates in internal derangement specimens with major histopathological changes; on the other hand, it is not expressed or only weakly expressed in TMJ discs of fetuses and normal TMJ discs.     

颞下颌关节盘前移位关节区组织病理变化的实验研究

目的通过建立关节盘前移位实验动物模型的方法,来研究人类关节盘前移位病变早期阶段的发展过程和病理学改变。方法１２只新西兰大白兔左颞下颌关节经实验诱导为关节盘前移位模型,右侧为手术对照组。于术后２４ｈ、１周、２周、３周、４周、１０周各处死２只,切取关节组织,ＨＥ染色,光镜观察。结果早期：关节结节、髁突关节软骨增生明显,髁突软骨下出血,骨组织内血管网消失;后期：髁突关节软骨、骨组织及滑膜出现骨关节炎（ＯＡ）样改变。结论实验诱导关节盘前移后关节区的病理学变化与人类相似;关节盘前移位关节区的创伤可引起关节骨关节炎样改变。     

Stress distribution in the temporomandibular joint affected by anterior disc displacement: a three-dimensional analytic approach with the finite-element method

The purpose of this study was to investigate the influences of anterior disc displacement on TMJ loading during maximum clenching by use of finite-element analysis. Based on a young human dry skull, an analytic model of the mandible including the TMJ was developed. In addition to the standard model with normal disc-condyle relation, two models were designed to simulate various degrees of anterior disc displacement. In the standard model, compressive stresses were induced in the anterior, middle and lateral areas on the condyle and glenoid fossa, whereas tensile stresses were observed in the posterior and medial regions. In the models with anterior disc displacement, compressive stresses were recognized in all the areas of TMJ components excluding the bilaminar zone. Shear stresses in the articular disc and bilaminar zone significantly increased in most areas. In conclusion, stress distributions in the TMJ with a normal disc position was substantially different from those with anterior disc displacement, suggesting that the progress in disc displacement may have some association with the nature of stress distributions in the TMJ, in the articular disc in particular.     

Substance P and mast cells: preliminary histologic analysis of the human temporomandibular joint

PURPOSE: Neuropeptide-containing nerves can serve as a mechanism for nervous system regulation of host defense responses. Because bacteria associated with reactive arthritis have been identified in the temporomandibular joint (TMJ), this study investigates whether the presence of substance P (SP) neuropeptide-containing nerves and mast cells can be identified in the TMJ. MATERIAL AND METHODS: Posterior bilaminar tissue removed during TMJ surgery from 9 women was evaluated for the presence of neuropeptide-containing nerves by staining with a monoclonal antibody to SP. Staining of the TMJ tissue sections with 0.5% toluidine blue was performed to identify the presence of mast cells. RESULTS: SP-containing nerves and mast cells were identified within the posterior bilaminar tissue associated with the vasculature. CONCLUSIONS: The presence of neuropeptide nerves and mast cells within the TMJ has been shown. Mast cell degranulation products and SP release can contribute to TMJ inflammation.     

Transmission electron microscopic and light microscopic study of condylar and joint disk in TMJ disturbance syndrome

Temporomandibular joint disturbance syndrome (TMJDS) is a complex disease. Its etiological factors and pathologic nature are not clear still. After studying the condyles and discs of 3 normals and 14 TMJDS patients by transmission and scanning electron microscopy and light microscopy, we found: The pathologic changes of TMJDS are similar to those of osteoarthritis. These changes may be associated with the microtrauma in TMJ. There are some repair reactions after destruction of the articular cartilage. The destruction of fibrils is one of the main destruction in TMJDS. The changes of bilaminar zone may be one of the causes of treatment failure by conservative methods in some patients.     

Studies on matrix components relevant to structure and function of the temporomandibular joint]

Proteoglycans (PGs), or their component glycosaminoglycan (GAG) chains, have long been recognized as small in quantity but as significant components for many connective tissues. The temporomandibular joint (TMJ) disc and synovial fluid were rarely investigated in this regard. This research was aimed at the biochemical analysis of the composition of collagen, GAGs and PGs in the normal human and porcine TMJ discs, and of PGs in the synovial fluid. 1. The collagen type analysis by gel electrophoresis revealed that the human and porcine TMJ discs were composed only of type I collagen. 2. The human TMJ disc contained 69.9% chondroitin sulfate, 24.5% dermatan sulfate, 5.6% hyaluronic acid and a trace amount of keratan sulfate, and the porcine TMJ disc, 5.8%, 91.4%, 2.8% and a trace amount, respectively. Immunohistochemical staining of the functional parts of the TMJ disc showed a universal distribution of these GAGs. 3. PGs were extracted from the TMJ disc with 4 M guanidine chloride and separated by ion-exchange and gel-filtration chromatography. A high molecular weight PG resembling the cartilage PG and two low molecular weight PGs having a core protein of Mr 40 K were isolated. 4. PGs suggested to be derived from the matrix of other tissues were found in the abnormal human synovial fluid. From these results it was suggested that the TMJ disc was thought not to be fibrocartilage but a fibrous tissue adapted against to the compressive and tensile force.     

颞下颌关节增强磁共振成像研究

目的：探讨磁共振对比增强剂Gd—DTPA对颞下额关节紊乱病的临床诊断意义。方法：对12名临床诊断为颞下颌关节紊乱病患进行磁共振增强前后扫描，观察影像增强效果。结果：Gd—DTPA对关节盘位置正常的关节闭口斜矢状位前伸部及张口位双板区具有显的增强效果；对可复性及不可复性关节盘前移位张闭口位前伸部及双板区均有明显的增强效果；对冠状位也有明显增强效果。结论：磁共振对比增强剂的增强效果明确，为提高临床诊断准确性及作为磁共振常规扫描的辅助手段提供理论依据。     

Disk position and the bilaminar zone of the temporomandibular joint in asymptomatic young individuals by magnetic resonance imaging

OBJECTIVE: The purpose was to study the disk position of the temporomandibular joint (TMJ) in young individuals without any clinical signs or symptoms or history of internal derangement or degenerative joint disease and to study the features of the bilaminar zone of the TMJ in sagittal magnetic resonance (MR) images and the behavior of the bilaminar zone during jaw opening. STUDY DESIGN: MR imaging examinations of 80 TMJs of 40 symptom-free healthy subjects (20 women and 20 men) with a mean age of 26.9 years formed the basis of this study. RESULTS: In 33 of the 40 symptom-free subjects (82.5%), there was a normal relationship between disk and condyle at occlusion, whereas 5 individuals had unilateral disk displacement and 2 had bilateral disk displacement. The superior part of the bilaminar zone could be identified in all of the 40 symptom-free subjects. The inferior band of the bilaminar zone was identified bilaterally in 57.5% of individuals and unilaterally in 20%. In 9 subjects, the inferior band of the bilaminar zone could not be identified in any of the TMJs. CONCLUSIONS: Disk displacement of the TMJ occurred in approximately 20% of the young individuals in this sample. The use of both sagittal and oblique coronal MR images is of importance for classification of the position of the disk in that the oblique coronal imaging plane rendered significant complementary information to that of the sagittal images. The identification of both the superior and the posterior band of the bilaminar zone must be considered new information. The superior band remained consistently in contact with the fossa at the open-mouth position.     

正常人牙尖交错位紧咬牙时颞下颌关节无单元—有限元耦合法三维生物力学研究

目的应用无单元—有限元耦合法探讨正常人牙尖交错位紧咬牙时颞下颌关节内的应力分布情况。方法利用中国可视化人体图像数据建立包括上下牙列、下颌骨、颞下颌关节在内的三维有限元模型和三维无单元—有限元耦合模型,用自行编制的耦合程序对已建立的正常颞下颌关节三维无单元—有限元耦合模型进行应力分析。结果无单元—有限元耦合模型与有限元模型所反映的颞下颌关节应力分布特点基本相同,但耦合模型对关节盘的应力分析更精细。颞下颌关节关节盘最薄弱的中间带区是应力最集中的地区,双板区也是高应力分布区,提示这两处是关节盘最易受损伤的区域。结论无单元—有限元耦合法是一种有效的数值模拟方法,计算过程大大简化,计算精度显著提高,在生物力学研究中有推广应用前景。     

过度张口对颞下颌关节软组织P物质样免疫反应的影响

目的深入探讨过度张口对颞下颌关节（ＴＭＪ）的损伤特点及其神经生物学机制。方法在对过度张口的组织病理学实验研究基础上，采用ＡＢＣ免疫组化法同步观察其ＴＭＪ软组织Ｐ物质样免疫反应（ＳＰＩＲ）的变化。结果过度张口主要使关节盘前伸部、双板区和关节囊滑膜下层ＳＰＩＲ显著增强，并随过度张口的延长而加重，去除刺激休息两周后，ＳＰＩＲ明显减弱。ＳＰＩＲ的变化与其组织病理学改变在变化部位、反应程度和治疗效果上基本一致，提示二者间确有某些内在联系。结论认识变化特点，把握内在联系，将有助于拓展ＴＭＪ损伤及疼痛的预防与诊治的思路及方法。     

Viscoelastic properties of the human temporomandibular joint disc in patients with internal derangement.

PURPOSE: This study investigated the viscoelastic properties of human temporomandibular joint (TMJ) discs in patients with severe internal derangement (ID). PATIENTS AND METHODS: TMJ discs obtained from 5 patients with severe TMJ internal derangement were analyzed. Normal discs derived from 2 fresh cadavers and 4 patients without ID served as the controls. The viscoelastic responses of the discs to tensile forces were evaluated by means of stress-strain analyses. RESULTS: The discs in both groups exhibited a nonlinear stress-strain relationship that was represented by a power function of the strain. However, after stress relaxation, the ID discs were likely to exhibit a linear stress-strain relationship. The instantaneous elastic moduli were almost the same in both discs, but the relaxed elastic modulus of the ID discs was significantly greater than that of the controls in lower strain range of less than 2%. CONCLUSIONS: ID discs are more rigid than normal discs. These findings suggest that the changes in viscoelastic property of the discs in patients with ID are somewhat different from those that occur with aging.     

The expression of substance P in human temporomandibular joint samples: an immunohistochemical study

The expression of neuropeptide substance P was examined in 18 human temporomandibular joint (TMJ) samples with internal derangement of the TMJ, and in 10 control specimens. The examination was carried out using an immunohistological technique, using paraffin-embedded tissue and specific anti-human substance P polyclonal antibody. We noted five characteristic distribution patterns of substance P expression: at the nerves' fibre bundles in the connective tissues of the anterior and/or posterior attachment; around the blood vessels in the attachments; at the margin of the TMJ disc and synovial membrane layer; on the surface of hypertrophic synovial membranes with inflammation and proliferation; and around the newly formed capillaries in the TMJ discs. In TMJs with internal derangement associated with severe pain, we found distinct substance P expression in most of the specimens. The expression was particularly intense at the margin of the TMJ disc and synovial membrane layer, on the surface of hypertrophic synovial membranes and around the newly formed capillaries in the TMJ discs. The clinical symptoms of internal derangement of the TMJ are thought to be associated with the degree of synovitis. We conclude that the expression of substance P seems to be closely related to histopathological changes of the human TMJ with internal derangement.     

Osteoarthritis and internal derangement of the temporomandibular joint: a light microscopic study

To describe osteoarthritic changes of the temporomandibular joint (TMJ) and their relation to internal derangements, 22 randomly selected TMJ autopsy specimens were dissected and studied by light microscopy. Normal disc position was seen in eight joints, partial anterior displacement of the discs in eight joints, and complete anterior displacement of the discs in five joints; one joint had a perforated disc. Degenerative changes, such as horizontal splitting, clustering of chondrocytes, bone marrow fibrosis, sclerosis, erosion, cyst formation, and reduction in TMJ size, were found in 11 of the 14 joints with displacement or perforation of the disc and in four of the eight joints with normal disc position. Internal derangement appeared to be associated with osteoarthritis. The relations between remodeling, aging, internal derangement, and osteoarthritis are discussed.     

Clinical investigation of early post-traumatic temporomandibular joint ankylosis and the role of repositioning discs in treatment

This study investigated the development of temporomandibular joint (TMJ) ankylosis after condylar fracture and the functional results of surgery that included repositioning of the articular discs. In a total of 18 patients, there were 13 cases of fibrous ankylosis (type I) and 11 of partial bony ankylosis (type II). CT scans for both groups and MRI scans for type I patients were analysed. Intraoperative inspection of the damaged disc, the sites of adhesion or bony fusion, and remaining intra-articular movement was recorded. After release arthroplasty and repositioning of discs, follow-up was for 1 to 3.5 years (mean 2.2 years). Post-traumatic TMJ ankylosis was highly associated with sagittal and comminuted condylar fractures. Type I ankylosis usually formed in the 4th to 5th month post-trauma with mean interincisal opening distance of 18.3+/-5.5mm. Progression from type I to II ankylosis occurred 1 year post-trauma and caused a reduction of 5mm in the range of mouth opening. The disc was displaced for each of the involved joints, and intra-articular adhesions or ossification initiated at the site where there was no intervening disc present. After surgical repositioning of the disc, stable joint function and mouth opening from 30 to 45 mm were obtained in all patients but one (recurrence due to dislocation). Sagittal and comminuted condylar fractures predispose the TMJ to ankylosis, and the displacement of the articular disc plays a critical role. Early surgical intervention to reposition the disc was successful for early trauma-induced TMJ ankylosis.     

Immunolocalization of vimentin and alpha-smooth muscle actin in dysfunctional human temporomandibular joint disc samples

The expression of vimentin and alpha-smooth muscle (alpha-SM) actin was examined in 10 human temporomandibular joint (TMJ) disc samples, with internal derangement and in two control specimens, in order to evaluate the phenotypic characteristics of TMJ disc cells in relationship to histological findings. This was accomplished by means of monoclonal antibodies specific for vimentin and alpha-SM actin and immunocytochemical technique. The study, revealed that every disc cell constantly expressed vimentin. Scattered alpha-SM actin positive cells could be appreciated in normal TMJ discs and tissues with minor pathological findings. In TMJ discs with severe alterations, i.e. tears and clefts, almost fibroblast-like cells, fibrochondrocytes and chondrocyte-like cells were strongly immunolabelled by anti-alpha-SM actin antibody. According to these findings it can be assumed that vimentin is expressed by all disc cell populations and it appears not to be influenced by any disease condition of the disc; on the other hand the up-regulation alpha-SM actin immunolabelling seems to be correlated to histopathological findings of tears and clefts. Cells, with a contractile phenotype, close to such defects, could be involved in disc tissue contraction and repair. The plasticity of disc cell populations which evolve towards a different phenotype when subjected to action of macro- and micro-environmental factors is also supported.