关节灌洗加透明质酸治疗不可复性关节盘前移位

目的　探讨颞颌关节不可复性盘前移引起的严重张口受限的非手术疗法。方法　对 5 9例不可复性盘前移 (包括 3 6例旋转移位 )的张口受限患者 ,行多次关节灌洗 ,配合木楔被动张口训练 ,透明质酸腔内注射治疗。结果　经 3次治疗后颞颌关节活动度明显增大 (P <0 .0 1)。基本无痛 ,无并发症。关节造影显示 :仅 3例关节盘部分复位。结论　该法操作简单 ,可反复进行 ,是治疗不可复性盘前移 (包括旋转移位 )引起张口受限的有效方法。     

腭穹隆形态对上颌全口义齿基托位移的影响

目的：研究腭穹隆形态对上颌全口义齿基托位移的影响。方法：模拟5种咬合状态，对尖、平、凹3种腭穹隆形态的上颌全口义齿的三维有限元模型进行加载。结果：3种腭穹隆形态上颌全口义齿基托在5种加载方式下，凹型腭穹隆形态基托的上腭前部及后缘区向黏膜组织的下压位移最大，基托边缘封闭区背离黏膜组织的位移最小。基托的位移方式因加载方式不同而不同。结论：上颌全口义齿基托位移方式及大小与加载方式有关；腭穹隆形态对上颌全口义齿基托位移方式无明显影响，对位移值大小有影响。     

Modified condylotomy versus conventional conservative treatment in painful reciprocal clicking—a preliminary prospective study in eight patients

Modified condylotomy may be relevant in severe painful reciprocal clicking of the temporomandibular joint (TMJ) where conservative treatment is insufficient. The effect of the modified condylotomy was analyzed and compared with conventional nonsurgical treatment in a randomized pilot study of eight patients, 19–44 years of age, with severe painful reciprocal clicking. Before and after treatment, assessments were performed by subjective reports, clinical recordings, and blinded evaluations of radiography and magnetic resonance imaging (MRI). Based on the clinical evaluations before treatment, all conditions were disc displacements with reduction and arthralgia (Research diagnostic criteria for temporomandibular disorders), but based on MRI, one patient had disc displacement without reduction and another had normal disc position. The treatment effect was significantly better and the disorders were significantly more reduced with condylotomy than with conventional nonsurgical treatment (P < 0.05, Mann–Whitney U test). In the surgical group, the clicking and locking had disappeared, the pain during function was significantly reduced (P < 0.05, Friedman ANOVA), and in two patients the disc position was normalized. The clicking still persisted in the nonsurgical patients and the disc position was unchanged. Our conclusion is that modified condylotomy is a promising option to reduce symptoms and signs in severe painful reciprocal clicking.     

The interrelationship between bolus breakdown, mandibular first molar displacement and jaw movement during mastication

The purpose of this study was to clarify the interrelationship between food bolus breakdown, mandibular first molar displacement and jaw movement during mastication. Finite element models were constructed of the maxillary first molar crown, the mandibular first molar consisting of crown, root, periodontal ligament and alveolar bone, as well as the food bolus were constructed. Based on the actual measurement of the jaw movement pattern and the characteristics of food bolus, the patterns of mandibular first molar displacement and bolus breakdown on time course in the progress of mastication were simulated, to investigate the biomechanical significance of tooth displacement and jaw movement during mastication, using finite element non-linear dynamic analysis. The results showed that the patterns of tooth displacement and jaw movement and characteristics of food bolus changed with an interrelationship to each other as mastication progressed. Particularly at the initial phase, it was suggested that the patterns of mandibular first molar displacement and jaw movement worked inter-dependently to accomplish an efficient hard-bolus breakdown.     

Experimental forward mandibular displacement in sheep.

In order to investigate growth modifications of the temporomandibular joint (TMJ) during dentofacial orthopaedic treatment, specific functional appliances have been used experimentally to prompt the mandible into a protrusive position in various animal models. The purpose of this study was to test the effectiveness of a functional appliance specially designed for sheep and to evaluate the sheep as a model for dentofacial orthopaedic research. Eight, 4-month-old, castrated male Merino sheep were randomly assigned to experimental or control groups, with four in each group. Cast functional appliances were fabricated for the animals in the experimental group. The treatment period was 15 weeks. Dental casts, endosseous implant markers and cephalograms were used to analyse the displacement of the mandible. Undemineralised sagittal sections of TMJ were used to evaluate the tissue responses induced by the appliances. The weight of the animals was measured monthly to monitor their growth. The growth of the metacarpus was also measured. During the experimental period, the animals maintained their weight within the normal range and grew normally. The appliance displaced the mandible to a downward and forward position. The adaptive responses in the TMJ induced by the appliances included changed anteroposterior shape of the condylar process, anteriorly thickened condylar cartilage, and a thickened compact bone layer along the anterior surface of the posterior wall of the glenoid fossa. The sheep coped well with the experimental procedures and the appliance used was demonstrably effective in inducing adaptive responses in the TMJ. Consequently, it is believed that the sheep is an appropriate animal model to study growth modifications in the TMJ region.     

颞下颌关节盘前移位后关节组织中S-100的表达

目的：探讨颞下颌关节盘前移位后关节组织中S-100表达的变化及其意义。方法：26只日本大耳白兔，在建立颞下颌关节盘前移位动物模型后，分别于术后1周、2周、4周、6周、8周、10周和12周处死，用免疫组织化学方法检测关节组织内S-100的分布。结果：正常时S-100的表达主要位于关节盘前带和后带的软骨细胞中，双板区内无软骨细胞亦无S-100的表达。1周时下板内有少量成纤维细胞和纤维软骨细胞弱表达S-100，2周时出现少量弱表达S-100的游离软骨细胞。以后软骨细胞数目逐渐增多、S-100表达逐渐增强。10周时，可见多数强表达S-100的软骨细胞，12周时，滑膜层亦可见软骨细胞的出现及S-100的表达。结论：关节盘前移位后双板区出现软骨细胞及S-100的表达，S-100的表达可能与双板区组织的适应性改建有关。     

The dynamic range of TMJ sounds

It is of clinical interest to record the amplitudes of temporomandibular joint (TMJ) sounds. The aim was to test the hypothesis that sealing the meatus, when placing a microphone in the ear canal affects such recording by increasing the sound pressure level (SPL). Bilateral recordings of 249 TMJ clickings were made from three subjects, using sampling rates of 48 or 96 kHz and 24 bits A/D conversion, with and without the ear canals sealed by Silicone putty. The peak-to-peak equivalent sound pressure level (peSPL) was higher (P < 0.001) when the ear canal was sealed (range of mean differences was 8.3-24.9 dB peSPL). This means that the signal to noise ratio can be improved by sealing the meatus because the electronic noise level is not increased. Most important is that the dynamic range of the clicking sounds was 62 dB that is larger than the effective dynamic range of a 16 bits sound card. Future studies are needed to establish normative peSPL values. However, cards with at least 24 bits A/D conversion will be required, especially in patients with suspected disc displacement with reduction, where the difference in loudness between opening and closing clicking often is large.     

Temporomandibular joint internal derangement: detection with 12.5 MHz ultrasonography

The purpose of this study was to determine whether 12.5 MHz ultrasonography (US) could be used to assess the presence or absence of temporomandibular joint (TMJ) internal derangement (ID). In 48 consecutive patients with TMJ disorders 192 TMJ positions were investigated by US to analyse the functional disc-condyle relationship (DCR). In order to compare the respective findings with those of a diagnostic method offering a high accuracy, coronal and sagittal magnetic resonance imaging was carried out immediately afterwards. With US showing a sensitivity of 0.58 and 0.75, and a specificity of 0.92 and 0.84 for disc displacement with and without reduction, the data revealed US to be marginal in detecting the presence, but sensitive in detecting the absence of the respective types of a TMJ ID. In addition, with a positive predictive value of 0.83 and 0.71, and a negative predictive value of 0.81 and 0.87 for disc displacement with and without reduction, the results indicate that US may be insufficient in establishing a correct diagnosis for the presence or absence of the respective types of TMJ ID. Regarding the diagnosis of absence or presence of TMJ ID, the results demonstrate high-resolution (HR)-US to be sensitive in detecting the absence, and reliable in predicting the presence of TMJ ID. In view of the fact that the 12.5 MHz US technique proved to be a reliable diagnostic aid for the detection of normal, and the prediction of abnormal DCR, the results of this study should be of further interest and encourage research in its potential uses and diagnostic capabilities.     

Type II collagen and aggrecan mRNA expression by in situ hybridization in rabbit temporomandibular joint posterior attachment following disc displacement

Pathological changes and mRNA expression were studied in the posterior attachment of 40 adult Japanese white rabbits. The right temporomandibular joints of 28 rabbits were subjected to surgical disc displacement. Joints were studied by histochemistry and in situ hybridization. The collagen in the posterior attachment became dense, especially near the posterior band of the disc. Chondrocytes were found not only in the disc but also in the posterior attachment. Sometimes cartilage formation was seen. Type II collagen mRNA expression was first detected in the posterior attachment 4 days postoperatively and became progressively stronger with time. Aggrecan expression in the posterior attachment decreased at first, then increased gradually. It was concluded that, in the temporomandibular joint, chondrocytes appear in the posterior attachment as a result of biomechanical stimuli and the attachment becomes fibrocartilaginous following disc displacement.     

Flexure deformation in temporomandibular joint disk displacement without reduction may predict treatment outcome

To identify whether the direction of disk flexure deformation predicts the prognosis in cases of anterior disk displacement without reduction of painful temporomandibular joint (TMJ), the relationship between the direction of flexure, observed on pseudodynamic magnetic resonance (MR) images, and the outcome of conservative treatment using a flat occlusal splint was analysed in 40 female patients who perceived occasional or constant pain at unilateral TMJ with disk displacement without reduction. From the MR findings, 20 patients were classified as having upward flexure deformation of the disk and 20 as having downward flexure deformation. Patients' TMJ pain, masticatory muscle pain, amount of maximal mouth opening, and MR findings were evaluated before treatment. All patients were treated with a flat occlusal splint for 6 months. The patients' signs and symptoms were analysed statistically within each group before treatment and 3 and 6 months afterwards, and were also compared between the upward and downward flexure groups. There was no statistical difference between the groups before treatment, except in the amount of maximal mouth opening and the extent of disk displacement. The upward flexure group had persistent TMJ pain and tendency of delayed alleviation of masticatory muscle pain compared with the downward flexure group, although maximal opening gradually increased in both groups. Thus, the direction of the flexure in deformation of the disk, which can be observed only with pseudodynamic MR imaging, may predict the prognosis of painful disk displacement without reduction following treatment with a flat occlusal splint.