Absence of joint pain identifies high levels of sleep masticatory muscle activity in myofascial temporomandibular disorder

Although the development of reliable diagnostic criteria for temporomandibular disorders (TMDs) has operationalised identification of a subgroup with myofascial pain (mTMD), causal mechanisms remain elusive. This study examines masticatory muscle activity (MMA) in more homogenous research subgroups of mTMD. Data from an existing case‐control study of women were used to subcategorise mTMD cases based on joint pain with palpation to isolate muscle‐only pain (M‐pain) vs muscle and joint pain (MJ‐pain). Differences in laboratory indicators of MMA, specifically research diagnostic criteria for sleep bruxism (SB) and high background EMG activity, and other clinical and sociodemographic indicators were examined between groups. Compared to controls, the MJ‐pain subgroup did not show elevated background EMG or sleep bruxism. In contrast, the M‐pain subgroup showed significantly higher background EMG and a trend towards elevated prevalence of sleep bruxism. These results may explain why it has been difficult for studies of SB in mixed TMD and even mTMD samples to find a consistent positive association, since a positive association may be limited to mTMD without joint pain. The subcategorising of mTMD based on joint pain with palpation (ie M‐pain, MJ‐pain) appears to reveal subgroups with relatively high and low sleep masticatory muscle‐specific activity. Findings need replication in a larger study with updated mTMD diagnostic criteria, but may prove useful for understanding mechanism of pain maintenance in mTMD with and without joint pain.     

再定位咬合板和稳定性咬合板治疗颞下颌关节紊乱病的临床疗效观察

目的：应用再定位和稳定性咬合板治疗颞下颌关节紊乱病（TMD）,研究不同咬合板对不同TMD症状的疗效对比。方法：TMD患者随机分为2组,分别采用再定位咬合板和稳定性咬合板进行治疗,在佩戴后第1、2、4、6月复查并调磨,同时做影像学检查,记录患者疼痛指数、关节弹响及张口度的变化。结果：稳定性咬合板对治疗关节疼痛效果优于再定位咬合板（P＜0．05）;再定位咬合板对治疗关节弹响效果明显高于稳定性咬合板（P＜0．01）;两种咬合板治疗6个月后张口度与治疗前比较才有效果（P＜0．05）,且两种咬合板疗效差别无统计学意义（P＞0．05）。结论：稳定性咬合板治疗关节疼痛效果较好,再定位咬合板对治疗关节弹响效果好,两种咬合板对改善颞下颌关节病的张口度稍有作用,两种咬合板都能使咬合紊乱的牙齿脱离接触而达到新的咬合关系,使髁突复位到关节窝的最佳位置。     

�������λ�׻�ת��ø������ؽ����Ҳ���ʹ�������о���չ

??Temporomandibular joint disorders??TMD??are one of the most common and refractory diseases??and significantly influence living quality and physical and psychological health. The risk factors of TMD are more complex??and at present the pathogenesis has not been fully elucidated. In recent years??more people are concerned about the effect of psychological factors??but the effect and mechanism are complex. In foreign literature research of catechol-O-methyltransferase??COMT??as a gene associated with pain shows that before and after stress the COMT gene expression changes in masticatory muscle tissue of patients with TMD??so it can be concluded that there are correlation between the psychological state and COMT gene polymorphism. This article focuses on the effect and adjustment mechanism of COMT gene in TMD.     

Factors associated with temporomandibular disorders pain in adolescents

To gain a better understanding of temporomandibular disorders (TMD) pain in adolescents, it is important to study the factors associated with its presence. Therefore, the aim of this study was to investigate potential predictors for TMD pain in adolescents, thereby including a diversity of factors from the biopsychosocial model to determine the strongest predictors. The sample of this cross‐sectional study consisted of 1094 adolescents. The presence of TMD pain was assessed using the RDC/TMD, Axis I. Apart from demographical characteristics, the roles of parafunctional habits, psychosocial aspects, menarche and other bodily pain complaints were evaluated. Single and multiple logistic regression models were used to identify associations between the predictor variables and TMD pain. Painful TMD had a prevalence of 25·5%. Logistic regression analyses showed that TMD pain was associated with sleep bruxism (OR = 1·8 95% CI = 1·34–2·34), awake bruxism (OR = 2·1 95% CI = 1·56–2·83), other parafunctional habits (OR = 2·2 95% CI = 1·17–4·08) and bodily pain complaints (OR = 5·0 95% CI = 3·48–7·28). Parafunctional habits and other bodily pain complaints may play an important role in the presence of TMD pain in adolescents. Of course, it remains unclear whether the observed associations between the investigated factors and the adolescent's TMD pain have a true causal linkage.     

颏兜对下颌骨及颞下颌关节影响的研究进展

颏兜是安氏Ⅲ类患者的辅助治疗手段之一,通过作用于下颌骨以改善安氏Ⅲ类患者的错(牙合)畸形,颏兜可以对颞下颌关节的形态及下颌骨生长产生作用,本文就近年来颏兜治疗对颞下颌关节影响的相关研究进展进行综述.     

Clinical outcomes in the treatment of unilateral condylar fractures: a cross-sectional study

The treatment of mandibular condyle fractures has been the subject of considerable discussion, especially whether open or closed treatment should be used. There is a need for practical, evidence-based guidelines, and both objective and subjective parameters should be measured. To date, few studies have considered clinically relevant subjective parameters. This study was performed to evaluate the outcomes of the treatment of condylar fractures using the Mandibular Function Impairment Questionnaire (MFIQ) and the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and to compare the outcomes of open and the closed treatment. Patients with condylar fractures and at least 1 year of follow-up were examined. These patients completed the MFIQ and other questionnaires, and were examined according to the DC/TMD. Seventy-four of 171 eligible patients participated in this study. The mean MFIQ score was 10.70 (standard error 2.9) in the open group and 4.96 (standard error 1.3) in the closed group (P = 0.023), an outcome in favour of the closed treatment group. Examination according to the DC/TMD did not reveal a significant prevalence of TMD complaints. Closed treatment appears to be a safe and appropriate modality for most unilateral condylar fractures. Although the open group in general showed similar outcomes, this treatment should be reserved for limited indications.     

Outcomes of office-based temporomandibular joint arthroscopy: a 5-year retrospective study

Temporomandibular joint (TMJ) arthroscopy is a minimally invasive surgical approach for intra-articular TMJ diseases. Office-based arthroscopy using the smallest TMJ scope allows for good visualization, as well as the ability to lavage the joint in an office setting. This study aimed to assess the efficacy of an office-based TMJ arthroscopic technique. A retrospective evaluation of 363 patients with a TMJ disorder was performed. These patients underwent office-based arthroscopy using the OnPoint 1.2 mm Scope System (Biomet Microfixation, Jacksonville, FL, USA) in Florida, USA, from July 2007. The following outcomes of the procedure were assessed: improvement in painless range of mandibular motion, pain on loading, and functional jaw pain; these were evaluated using a visual analog scale (VAS) over an average follow-up period of 263.81 ± 142.1 days. The statistical analysis was performed using IBM SPSS Statistics version 20. Statistically significant improvements in TMJ pain and function, and other variables (P = 0.001) were shown following TMJ arthroscopic lysis and lavage. Office-based arthroscopy using the OnPoint System was demonstrated to be a safe and efficient procedure for the treatment of patients with TMJ disorders as the first level of the algorithm of care.     

Immunologic and functional characterization of anti-HLA-DR rabbit antibodies induced by synthetic peptides

Three peptides selected from the amino acid sequence of the alpha- and beta-chains of DR2 histocompatibility antigens were chemically synthesized and coupled to carrier proteins to be used as immunogens in rabbits. This immunization resulted in the production of specific antibodies that readily recognized the antigen. However, only one of the four antibody preparations, antibody 6148, elicited by a short peptide from the beta-chain (residues 61-73), reacts with native membrane glycoproteins as well as intact human lymphoblastoid cells in enzyme-linked immunosorbant assays. This antibody was found to react also with membrane glycoproteins solubilized by nonionic detergents from cells bearing a different HLA-DR specificity: therefore it is likely that the peptide responsible for eliciting antibody 6148 represents a common framework determinant of DR alloantigens that is accessible on the surface of lymphoblastoid cells. The ability of antibody 6148 to bind to intact cells was confirmed by indirect immunofluorescence and by fluorescein-activated cell sorter analysis. This antibody is also capable of mediating antibody-dependent cellular cytotoxicity as determined by a 51Cr-release assay.     

Thrombopoietin level is inversely related to blast count,not platelet number,in Down syndrome neonates with transient myeloproliferative disorder

Transient myeloproliferative disorder (TMD) in neonates with Down syndrome is characterized by increased megakaryoblastic cells in the peripheral blood. Despite their spontaneous regression in weeks, prognosis is not always favorable because of fatal hepatic fibrosis. In this study, blood thrombopoietin (TPO) levels were measured by ELISA in six TMD patients and the expression of c-Mpl, a ligand for TPO, was examined on the blast cells from four patients by flow cytometer. At the onset, TPO level was undetectable in one patient and significantly lower in five patients than six neonatal controls (mean 0.52 fmol/ml, range 0.30–0.93 vs. 3.70, 1.38–8.33, P < 0.001), although platelet counts were similar (mean 321 × 10⁹/l, range 42–1,040 vs. 253 × 10⁹/l, 124–381). Two patients died of hepatic failure. TPO levels were measured in five patients after regression of the blast cells. With regression of blast cells, TPO levels were remarkably increased in four survived patients. In one patient with hepatic failure, TPO level was poorly elevated and relatively lower compared to the others. TPO levels were inversely correlated with blast numbers (r = −0.85, P < 0.001), but not with platelet counts (r = 0.426). Blast cells from four patients were all positive for c-Mpl. Our findings suggest that megakaryocyte mass is a major regulator of TPO levels and hepatic failure may affect the TPO level because liver is a major source of TPO production. Am. J. Hematol. 58:267–272, 1998. © 1998 Wiley-Liss, Inc.     

下颌骨折后不同手术固定方法对颞下颌关节的影响

目的：研究下颌骨折后不同手术固定方法对颢下颌关节的影响。方法：建立下颌角、下颌体部颏孔区及正中联合区3种单一线形骨折体外模型,用MNS104型钛小夹板及M2B单皮质螺钉采用不同方法进行骨折固定。对固定后的下颌骨骨折模型进行体外模拟功能负载。测定下颌功能活动时骨折侧髁状突的前后及左右的水平位移。用Origin6．0软件进行结果分析处理。结果：单一钛小夹板沿中线固定下颌角区,体部颏孔区及正中联合区,骨折侧髁状突均产生较大的向后的水平位移。应用单夹板外斜线固定下颌角骨折和双钛夹板固定体部颏孔区及正中联合区骨折,可明显降低骨折侧髁状突的向后水平位移。结论：任何骨折固定法必须有效对抗髁状突非生理性的位移,杜绝颞下颌关节微小创伤来源,降低病人患颢下颌关节紊乱病的风险因素。