Interleukin-1 beta affects cyclooxygenase-2 expression and cartilage metabolism in mandibular condyle

Extracellular matrix degradation in mandibular condylar cartilage is mediated by various cytokines in the temporomandibular joint (TMJ). Interleukin-1 beta (IL-1β) is detected in joint structures with pathologic status, and participates in catabolic action in the extracellular matrix. The purpose of this study was to investigate the effects of IL-1β on cyclooxygenase-2 (COX-2) expression and cartilage metabolism using cultured chondrocytes from mandibular condyle. Articular chondrocytes from the porcine mandibular condylar cartilage around the surface were cultured and treated with 0–10 ng/ml IL-1β or 0–1000 ng/ml prostaglandin (PGE₂) for 0–24 h. The mRNA levels of COX-2, MMP-1, -3, and -13 were evaluated by real-time PCR analysis. The protein levels of PGE₂ and MMPs were examined by ELISA and Western blot analysis, respectively. The expression levels of COX-2 and PGE₂ were enhanced by exogenous IL-1β in chondrocytes. The mRNA levels of MMP-1, -3, and -13 were up-regulated by PGE₂ treatment dose-dependently. It is shown that the expression of COX-2/PGE₂ was enhanced by IL-1β in articular chondrocytes from mandibular condyle, and that MMP-1, -3, and -13 were induced by PGE₂, suggesting that IL-1β-induced COX-2/PGE₂ play a crucial role in catabolic processes of mandibular condylar cartilage under inflammatory conditions.     

A simple method to expand the joint space for TMJ surgery

When performing open surgery for internal derangement of the temporomandibular joint, it is essential to expand the joint spaces to access the lesions and perform various procedures. This paper presents a simple method to achieve this goal.     

Histological findings in soft tissues around temporomandibular joint prostheses after up to eight years of function

Early temporomandibular joint (TMJ) prostheses articulated on material with poor wear resistance. Wear debris was deposited in the surrounding tissues, causing severe foreign body cell reactions. Recent TMJ prostheses use modern orthopaedic materials, such as ultra high molecular weight polyethylene (UHMWPE) for the fossa component, and cobalt-chromium, or cobalt-chromium-molybdenum for the condylar head. These designs are reliable in long-term follow-up studies. The authors report histological findings in soft tissue samples obtained from around two types of TMJ prostheses after up to 8 years of function. The devices were four Biomet (Biomet Microfixation, Jacksonville, FL, USA), and two TMJ Concepts (TMJ Concepts, Ventura, CA, USA). All joint capsule samples demonstrated dense, fibrous connective tissue with no inflammatory cells or foreign body reactions. The joint disc tissues showed even denser fibrous connective tissue, free from inflammatory reactions. Some samples from the junction between capsule and disk demonstrated synovial-like tissue. The observations reported in this paper indicate that modern TMJ prostheses with Cr-Co-Mb or Cr-Co articular condyles articulating on UHMWPE fossa components appear to function without foreign body reactions in he surrounding tissues.     

Post-surgical neuromas in patients with total alloplastic temporomandibular joint reconstruction: a retrospective case series

This study evaluated pain scores and maximal incisal opening (MIO) in patients with total alloplastic temporomandibular joints found to have post-surgical neuromas following revision arthroplasty, compared with patients who underwent revision arthroplasty without neuromas. 19 cases were reviewed of which 11 had neuromas excised. Data were available for 8 cases in the immediate postoperative period and 7 cases had follow-up data. 8 patients had revision arthoplasty with excision of scar tissue (7 with postoperative, 4 with long-term data). Follow-up ranged from 2 months to 5.9 years (mean 1.2 years). 6 of 8 patients obtained clinically significant pain reduction in the immediate postoperative period when their neuromas were excised, compared with 3 of 7 patients without neuromas. On long-term follow-up, 3 of 7 patients in the neuroma group had clinically significant pain reduction, 3 reported lower pain scores, 1 had no pain change. No patients had increased pain. 1 of 4 patients in the scar revision group had clinically significant pain reduction, 2 had no change, 1 reported increased pain. Mean MIO was 23 mm preoperative and 28 mm postoperative in patients with neuromas, compared with 27.75 mm and 31.25 mm, respectively, in patients without neuromas.     

Effects of Initial Cell Seeding Density for the Tissue Engineering of the Temporomandibular Joint Disc

Tissue engineering may provide a better treatment modality for postoperative discectomy patients. The TMJ disc is an ideal candidate for tissue engineering approaches because of its lack of an intrinsic regenerative ability. Unfortunately, basic knowledge related to TMJ disc tissue engineering is still at an infancy level and not on par to that related to articular cartilage tissue engineering. The objective of this study was to examine the effects of initial cell density of TMJ disc cells seeded in nonwoven poly-glycolic acid (PGA) scaffolds on the biochemical and biomechanical properties of constructs examined at 0, 3, and 6 weeks after seeding. Low, medium, and high seeding densities were chosen to be 15, 30, and 120 million cells per ml of scaffold, which were seeded using a spinner flask. Significant differences were found temporally and as a function of seeding density in morphology, total collagen, GAG content, and permeability of the constructs, but not in aggregate modulus. The high seeding density group outperformed the low and medium groups in collagen and GAG content at all time points measured. The high-density group produced a total of 55.37 ± 3.56 μg of collagen per construct, maintained 15.77 ± 1.86 μg of GAG per construct, and only shrunk to 50% of the original scaffold size. Permeability of the constructs at 6 weeks was decreased by 70% compared to 0 weeks.     

咬合接触对颞下颌关节生物力学影响的有限元研究

目的建立用于研究咬合接触与颞下颌关节生物力学关系的三维有限元模型,并设计不同的工况来分析不同咬合接触情况下颞下颌关节应力的变化规律。方法尸体头颅1具,平行于眶耳平面作CT扫描;取石膏模型,以三维扫描仪对牙列(牙合)面扫描;将石膏模型扫描参数与CT扫描参数换算到同一坐标系下,在髁突上方设均厚的类关节盘,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。工况一:左侧下颌不同牙位咬合接触面加载;工况二:在包括左侧下颌第二磨牙的颞下颌关节三维有限元模型上,设计下颌第二磨牙牙尖交错(牙合)、远中方向和颊侧方向三种加载部位的工况,研究不同工况下双侧髁突处应力分布变化的规律。结果(1)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。(2)咬合加载牙位不同,双侧髁突应力效应不同,髁突外、中、前、顶等处为承受较高压强的区域。(3)咬合加载部位牙面承载形态不同,双侧髁突应力效应也不同,其变化包括应力性质和应力的分布特点等方面,远中加载和颊侧加载时分别可致加载侧髁突内极和加载对侧髁突内极应力集中。结论咬合接触部位及方向变化可影响髁突应力分布。     

Temporomandibular joint ankylosis—“Knowing when not to operate”: Case report and qualitative systematic review of literature

Temporomandibular joint ankyloses (TMJA) may manifest in patients with several predisposing systemic conditions. A case of extraarticular TMJA is presented in a patient diagnosed with fibrodysplasia ossificans progressive (FOP) is presented. The features, diagnosis, and management of TMJA superimposed on this condition are presented through a qualitative systematic review of literature.     

Efficacy of laser therapy for temporomandibular disorders: A systematic review and meta-analysis

ObjectiveThe aim of this systematic review was to evaluate the efficacy of laser therapy in temporomandibular disorders (TMD).MethodsRandomized controlled trials (RCTs) in regard to this issue were searched in electronic databases. Three investigators independently screened the eligible studies, and the quality of the included studies was assessed according to the risk of bias tool recommended by the Cochrane handbook. The primary outcome measure was the degree of pain, reported on a visual analog scale (VAS), and the secondary outcome measures were TMJ function, including maximum active vertical opening (MAVO), maximum passive vertical opening (MPVO), left and right lateral movement (LLE, RLE). Pooled effect sizes were calculated using random effects models and 95% confidence interval (95% CI).ResultsA total of 28 randomized controlled trials were included. Laser therapy had a more significant effect in terms of VAS (SMD=﹣1.88; 95% CI=﹣2.46 to﹣1.30; P < 0.00001; I² =93%), MAVO (MD = 4.90; 95% CI= 3.29–6.50; P < 0.00001; I² =72%), MPVO (MD=5.8²; 95% CI= 4.62–7.01; P < 0.00001; I² =40%) and RLE (MD = 0.73; 95% CI= 0.23–1.22; P = 0.004; I² = 0%) as compared to placebo group. However, there was no significant difference in LLE between two groups (MD= 0.35; 95% CI=﹣0.31–1.01; P = 0.30; I² =0%).ConclusionsLaser therapy can effectively reduce pain but have small effect on improving mandibular movement of TMD patients. More well-designed RCTs with large sample sizes are needed for further validation. And these studies should report detailed laser parameters and provide complete outcome measure data.     

正常成人颞颌关节的CT和MRI影相分析

本文对10名正常成人双侧TMJ进行了CT扫描,其中3名作了MRI扫描。对所有CT片作了TMJ骨性结构的三维分析,观察了正常人髁状突和关节凹的形态类型,并发现双侧形态均为同型,双侧髁状突运动范围一致。同时,还用CT软组织窗位相(闪烁相)对关节盘进行了正中(牙合)位和尽力开口位的观察,并用MRI对其结果加以证实。本研究所得结果较其它方法准确,更具有可比性。因为本研究选用CT对双测TMJ进行同时扫描,消除了以往X光片需分侧和多种投照检查所造成的误差。     

颞颌关节关节盘再造的研究

目的：用组织工程方法进行颞颌关节关节盘的再造。方法：用Ⅱ型胶原酶消化法收集兔耳廓软骨细胞，将细胞按5×10^7／ml的终浓度接种于纤维蛋白原中，固化成为膜片状后，将负载软骨细胞的纤维蛋白植入裸鼠背部皮下组织中，2个月后取材，通过大体标本观察、组织学观察颞颌关节关节盘的构建情况。结果：植入术后2个月，在裸鼠背部形成了膜片状的组织，为亮白色，具有一定的弹性和韧性；组织学检查见新形成的组织由软骨构成，纤维蛋白己完全吸收。结论：纤维蛋白负载软骨细胞，可以有效进行颞颌关节关节盘的再造。