A three-dimensional method of visualizing the temporomandibular joint based on magnetic resonance imaging in a case of juvenile chronic arthritis

Summary. Aim . The purpose of this study was to present a new visualizing method for temporomandibular joint (TMJ) pathology in 3D at several condylar positions and to apply the method to a case of juvenile chronic arthritis (JCA) with previously diagnosed bilateral TMJ disorder and to a subject without signs and symptoms from the TMJ.
Subject . The 20-year-old female patient had suffered from polyarticular JCA from the age of 6 years 8 months. The present study is based on a follow-up examination after the completion of orthodontic treatment with the Herbst appliance. Both TMJs were examined using magnetic resonance imaging (MRI) at closed and open mouth positions. The mandibular condyle, the glenoid fossa and the articular disc were segmented and 3D reconstruction of these structures was carried out.
Results. The condyle was characterized by an increased sagittal diameter with osteophyte-like formation at the anterior aspect of the condylar head and flattening of the superior surface. The depth of the glenoid fossa was reduced and the articular eminence was remarkably flat. The articular disc was markedly diminished and posteriorly placed on the condylar head. The distance of the condylar path during mouth opening was reduced and the curvature of the condylar path was quite flat. The disc moved slightly posteriorly on the condylar head and remained in the glenoid fossa during mouth opening.
Conclusion. The imaging modality described improves visualization of TMJ morphology and gains insight into the TMJ pathology of the JCA patient, adding to understanding of the clinical problems.     

颞下颌关节盘前移位患者关节骨形态与矢状向关节盘位置的关系

目的　利用磁共振成像（MRI）技术和锥形束CT（CBCT）分析颞下颌关节盘前移位患者矢状向关节盘位置与关节骨形态的关系。方法　对97例患者的178个颞下颌关节（TMJ）进行回顾性分析，根据矢状向MRI上关节盘的位置分成4组，即对照组（关节盘无移位）、轻度组（关节盘轻度前移位）、中度组（关节盘中度前移位）和重度组（关节盘重度前移位）。然后利用Mimics 20软件基于CBCT数据进行TMJ的相关形态学参数测量，包括髁突线性尺寸（宽度、长度和高度）、髁突体积和表面积，关节窝的深度和长度，关节结节倾斜角，关节前、上、后间隙等，并对各组矢状髁突位置进行评估。使用方差分析、非参数检验和卡方检验等比较关节形态及位置参数的组间差异，采用相关性分析探索矢状关节盘位置与关节测量参数之间的相关性。结果　髁突的线性尺寸、关节窝深度、关节倾斜角、关节间隙和矢状髁突位置分布在4组间差异有统计学意义，而关节窝长度在4组间差异没有统计学意义；相关性分析显示：髁突的线性尺寸、髁突的体积及表面积、关节窝的深度、关节结节倾斜角和关节上间隙与关节盘矢状位置之间存在显著负相关，而关节后间隙与矢状关节盘位置之间存在显著正相关。结论　TMJ骨形态与不同矢状关节盘位置之间存在相关性，应警惕临床看到的关节骨形态的退行性改变可能是患者存在关节盘前移位的标志。     

Potential role of disc repositioning in preventing postsurgical recurrence of traumatogenic temporomandibular joint ankylosis: a retrospective review of 17 consecutive cases

The potential role of disc repositioning in preventing postsurgical recurrence of traumatogenic temporomandibular joint (TMJ) ankylosis was investigated. Seventeen cases of traumatogenic TMJ ankylosis underwent disc repositioning during arthroplasty. During surgery, the dislocated disc was carefully dissected outside the ankylotic TMJ and repositioned over the top of the condylar stump, and then sutured to the soft tissue of the zygomatic root. In the 22 ankylotic TMJs of the 17 patients, dislocated discs were found in front of the ankylotic TMJ, behind the ankylotic TMJ or between the ramus and fossa. At the last follow-up (longer than 1 year) examination, interincisal opening distances ranged from 24 to 43 mm (mean 32.86 mm). No recurrence and TMJ symptoms were found during the period of follow-up. Disc repositioning in the treatment of traumatogenic TMJ ankylosis proves to be a feasible and effective method of preventing recurrence of this condition.     

人体颞下颌关节关节盘及关节软骨渗透性的研究

目的 测量人体颞下颌关节（TMJ）关节盘及关节软骨的渗透性,为口腔生物力学和口腔组织工程提供基本参数,并从生物力学角度探讨其抗力及分散载荷的机制。方法 4具新鲜人尸体TMJ标本按照关节盘、髁突及关节窝取材共制成不同直径（2 mm,3 mm,4 mm）试件128个,使用与试件直径相同的压缩头,以围限压缩方法测量TMJ渗透性。结果 关节各区中关节盘渗透性最大,关节窝渗透性最小。小直径试件比大直径试件渗透性低,随着试件直径的增加,关节盘、髁突和关节窝的渗透性均增加。结论 在正常生理范围内,关节软组织可以通过降低渗透性保护关节组织;关节盘由于具有较大渗透性,是TMJ的薄弱易损区域,关节盘破坏是TMJ损伤的始动因素。     

The influence of pre- and intraoperative positioning of the condyle in the centre of the articular fossa on the position of the disc in orthognathic surgery. A magnetic resonance study

OBJECTIVE: We investigated the changes in the temporomandibular joint (TMJ) after bilateral sagittal split osteotomy of the mandible for orthognathic surgery and the influence of positioning of the condylar process in the centre of the articular fossa before and during the operation for preventing changes in the TMJ postoperatively. STUDY DESIGN: A total of 28 patients with mandibular retrognathism had bilateral sagittal split osteotomies for mandibular advancement. In one group of 14 patients (28 TMJ), the condyles were placed in the centre of the articular fossa before and during the operation, and in the other group they were not. Differences on magnetic resonance imaging (MRI) were calculated and the results were evaluated. RESULTS: The main differences were found at maximal mouth opening. 15/28 TMJs (54%) that had not been positioned changed the position of the disc from physiological to anterior disc derangement with and without reduction postoperatively. In the 28 that had been positioned, changes were found in only 3 TMJs (11%) postoperatively. CONCLUSIONS: Fixing the condylar process in the centre of the articular fossa intraoperatively before bilateral sagittal split osteotomy is a factor in preventing postoperative structural changes in the temporomandibular joint.     

Physiological effects of anterior repositioning splint on temporomandibular joint disc displacement: a quantitative analysis

Anterior repositioning splints (ARS) are used primarily for the management of temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDwR). However, the exact physiological effects of ARS are still unclear. This study investigated the short and long‐term effects of ARS on disc and condyle angles/positions by metric analysis. Twenty‐two subjects diagnosed with ADDwR were recruited. Maxillary full‐coverage ARS were fabricated, and MRI of TMJs was obtained before splint treatment, immediate post‐insertion and 6 months after splint treatment. Disc–condyle relationship was determined by disc–condyle angle measurement. Disc and condyle positions were described as X‐Y coordinates with the summit of glenoid fossa as the origin of the coordinates. Thirty‐two TMJs were classified as ADDwR and 12 were normal. Upon ARS insertion, all TMJs with ADDwR got normal disc–condyle relationships. The condyles moved significantly forward and downward, while the discs moved significantly backward and upward. MRI at 6 months after treatment (without ARS insertion) indicated that only 40·6% (13/32) of the joints were maintained in the normal disc–condyle relationship. The majority of condyles returned to their pre‐treatment positions, while the discs generally moved anteriorly again. The use of ARS resulted in forward and downward condyle movement, and a concurrent backward movement of the disc resulting in ideal spatial disc–condyle relationship. The stability of this relationship, however, could not be maintained in the majority of TMJs upon ARS removal. Findings explain the good short‐term clinical outcomes with ARS and their relatively lower efficacy in the long term.     

Magnetic resonance imaging of the TMJ disc in asymptomatic volunteers

Forty-two temporomandibular joints (TMJs) in 21 asymptomatic volunteers were visualized by magnetic resonance imaging (MRI). The subjects, 12 males and nine females, were between 23 and 43 years of age and had no history of TMJ pain, joint noise, limited opening, or previous treatment for TMJ disorder. A cephalometric head-holder was designed to position the TMJ in an accurate and reproducible manner and multisection parasagittal images were obtained perpendicular to the longitudinal axis of the condyle. MR images depicted anterior disc position in 32% of the asymptomatic joints (8/24 males, 5/18 females). Anterior disc position in asymptomatic subjects may be a predisposing factor to TMJ dysfunction or simply an anatomic variant whose prevalence must be considered when evaluating TMJ dysfunction.     

颞下颌关节MR冠状影像测量与分析

目的 探讨颞下颌关节冠状面形态结构的关系。方法将福尔马林液浸泡1年以上的，能将下颌固定在牙尖交错位的15具尸头的28侧TMJ，斜冠状位磁共振质子加权扫描，以下颌升支中线为基准，作相应测量。结果①横径由大到小排序为：关节窝内外径、髁突内外径、关节窝内径、髁突内径、髁突外径、关节窝外径。②髁突外径与关节窝外径间，髁突内径与关节窝内径间，髁突内外径和关节窝的内外径间均存在正相关关系。③变异系数关节窝外径大于髁突外径、内径大于其他横径。④关节间隙面积与关节盘断面面积正相关。结论颞下颌关节各结构的冠状形态及大小具有高度协调性，髁突相对于关节窝的内外位置关系具有较大的变异范围。     

The evaluation of temporomandibular joint disc position in TMJ disorders using MRI

The purpose of this study was to correlate disc position and the type of disc displacement, intra-capsular effusion and degenerative changes of the condyle as demonstrated in MRI studies. In this study, 126 temporomandibular joints (TMJs) of 63 patients with TMJ disorders were investigated using clinical examination and MRI. One hundred and twelve TMJs were found to have internal derangement as disc displacement. The angle between the posterior margin of the disc and the vertical line drawn through the centre of the condyle was measured on MRI for each TMJ. The positions of the discs were normal, 0 degrees-10 degrees, in 11.11%; slightly displaced, 11 degrees-30 degrees, in 37.30%; mildly displaced 31 degrees-50 degrees, in 15.08%; moderately displaced, 51 degrees-80 degrees, in 7.14% of the TMJs with anterior displacement with reduction (ADDR). The disc position was severely displaced anteriorly, as over 80 degrees, in all TMJs with anterior disc displacement without reduction (ADD), constituting 27.78% of all cases. We found that the smaller the degree of disc displacement the milder the internal derangement and that the intra-capsular effusion was more frequently associated with TMJ with ADDR. The degenerative condylar changes were more severe with an increased degree of anterior disc displacement.     

Activator矫治安氏Ⅱ类错(牙合)前后髁突和关节盘位置改变的MRI研究

目的分析Activator功能矫治对髁突、关节盘的位置及盘髁关系的影响。方法选择20个AngleⅡ1错[牙合]患者,在斜矢状位闭口MRI影像上测量Activator功能矫治前后髁突和关节盘位置的改变。结果在无症状AngleⅡ1错[牙合]中有40％出现关节盘前移位,功能矫治前后其髁突和关节盘位置没有明显改变。结论Activator治疗不会改变髁突在关节窝中的位置,不会引起正常位置的关节盘前移位,也不会使已经存在的盘前移位复位。     

颞下颌关节MR冠状影像测量与分析

目的　探讨颞下颌关节冠状面形态结构的关系。方法　将福尔马林液浸泡1年以上的,能将下颌固定在牙尖交错位的15具尸头的28侧TMJ,斜冠状位磁共振质子加权扫描,以下颌升支中线为基准,作相应测量。结果　①横径由大到小排序为:关节窝内外径、髁突内外径、关节窝内径、髁突内径、髁突外径、关节窝外径。②髁突外径与关节窝外径间,髁突内径与关节窝内径间,髁突内外径和关节窝的内外径间均存在正相关关系。③变异系数关节窝外径大于髁突外径、内径大于其他横径。④关节间隙面积与关节盘断面面积正相关。结论　颞下颌关节各结构的冠状形态及大小具有高度协调性,髁突相对于关节窝的内外位置关系具有较大的变异范围。     

The relationship between bone marrow edema and bone changes in the mandibular condyle: A longitudinal study with MR imaging

PurposeDecreased signal intensity on T1- or proton-density weighted magnetic resonance imaging (MRI) and increased signal intensity on T2-weighted MRI in the bone marrow space are thought to reflect bone marrow edema (BME). The purpose of this study was to determine whether condyle BME is associated with condyle bone changes.MethodsThe subjects were 57 patients [65 temporomandibular joints (TMJs)] with TMJ disorders showing condyle BME on initial MRI. Condyle bone changes were compared between TMJs that showed a persistent BME pattern (group P, 43 TMJs in 40 patients) and those that showed normal bone marrow signals, indicating disappearance of BME (group D, 21 TMJs in 22 patients) on follow-up MRI.Results(1) In TMJs with a condyle with a normal shape on initial MRI, condyle bone changes were present in 53.9% of TMJs in group P in follow-up MRI, whereas the normally shaped condyle remained in all TMJs in group D. (2) In TMJs with condyle erosion on initial MRI, condyle erosion was also present in 35.7% of TMJs in group P in follow-up MRI, but had disappeared in all TMJs in group D. (3) In TMJs with condyle osteophytes on initial MRI, erosion was present in 22.2% of TMJs in group P, whereas osteophytes remained in all TMJs in group D.ConclusionsThe longitudinal study showed that condyle BME is associated with condyle bone changes and may cause condyle erosion.     

MRI and arthroscopic findings in the temporomandibular joint after mandibulectomy including the unilateral condyle. Report of two cases

In this report, the MRI and arthroscopic findings in the temporomandibular joint (TMJ) of two patients who underwent partial mandibulectomy including the condyle are presented. The disc and superior joint compartment of the affected TMJs were preserved in both patients. MRI of the affected TMJs without condyle demonstrated that the intermediate zone of the discs was located anteriorly to the summit of the articular eminence. Joint effusion was detected in the superior joint compartment of one patient. Fibrous adhesions were observed arthroscopically in the superior joint compartment of both affected TMJs. In contrast, no specific findings were demonstrated in the contralateral TMJs connected with the residual mandibular fragment.     

Biometric parameters of the temporomandibular joint and association with disc displacement and pain: a magnetic resonance imaging study

The aim of this study was to evaluate the relationship between biometric parameters of the components of the temporomandibular joint (TMJ), articular disc displacement, and TMJ pain. Magnetic resonance imaging (MRI) examinations of 185 patients were assessed (39 males and 146 females (370 TMJs), mean age 41.3 years, range 18–79 years). The antero-posterior length of the condyle was measured in its medial and lateral regions, as well as the transverse length of the condyle. Possible associations between linear measurements of the condyle, presence of disc displacement, and joint pain were tested. Although pain was more commonly reported among patients with disc displacements, this association was not statistically significant. We found statistically significant associations showing that the antero-posterior length of the condyle at the lateral pole (D1L), the antero-posterior length of the condyle at the medial pole (D1M), and the transverse length of the condyle (D2) were higher among patients without disc displacements when compared to those with unilateral or bilateral displacements. This study showed that disc displacement was associated with smaller condyles in the antero-posterior and transverse dimensions when compared to condyles in subjects with normal disc position.     

无牙牙合患者修复前后双侧颞下颌关节盘-髁关系的初步分析

目的:观察无颞下颌关节症状和体征的无牙颌患者修复前后双侧颞下颌关节(TMJ)盘-髁关系、关节腔积液及髁突骨质异常的变化。方法:通过8例无牙颌患者全口义齿修复前后双侧颞下颌关节的磁共振成像(MRI)检查,比较其修复前后双侧颞下颌关节MRI影像表现的差异。结果:修复前,8例无牙颌患者的16个关节中,10个关节盘移位(62.5%),包括7个关节盘内侧移位(43.8%),2个关节盘外侧移位(12.5%),1个关节盘前移位(6.25%);关节腔积液7个关节(43.8%);髁突骨质异常4个关节(25.0%)。修复后,8例无牙颌患者的16个关节中,10个关节盘移位(62.5%),包括7个关节盘内侧移位(43.8%)、2个关节盘外侧移位(其中1个关节盘外侧移位好转)和1个关节盘前移位(6.25%);关节腔积液7个关节(43.8%);髁突骨质异常4个关节(25.0%)。除1个关节的积液增加外,其余关节积液无变化。结论:长期缺牙可能引起无牙颌患者颞下颌关节的结构紊乱。无牙颌患者全口义齿修复后近期,关节盘移位、关节腔积液及髁突骨质异常无明显改变。     

Virtual arthroscopy of the visible human female temporomandibular joint.

PURPOSE: This study was designed to obtain views of the temporomandibular joint (TMJ) by means of computed arthroscopic simulation (virtual arthroscopy) using three-dimensional (3D) processing. MATERIAL AND METHODS: Volume renderings of the TMJ from very thin cryosection slices of the Visible Human Female were taken off the Internet. Analyze(AVW) software (Biomedical Imaging Resource, Mayo Foundation, Rochester, MN) on a Silicon Graphics 02 workstation (Mountain View, CA) was then used to obtain 3D images and allow the navigation "fly-through" of the simulated joint. RESULTS: Good virtual arthroscopic views of the upper and lower joint spaces of both TMJs were obtained by fly-through simulation from the lateral and endaural sides. It was possible to observe the presence of a partial defect in the articular disc and an osteophyte on the condyle. Virtual arthroscopy provided visualization of regions not accessible to real arthroscopy. CONCLUSION: These results indicate that virtual arthroscopy will be a new technique to investigate the TMJ of the patient with TMJ disorders in the near future.     

Clinical protocol for managing acute disc displacement without reduction: a magnetic resonance imaging evaluation

This study investigated the efficacy of a sequential combination of arthrocentesis, mandibular manipulation, and anterior repositioning splint (ARS) in the management of acute temporomandibular joint (TMJ) disc displacement without reduction (DDwoR). Twenty-one consecutive patients diagnosed with acute DDwoR by Diagnostic Criteria for Temporomandibular Disorders and magnetic resonance imaging (MRI) were recruited and managed with this method. Clinical and MRI data were obtained before and at 1 week after treatment. The disc–condyle relationship was determined by disc–condyle angle measurement. Condyle/disc positions were described as x–y coordinates with the summit of the articular fossa as the coordinate origin. Statistical analyses including independent/paired samples t-tests were conducted; significance was set at P < 0.05. Clinical success was observed in 95.2% of patients (20/21) with 22 joints affected by acute DDwoR. After combined treatment and ARS insertion, TMJs with DDwoR showed (a) normal disc–condyle relationships with substantial forward and downward condyle movement and significant disc reduction in closed position, and (b) discs with an intermediate zone located between the condylar head and articular eminence in open position. The combined approach was highly effective in ‘unlocking’ acute TMJ DDwoR and achieving spatial full disc reduction and a normal disc–condyle relationship. The duration of acute DDwoR appears to be critical for success.     

Changes in temporomandibular joint morphology in class II patients treated with fixed mandibular repositioning and evaluated through 3D imaging: a systematic review

To estimate the effects of skeletal class II malocclusion treatment using fixed mandibular repositioning appliances on the position and morphology of the temporomandibular joint (TMJ). Two independent reviewers performed comprehensive electronic searches of MEDLINE, EMBASE, EBM reviews and Scopus (until May 5, 2015). The references of the identified articles were also manually searched. All studies investigating morphological changes of the TMJ articular disc, condyle and glenoid fossa with 3D imaging following non‐surgical fixed mandibular repositioning appliances in growing individuals with class II malocclusions were included in the analysis. Of the 269 articles initially reviewed, only 12 articles used magnetic resonance imaging and two articles used computed tomography (CT) or cone‐beam CT images. Treatment effect on condyle and glenoid fossa was discussed in eight articles. Treatment effect on TMJ articular disc position and morphology was discussed in seven articles. All articles showed a high risk of bias due to deficient methodology: inadequate consideration of confounding variables, blinding of image assessment, selection or absence of control group and outcome measurement. Reported changes in osseous remodelling, condylar and disc position were contradictory. The selected articles failed to establish conclusive evidence of the exact nature of TMJ tissue response to fixed mandibular repositioning appliances.     

成人与儿童颞下颌关节骨性形态比较研究

目的:比较成人与儿童颞下颌关节(temporomandibular joint,TMJ)骨性形态的差异。方法:用多排螺旋 CT(multislice CT,MSCT)对30例健康成年志愿者和20具咬合关系正常的儿童尸体 TMJ 扫描,结合影像中心保存的10例正常儿童 TMJ 的 MSCT 资料,在工作站上对上述60例120侧 TMJ 的 MSCT 图像进行多平面重建和参数测量,SPSS 软件对反映 TMJ 骨性形态特征的参数或其比值作统计学分析。结果:髁突纵轴倾斜角、髁突颈最小/髁突头最大横断面积、髁突前后径/关节窝前后径、髁突内外径/关节窝内外径、髁突在关节窝中后间隙/前间隙、关节窝前斜面倾角、关节窝深度、关节结节倾角,成人和儿童差异有显著性(P<0.05)。结论:成人与儿童 TMJ 骨性形态存在部分差异,它对 TMJ 疾病的防治有指导意义。     

髁突纵行骨折与横断骨折的对比实验研究

目的 探讨幼年期髁突纵行和横断骨折对颞下颌关节的继发性影响。方法 中国实验用小型猪１４头,２－３月龄,分别造成左侧髁突纵行和横断骨折模型。在术后３个月与６个月进行肉眼和光镜观察。结果 髁突横断骨折引起ＴＭＪ的适应性变化,而髁突纵行骨折后ＴＭＪ形成明显的关节盘髁突粘连及双髁突畸形。光镜下显示：盘突 组织内可见大量成纤维细胞及软骨细胞,关节盘内出现血管及脂肪细胞。结果 幼年期髁突纵行与横断骨折对ＴＭＪ