Correlation between eminence steepness and condyle disc movements in temporomandibular joints with internal derangements on magnetic resonance imaging.

A steep articular eminence is reported to be a predisposing factor for the development of disc displacement. The purpose of this study was to evaluate the biomechanics of the temporomandibular joint (TMJ) in internal derangements and, additionally, to investigate whether a relationship exists between the steepness of the articular eminence and disc displacement, with (DDR) and without reduction (DDWR). The material consisted of the sagittal TMJ magnetic resonance images (MRIs) of 39 joints (26 DDR and 13 DDWR). Sagittal and coronal TMJ MRIs were obtained at maximum inter-cuspation and in the maximum mouth-opening position. The steepness of the articular eminence, disc, and condyle rotation, and condyle translation were investigated. A Student's t-test was performed and correlation coefficients calculated. The results revealed an increase in disc rotation in the DDR group and in condyle translation in the DDWR group (P < 0.01). Condyle rotation and the steepness of the articular eminence were similar in both groups. Disc rotation was positively correlated with condyle rotation and negatively correlated with condyle translation in the DDR group (P < 0.05, r = 0.44). Condyle translation was positively correlated with steepness of the articular eminence in the DDWR group (P < 0.01, r = 0.74). There was no correlation between movements of the disc-condyle assembly and the steepness of the articular eminence in the DDR group. Nevertheless, a relationship between condyle translation and the steepness of the articular eminence was found in the DDWR subjects.     

Analysis of magnetic resonance imaging characteristics and pain in temporomandibular joints with and without degenerative changes of the condyle

The aim of this study was to investigate temporomandibular joint (TMJ) pain and magnetic resonance imaging characteristics in 104 TMJs with and 58 without degenerative changes of the condyle, such as osteophytes, erosion, avascular necrosis, subcondral cyst and intra-articular loose bodies. TMJ images were also assessed for flattening, retropositioning and hypomobility of condyle and disc displacement. Comparison of the TMJ side-related data showed a significant relationship between disc displacement without reduction (DDwoR) and the presence of degenerative bony changes (p=0.00). Flattening, retropositioning and hypomobility of condyle showed no significant difference in relation to the presence or absence of degenerative bony changes. Retropositioning of the condyle was significantly associated to disc displacement with reduction (DDwR) (p=0.00), while condylar hypomobility was significantly more frequent in TMJ with DDwoR (p<0.05). Independent of the presence or type of DD, TMJ pain was more frequent in the presence of degenerative bony changes. When considering only DDwR, TMJ pain was significantly associated to a degenerative condition (p=0.03). When there were no degenerative bony changes, TMJ pain was significantly more frequent in DDwoR (p=0.04). Despite the present findings, the absence of symptoms in some patients with condylar bony changes suggests that the diagnosis of osteoarthritis should be established by evaluation of magnetic resonance images in association with clinical examination.     

Comparison of magnetic resonance imaging findings in temporomandibular joints of the two sides

Objectives

The aim of this investigation was to assess the association of magnetic resonance imaging (MRI)-diagnosed temporomandibular joint (TMJ) disorders [i.e., disc displacement with reduction, disc displacement without reduction (DDNR), osseous changes (OC), joint effusion] on the same side as well as in the joints of the two sides of the same individual.

Materials and methods

A total of 199 patients undergoing bilateral MRI of the TMJs were included in the study. A single variable correlation matrix was created to assess the within- and between-side correlation of single diagnoses. Then, based on 12 possible combinations of diagnoses per each side, a contingency table was created to assess the chi-square values of the differences between the observed and expected frequencies of the different cross-combinations. Multiple variable permutation test was performed to assess the null hypothesis that the diagnoses in the right and left joints are not related.

Results

Within the signs of the same side, DDNR was positively correlated with OC. As for combination of diagnoses, the presence of a specific combination of signs on one side implied the same combination of signs on the other side. The global multivariate permutation test with Tippett combination was significant at p?<?0.001, showing that the null hypothesis of independence between diagnoses of the two sides was rejected.

Conclusions

It can be suggested that disc displacement without reduction is associated with osseous changes of the same joint and that joints of the two sides are likely to be affected by the same combinations of MRI signs.

Clinical relevance

This investigation supports the concept that the two temporomandibular joints work as a unit.     

Association between temporomandibular joint disc position evaluated by magnetic resonance imaging and mandibular condyle inclination evaluated by computed tomography

Temporomandibular joint disc displacement is common in the world's population and could be associated with bone and functional characteristics of the temporomandibular joint. The aim of these study was to analyse the association between temporomandibular joint disc position evaluated by magnetic resonance imaging (MRI) and the inclination of the mandibular condyle evaluated by computed tomography (CT). One hundred and seventy temporomandibular joints (TMJ) were retrospectively analysed. The temporomandibular disc position was evaluated by MRI and classified into three types: normal (N), disc displacement with reduction (DDWR) and disc displacement without reduction (DDWoR). The mandibular condyle measurements evaluated by CT included horizontal, sagittal and coronal inclination. ANOVA followed by post hoc Tukey's test was used to evaluate the interaction between condylar inclination and disc position. There was an association between disc position and the horizontal and sagittal condylar inclination (P < .05). There are statistically significant differences in the mean of horizontal and sagittal inclination of the mandibular condyle between the DDWoR and the other disc positions (P = .002 and P = .004). Disc position was not statistical associated with coronal inclination of condyle (P > .05). These results indicate that the inclination of the mandibular condyle may be different in TMJ with various disc position. A more medial horizontal inclination and a more posterior sagittal inclination of the mandibular condyle are associated with DDWoR.     

Statistical study of the angle formed by the lateral part of the mandibular condyle and the horizontal plane

The angle between the LCA and frontal plane and the inclination of the lateral part of the mandibular condyle and the horizontal plane were measured in a sample of the skulls used in the study. Correlation between the two angles was found to be almost insignificant. Fifty-eight percent of the TMJs had an inclination of the lateral part of the condyle less than 15 degrees. The maximum value for this angle was found to be 45 degrees, and the minimum was -6 degrees.     

Cinematic study of temporomandibular joint motion using ultra-fast magnetic resonance imaging

Magnetic Resonance Images (MRI) of the temporomandibular joint (TMJ) are usually performed to study the opening/closing movements of the mandible and have up to now been pseudodynamic step-by-step images simulating condylar motion by post-processing reconstruction. The aim of this study was: 1. to optimize a TMJ cine-imaging method to give a better clinical result than the step-by-step methods; 2. to develop an ultra-fast MRI Gradient Echo (GE) sequence for this purpose; and 3. to analyze condylar movements in the sagittal, coronal and para-axial planes during border mandibular displacements and chewing. Both TM joints were studied in six asymptomatic volunteers. The method involved a compromise between in-plane resolution, slice thickness, signal-to-noise ratio and time resolution. Routine clinical use was found to be a GE pulse sequence providing three images per second with an isometric voxel resolution of approximately two millimeters in ridge. This did not allow visualization of the disk. Using this sequence enabled real and simultaneous condylar displacement observation in the three planes of space and therefore contributed to a better functional diagnosis of pathologic TMJ motions.     

Quantitative measurements of the articular areas of mandibular condyles with temporomandibular joint disorders using magnetic resonance imaging

Objective: The authors sought to clarify the variation in the condylar anterior functional surface (AFS) of patients with temporomandibular joint (TMJ) disorders using quantitative measurements by magnetic resonance imaging (MRI).

Methods:MR images of 68 joints (2 males, 32 females) were used. The subjects were classified into three groups: with/without defects of cortical bone groups and a combination group without defects. The AFS was measured as the length between the protrusive point and the apex of the condyle on MRI (4-mm-thick slices), and the quad value of the length was defined as the area on the slice. The summed quad values of all slices were used as the AFS area. Differences in the areas among the three groups were compared by one-way analysis of variance (ANOVA).

Results:The non-defect group had significantly larger AFS areas than the defect group.

Conclusions:Quantitative measurement on MR images clarified the changes in the condylar sagittal appearance.     

Functional magnetic resonance imaging of temporomandibular joint disorders

Fifty-eight temporomandibular joints (TMJs) from 40 patients with TMJ-related symptoms were examined by means of magnetic resonance scans with modified gradient echo sequences and a special double coil. This technique yielded a good spatial resolution of the intra-articular soft tissues, especially the articular disc and the bone structure of the TMJ. In combination with an incremental jaw opener, the disc-condyle complex was analysed in various closed and open mouth positions, depending on the clinical examination. Open mouth movement with differentiation of disc-condyle rotational and translation movement was demonstrated. Disturbances of TMJ motion showed interrupted condylar translation combined with mandibular deviation during open mouth movement (n = 8/58). Early phases of internal derangement of the TMJ with partial anterior disc displacement with (n = 12/58) or without (n = 2/58) reduction, total anterior disc displacement without reduction (n = 10/58), disc deformation (n = 10/58), disc adhesion (n = 2/58), condylar hypermobility (n = 6/58), condylar displacement (n = 8/58), and late phases of internal derangement of the TMJ with osteoarthrosis (n = 14/58) were clearly identified. Bilateral TMJ disorder was found in 72.5 per cent of the patients. By using motion-adapted, semi-dynamic magnetic resonance imaging (MRI), it is possible to improve the understanding of the complexity of TMJ movements.     

Changes in position of the temporomandibular joint disc and condyle after disc repositioning appliance therapy: a functional examination and magnetic resonance imaging study

Disc-repositioning splints are routinely used in the treatment of anteriorly displaced discs. The rationale of these appliances is to direct the mandibular condyle anteriorly in the glenoid fossa and to recapture the disc onto the condyle. The stability of disc recapture depends on reestablishment of the occlusion and the adaptive capabilities of the temporomandibular joint. It could therefore be suggested that treatment success is potentially higher in the active growth period. In this case report, partial disc recapture was observed on magnetic resonance images after application of a maxillary disc-repositioning appliance. Orthodontic treatment was applied for the retention of disc recapture.     

Diagnostic magnetic resonance imaging in synovial chondromatosis of the temporomandibular joint

The aim of this paper was to investigate the clinical and magnetic resonance imaging (MRI) features of synovial chondromatosis (SC) of the temporomandibular joint (TMJ). Fourteen patients with SC of the TMJ were included in the study. Clinical and MRI features were analysed and divided into three types based on MRI classification: type I with loose bodies, type II with homogeneous masses, and type III with a mixture of loose bodies and homogeneous masses. All SCs occurred in the superior compartment of the TMJ. There were two patients (14%) categorised as type I, five (36%) as type II and seven (50%) as type III. Four patients (29%) had disc perforation, and nine had bone erosion; among those nine, seven (78%) had type III and two (22%) type II. Histological examination showed inflammation and calcification in the synovial membrane and, and cartilage of the hyaline type in all cases. MRI has advantages in the diagnosis of SC.     

Osteoarthritis and abnormal bone marrow of the mandibular condyle

OBJECTIVE: The purpose of this study was to analyze the relationship between abnormal bone marrow of the mandibular condyle and osteoarthritis. STUDY DESIGN: The relationship between abnormal bone marrow and osteoarthritis of the mandibular condyle was analyzed in magnetic resonance images of the temporomandibular joints of 74 patients. Thirty-seven patients had magnetic resonance evidence of abnormal bone marrow, and 37 control patients had magnetic resonance images with normal bone marrow. RESULTS: Fifteen of 37 patients with magnetic resonance evidence of abnormal bone marrow had no magnetic resonance evidence of osteoarthritis; the other 22 patients had both abnormal bone marrow and osteoarthritis. CONCLUSIONS: Abnormal bone marrow of the mandibular condyle can occur separately from osteoarthritis; nearly one half of the joints with magnetic resonance evidence of abnormal bone marrow did not have any evident osteoarthritis. Abnormal bone marrow may therefore initially represent a separate disease entity. Over time, secondary osteoarthritis probably develops in joints with initial bone marrow abnormalities.     

Long-term magnetic resonance imaging after temporomandibular joint discectomy without replacement.

PURPOSE: The intracapsular changes in patients who underwent discectomy without disc replacement were evaluated by magnetic resonance imaging (MRI) to determine the long-term outcome of this procedure. PATIENTS AND METHODS: Thirty-three patients observed for an average of 9 years 4 months (5 to 24 years) and 10 asymptomatic volunteers underwent MRI using T1- and T2-weighted images and 3-dimensional fast imaging with a steady precession sequence (FISP-3D) technique. The intracapsular changes, especially those in the joint space, were compared with the postoperative clinical findings. RESULTS: MRI examination of the temporomandibular joint in the 33 patients (35 joints) indicated the presence of tissue with an intermediate or high signal intensity in the joint space. This tissue covered the articular surface of the condyle and fossa. Thirty-two joints had no pain or only occasional, mild pain (3 joints). No patient had severe joint pain or a low signal intensity in the joint space on MRI examination. There was no correlation between joint noise and the presence of a tissue deformity in the joint space. MRI of 2 patients with limited mouth opening showed tissue with high signal intensity in the joint space as well as an exostosis on the eminence and hypertrophy of the condyle. CONCLUSION: Long-term success is possible with discectomy without replacement. This appears to be attributable to the formation of new tissue between the condyle and fossa that acts as a pseudodisc.     

两种异常咬合刺激对小鼠髁突影像及组织形态学影响研究

目的 探究异常咬合刺激对小鼠髁突影像及组织形态学影响.方法 选取6周龄雌性C57BL/6J小鼠36只,根据饲养时间(3、7周)均分小鼠后,再随机分为对照组、单侧前牙反(unilateral anterior crossbite,UAC)组和双侧前牙咬合抬高(bilateral anterior elevation,B...     

功能矫治前徙下颌对颞下颌关节盘-突-窝位置关系影响的MRI研究

目的研究安氏Ⅱ类1分类错[牙合]患者功能前徙下颌后颞下颌关节（temporomandibular joint，TMJ）盘-突-窝位置关系的改变，探讨功能矫治对TMJ结构产生的影响。方法25例安氏Ⅱ类1分类错[牙合]患者（男性10例，女性15例），平均（11．1±1．1）岁（8．1～13．0岁），接受Activator功能矫治，平均疗程10．9个月，矫治效果满意。治疗前后分别对患者TMJ进行MRI扫描检查并用配对t检验进行盘-突-窝位置关系的定量对比分析。结果治疗前后左侧TMJ髁突前缘与关节窝拐点的距离（Ca-Tm）[分别为（-0．1±1．5）mm和（-0．6±0．9）mm]、右侧TMJ关节前间隙（Ca-Ca′）[分别为（2．3±0．8）mm和（1．8±0．5）mm]的差异有统计学意义（P〈0．05），反映髁突向前移位。反映双侧关节盘在关节窝中位置的各测量项目治疗前后的差异均无统计学意义（P〉0．05）。反映双侧关节盘相对于髁突位置的各测量项目治疗前后的差异均无统计学意义（P〉0．05）。结论功能矫治安氏Ⅱ类1分类错[牙合]在促进下颌发育、改善患者[牙合]-颌一面畸形的同时，不会对TMJ功能产生不利影响，相反可能有助于改善患者治疗前存在的不良的TMJ功能状态。     

3T磁共振成像显示颞下颌关节盘的技术研究

目的探索3T磁共振成像（MRI）显示颞下颌关节盘的序列、参数及电影成像方式的技术特点,并为临床研究颞下颌关节盘病变提供形态与功能影像学参照。方法选择15例正常志愿者和7例颞下颌关节损伤患者为研究对象,采用GE Signa HD 3T MRI和颞下颌关节专用表面线圈对颞下颌关节进行扫描,获得斜矢状、斜冠状闭口位FSE-XL/T1WI、FLAIR/T1WI、FSE-XL/PDWI、FSE/PDWI+FS、FRFSE-XL/T2WI、FRFSE/T2WI+FS扫描及斜矢状张口位FSE-XL/T1WI、FSE-XL/PDWI图像。由口腔颌面外科医师和MRI医师共同对各序列进行打分,分析各序列不同加权像对颞下颌关节盘的显示效果。结果PDWI对关节盘的显示效果得分最高,能清楚显示关节盘的解剖结构与形态。T2WI对关节盘损伤、撕裂、穿孔和关节囊积液显示良好,对关节盘移位情况则以PDWI序列显示效果为好。结论3T MRI可以清楚地显示关节盘在关节运动中的动态改变与病变受累情况,对颞下颌关节软组织损伤的诊治有重要价值。T1WI、PDWI及T2WI应作为常规的扫描方法。     

Three-dimensional reconstruction system for imaging of the temporomandibular joint using magnetic resonance imaging

This study was undertaken to develop a three-dimensional reconstruction system using magnetic resonance (MR) images in order to visualize three-dimensional images of the temporomandibular joint (TMJ) including the disk. The computerized reconstruction program (written using Visual Basic for Windows, Microsoft Corp.) could reliably generate three-dimensional images of the TMJ. Image processing techniques made the tracing of images unnecessary, reduced complex human manipulation and associated measurement errors. This system, capable of treating fifty thousand pixels or more, generates smooth three-dimensional images of the TMJ.     

Fr?nkel appliance therapy and the temporomandibular disc: a prospective magnetic resonance imaging study.

This prospective clinical study assessed the effect of the Fr?nkel Functional Regulator-II (FR-II) treatment on the position and shape of the articular disc of the temporomandibular joint. The sample included magnetic resonance images of 112 temporomandibular joints taken initially (T1) and after 18 +/- 1 months (T2). The subjects were 56 white Brazilian children who were beginning their pubertal growth spurt. They had Class II Division 1 malocclusions and were selected from 800 children in neighborhood schools. They were randomly dichotomized into either the treated group (treated with the FR-II for 18 months) or the control group (not treated during the observation period). Our findings showed a low prevalence (3.57%) of disc displacement in the 112 temporomandibular joints. Mandibular propulsion with the FR-II had no unfavorable effect on the temporomandibular joints of the treated group; 100% of the patients kept an upper and interposed disc position (closed and open mouth, respectively) at T1 and T2. The control group had 7.1% partial anterior medial disc displacement, both at T1 and T2. Regarding disc morphology, the control group showed biconcave-shaped discs in 82.1% of the joints, statistically similar to the treated group (89.3%) at the beginning of the observation period. At T2, the articular disc morphology of the control group was unchanged, but that of the treated group was significantly more normal (P =.016), progressing from nonbiconcave at T1 (10.7%) to biconcave at T2 (100%). Our results showed that disc displacement is not a complication of functional appliance therapy; in fact, such treatment might help some children with incipient temporomandibular disorders.