Reconsideration of the TMJ condylar position during internal derangement: comparison between condylar position on tomogram and degree of disk displacement on MRI

Morphologic characteristics of temporomandibular joint on the patients with anterior disc displacement without osteoarthritis: a case-based research

We investigated the effect of anterior disc displacement without osteoarthritis (ADDwoOA) on the morphology of the temporomandibular joint (TMJ) utilizing three-dimensional (3D) models of 23 asymptomatic individuals and 30 ADDwoOA patients. Statistical analyses between the groups were performed by measuring 10 morphological parameters. ADDwoOA patients showed significantly decreased levels of the sagittal ramus angle (SRA) and joint spaces compared with asymptomatic subjects. Moreover, the patients who had recovered exhibited normal joint spaces levels. Consequently, ADDwoOA caused the condyles to move backward and upward, approaching the articular fossa. Joint spaces can serve as an important observation during the treatment of ADD.

Clinical characteristics of temporomandibular disorders presenting posterior open bite - A report of 12 cases

Background/purpose

There is a paucity of comprehensive information about posterior open bite (POB) in patients with temporomandibular disorders (TMD) because of its rare prevalence. The purpose of this study was to investigate the etiologies, clinical characteristics, and treatment outcomes of patients with TMD presenting POB.

Materials and methods

This study includes a careful review of medical records and imaging findings of 12 patients with TMD (seven men and five women, 50.9 ± 19.2 years, 15–72 years) complaining of POB.

Results

In total, 11 had unilateral POB, whereas 1 had bilateral POB. In 11 patients, POB was caused by inflammatory disorders of temporomandibular joint (TMJ). In the remaining one patient, TMJ medial disc displacement (MDD) was responsible for POB. Of 11 patients with inflammatory conditions of TMJ, four patients had unilateral TMJ internal derangement (ID), two had bilateral TMJ ID, and one had rheumatism. POB was resolved in 10 of 11 patients with TMJ inflammation following the administration of non-steroidal anti-inflammatory drugs and self-management instructions. Prosthodontic treatment was needed in one patient to resolve POB. POB was resolved in the patient with TMJ MDD after stabilization splint therapy.

Conclusion

POB in patients with TMD was mostly caused by inflammatory disorders of TMJ. TMJ MDD could also be a reason. Although almost all POB was resolved by conservative treatments including medications, the possibility of prosthodontic, orthodontic, or surgical treatments also must be considered.

Imaging modalities for temporomandibular joint disorders: an update

The diagnosis and management of temporomandibular disorders (TMD) require both clinical and imaging examinations of the temporomandibular joint (TMJ). A variety of modalities can be used to image the TMJ, including magnetic resonance imaging (MRI), computed tomography (CT), cone beam CT, ultrasonography, conventional radiography. The present review outlines the indications of the most frequently used imaging techniques in TMD diagnosis. Because of the anatomic complexity of the TMJ, imaging can be difficult. Choosing the proper imaging technique is essential. Conventional radiography, nowadays, is of limited interest. The use of flat plane films for TMJ pathology is not sufficient, because this joint requires three dimensional imaging views. Osseous changes are better visualized with CT and cone beam CT. Cone beam CT provides high-resolution multiplanar reconstruction of the TMJ, with a low radiation dose, without superimposition of the bony structures. MRI is a noninvasive technique, considered to be the gold standard in imaging the soft tissue components of the TMJ. MRI is used to evaluate the articular disc in terms of location and morphology. Moreover, the early signs of TMD and the presence of joint effusion can be determined. High-resolution ultrasonography is a noninvasive, dynamic, inexpensive imaging technique, which can be useful in diagnosing TMJ disc displacements. The diagnostic value of high-resolution ultrasonography is strictly dependent on the examiner's skills and on the equipment used.

Changes in temporomandibular joint spaces after arthroscopic disc repositioning: a self-control study

Disc repositioning is a common procedure for patients with anterior disc displacement (ADD). The purpose of this retrospective record-based study was to evaluate changes in the widths of joint spaces and condylar position changes in patients with unilateral ADD following arthroscopic disc repositioning, with the healthy sides as self-control, using magnetic resonance images (MRI).Widths of anterior, superior, and posterior joint spaces (AS, SS, and PS) were measured. The condylar position was described as anterior, centric or posterior, expressed as . Paired-t test and Chi-square test were used to analyze the data. Fifty-four records conformed to the inclusion criteria (mean age of 21.02 years). Widths of SS and PS increased significantly after surgery (P < 0.001) on the operative sides, while joint spaces of healthy sides and AS of operative sides had no significant changes. Dominant location of condyles of operative sides changed from a posterior position to an anterior position, while healthy sides were mostly centric condylar position no matter preoperatively or postoperatively. Therefore, the results of this study indicate that unilateral arthroscopic disc repositioning significantly increases the posterior and superior spaces of the affected joints, without affecting spaces of the healthy sides.

Current status of temporomandibular joint disorders and the therapeutic system derived from a series of biomechanical, histological, and biochemical studies

This article was designed to report the current status of temporomandibular joint disorders (TMDs) and the therapeutic system on the basis of a series of clinical, biomechanical, histological and biochemical studies in our research groups. In particular, we have focused on the association of degenerative changes of articular cartilage in the mandibular condyle and the resultant progressive condylar resorption with mechanical stimuli acting on the condyle during the stomatognathic function. In a clinical aspect, the nature and prevalence of TMDs, association of malocclusion with TMDs, association of condylar position with TMDs, association of craniofacial morphology with TMDs, and influences of TMDs, TMJ-osteoarthritis (TMJ-OA) in particular, were examined. In a biomechanical aspect, the nature of stress distribution in the TMJ from maximum clenching was analyzed with finite element method. In addition, the pattern of stress distribution was examined in association with varying vertical discrepancies of the craniofacial skeleton and friction between the articular disk and condyle. The results demonstrated an induction of large compressive stresses in the anterior and lateral areas on the condyle by the maximum clenching and the subsequent prominent increases in the same areas of the mandibular condyle as the vertical skeletal discrepancy became more prominent. Increase of friction at the articular surface was also indicated as a cause of larger stresses and the relevant disk displacement, which further induced an increase in stresses in the tissues posterior to the disks, indicating an important role of TMJ disks as a stress absorber. In a histological or biological aspect, increase in TMJ loading simulated by vertical skeletal discrepancy, which has already been revealed by the preceding finite element analysis or represented by excessive mouth opening, produced a decrease in the thickness of cartilage layers, an increase in the numbers of chondroblasts and osteoclasts and the subsequent degenerative changes in the condylar cartilage associated with the expression of bone resorption-related factors. In a biochemical or molecular and cellular aspect, excessive mechanical stimuli, irrespective of compressive or tensile stress, induced HA fragmentation, expression of proinflammatory cytokines, an imbalance between matrix metalloproteinases and the tissue inhibitors, all of which are assumed to induce lower resistance to external stimuli and degenerative changes leading to bone and cartilage resorption. Excessive mechanical stimuli also reduced the synthesis of superficial zone protein in chondrocytes, which exerts an important role in the protection of cartilage and bone layers from the degenerative changes. It is also revealed that various cytoskeletal changes induced by mechanical stimuli are transmitted through a stretch-activated or Ca2+channel. Finally, on the basis of the results from a series of studies, it is demonstrated that optimal intra-articular environment can be achieved by splint therapy, if indicated, followed by occlusal reconstruction with orthodontic approach in patients with myalgia of the masticatory muscles, and TMJ internal derangement or anterior disk displacement with or without reduction. It is thus shown that orthodontic treatment is available for the treatment of TMDs and the long-term stability after treatment.

Establishing better biological models to understand occlusion. I: TM joint anatomic relationships

Belief in and rejection of a relationship of occlusion and temporomandibular joint (TMJ) condyle-fossa position with normal and abnormal function are still contentious issues. Clinical opinions can be strong, but support in most published data (mostly univariate) is problematic. Distribution overlap, low sensitivity and specificity are a common basis to reject any useful prediction value. Notwithstanding, a relationship of form with function is a basic tenet of biology. These are multifactor problems, but the questions mostly have not been analysed as such. This review moves the question forward by focusing on TM joint anatomic organisation as the multifactor system it is expected to be in a closed system like a synovial joint. Multifactor analysis allows the data to speak for itself and reduces bias. Classification tree analysis revealed useful prediction values and usable clinical models which are illustrated, backed up by stepwise logistic regression. Explained variance, R(2), predicting normals from pooled TMJ patients was 32·6%, sensitivity 67·9%, specificity 85·7%; 37% versus disc displacement with reduction; and 28·8% versus disc displacement without reduction. Significant osseous organisational differences between TM joints with clicking and locking suggest that this is not necessarily a single disease continuum. However, a subset of joints with clicking contained characteristics of joints with locking that might contribute to symptom progression versus resistance. Moderately strong models confirm there is a relationship between TMJ osseous organisation and function, but it should not be overstated. More than one model of normals and of TM derangement organisation is revealed. The implications to clinical decision-making are discussed.

Comparison of reference points in different methods of temporomandibular joint imaging

PURPOSE

Conventional radiography is a well-established method for imaging of the temporomandibular joint (TMJ) structures. However, the dental computer tomography becomes more important for the visualization of teeth in the jaw-bone. The applicability of dental computer tomography for the visualization of the TMJ it not yet been proven. The aim of the study was to identify TMJ structures using reference points with the magnetic resonance imaging (MRI) and the computed tomography (CT).

METHODS

In order to compare the visualization and measurement of the TMJ a total of eight human cadaver heads was examined with CT and MRI and analysed using reference points.

RESULTS

In both imaging techniques the selected reference points and distances are well definable and allow objective evaluation of anatomical structures. The CT images display a clearly better contrast to noise ratio than the MR images. The distance measurement of different width and length showed significant correlation of both images techniques.

CONCLUSIONS

In TMJ diagnostics, maximum information could be obtained using both imaging techniques together due to synergistic effects.

Quantification of disc displacement in internal derangement of the temporomandibular joint using magnetic resonance imaging

Many measures have been developed to determine the extent of disc displacement in internal derangements of the temporomandibular joint (TMJ) using magnetic resonance imaging. The purpose of this study was to develop a quantitative method of analyzing disc position and to evaluate the positions of the disc in internal derangements of the TMJ (group 1, with reduction; group 2, without reduction). Magnetic resonance images of 150 TMJs in 20 healthy volunteers and 55 patients with internal derangements were evaluated. The anatomical points of interest of the TMJ, including the anterior (DA) and posterior (DP) points of the disc, were marked on parasagittal magnetic resonance images of the TMJ disc taken in both the closed- and the open-mouth positions. All points were recorded using an x-y coordinate system, with reference to a referral line. In the closed-mouth position, the DP in patients in group 1 was situated in a more-anterior direction than the DP in volunteers. The DP in group 2 was located further anterior and inferior than the DP in group 1. However, the position of the DA did not differ between group 1 and group 2. In the open-mouth position, the DP was displaced anteroinferiorly to a greater extent in group 2 than in group 1 (one-way ANOVA, followed by Scheffe's test; P < 0.0001). The distance between the disc points in the closed- and open-mouth positions was also evaluated. Comparison of the disc point position in the closed- and open-mouth positions in symptomatic and asymptomatic displaced TMJ discs revealed no significant difference. In conclusion, most of our results quantitatively support previously reported findings in imaging, surgical, and histopathological studies of TMJ internal derangement. We suggest that our measure of disc position of the TMJ would be useful to assess the status and response to treatment of internal derangements of the TMJ.

Research diagnostic criteria for temporomandibular disorders (RDC/TMD): development of image analysis criteria and examiner reliability for image analysis

OBJECTIVE

As part of the Multisite Research Diagnostic Criteria For Temporomandibular Disorders (RDC/TMD) Validation Project, comprehensive temporomandibular joint diagnostic criteria were developed for image analysis using panoramic radiography, magnetic resonance imaging (MRI), and computerized tomography (CT).

STUDY DESIGN

Interexaminer reliability was estimated using the kappa (kappa) statistic, and agreement between rater pairs was characterized by overall, positive, and negative percent agreement. Computerized tomography was the reference standard for assessing validity of other imaging modalities for detecting osteoarthritis (OA).

RESULTS

For the radiologic diagnosis of OA, reliability of the 3 examiners was poor for panoramic radiography (kappa = 0.16), fair for MRI (kappa = 0.46), and close to the threshold for excellent for CT (kappa = 0.71). Using MRI, reliability was excellent for diagnosing disc displacements (DD) with reduction (kappa = 0.78) and for DD without reduction (kappa = 0.94) and good for effusion (kappa = 0.64). Overall percent agreement for pairwise ratings was >or=82% for all conditions. Positive percent agreement for diagnosing OA was 19% for panoramic radiography, 59% for MRI, and 84% for CT. Using MRI, positive percent agreement for diagnoses of any DD was 95% and of effusion was 81%. Negative percent agreement was >or=88% for all conditions. Compared with CT, panoramic radiography and MRI had poor and marginal sensitivity, respectively, but excellent specificity in detecting OA.

CONCLUSION

Comprehensive image analysis criteria for the RDC/TMD Validation Project were developed, which can reliably be used for assessing OA using CT and for disc position and effusion using MRI.

Relationship between appearance of a double contour on the mandibular condyle and the change in articular disc position after splint therapy

OBJECTIVE

The aim was to investigate the relationship between the appearance of double contours on the mandibular condyle and changes in articular disc position after splint therapy.

STUDY DESIGN

Panoramic radiographs and magnetic resonance images of 82 joints in 41 patients taken before and after treatment were studied. The number of cases showing a double contour after treatment was compared between the 2 groups with and without disc displacement before treatment, and between the 2 groups with and without reduction in the displacement group; a comparison was also made among age groups and among 3 groups showing improvement, aggravation, or no change in displacement after treatment.

RESULTS

All joints showing a double contour after treatment showed articular disc displacement before treatment. No double contours were observed after treatment on joints without articular disc displacement before treatment. All joints showing a double contour showed improvement in disc displacement.

CONCLUSION

The results indicate that a double contour on the mandibular condyle is the result of repositioning of, or positional improvement in, a displaced articular disc.

Condylar and disk position and signs and symptoms of temporomandibular disorders in stress-free subjects

BACKGROUND

The authors conducted a study in subjects who tested free of psychological stress to determine the position of the condyle and whether that position was related to signs and symptoms of temporomandibular disorders (TMDs).

METHODS

Forty subjects underwent psychological evaluation to ensure freedom from psychological stress. The authors evaluated tenderness of the masticatory muscles and temporomandibular joints (TMJs) by means of bimanual digital palpation, and they determined the positions of the condyle and disk by using magnetic resonance imaging.

RESULTS

A total of 23.75 percent of the condyles were displaced away from the centric position either anteriorly (3.75 percent) or posteriorly (20.00 percent). chi(2) analysis showed a relationship between the position of the condyle and displacement of the disk, as well as a relationship between the position of the condyle and tenderness of the TMJs.

CONCLUSION

Although these relationships proved significant, it cannot be assumed that displacement of the condyle away from the centric position is predictive of TMD.

CLINICAL IMPLICATIONS

Only two subjects were judged to have had TMJ internal derangement. Thus, the absence of psychological stress seems to have played a role in this finding.

Relationship of condylar position to disc position and morphology

INTRODUCTION/OBJECTIVE

The purpose of this study was to assess whether condylar position, as depicted by magnetic resonance imaging, was an indicator of disc morphology and position.

METHODS AND MATERIAL

One hundred and twenty two TMJs of 61 patients with temporomandibular joint disorder were examined. Condylar position, disc deformity and degree of anterior disc displacement were evaluated by using magnetic resonance imaging.

RESULTS AND DISCUSSION

Posterior condyle position was found to be the main feature of temporomandibular joints with slight and moderate anterior disc displacement. No statistical significance was found between the condylar position, and reducing and nonreducing disc positions. On the other hand, superior disc position was found to be statistically significant for centric condylar position.

CONCLUSION

It was concluded that posterior condyle position could indicate anterior disc displacement whereas there was no relation between the position of condyle and the disc deformity.

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.

A comparative assessment of mandibular condylar position in patients with anterior disc displacement of the temporomandibular joint

PURPOSE

The purpose of this study was to determine whether the position of the mandibular condyle in patients with anterior disc displacement (ADD) is different from that of a control group with normal joints using a novel method to quantify the irregular shape of the temporomandibular joint (TMJ).

MATERIALS AND METHODS

Twenty-six magnetic resonance images of TMJs with ADD were evaluated and compared with 14 normal joints. The position of the condyle was determined by using 2 different methods: 1) measuring the horizontal and vertical normalized distances in millimeters between the geometric centers of the glenoid fossa and the condyle and 2) calculating the anteroposterior joint space ratio.

RESULTS

Using the first method, the horizontal distance between the centers of the condyle and the glenoid fossa was 14.0 +/- 11.1 in the ADD group and 5.3 +/- 10.9 in the control group (P <.001). The vertical distance was 64.7 +/- 22.7 in the ADD group and 68.3 +/- 32.9 in the control group (P =.015). The ratio of the horizontal and the vertical condylar displacement in the ADD group was 2.4. Using the second method, the anteroposterior joint space ratios in the ADD group and in the control group were 1.7 +/- 0.5 and 1.2 +/- 0.4, respectively (P =.001).

CONCLUSION

This study found that condyles of patients with ADD were situated more posterior and superior in the fossa than those in the control group. Moreover, in the ADD group, the posterior condylar displacement was noted to be 2.4 times greater than the superior condylar displacement.

Bone SPECT imaging of patients with internal derangement of temporomandibular joint before and after splint therapy

OBJECTIVE

Temporomandibular joint (TMJ) patients with disc displacement without reduction have a misaligned disc-condyle structural relation. As the condition becomes chronic, painful osteoarthritic changes may occur. For these patients, splint therapy may help to position the condyle to a more structurally compatible and functional position and to decrease the loading force of articular surfaces. The aim of this study was (1). to evaluate osseous reactions and pain relief in patients with disc displacement without reduction after splint therapy and (2). to use single photon emission tomography (SPECT) bone imaging to compare the results with the opposite joint of the patient.

STUDY DESIGN

Twelve patients, who presented with pain involving the TMJ and limited mouth opening and were confirmed by soft tissue imaging as having disc displacement without reduction, were included in the study. Each patient underwent bone SPECT imaging, after which semiquantitative evaluation of transaxial images was conducted. The ratios of affected TMJ to nonaffected TMJ, affected TMJ to occipital bone, and nonaffected TMJ to occipital bone were calculated. After 6 months of splint therapy, bone SPECT examinations were repeated.

RESULTS

Before splint therapy, the ratios of affected TMJ to nonaffected TMJ and of affected TMJ to occipital bone were found to be significantly higher than the ratios after splint therapy (P < 0.005).

CONCLUSION

Six-month splint therapy has a positive effect on the osseous reaction and pain related to internal derangements of TMJs.