Flexure deformation of the temporomandibular joint disk in pseudodynamic magnetic resonance images

Introducing a novice-friendly classification system for magnetic resonance imaging of the temporomandibular joint disc morphology

OBJECTIVE

To introduce a new classification, aiming to correspond TMJ disc configuration with diagnosis, meanwhile reduce difficulty and subjectivity in TMJ MRI evaluation and training of TMD diagnosis for dental students.

METHODS

90 patients sought for TMD treatment were enrolled in the study, whose MRIs were used to establish the new classification. A total of 180 discs were evaluated using MRI for position (normal, DDWR or DDWoR) and classified by morphology according to previous (Murakami's classification) and new classification respectively. 60 discs were selected and judged by two groups (2 TMJ specialists and 30 dental students) to assess the reliability and validity of the new classification. Questionnaires were acquired for all observers to assess the attitude toward two classification systems. Descriptive statistics, Spearman's rank correlation coefficient, and intraclass correlation coefficient were performed. P < 0.05 was considered statistically significant.

RESULTS

In the new classification, Class 1 disc was significantly correlated with DDWR and Class 3 disc was significantly correlated with DDWoR. Interobserver reliability/consistency for observers between TMJ specialists was 0.867 when Murakami's classification was applied and 0.948 when the new classification was applied. Interobserver ICC value for dental students was 0.656 when using Murakami's classification, and 0.831 when using the new classification. The difference in attitude toward different classification systems was statistically significant.

CONCLUSION

A new classification of TMJ disc configuration is presented. The correlation between disc morphology and position revealed helps diagnosis and management. The new classification improves TMJ MRI interpreting accuracy and provides a better learning and using experience.

Classification of temporomandibular joint internal derangement based on magnetic resonance imaging and clinical findings of 435 patients contributing to a nonsurgical treatment protocol

This prospective clinical study aimed to establish a new classification system for TMJ internal derangement based on MRI in correlation with clinical findings contributing to a nonsurgical treatment protocol. A consecutive sample of 435 internal derangement patients was enrolled in the study. Clinical and MRI studies were used to establish the new classification system. A total of 747 joints were classified according to our staging system and received treatment according to the associated nonsurgical treatment protocol. The primary outcome variables were maximum voluntary mouth opening and visual analogue scale pain scores. The secondary outcome variable was joint sound. Statistical analysis of the differences between pretreatment and posttreatment measurements showed an increase in mouth opening throughout the study period (P < 0.001 at 12 m posttreatment). Statistical analysis of the VAS scores showed a statistically significant decrease in all study groups during all study periods, with P < 0.0001 at 12 months posttreatment. Statistical analysis of joint sounds showed significant improvement during all study periods. The new classification system is a simple, & reasonable including a detailed description of all the pathologic changes of the joint. The nonsurgical treatment protocol was Simple, effective and specific depending on the pathological changes in joint.

Association of bone marrow edema with temporomandibular joint (TMJ) osteoarthritis and internal derangements

PURPOSE

This study reviewed the dental literature in order to determine the association of bone marrow edema with osteoarthritis and temporomandibular joint (TMJ) internal derangement disorders.

METHODS

A literature search was performed using electronic databases PubMed/Medline (National Library of Medicine, Bethesda, Maryland) and Cochrane for articles published during the last 15 years (January 2000-December 2014). A predetermined inclusion and exclusion criteria were used for filtering the scientific papers. Research articles fulfilling the basic inclusion criteria were included in the review.

RESULTS

The reviewed studies showed that bone marrow edema is found in painful joints with osteoarthritis in a majority of cases. A few cases with no pain or significant degenerative changes are reported to have a bone marrow edema pattern as well.

CONCLUSIONS

Bone marrow edema, increased fluid level, and pain are associated with osteoarthritis in the majority of patients reporting TMJ arthritis. Degenerative and disc displacement conditions are multifactorial and require further investigations. Magnetic resonance imaging can be employed to detect bone marrow edema even in the absence of pain and clinical symptoms in the patients of internal derangements.

Biomechanical and biochemical outcomes of porcine temporomandibular joint disc deformation

OBJECTIVE

The structure-function relationship in the healthy temporomandibular joint (TMJ) disc has been well established, however the changes in dysfunctional joints has yet to be systematically evaluated. Due to the poor understanding of the etiology of temporomandibular disorders (TMDs) this study evaluated naturally occurring degenerative remodeling in aged female porcine temporomandibular joint (TMJ) discs in order to gain insight into the progression and effects on possible treatment strategies of TMDs.

DESIGN

Surface and regional biomechanical and biochemical properties of discal tissues were determined in grossly deformed (≥Wilkes Stage 3) and morphologically normal (≤Wilkes Stage 2) TMJ discs.

RESULTS

Compared to normal disc structure the deformed discs lacked a smooth biconcave shape and characteristic ECM organization. Reduction in tensile biomechanical integrity and increased compressive stiffness and cellularity was found in deformed discs. Regionally, the posterior and intermediate zones of the disc were most frequently affected along with the inferior surface.

CONCLUSIONS

The frequency of degeneration observed on the inferior surface of the disc (predominantly posterior), suggests that a disruption in the disc-condyle relationship likely contributes to the progression of joint dysfunction more than the temporodiscal relationship. As such, the inferior joint space may be an important consideration in early clinical diagnosis and treatment of TMDs, as it is overlooked in techniques performed in the upper joint space, including arthroscopy and arthrocentesis. Furthermore, permanent damage to the disc mechanical properties would limit the ability to successfully reposition deformed discs, highlighting the importance of emerging therapies such as tissue engineering.

Comparing proton density and turbo spin echo T2 weighted static sequences with dynamic half-Fourier single-shot TSE pulse sequence at 3.0 T in diagnosis of temporomandibular joint disorders: a prospective study

OBJECTIVES

The aim of this prospective study was to compare dynamic and static sequences in the evaluation of temporomandibular joint disorders using a 3.0 -T imaging unit.

METHODS

194 patients were evaluated by static (double echo proton density weighted/turbo spin echo T2 weighted sequences) and dynamic (half-Fourier single-shot turbo spin echo sequences)imaging. Two radiologists evaluated in consensus the quality of images, the disc position and morphological alterations. The Kendall rank correlation coefficient (τ-b) was used to compare the qualitative rating between static and dynamic sequences. Cohen's kappa coefficient (k) was used to assess the agreement of disc position and morphological alterations between both sequences. The intraclass correlation coefficient was used to calculate the intraobserver variability. The significance was set at p ≤ 0.05.

RESULTS

The correlation between both sequences in the qualitative evaluation was τ-b = 0.632. The agreement between both techniques in the evaluation of disc position was k = 0.856. The agreement between both techniques in assessing the morphological alterations was k = 0.487. In the static sequences, the intraclass correlation coefficient was 0.915 in the qualitative evaluation, 0.873 in the evaluation of disc position and 0.934 in the assessment of morphological alterations. In the dynamic sequences, the intraclass correlation coefficient was 0.785 in the qualitative evaluation, 0.935 in the evaluation of disc position and 0.826 in the assessment of morphological alterations.

CONCLUSIONS

Static imaging remains the gold standard in the evaluation of the temporomandibular joint. Dynamic imaging is a valuable tool that can provide additional information about topographic changes in the disc-condyle relationship.

Magnetic resonance imaging evaluation of mandibular condyle bone marrow and temporomandibular joint disc signal intensity in anaemia patients

OBJECTIVES

To compare the signal intensity (SI) of mandibular condyle bone marrow (MCBM) and the temporomandibular joint (TMJ) disc in patients with chronic anaemia and healthy subjects, and to investigate the relationships between bone marrow changes, age, types of anaemia and severity of anaemia.

METHODS

MRIs of 18 patients with chronic anaemia were compared with those of 12 healthy subjects. The SI of MCBM and the TMJ disc were quantitatively evaluated. The SI of the grey matter (GM), white matter (WM) and the lateral pterygoid muscle were also investigated. Relationships between age, MCBM and TMJ disc signal-intensities and anaemia severity, and correlations between the groups, were analysed.

RESULTS

The mean MCBM SI was lower in anaemia patients (including both subgroups and also separately) than in healthy subjects (P < 0.05). No statistical significance was found for GM, WM and the muscle SI between the anaemia patients and healthy patient group (P > 0.05). No statistical significance was found between the groups with respect to the anterior band, whereas the mean SI value of the posterior band in the study group was significantly lower than in healthy subjects (P < 0.05). There were no correlations between age and MCBM SI, or between anaemia severity and MCBM SI.

CONCLUSIONS

Anaemia may cause bone marrow alterations without any internal derangement. Patients with chronic anaemia exhibit lower mandibular condyle bone marrow and posterior band SI than healthy subjects.

Temporomandibular joint osteochondritis dissecans: case report

BACKGROUND

Osteochondritis dissecans is a process in which segment(s) of cartilage separate from an articular surface. It is most often reported in the larger joints of the body, including the knee, elbow, hip, wrist, and ankle. Involvement of the temporomandibular joint (TMJ) is exceedingly rare.

OBJECTIVES

To describe a probable case of osteochondritis dissecans and discuss the differential diagnosis for this condition.

STUDY DESIGN

In addition to clinical examination the patient was imaged using panoramic radiography, computed tomography and magnetic resonance imaging.

RESULTS

Panoramic radiography showed separation of 2 rounded fragments superior to the right mandibular condyle. These were more precisely located using 3-dimensional computerized tomographic reconstructions. Magnetic resonance imaging demonstrated the right condyle as having low signal intensity area on T1-weighted images and a heterogeneous signal on T2-weighted images, with low signal dominance. No abnormality was apparent in the left TMJ.

CONCLUSIONS

The patient was treated nonsurgically with a splint, occlusal adjustment, physiotherapy, and nonsteroidal antiinflammatory medications. Maximum mouth opening has increased from 24 mm to 39 mm 6 months following initiation of treatment, and pain has subsided.

Comparison of altered signal intensity, position, and morphology of the TMJ disc in MR images corrected for variations in surface coil sensitivity

OBJECTIVE

The purpose of this study is to evaluate the corrections of signal intensity of the temporomandibular joint (TMJ) disc caused by variations in sensitivity of the magnetic resonance imaging (MRI) surface coil, to compare the modified signal intensities of the posterior and anterior bands, and then to evaluate the relationship of the signal intensity difference to altered disc position and morphology in a group of TMJ patients.

STUDY DESIGN

MRI was performed on 96 joints. All patients underwent imaging in axial, coronal, and sagittal planes using fast-spin echo sequences (FSE). The images were taken in the closed, partially opened, and maximum opened mouth positions in 2 sequences. Classifications were made according to the position and morphology of the disc. TMJs were divided into normal, anterior disc displacement with reduction (ADDwR), anterior disc displacement without reduction (ADDwoR), and partial anterior disc displacement with reduction (PDDwR). Disc morphology was subdivided as biconcave, lengthened, biconvex, thick posterior band, and others (defined as folded and rounded). The correction of the inhomogeneous sensitivity of the surface coil was done with the original software. The signal intensities (SI) of the posterior band and anterior band of TMJ discs were measured. The correlations among the groups of TMJs and disc morphologies and SI were statistically analyzed by using Bonferroni/Dunn multicomparison method test.

RESULTS

Of the total number of joints studied with the help of MRI, 37 were normal, 12 exhibited ADDwR, 32 ADDwoR, and 9 PDDwR. The corrected MR images indicated that SI of the posterior bands were higher than the anterior band of the discs. It can also be concluded that the SI of the posterior bands increased significantly in the following order: normal, PDDwR, ADDwR, and ADDwoR, while there is no statistical difference in the SI of the anterior band of the discs. In ADDwR and ADDwoR, thick posterior band is the most common shape. In normal TMJ, the biconcave shape is identified as the most frequently encountered shape.

CONCLUSIONS

It was demonstrated that the SI of the posterior bands increase with the progress of internal derangement, and was found to be higher than that of the anterior band of the discs. It appears that disc degeneration starts from the posterior band of the disc.

Flexure deformation in temporomandibular joint disk displacement without reduction may predict treatment outcome

To identify whether the direction of disk flexure deformation predicts the prognosis in cases of anterior disk displacement without reduction of painful temporomandibular joint (TMJ), the relationship between the direction of flexure, observed on pseudodynamic magnetic resonance (MR) images, and the outcome of conservative treatment using a flat occlusal splint was analysed in 40 female patients who perceived occasional or constant pain at unilateral TMJ with disk displacement without reduction. From the MR findings, 20 patients were classified as having upward flexure deformation of the disk and 20 as having downward flexure deformation. Patients' TMJ pain, masticatory muscle pain, amount of maximal mouth opening, and MR findings were evaluated before treatment. All patients were treated with a flat occlusal splint for 6 months. The patients' signs and symptoms were analysed statistically within each group before treatment and 3 and 6 months afterwards, and were also compared between the upward and downward flexure groups. There was no statistical difference between the groups before treatment, except in the amount of maximal mouth opening and the extent of disk displacement. The upward flexure group had persistent TMJ pain and tendency of delayed alleviation of masticatory muscle pain compared with the downward flexure group, although maximal opening gradually increased in both groups. Thus, the direction of the flexure in deformation of the disk, which can be observed only with pseudodynamic MR imaging, may predict the prognosis of painful disk displacement without reduction following treatment with a flat occlusal splint.

Evaluation of disc position in edentulous patients with complete dentures

OBJECTIVE

This study evaluated the condyle-disc relationship on magnetic resonance image (MRI) in a group of subjects with silent temporomandibular joints (TMJs) when tested clinically with those in subjects with discernible temporomandibular sounds. Study design Twenty-five completely edentulous patients were selected to participate in this study. The study was based on bilateral MRIs of 15 patients (with articular sound) and 10 symptom-free volunteers (control).

RESULTS

It was noted that disc displacement was found in 45% of the TMJs with no history of articular sounds. In 6 TMJs of control group, a reducing disc displacement was found, and in 3 TMJs a permanent displacement was found. Disc displacements were identified in 70% of patients. Reducing disc displacement was found in 19 of these TMJs, whereas permanent displacement was found in 2 TMJs. In 9 of the joints of the symptomatic group, a superior disc position was found. Also verified was a significant association between reducing disc displacement and biconvex disc.

CONCLUSION

These observations demonstrated that internal derangements can not be associated to clicking joints or symptoms of temporomandibular disorders in elderly edentulous patients, and the presence of displaced discs seems to be associated to altered disc morphology, but not to osseous abnormalities.

MR abnormalities of the lateral pterygoid muscle in patients with nonreducing disk displacement of the TMJ

The aim of this study was to investigate the pathological changes of the lateral pterygoid muscle (LPM) using magnetic resonance imaging (MRI) in patients with anterior disk displacement with nonreduction (ADDnr) of the temporomandibular joint (TMJ) and to compare the abnormal findings of the LPM with the clinical symptoms and other pathological MRI alterations of the TMJ. Bilateral or unilateral ADDnr was demonstrated in 142 patents by MRI (176 TMJs; 106 females; 36 males; range 19 to 72 years; mean 43.9 years). In 123 TMJs, the LPMs were clearly observed in MRIs and analyzed in this study. Pathological changes of the LPM were found in 92 TMJs (74.8%) in MRI. Hypertrophy, atrophy and/or contracture were detected in the superior belly of the LPM (SBLPM) (35.8%, 44/123) or in the inferior belly of the LPM (IBLPM) (9.8%, 12/123) or in both bellies (29.3%, 36/123). The pathological changes of the LPM in MRI presented a significant association with the main clinical symptoms of TMJs with ADDnr, i.e. pain on jaw movement (P<0.01), pain in the LPM (P<0.01), pain in TMJ (P<0.05) and restricted jaw opening (P<0.05). The proportion of the abnormalities in LPM was significantly lower in TMJs with condylar limitation (63.6%) than in TMJs with condylar hypermobility (83.3%) and normal motion (88.9%)(P=0.008). Osteoarthritis was found to be correlated with condylar limitation (P<0.01). The results of this study indicate that the pathological changes of the LPM in TMJs with ADDnr could be detected by MRI and have a significant association with the main clinical symptoms of the patients. When condylar limitation happened, on the contrary, the pathological changes of the LPM in MRI were reduced. The alteration of the clinical symptoms in the patents with ADDnr might be associated with the pathological situations and symptoms of the LPM.