Current trends in temporomandibular joint imaging

Combined Gap and Interpositional Arthroplasty Utilizing Three-Dimensional Printed Model in a Dog with Temporomandibular Joint Ankylosis and Pseudoankylosis

Objective: To report the surgical treatment of a canine with both ankylosis and pseudoankylosis of temporomandibular joint (TMJ). Methods: The patient presented for inability to open his mouth. Facial asymmetry with normal dental occlusion was appreciated and computed tomography (CT) was performed. CT was used to diagnose ankylsosis and pseudoankylosis of left TMJ secondary to chronic maxillofacial trauma. A gap arthroplasty followed by interpositional arthroplasty using temporalis muscle fascia was performed to remove the site of fusion and prevent re-ankylosis between remaining cut boney surfaces. A three-dimensional (3D) printed skull for surgical planning and intraoperative spatial localization was employed. Results: Following preoperative and intraoperative evaluation of the 3D printed skull, the surgery was performed successfully without major complications. The patient's TMJ range of motion was markedly improved and remains improved as noted by inter-incisal distance measurements, ability to pant, and ease of chewing. Conclusion: A combined Gap and interpositional arthroplasty was assisted with the use of a 3D printed skull and immediately resulted in improved TMJ range of motion and patient quality of life. Three-month postoperative CT revealed stable ostectomies with no complications, with the exception of left-sided disuse masticatory muscle atrophy. Long-term follow-up is warranted. Clinical Significance: Three-dimensional printed skull models may be utilized preoperatively and intraoperatively to determine individual variants and landmarks, especially in cases where anatomical structures are difficult to recognize. Gap arthroplasty with interpositional myofascial transposition is an option for a patient with both anklyosis and pseudoankylosis of the TMJ.

Automated segmentation of articular disc of the temporomandibular joint on magnetic resonance images using deep learning

Temporomandibular disorders are typically accompanied by a number of clinical manifestations that involve pain and dysfunction of the masticatory muscles and temporomandibular joint. The most important subgroup of articular abnormalities in patients with temporomandibular disorders includes patients with different forms of articular disc displacement and deformation. Here, we propose a fully automated articular disc detection and segmentation system to support the diagnosis of temporomandibular disorder on magnetic resonance imaging. This system uses deep learning-based semantic segmentation approaches. The study included a total of 217 magnetic resonance images from 10 patients with anterior displacement of the articular disc and 10 healthy control subjects with normal articular discs. These images were used to evaluate three deep learning-based semantic segmentation approaches: our proposed convolutional neural network encoder-decoder named 3DiscNet (Detection for Displaced articular DISC using convolutional neural NETwork), U-Net, and SegNet-Basic. Of the three algorithms, 3DiscNet and SegNet-Basic showed comparably good metrics (Dice coefficient, sensitivity, and positive predictive value). This study provides a proof-of-concept for a fully automated deep learning-based segmentation methodology for articular discs on magnetic resonance images, and obtained promising initial results, indicating that the method could potentially be used in clinical practice for the assessment of temporomandibular disorders.

Evaluation of horizontal condylar angle in malocclusions with mandibular lateral displacement using cone-beam computed tomography

OBJECTIVES

To evaluate the horizontal condylar angle (HCA) in mandibular lateral displacement (MLD).

MATERIALS AND METHODS

HCA in MLD malocclusions were examined using cone-beam computed tomography data in subjects with MLD and control subjects.

RESULTS

HCA in joints of control patients and contralateral side joints of MLD patients were not significantly different. The mean HCA on the shifted side was larger than on the contralateral side (P < .001) in the different HCA groups. HCA was significantly larger on the shifted side than on the contralateral side in skeletal Class I, Class II, and Class III groups (P < .001).

CONCLUSIONS

(1) There was no statistically significant difference between HCA in control patients and on the contralateral side in MLD patients. (2) HCA was significantly larger on the shifted side than on the contralateral side. (3) HCA on the shifted side and the contralateral side in MLD Class I, Class II, and Class III are significantly different.

Synovial chondromatosis of the temporomandibular joint with 400 loose bodies: a case report and literature review

Synovial chondromatosis (SC) is a benign condition characterized by the formation of metaplastic cartilage in the synovial membrane of the joint, resulting in numerous attached and unattached osteocartilaginous bodies. SC mostly affects the large synovial joints, especially the knee, hip, elbow, and ankle, whereas involvement of the temporomandibular joint (TMJ) is rare. Approximately 240 cases of SC of the TMJ have been reported in the English-language literature to date. The number of loose bodies varies among patients but usually ranges from the dozens to around 100. We herein report a case of SC of the TMJ accompanied by approximately 400 loose bodies in a healthy 53-year-old woman. Such a high number of loose bodies within a small space is extremely rare. We also include a brief discussion about the differential diagnoses and current diagnostic approaches to SC of the TMJ. Notably, delayed diagnosis or misdiagnosis is common because of the nonspecific nature of the presenting complaints.

Analysis of three-dimensional imaging findings and clinical symptoms in patients with temporomandibular joint disorders

Background

The purpose of this study was to analyze cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) findings in temporomandibular joint disorder (TMD) patients and to comprehensively assess the relationships between these imaging findings and clinical symptoms.

Methods

A total of 754 temporomandibular joints (TMJs) in 377 patients with clinical symptoms of TMD who underwent both CBCT and MRI examinations were retrospectively reviewed. Clinical symptoms included TMJ pain, TMJ sound, and limitation of mouth opening. Oral radiologists evaluated osseous changes of the condylar head on CBCT, as well as the disc configuration, internal derangement, and joint effusion on MRI. The frequency of CBCT and MRI findings and the mean and standard deviation of age were analyzed. Logistic regression analysis was used to identify associations between these imaging findings and clinical symptoms using SPSS version 25.0 for Windows (IBM Corp., Armonk, NY, USA). The model fit was evaluated using the Hosmer and Lemeshow test.

Results

TMD patients consisted of 294 females and 83 males, and the age group of 20-39 accounted for 47.2% of the patients. Normal findings regarding osseous changes of the condylar head on CBCT were found in 65.1% of the patients. On MRI, a change in disc configuration was found in 54.9% of the patients, internal derangement in 62.6%, and joint effusion in 46.0%. TMJ pain was significantly associated with sclerosis [odds ratio (OR): 3.81], disc displacement without reduction (DDWOR) (OR: 3.22), grade 2 joint effusion (OR: 2.33), and grade 3 joint effusion (OR: 5.54). TMJ sound was significantly associated with disc displacement with reduction (DDWR) (OR: 3.04), DDWOR (OR: 2.50), grade 2 joint effusion (OR: 2.37), and grade 3 joint effusion (OR: 3.23). Limitation of mouth opening was significantly associated with flattened disc configuration (OR: 2.08), folded disc configuration (OR: 2.30), and grade 3 joint effusion (OR: 2.85).

Conclusions

CBCT findings had little to do with clinical symptoms. In contrast, MRI findings, including disc configuration, internal derangement, and joint effusion, were associated with clinical symptoms. These results suggest that MRI should be recommended over CBCT for the proper diagnosis of TMD patients.

Are Signs of Degenerative Joint Disease Associated With Chin Deviation?

PURPOSE

Degenerative joint changes commonly affect the temporomandibular joint (TMJ) and can result in chin deviation. However, the extent of degenerative TMJ changes and chin deviation has not been well-characterized. The present study sought to correlate degenerative TMJ changes with condylar volume, grayscale measures, and chin deviation.

MATERIALS AND METHODS

The present cross-sectional study had enrolled women with skeletal Class III malocclusion. Cone-beam computed tomography scans were acquired preoperatively. For each condyle, degenerative TMJ signs were analyzed and the condylar volume and grayscale were measured. The predictor variable was the presence of degenerative TMJ signs, classified as categorical data: 0, if none; 1, only present in 1 joint; and 2, present in both joints. The primary outcome variable was a chin deviation of 3 mm or more. Other associated variables were grouped by age, cephalometric data, and 3-dimensional condylar measurements. Descriptive bivariate statistics were computed, and univariate and multiple logistic regression analyses were conducted to identify any associations between degenerative TMJ disease and chin deviation.

RESULTS

We included 85 patients, who were classified into 2 groups: less than 3 mm of chin deviation (n = 43) and 3 mm or more of chin deviation (n = 42). The presence of more than 10 degenerative TMJ signs was significantly associated with the presence of 3 mm or more of chin deviation (P < .001). In multiple regression models, the presence of subcortical sclerosis in 1 joint and in both joints (adjusted odds ratio [OR], 3.698; 95% confidence interval [CI], 1.051 to 13.012; adjusted OR, 5.001; 95% CI, 1.461-17.119, respectively) correlated significantly with the presence of 3 mm or more of chin deviation (P < .05). The volume difference between the 2 condyles was significantly greater in the group with more than 10 degenerative TMJ signs and 3 mm or more of chin deviation than in the group with 10 or fewer degenerative TMJ signs and less than 3 mm of chin deviation (P = .016 and P < .001, respectively).

CONCLUSIONS

In women with skeletal Class III malocclusion, the presence of more than 10 degenerative TMJ signs increased the prevalence of 3 mm or more of chin deviation. The presence of subcortical sclerosis in either 1 or both joints and volume differences between the 2 condyles were associated with greater chin deviation.

Relationship between mandibular condyle and articular eminence cortication with mandibular cortical index on cone-beam CT

PURPOSE

Mandibular condyle development can be evaluated with radiographic evaluation of subchondral cortical bone. The aim of this study is to investigate mandibular condyle cortication (MCC), articular eminence cortication (AEC) and mandibular cortical index (MCI) according to age and gender on CBCT, and relationship between each other.

METHODS

CBCT scans of 520 patients (312 male and 208 female, age range 7-84) were retrospectively investigated to evaluate MCC, AEC and MCI. MCC and AEC were examined in sagittal section and MCI in panoramic reformatted image. MCC and AEC were classified as Type I, Type II and Type III according to density difference between the cortical bone enclosing condyle and articular eminence. Categorical variables were tested by Chi square.

RESULTS

When MCC, AEC and MCI were compared, a significant relationship was detected (p < 0.05). According to age, there was a significant difference between MCC, MCI and AEC types with each other (p < 0.05). No significant discrepancy was found between gender and MCC, AEC and MCI (p > 0.05).

CONCLUSIONS

This study evaluated the distribution of MCC, AEC, MCI according to age and gender and detected that these cortications were correlated. This result may be caused by anatomical proximity bone components and functional stimuli. Knowledge of these cortications can be important for accurate diagnosis of TMJ disorders and may also be helpful for prediction of osteoporotic changes.

Temporomandibular joint damage in juvenile idiopathic arthritis: Diagnostic validity of diagnostic criteria for temporomandibular disorders

BACKGROUND

Diagnostic criteria reported in the expanded taxonomy for temporomandibular disorders include a standardised clinical examination and diagnosis (DC/TMD 3.B) of temporomandibular joint (TMJ) damage in patients with juvenile idiopathic arthritis (JIA); however, their validity is unknown.

OBJECTIVES

To assess the validity of DC/TMD 3.B for the identification of TMJ damage in JIA-patients, using magnetic resonance imaging (MRI) as gold standard, and to investigate the relation between clinical findings and TMJ damage.

METHODS

Fifty consecutive JIA patients (9-16 years) were recruited. DC/TMD 3.B were compared with TMJs MRI (100 TMJs) performed maximum at 1 month from the visit. The severity of TMJ damage was scored in four grades. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), logistic regression models with odds ratio of DC/TMD 3.B and clinical findings respect to MRI were calculated.

RESULTS

The DC/TMD 3.B were inadequate in the identification of TMJ damage (sensitivity = 0.15, specificity = 0.92, PPV = 0.85, NPV = 0.28, P = 0.350). Chin deviation and TMJ crepitus were associated with worse TMJ damage (P = 0.006; P = 0.034). Reduced mouth opening (OR = 3.91, P = 0.039) and chin deviation (OR = 13.7, P = 0.014) were associated with the presence of TMJ damage. Combining "pain" (history of pain, TMJ pain, pain during movements) and "function" (TMJ crepitus, reduced mouth opening, chin deviation) clinical findings, the sensitivity and the specificity were 0.88 and 0.54.

CONCLUSION

DC/TMD 3.B present a low sensitivity to diagnose TMJ damage. Chin deviation, reduced mouth opening and TMJ crepitus are associated with TMJ damage. We suggest combining "pain" and "function" findings for the evaluation of TMJ damage in JIA patients.

Osteoarthritis of the temporomandibular joint and increase of the horizontal condylar angle: a longitudinal study

OBJECTIVE

Our previous study of patients with unilateral temporomandibular joint (TMJ) osteoarthritis (OA) showed that the affected joints had greater horizontal condylar angle (HCA) compared with the contralateral unaffected joints. However, it was unclear whether the HCA changes preceded or were the result of OA changes. The aim of this longitudinal study was to investigate the relationship between HCA and OA progression.

STUDY DESIGN

In total, 127 patients (with or without TMJ disorders) completed baseline and follow-up examinations (average time to follow-up 7.9 years). Generalized estimating equation models were used to account for correlation of observations within the same patients.

RESULTS

(1) HCA was greater in OA-affected joints than in unaffected joints (P = .04). (2) Increased HCA at follow-up was associated with change in joint status from no OA to OA. (P = .001). (3) Baseline HCA value alone did not predict future OA diagnosis. (4) All OA changes in fossa/articular eminence morphology, and some combinations of condylar changes, were associated with a greater HCA. (5) OA diagnosis was associated with pain during maximum opening (P = .005) and pain history (P = .002). (6) Aging alone was not correlated with increased HCA.

CONCLUSIONS

Clinical progression of OA preceded increases in HCA. HCA alone did not predict OA development.

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.

CBCT and MRT imaging in patients clinically diagnosed with temporomandibular joint arthralgia

OBJECTIVES

To compare cone beam computed tomography (CBCT) and magnetic resonance tomography (MRT) in patients with temporomandibular joint (TMJ) arthralgia in respect of the evaluation of bony structures, and to correlate joint space distances measured in CBCT with the morphology and the position of the disc visualized in MRT.

MATERIALS & METHODS

26 temporomandibular joints (TMJs) in 13 patients clinically diagnosed with TMJ arthralgia were examined by both CBCT and MRT. All images were evaluated by use of a form. The results were compared in regard of conformability of the diagnoses of osseous structures established by each imaging method. Anterior, superior and posterior joint space distances measured in CBCT-images were related to disc morphology and position visualized in MRT.

RESULTS

Conformability of CBCT and MRT in the evaluation of bony TMJ structures ranged from 69.3 to 96.6 %. Osseous alterations such as erosions, osteophytes and cysts detected by CBCT could partly not be discerned by MRT. The correlation of joint space distances with disc morphology (biconcave or not biconcave) was not statistically significant. The correlation of joint space distances and disc position was statistically significant only for the superior joint distance.

CONCLUSION

CBCT outclasses MRT in the visualization of osseous alterations, which are diacritic in the differentiation of simple arthralgia from osteoarthritis. Therefore, CBCT imaging is appropriate in patients clinically diagnosed with TMJ arthralgia.Superior joint space distance not being the highest joint space in sagittal CBCT indicates an anterior disc displacement.For the visualization of structural changes or displacement of the disc frequently associated with osseous changes, MRT is the optimal tool. Thus, the combination of the two imaging methods allows a comprehensive diagnosis in TMJ arthralgia patients.

Evaluation of the relationship between mandibular condyle cortication and chronologic age with cone beam computed tomography

PURPOSE

The aim of the present study is to evaluate the relationship between mandibular condyle cortication and chronologic age and gender via cone-beam computed tomography (CBCT) and to investigate the effectiveness of using the condylar cortication as a new method of age estimation.

METHODS

CBCT images from 433 subjects aged 8 to 31 years were included in this study. The right and left condyle cortication were assessed on the sagittal plane separately for each individual by the same investigator via a new method that describes the cortication of the condyle. Type I: There is no cortication on the condyle. Type II: The bone that is on the superior surface of the condyle is seen less density than the structures around the condyle. Type III: The surface of the condyle is seen similar or higher density than the surrounding cortical areas.

RESULTS

The type of the condyle cortication in the right and left mandible was similar for almost each subject and there was no statistically significant different between them (p = 0.375). When we evaluated the results without including these patients for male, Type I cortication of the condyle was seen at 14.14 ± 2.3 years, Type II cortication of the condyle was seen at 16.11 ± 3.18 years and Type III cortication of the condyle was seen at 19.39 ± 3.96 years. For the female, Type I cortication of the condyle was seen at 13.01 ± 2.16 years, Type II cortication of the condyle was seen at 15.52 ± 2.71 years and Type III cortication of the condyle was seen at 17.95 ± 3.13 years. The minimum age of Type III cortication was 11 and 15 years old for male and female, respectively. However, there are subjects, who are 30 year old man and 31 year old female, have no cortication as much as similar or higher than the surrounding the cortical areas.

CONCLUSION

This study is the first investigation of the relationship between condyle cortication and chronologic age with CBCT in the Turkish population. The type of cortication in the right and left condyle may be different for the same individual. Chronologic age increased as the stages of the cortication process from Type I to Type III in male and female individuals, and all the stages of the cortication in the mandibular condyle of male occur later time according to female.

The association between condylar bone changes revealed in cone beam computed tomography and clinical dysfunction index in patients with or without temporomandibular joint disorders

OBJECTIVE

The aim of the present study was to compare cone beam computed tomography (CBCT) findings pertinent to patients with temporomandibular disorder (TMD) and patients without TMD (non-TMD), as well as to investigate the correlation between these findings and the clinical dysfunction index (Di).

STUDY DESIGN

In this cross-sectional study, CBCT images of temporomandibular joints (TMJs) were evaluated for condylar bone changes in 84 patients with TMD. The patients were assigned a score using Helkimo's clinical Di, ranging from 1 to 25, and were thereafter subdivided into 3 groups based on the degree of Helkimo's Di. CBCT and clinical records of sex- and age-matched non-TMD patients were used as the control group.

RESULTS

There was a significant difference in the prevalence of all types of bone changes between TMD and non-TMD groups (all P < .05), except for loose joint bodies. Furthermore, there was a significant correlation between the total amount of bone change and the Helkimo Di score (P < .001).

CONCLUSION

Evaluation of CBCT images in the present study revealed significant differences between TMD and non-TMD condyles. There was also a significant relationship between the Helkimo clinical Di and the total amount of condylar bone change in patients with TMD.

Magnetic resonance imaging of temporomandibular joint: morphometric study of asymptomatic volunteers

BACKGROUND

The aims of this study were to determine the best suited magnetic resonance imaging scanning plane, scanning sequence, and imaging modality for the evaluation of the temporomandibular joint (TMJ) and quantitatively assess the relationship of articular disk position to condyle position.

METHODS

One hundred four TMJs in 52 symptom-free heads were examined by magnetic resonance imaging. The best scanning plane, scanning sequence, and scanning parameter were determined according to the imaging time and image quality. Bilateral symmetry of the articular disk and mandibular condyle was measured by using the automatic measurement of 3.0-T GE Excite Signa MR scanner.

RESULTS

Fast spin-echo sequence, oblique sagittal imaging plane, and proton density imaging were the best suited scanning sequence, scanning planes, and imaging modality, respectively. The thicknesses of the anterior and posterior bands and for the intermediate zone were not statistically different for both sides. The posterior band of the disk was found to originate in an area adjacent to the 12-o'clock position of the condyle (± 5 degrees), whereas the anterior band of the disk originated adjacent to 1-o'clock position (28 ± 6 degrees). The anteroposterior diameter and mediolateral diameter of the condylar processes were not statistically different for both sides. The axial condylar angle between the plane of the greatest mediolateral diameter of the condylar processes and the midsagittal plane were also not statistically different for both sides.

CONCLUSIONS

The magnetic resonance images can depict clearly major regional anatomic structures and position in the TMJ, which can be used in the early diagnosis for the TMJ disorder.

False ankylosis of the temporomandibular joint in a cat. Correction by partial zygomatic arch resection

OBJECTIVE

To describe the use of two-dimensional computer-assisted tomography (CT) with three-dimensional (3D) reconstruction in the diagnosis and planning of surgical treatment of a case of false ankylosis of the temporomandibular joint.

CASE REPORT

A young European Shorthaired cat was presented with the complaint of inability to eat and open its jaws. A CT scan with 3D reconstruction allowed visualization of the lesion which was causing extra-articular ankylosis of the temporomandibular joint. Surgery was performed to resect an osseous lesion of the zygomatic arch, thus freeing the temporomandibular joint. Postoperative physical therapy was initiated immediately following surgery, and then carried out by the owner with a one year follow-up. Clinical examination of the cat was performed during regular office visits (at 1 month and 3 months following surgery), which allowed objective assessment of postoperative recuperation. At the end of a year, the owners reported that the cat had maintained sufficient jaw opening without any signs consistent with chronic pain.

CONCLUSION

Computed tomography scan with 3D reconstruction allowed planning of the surgical correction of extra-articular ankylosis of the temporomandibular joint, and in this case condylectomy was avoided, since temporomandibular joint range-of-motion was maintained.

Temporomandibular joint diagnostics using CBCT

The present review will give an update on temporomandibular joint (TMJ) imaging using CBCT. It will focus on diagnostic accuracy and the value of CBCT compared with other imaging modalities for the evaluation of TMJs in different categories of patients; osteoarthritis (OA), juvenile OA, rheumatoid arthritis and related joint diseases, juvenile idiopathic arthritis and other intra-articular conditions. Finally, sections on other aspects of CBCT research related to the TMJ, clinical decision-making and concluding remarks are added. CBCT has emerged as a cost- and dose-effective imaging modality for the diagnostic assessment of a variety of TMJ conditions. The imaging modality has been found to be superior to conventional radiographical examinations as well as MRI in assessment of the TMJ. However, it should be emphasized that the diagnostic information obtained is limited to the morphology of the osseous joint components, cortical bone integrity and subcortical bone destruction/production. For evaluation of soft-tissue abnormalities, MRI is mandatory. There is an obvious need for research on the impact of CBCT examinations on patient outcome.

Diagnostic index of three-dimensional osteoarthritic changes in temporomandibular joint condylar morphology

This study aimed to investigate imaging statistical approaches for classifying three-dimensional (3-D) osteoarthritic morphological variations among 169 temporomandibular joint (TMJ) condyles. Cone-beam computed tomography scans were acquired from 69 subjects with long-term TMJ osteoarthritis (OA), 15 subjects at initial diagnosis of OA, and 7 healthy controls. Three-dimensional surface models of the condyles were constructed and SPHARM-PDM established correspondent points on each model. Multivariate analysis of covariance and direction-projection-permutation (DiProPerm) were used for testing statistical significance of the differences between the groups determined by clinical and radiographic diagnoses. Unsupervised classification using hierarchical agglomerative clustering was then conducted. Compared with healthy controls, OA average condyle was significantly smaller in all dimensions except its anterior surface. Significant flattening of the lateral pole was noticed at initial diagnosis. We observed areas of 3.88-mm bone resorption at the superior surface and 3.10-mm bone apposition at the anterior aspect of the long-term OA average model. DiProPerm supported a significant difference between the healthy control and OA group ([Formula: see text]). Clinically meaningful unsupervised classification of TMJ condylar morphology determined a preliminary diagnostic index of 3-D osteoarthritic changes, which may be the first step towards a more targeted diagnosis of this condition.

The effects of voxel size on cone beam computed tomography images of the temporomandibular joints

OBJECTIVES

This clinical study assesses the effect of cone beam computed tomography (CBCT) voxel size on the ability to detect osseous changes associated with degenerative disease of the temporomandibular joint (TMJ). The effect of voxel size on perceived CBCT image quality is also evaluated.

STUDY DESIGN

Twenty-two patients presenting for TMJ imaging with suspected degenerative disease were imaged with the Carestream 9000 CBCT unit, using separate right and left joint acquisitions (n = 44). Images were archived at native and downsampled voxel resolutions of 76 μm and 300 μm, respectively. Three oral and maxillofacial radiologists evaluated the images for osseous changes, as well as image quality by using a visual analog scale.

RESULTS

There was no statistically significant difference between the voxel sizes in the detection of TMJ osteoarthritic changes. The mean visual analog scale response did, however, differ significantly between the two groups (P = .02).

CONCLUSIONS

Despite no improvement in diagnostic efficacy with a smaller voxel size, perceived image quality is consistently higher for images with greater spatial resolution.

Three-dimensional imaging techniques: A literature review

Imaging is one of the most important tools for orthodontists to evaluate and record size and form of craniofacial structures. Orthodontists routinely use 2-dimensional (2D) static imaging techniques, but deepness of structures cannot be obtained and localized with 2D imaging. Three-dimensional (3D) imaging has been developed in the early of 1990's and has gained a precious place in dentistry, especially in orthodontics. The aims of this literature review are to summarize the current state of the 3D imaging techniques and to evaluate the applications in orthodontics.

Comparison of the T2 relaxation time of the temporomandibular joint articular disk between patients with temporomandibular disorders and asymptomatic volunteers

BACKGROUND AND PURPOSE

T2 relaxation time is a quantitative MR imaging parameter used to detect degenerated cartilage in the knee and lumbar intervertebral disks. We measured the T2 relaxation time of the articular disk of the temporomandibular joint in patients with temporomandibular disorders and asymptomatic volunteers to demonstrate an association between T2 relaxation time and temporomandibular disorder MR imaging findings.

MATERIALS AND METHODS

One hundred forty-four patients with temporomandibular disorders and 17 volunteers were enrolled in this study. An 8-echo spin-echo sequence for measuring the T2 relaxation times was performed in the closed mouth position, and the T2 relaxation time of the entire articular disk was measured. Patients were classified according to the articular disk location and function, articular disk configuration, presence of joint effusion, osteoarthritis, and bone marrow abnormalities.

RESULTS

The T2 relaxation time of the entire articular disk was 29.3 ± 3.8 ms in the volunteer group and 30.7 ± 5.1 ms in the patient group (P = .177). When subgroups were analyzed, however, the T2 relaxation times of the entire articular disk in the anterior disk displacement without reduction group, the marked or extensive joint effusion group, the osteoarthritis-positive group, and the bone marrow abnormality-positive group were significantly longer than those in the volunteer group (P < .05).

CONCLUSIONS

The T2 relaxation times of the articular disk of the temporomandibular joint in patients with progressive temporomandibular disorders were longer than those of healthy volunteers.

Magnetic Resonance Evidence of Joint Effusion of the Temporomandibular Joint After Fractures of the Mandibular Condyle: A Preliminary Report

To investigate the clinical significance of magnetic resonance (MR) evidence of joint effusion of the temporomandibular joint after mandibular condylar fractures, magnetic resonance imaging (MRI) was performed on 18 joints in 15 patients with either unilateral or bilateral mandibular condylar fractures using a 1.5 Tesla MRI scanner (Signa, General Electric, Milwaukee, WI). MR evidence of joint effusion was evaluated and compared with the types and the positions of the fractures. MR evidence of joint effusion was observed in 11 of 18 TMJs, which was 61% of the condylar fractures. It appeared more frequently after fractures with dislocation than those without dislocation (p < 0.05). In addition, MR evidence of effusion appeared more frequently in TMJs after high condylar fractures (head to upper neck) than low condylar fractures (lower neck to subcondylar) (p < 0.05). These findings indicate that MR evidence of joint effusion may serve as a marker for the detection of severe intra-articular damage to the TMJ after mandibular condyle fractures.

The prevalence, radiographic appearance, and characteristics of zygomatic air cell defects (ZACDs) in symptomatic temporomandibular joint disorder patients in North Indian population

PURPOSE

Although the incidence of zygomatic air cell defects (ZACDs) is significantly low in general population, still they pose as a risk factor during surgical procedures like eminectomies and eminoplasties because there is a risk of spread of infection intracranially. Furthermore, such procedures are more common in TMD patients. With this fact in mind, this study was designed to find out the prevalence, radiographic appearance, and characteristics of zygomatic air cell defects in diagnosed symptomatic temporomandibular joint disorder patients.

METHOD

The study comprised of evaluation of panoramic radiographs of 70 temporomandibular joint disorder (TMD) patients in the age range of 18-30 years selected on the basis of Research Diagnostic Criteria (RDC/TMD). The radiographs were evaluated regarding the presence, variations, and characteristics of ZACDs. Groups were compared by χ (2) analysis.

RESULTS

ZACDs were identified in 21 TMD subjects out of 70, giving an overall prevalence of 30 %. Out of 21 ZACDs, nine were in males (42.8 %) and 12 were in females (52.38 %). ZACDs were unilateral in ten TMD patients (47.61 %) and were bilateral in 11 patients (52.38 %).

CONCLUSION

It can be concluded that the number of ZACDs is surprisingly more in diagnosed TMD patients. This strengthens the need for thorough preoperative imaging evaluation of ZACDs in such patients. Further longitudinal studies are required to find out the long-term effect of ZACDs on symptomatic as well as non-symptomatic TMD subjects. This may prove helpful to appreciate that whether ZACDs have any role in the development TMDs and vice versa. As with many TMD studies, caution should be exercised in interpreting these results until further studies have been carried out on this topic. Ideally, some prospective randomised evaluations with "hard" evidence of the diagnosis with MRI support.

Small field of view cone beam CT temporomandibular joint imaging dosimetry

OBJECTIVES

Cone beam CT (CBCT) is generally accepted as the imaging modality of choice for visualisation of the osseous structures of the temporomandibular joint (TMJ). The purpose of this study was to compare the radiation dose of a protocol for CBCT TMJ imaging using a large field of view Hitachi CB MercuRay™ unit (Hitachi Medical Systems, Tokyo, Japan) with an alternative approach that utilizes two CBCT acquisitions of the right and left TMJs using the Kodak 9000(®) 3D system (Carestream, Rochester, NY).

METHODS

25 optically stimulated luminescence dosemeters were placed in various locations of an anthropomorphic RANDO(®) Man phantom (Alderson Research Laboratories, Stanford, CT). Dosimetric measurements were performed for each technique, and effective doses were calculated using the 2007 International Commission on Radiological Protection tissue weighting factor recommendations for all protocols.

RESULTS

The radiation effective dose for the CB MercuRay technique was 223.6 ± 1.1 μSv compared with 9.7 ± 0.1 μSv (child), 13.5 ± 0.9 μSv (adolescent/small adult) and 20.5 ± 1.3 μSv (adult) for the bilateral Kodak acquisitions.

CONCLUSIONS

Acquisitions of individual right and left TMJ volumes using the Kodak 9000 3D CBCT imaging system resulted in a more than ten-fold reduction in the effective dose compared with the larger single field acquisition with the Hitachi CB MercuRay. This decrease is made even more significant when lower tube potential and tube current settings are used.

Dynamic MRI of the TMJ under physical load

OBJECTIVES

The objective of this study was to examine the kinematics of structures of the temporomandibular joint (TMJ) under physiological load while masticating.

METHODS

Radial MRI was chosen as a fast imaging method to dynamically capture the motions of the joint's anatomy. The technique included a golden ratio-based increment angle and a sliding window reconstruction. The measurements were performed on 22 subjects with and without deformation/displacement of the intra-articular disc while they were biting on a cooled caramel toffee.

RESULTS

The reconstructed dynamic images provided sufficient information about the size and localization of the disc as well as the change of the intra-articular distance with and without loading.

CONCLUSIONS

The feasibility of the golden ratio-based radial MRI technique to dynamically capture the anatomy of the TMJ under physical load was demonstrated in this initial study.

Increased levels of interleukin-6 in synovial lavage fluid from patients with mandibular condyle fractures: correlation with magnetic resonance evidence of joint effusion

PURPOSE

The aim of the present study was to investigate the relation between magnetic resonance (MR) evidence of joint effusion and concentrations of proinflammatory cytokines, including interleukin (IL)-1β and IL-6, in washed-out synovial fluid samples obtained from patients with mandibular condyle fractures.

PATIENTS AND METHODS

Twenty-five joints in 23 patients with mandibular condyle fractures were examined. Computed tomography was used to determine the position of the fracture and MR examination was performed in all cases. Twenty-five joints underwent temporomandibular joint (TMJ) irrigation before surgical treatment for the fractures. The detection rates and concentrations of the tested cytokines were determined, and their relations to evidence of joint effusion and positions of the condylar fractures were analyzed.

RESULTS

Six TMJ fractures were found in the head, 10 in the upper neck, 4 in the lower neck, and 5 in the subcondyle. MR evidence of joint effusion was observed in 17 of 25 TMJs (68.0%). The detection rate and concentration of IL-6 were significantly higher in patients with MR evidence of joint effusion and those with high condylar fractures. Moreover, there was a correlation between joint effusion grade and IL-6 concentration.

CONCLUSIONS

The present findings showed a correlation between MR evidence of joint effusion and concentration of IL-6 in washed-out synovial fluid samples collected from patients with mandibular condyle fractures. These results may provide support for arthrocentesis as a reasonable treatment modality for high condylar fractures.

Magnetic resonance images of patients with temporomandibular disorders: prevalence and correlation between disk morphology and displacement

Using magnetic resonance imaging (MRI), this study aimed to evaluate the morphology of the articular disc of the temporomandibular joint (TMJ) in patients with temporomandibular disorder (TMD). There were 218 TMJ of 109 assessed patients; 88 were females and 21 males, and all were diagnosed as symptomatic for temporomandibular disorder. The articular disc positions were classified in the normal position and with anterior disc displacement with and without reduction. Regarding the morphology, the discs were classified as follows: biconcave (normal), biplanar, rounded, biconvex, folded, thickening in the posterior band, thickening in the anterior band and hemiconvex. The results indicated that females were the most affected by morphological changes of the articular disc (p=0.008/Cramer's V=0.295). There was no statistical significance when correlating the disc morphology with the sides (right and left). There was a significant correlation between the position and morphology of the articular disc (p<0.001/Cramer's V=0.609), and in the normal position of the discs presenting biplanar and biconcave morphologies. In TMJ with anterior displacement of the disc with reduction (ADDR), there was a greater correlation with rounded, hemiconvex and biconvex morphologies. Already in the TMJ with displacement without reduction (ADDWR), there was a higher prevalence of folded discs. It can be concluded that morphological changes in the disc are influenced by the type of displacement, and more serious deformations are associated with ADDWR cases.

The use of arthrography in the diagnosis of temporomandibular joint synovial chondromatosis

Synovial chondromatosis (SC) involving the temporomandibular joint (TMJ) is very rare and can occur in either or both cavities. Differentiation of the affected cavity in SC is therefore as important as making the diagnosis. This report presents a case of SC in which both cavities were thought to be affected, but arthrography using cone beam CT (CBCT) allowed us to see that involvement was limited to the superior joint cavity. In addition, we describe the usefulness of arthrographic CBCT for diagnosis and treatment planning in SC of the TMJ.

Correlating cone beam CT results with temporomandibular joint pain of osteoarthritic origin

OBJECTIVES

The purpose of this study was to determine whether bony changes in temporomandibular joint (TMJ) osteoarthritis (OA) is correlated with pain and other clinical signs and symptoms.

METHODS

Clinical data and cone beam CT (CBCT) images of 30 patients with TMJ OA were analysed. The criteria of Koyama et al (Koyama J, Nishiyama H, Hayashi T. Follow-up study of condylar bony changes using helical computed tomography in patients with temporomandibular disorder. Dentomaxillofac Radiol 2007; 36: 472-477.) and Ahmad et al [Ahmad M, Hollender L, Anderson Q, Kartha K, Ohrbach R, Truelove EL, et al. Research diagnostic criteria for temporomandibular disorders (RDC/TMD): development of image analysis criteria and examiner reliability for image analysis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 107: 844-860.] were used to classify the condyles observed on the CBCT. Clinical measures included self-reported pain, mandibular range of motion, TMJ sound, pain on palpation of the TMJ and masticatory muscles, and pain on jaw function. Generalized linear modelling was used to correlate the clinical and radiographic findings and Spearman's rho was used to correlate the two classification systems.

RESULTS

There was poor correlation between the maximum condyle change and pain rating (Koyama: r² = 0.1443, p = 0.3995; Ahmad: r² = 0.0273, p = 0.9490), maximum mouth opening (Koyama: r² = 0.2910, p = 0.0629; Ahmad: r² = 0.2626, p = 0.0951), protrusion (Koyama: r² = 0.0875, p = 0.7001; Ahmad: r² = 0.1658, p = 0.3612), right lateral motion (Koyama: r² = 0.0394, p = 0.9093; Ahmad: r² = 0.0866, p = 0.6877) and left lateral motion (Koyama: r² = 0.0943, p = 0.6494; Ahmad: r² = 0.1704, p = 0.3236). Strong correlation was observed between Koyama et al's and Ahmad et al's classifications for average (r = 0.9216, p < 0.001) and maximum (r = 0.7694; p < 0.0001) bony change.

CONCLUSIONS

There was poor correlation between condylar changes (as observed on CBCT images), pain and other clinical signs and symptoms in TMJ OA.

How should the articular disk position be analyzed?

PURPOSE

To compare 2 methods used to determine the disk position based on sagittal magnetic resonance images.

PATIENTS AND METHODS

A cross-sectional study of patients with the signs and symptoms of temporomandibular disorders was conducted. The patients' ages and gender distributions were collected. The disk position diagnosis from the clinical examination was considered the primary outcome. Three observers evaluated the presence of anterior displacement on magnetic resonance images according to 2 criteria: method 1 (12-o'clock position) and method 2 (location of the intermediate zone). To assess the intraobserver variability of the 2 methods, the examiners evaluated the same magnetic resonance images at the beginning of the study (time 1) and 40 days later (time 2). The intraobserver agreement was assessed using the observed agreement and the kappa statistic. McNemar's test was used to assess the differences between each method and the clinical examination findings (P < .05). The accuracy, sensitivity, specificity, and positive and negative predictive values were calculated by comparing the diagnosis from each method with that from the clinical examination (considered the reference standard).

RESULTS

The final sample was composed of 20 subjects with a mean age of 33.0 ± 33.7 years; 3 were men (15%) and 17 were women (85%). A statistically significant difference between the 2 methods was found. Method 1 yielded a greater percentage of anterior displaced disks (52.5%). The agreement between the clinical diagnosis and method 1 was lower (70.0%) than that between the clinical diagnosis and method 2 (87.5%). No statistically significant difference was found between the clinical diagnosis and method 2.

CONCLUSION

The disk position should be judged according to the intermediate zone criterion.

Sodium iodoacetate induced osteoarthrosis model in rabbit temporomandibular joint: CT and histological study (part I)

Studies to elucidate the pathophysiology of osteoarthrosis have been hampered by the lack of a rapid, reproducible animal model that mimics the histopathology and symptoms associated with the disease. The aim of this study is to evaluate the radiological, histological and histomorphometrical findings of four different concentrations of sodium iodoacetate (MIA) to create osteoarthrosis by using an arthrocentesis technique on rabbit temporomandibular joint (TMJ). 12 New Zealand white male rabbits received an injection of MIA (50 μl dose of 1.5, 2, 2.5, 3mg/ml concentrations) to a single joint of each group by arthrocentesis. Computed tomography (CT) images were obtained pre- and post-injections at 2, 4 and 6 weeks. Early osteoarthritic changes in the rabbit TMJ were found histologically at 4 weeks and with a 3mg/ml concentration of MIA. The mean subchondral bone volume depended on the concentration of MIA and was 62±2.6%, 63±4.1%, 42±3.6% and 38±3.8%, respectively. A minor abnormality was found on CT in six joints at the 4-week follow up. MIA injection and arthrocentesis offer a rapid and minimally invasive method of reproducing histologically osteoarthrotic lesions in the rabbit TMJ.

Evaluation of the usefulness of magnetic resonance imaging in the assessment of the thickness of the roof of the glenoid fossa of the temporomandibular joint

OBJECTIVE

The aim of this study was to evaluate the usefulness of magnetic resonance imaging (MRI) in measuring thickness of the roof of the glenoid fossa (RGF) of the temporomandibular joint (TMJ).

STUDY DESIGN

Minimum RGF thickness in 95 TMJs of 59 patients with temporomandibular disorders were measured and compared on both sagittal-section MRI and cone-beam computed tomography (CBCT). RGF thickness on MRI was also compared with MRI, CBCT, and arthrographic findings.

RESULTS

Minimum RGF thickness was greater on MRI (1.46 mm) than on CBCT (0.90 mm). Spearman's correlation coefficient by rank for these 2 types of measurements was 0.63. RGF thickness on MRI differed significantly between those with and without degenerative joint changes (1.69 vs 1.32 mm; P < .01) and between those with and without disk displacement (1.58 vs 1.35 mm; P = .04), but showed no associations with disk deformity, joint effusion, or disk perforation.

CONCLUSIONS

MRI is useful in measuring RGF thickness from diagnostic as well as radiation protection standpoints.

Investigation of the clinical and radiographic features of osteoarthrosis of the temporomandibular joints in adolescents and young adults

OBJECTIVE

The objective of this study was to investigate the clinical and radiographic features of osteoarthrosis (OA) of the temporomandibular joints (TMJOA) in human adolescents and young adults.

STUDY DESIGN

Patients (n = 4883) with temporomandibular disorders (age, 11 to 30 years) underwent clinical and radiographic examinations. The radiographic findings were classified as erosive bony changes, proliferative changes mainly, including flattening with uneven sclerosis, and osteophytes of the condyle, and bilaterally short condylar processes. In addition, we interpreted the reassessment radiographs of 156 of the patients.

RESULTS

Seven hundred eleven patients had radiographic signs of OA. The frequency of OA was higher in women (563/3360, 16.8%) than in men (148/1523, 9.7%). Most patients (541/711, 76.1%) with signs of OA showed proliferative changes of OA. Moreover, 56.4% of patients with TMJOA (88/156) remained stable.

CONCLUSIONS

These results suggest that although OA is an age-related disease, aging is not the crucial factor in the pathogenesis of OA.

Temporomandibular joint involvement in rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis

The aim of the present study was to estimate the prevalence of temporomandibular joint (TMJ) symptoms and clinical findings in Albanian patients with rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis. The authors examined 124 consecutive hospitalized patients (88 with rheumatoid arthritis, 22 with systemic lupus erythematosus and 14 with systemic sclerosis) and 124 age- and gender-matched healthy controls using a questionnaire and an oro-facial clinical examination for assessing the presence of TMJ sounds, pain in the TMJ area, tenderness of masticatory muscles and limited mouth opening. Significantly more patients (67%) reported TMJ symptoms than controls (19%). A significantly higher proportion of patients (65%) exhibited clinical signs of temporomandibular dysfunction compared with controls (26%). The most frequent findings in rheumatoid arthritis were temporomandibular sounds and pain. Pain was found in a significantly higher proportion in patients with systemic lupus erythematosus compared with controls. Difficulty and limitation in mouth opening were observed in the majority of systemic sclerosis patients, and in only a minority of rheumatoid arthritis patients. This study supports the notion that TMJ examination should be encouraged in the rheumatology setting and clinicians should be able to provide pain management and patient support.

Diagnostic accuracy of cone beam computed tomography and conventional multislice spiral tomography in sheep mandibular condyle fractures

OBJECTIVES

the aim of this study was to compare diagnostic accuracy of cone beam CT (CBCT) and multislice CT in artificially created fractures of the sheep mandibular condyle.

METHODS

63 full-thickness sheep heads were used in this study. Two surgeons created the fractures, which were either displaced or non-displaced. CBCT images were acquired by the NewTom 3G CBCT scanner (NIM, Verona, Italy) and CT imaging was performed using the Toshiba Aquillon multislice CT scanner (Toshiba Medical Systems, Otawara, Japan). Two-dimensional (2D) cross-sectional images and three-dimensional (3D) reconstructions were evaluated by two observers who were asked to determine the presence or absence of fracture and displacement, the type of fracture, anatomical localization and type of displacement. The naked-eye inspection during surgery served as the gold standard. Inter- and intra-observer agreements were calculated with weighted kappa statistics. The receiver operating characteristics (ROC) curve analyses were used to compare statistically the area under the curve (AUC) of both imaging modalities.

RESULTS

kappa coefficients of intra- and interobserver agreement scores varied between 0.56 - 0.98, which were classified as moderate and excellent, respectively. There was no statistically significant difference between the imaging modalities, which were both sensitive and specific for the diagnosis of sheep condylar fractures.

CONCLUSIONS

this study confirms that CBCT is similar to CT in the diagnosis of different types of experimentally created sheep condylar fractures and can provide a cost- and dose-effective diagnostic option.

Diagnostic performance of magnetic resonance imaging for detecting osseous abnormalities of the temporomandibular joint and its correlation with cone beam computed tomography

OBJECTIVE

With cone beam CT (CBCT) as the reference standard, the objective of this study was to determine the diagnostic accuracy of MRI for assessing osseous abnormalities of the temporomandibular joint (TMJ).

METHODS

106 TMJs from 55 patients with temporomandibular disorder were examined by CBCT and MRI. CBCT images were evaluated by two experienced oral radiologists with regard to the presence or absence of each of the following eight types of osseous abnormalities: Type 1, destructive and erosive osseous changes of the condyle; Type 2, flattening of the articular surface of the condyle; Type 3, deformity of the condyle; Type 4, sclerosis of the condyle; Type 5, osteophyte formation; Type 6, ankylosis; Type 7, erosion of the articular fossa and/or eminence; and Type 8, sclerosis of the articular fossa and/or eminence. For detection of these osseous abnormalities by MRI, proton density-weighted images and T(2) weighted images were evaluated independently by three observers. Using CBCT findings as the reference standard, the diagnostic performance of MRI for detecting various types of osseous abnormalities was evaluated by calculating its sensitivity and specificity.

RESULTS

Out of 106 joints, CBCT revealed Types 1, 2, 3, 4, 5, 6, 7 and 8 abnormalities in 25, 19, 26, 20, 14, 5, 19 and 22 joints, respectively. The mean sensitivities of MRI among the three observers for detecting Types 1, 2, 3, 4, 5, 6, 7 and 8 abnormalities were 61%, 30%, 82%, 40%, 48%, 34%, 61% and 41%, respectively, whereas the mean specificities were 86%, 92%, 91%, 95%, 84%, 98%, 89% and 91%, respectively.

CONCLUSIONS

Although high specificity (84-98%) was obtained with MRI, this modality showed relatively low sensitivity (30-82%) for detecting osseous abnormalities of the TMJ. The value of MRI for the detection of TMJ osseous abnormalities is considered to be limited.

Clinical and radiologic findings of synovial chondromatosis affecting the temporomandibular joint

OBJECTIVES

Our aim was to study the clinical and radiologic findings of synovial chondromatosis (SC) affecting the temporomandibular joint (TMJ) and provide references for diagnosis and treatment.

STUDY DESIGN

Twenty patients confirmed as SC histopathologically were included in the investigation. Nineteen cases were treated with arthrotomy and 1 case with arthroscopy. The clinical manifestations, radiographic findings, histopathologic features, surgical treatment, and differential diagnosis were combined to study this disease. The SC features of TMJ on magnetic resonance (MR) images were summarized on proton density-weighted (PD) and T2-weighted images.

RESULTS

Synovial chondromatosis of TMJ occurred more often in women and on the right. Symptoms included preauricular pain, swelling, limitation of mouth opening, crepitations, and deviation on opening. The detection rate of calcified loose bodies was 30% on conventional radiographs and 53.3% on computerized tomography. Multiple small ring-like or tubular signals could be seen on PD and T2-weighted MR images. SC mainly affected the superior joint space; it could involve the inferior space when a perforated or deformed disc was present. SC could extend into intracranial fossa, infratemporal fossa, and lateral pytergoid muscle.

CONCLUSIONS

The characteristic ring-like signals could be found on MR images of the patients with SC of TMJ. This lesion should be differentially diagnosed with TMJ disorders and preauricular masses. Considering its recurrence and the different behavior of SC in different patients, various treatment strategies should be considered.

Diagnostic value of ultrasonography in the evaluation of the temporomandibular joint anterior disc displacement

The aim of the study was to evaluate the extent of agreement between the findings of ultrasonography (US) and magnetic resonance imaging (MRI) in the assessment of anterior disc displacement (ADD), with or without reduction, and to assess the sensitivity, specificity and the accuracy of the US examination in establishing diagnosis. Fifty-two temporomandibular joints (TMJ) in 52 patients with chronic TMJ pain were examined by US and MRI with respect to ADD, with, and without reduction of the TMJ. The level of agreement between US and MRI findings was evaluated. The sensitivity, specificity, and the accuracy of US were found to be respectively 91%, 16% and 82% in the assessment of ADD; 70%, 38% and 57% in ADD with reduction; 50%, 89% and 76% in ADD without reduction. The findings of both methods were in agreement with each other. US method is fairly sensitive especially in detecting ADD, and it is very reliable in determining the absence of ADD without reduction. However, it was not found to be as quite effective in demonstrating ADD whether it was with or without reduction.