Imaging diagnosis of the temporomandibular joint: critical review of indications and new perspectives

Relationship between the condyle morphology and clinical findings in terms of gender, age, and remaining teeth on cone beam computed tomography images

Aim: This study aimed to evaluate the relationship between clinical findings and some factors such as age, gender, and remaining teeth on the anatomy of the temporomandibular joint in order to diagnose normal variations from abnormal cases. Methods: In this cross-sectional study, cone-beam computed tomography (CBCT) images of 144 patients referring to Tabriz Dental School for various reasons were selected and evaluated. The different aspects of the clinical parameters and the morphology of the condyle were evaluated on coronal, axial, and sagittal views. The CBCT prepared using the axial cross-sections had been 0.5 mm in thickness. The sagittal cross-sections had been evaluated perpendicular to the lengthy axis of the condyle at a thickness of 1 mm and the coronal cross-sections had been evaluated parallel to the lengthy axis of the condyle at a thickness of 1 mm. Data were analyzed with descriptive statistical methods and t-test, chi-squared test, using SPSS 20. The significance level of the study was p < 0.05. Results: There was a significant relationship between the condyle morphology, number of the teeth, and mastication side (p = 0.040). There were significant relationships between the condyle morphology, age between 20-40, and occlusion class I on the all the three views (coronal, axial, sagittal) (p = 0.04), (p = 0.006), (p = 0.006). Also, significant relationships were found in the condyle morphology and location of pain according to age, the number of remaining teeth, and gender. (p = 0.046) (p = 0.027) (p = 0.035). Conclusion: There are significant relationships between the clinical symptoms and condyle morphology based on age, gender, and the number of remaining teeth. The clinical finding that has the most significant relationship between the condyle morphology, remaining teeth (9-16 teeth), all of the age range (20-80 year), and gender was mastication side.

Evaluation of Changes in Condylar Cartilage Thickness Using MRI and Ultrasound Imaging in Patients Treated by Mandibular Advancement With Myofunctional Appliance: An In-Vivo Pilot Study

Introduction

The changes occurring due to growth modulation of the condylar cartilage act as an important mechanism for mandibular advancement using myofunctional appliance therapy. So this study aims to evaluate the condylar cartilage thickness by using MRI and USG in patients undergoing myofunctional appliance therapy for mandibular advancement with the null hypothesis being that there are no changes seen in the thickness of condylar cartilage in growing children.

Materials and methods

A prospective evaluation of samples having skeletal Class-II malocclusion ranging between cervical vertebral maturation index (CVMI) stage II and III, requiring twin block functional therapy was performed. Ten patients were selected randomly who underwent MRI and USG in the open and close positions for the evaluation of condylar cartilage thickness and the dimensional changes in the width of the right and left condyle in mm at T0 and T1.

Result

There was no statistically significant difference between the values interpreted by MRI or USG imaging when compared at T0 and T1 and in the open and closed mouth on the left and right sides. At T0, the mean thickness noted was 0.49 mm and 0.48 mm during opening and closing on the left side and 0.52 mm in both positions on the right side. At T1, the mean thickness noted was 0.8 and 0.79mm during opening and closing on the left side, whereas it was 0.81 mm in both positions on the right side.

Conclusion

The condylar cartilage thickness increases significantly after twin block therapy suggestive of mandibular growth in skeletal class II malocclusion. It can be inferred that both MRI and USG carry equal diagnostic interpretation, as there was no statistically significant difference between the two imaging modalities.

Low-dose cone-beam computed tomography in simulated condylar erosion detection: a diagnostic accuracy study

OBJECTIVES

The purpose of the present study was to assess the diagnostic accuracy of low-dose cone-beam computed tomography (CBCT) in the detection of simulated mandibular condyle erosions.

METHODS

102 simulated erosions were performed on the condyles of eight dry human mandibles. Each mandible was subjected to four CBCT scan protocols: high-definition (HD), normal definition (NORM), ultra-low-dose high-definition (ULD-HD), and ultra-low-dose normal definition (ULD-NORM). All scans were analyzed by two observers. The inter-observer and intra-observer agreement as well as the agreement with the gold standard were assessed. The sensitivity, specificity, positive-predictive value, negative-predictive value and accuracy of erosion detection were calculated.

RESULTS

A substantial to almost perfect agreement with the gold standard was found regarding the HD protocol and substantial agreement in NORM and ULD-HD protocols; however, moderate agreement was found regarding the ULD-NORM protocol. The sensitivity, specificity and accuracy values were highest for the HD protocol followed by the NORM and ULD-HD which showed comparable results; while, the ULD-NORM protocol showed the least values.

CONCLUSIONS

The studied ULD-HD CBCT protocol can be recommended for the detection of mandibular condylar erosions due to the reduced radiation dose; however, ULD-NORM is not advocated for similar clinical use.

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.

Assessment of the trabecular structure of mandibular condyles in patients with temporomandibular disorders using fractal analysis

OBJECTIVES

The aim of this study was to evaluate changes in the trabecular structure of the mandibular condyle in patients with temporomandibular disorders (TMDs) using fractal analysis.

STUDY DESIGN

A total of 100 patients ages 18 to 73 years were clinically assessed using the Diagnostic Criteria for Temporomandibular Disorders. The control group was age- and sex-matched with the patient group. Panoramic radiographs were obtained using a Kodak 8000 digital device with 73 kVp and 5 mA fixed parameters. The degree of degeneration in the mandibular condyles was calculated. Regions of interest (84 × 84 pixels) were selected within the cortical boundary of the mandibular condyle, and the fractal dimension (FD) was calculated using ImageJ version 1.48.

RESULTS

Radiographic degenerative changes were more frequently present and more severe in the patient group (P < .001). The mean value of FD was 1.22 ± 0.06 in the patient group and 1.25 ± 0.06 in the control group (P = .001). A significant decrease in FD was observed (P = .001) in the left temporomandibular joints of the patient group, whereas a nonsignificant decrease in FD was observed in the right temporomandibular joints (P = .073) as degenerative changes increased.

CONCLUSIONS

Lower FD values were associated with more severe degenerative changes in the patient group. The trabecular structure of condyles in patients with TMD exhibited decreased complexity when erosive and sclerotic changes were evident. As a result, fractal analysis enhanced the use of panoramic radiography in detecting degenerative changes in patients with TMD.

Common positioning errors in panoramic radiography: A review

Professionals performing radiographic examinations are responsible for maintaining optimal image quality for accurate diagnoses. These professionals must competently execute techniques such as film manipulation and processing to minimize patient exposure to radiation. Improper performance by the professional and/or patient may result in a radiographic image of unsatisfactory quality that can also lead to a misdiagnosis and the development of an inadequate treatment plan. Currently, the most commonly performed extraoral examination is panoramic radiography. The invention of panoramic radiography has resulted in improvements in image quality with decreased exposure to radiation and at a low cost. However, this technique requires careful, accurate positioning of the patient's teeth and surrounding maxillofacial bone structure within the focal trough. Therefore, we reviewed the literature for the most common types of positioning errors in panoramic radiography to suggest the correct techniques. We would also discuss how to determine if the most common positioning errors occurred in panoramic radiography, such as in the positioning of the patient's head, tongue, chin, or body.

Aplasia of the mandibular condyle associated with some orthopaedic abnormalities

A rare case of aplasia of mandibular condyle associated with some other orthopaedic problems is presented. A 5-year-old boy attended our clinic with a chief complaint of facial asymmetry and chewing difficulty. The mandible was deviated to the left. The occlusion also showed a deflection to the left of the mandibular midline. He also had walking difficulty owing to a hip abnormality. Panoramic radiographic examination of the patient revealed that the left mandibular condyl was totally absent. The right condyle was unremarkable. His history revealed neither trauma nor any significant disease. Aplasia is a rare anomaly and means the insufficient development of the mandibular condyle. True agnesis of the mandibular condyle is extremely rare. Association of the manifestations of the patient with some orthopaedic problems makes this case interesting.