MR imaging of temporomandibular joint dysfunction: a pictorial review

Clinical effect of digitalized designed and 3D-printed repositioning splints in the treatment of anterior displacement of temporomandibular joint disc

OBJECTIVE

To compare the treatment effectiveness of digitized and 3D-printed repositioning splints with that of conventional repositioning splints in the treatment of anterior displacement of the temporomandibular joint disc.

METHODS

This retrospective study included 96 patients with disc displacement of the anterior temporomandibular joint. They were treated with either digitally designed and 3D-printed repositioning splints or traditional splints and followed up for at least six months. Changes in signs and symptoms such as pain and mouth opening before and after treatment were recorded to evaluate treatment outcomes.

RESULTS

During the first month of treatment, both the digitally designed and 3D-printed repositioning splint groups (Group B) and the traditional repositioning splint group (Group A) showed significant increases in mouth opening, with increases of 4.93 ± 3.06 mm and 4.07 ± 4.69 mm, respectively, and there was no significant difference between the two groups. Both groups had a significant reduction in visual analog scale (VAS) pain scores, with Group B showing a greater reduction of 1.946 ± 1.113 compared to 1.488 ± 0.978 in Group A (P < 0.05). By the sixth month, Group B's mouth opening further improved to 38.65 ± 3.22 mm (P < 0.05), while Group A's mouth opening did not significantly improve. Regarding pain, Group A's VAS score decreased by 0.463 ± 0.778 after one month, and Group B's score decreased by 0.455 ± 0.715; both groups showed significant reductions, but there was no significant difference between the two groups.

CONCLUSION

Compared with traditional repositioning splints, digitally designed and 3D-printed repositioning splints are more effective at reducing patient pain and improving mouth opening. 3D-printed repositioning splints are an effective treatment method for temporomandibular joint disc displacement and have significant potential for widespread clinical application.

Mouth opening, jaw disability, neck disability, pressure pain thresholds, and myofascial trigger points in patients with disc displacement with reduction: A descriptive and comparative study

OBJECTIVE

To assess jaw and neck function, pressure pain threshold (PPT), and the presence of trigger points (TrPs) in disc displacement with reduction (DDWR) subjects compared to healthy subjects.

METHODS

One hundred DDWR subjects and 100 matched controls were studied. Clinical evaluations included demographic data, range of motion, jaw and neck disability, PPT, and muscle TrPs.

RESULTS

DDWR subjects have limited pain-free opening limitation (p < 0.001), jaw and neck disability limitation (p < 0.001), and higher presence of active and latent TrPs limitation (p < 0.001) compared to healthy subjects.

CONCLUSION

DDWR subjects present a limited pain-free mouth opening, higher jaw and neck disability, lower PPT, and major presence of active and latent TrPs compared to healthy subjects. Cervical spine and TMJ evaluation and treatment should be considered in DDWR patients.

Reliability of magnetic resonance for temporomandibular joint disc perforation: A 12 years retrospective study

The aim of this study was to evaluate the reliability of magnetic resonance imaging (MRI) in detecting disc perforations in the temporomandibular joint (TMJ), and to establish diagnostic criteria for this purpose. The retrospective analysis included patients who had undergone preoperative MRI and TMJ arthroscopy at the same hospital. Direct and indirect signs of disc abnormalities on MRI were compared with arthroscopic findings of disc perforation. Out of 355 joints evaluated in 185 patients, arthroscopy confirmed disc perforations in 14.7% of cases. Several MRI findings were significantly associated with disc perforation, including anterior disc displacement without reduction (ADDwoR), signal alterations in the mid-disc area, disc deformity (SAMD), retrocondylar disc fragments, osteophytes, condylar bone marrow degeneration (CBMD), and joint effusion in both joint spaces (ESJS-EIJS). Regression analysis revealed that SAMD, osteophytes, and CBDM were strongly associated with disc perforation. The ROC curve showed that MRI had an AUC = 0.791, with a sensitivity of 88.5% and a specificity of 61.5%. Two diagnostic methods, one based on three findings (osteophytes, ADDwoR, and SAMD) and one based on two direct signs (ADDwoR and SAMD), yielded high sensitivity and specificity values of 80.4% and 69.8%, and 84.3% and 62.5%, respectively. In conclusion, MRI demonstrated acceptable accuracy in the detection of TMJ disc perforations, with specific diagnostic criteria offering high sensitivity and specificity. Significant MRI indicators of disc perforation included SAMD, osteophytes, and CBDM. This study provides valuable information on the use of MRI as a diagnostic tool for TMJ disc perforations.

Imaging Evaluation of the Temporomandibular Joint

This article describes the anatomy and function of the temporomandibular joint (TMJ), provides an overview of the various imaging modalities available for evaluating the TMJ, and discusses a variety of miscellaneous diseases that affect the TMJ.

Diagnostic accuracy of MRI-CBCT fused images in assessment of clinically diagnosed internal derangement of the temporomandibular joint

OBJECTIVES

To evaluate the diagnostic accuracy of Fused (MRI)-CBCT images in the assessment of internal derangement of the temporomandibular joint.

METHODS

MRI and CBCT images of the TMJ were evaluated bilaterally in 10 patients with clinically diagnosed internal derangement. Image fusion was performed using Amira 3D Software (version 5.4.3, Thermo Fisher Scientific Inc.).

RESULTS

The AUC index for MRI-CBCT fused images was 0.83, which was significantly different from the null hypothesis value of 0.5. This was confirmed by inter-examiner reliability index of 0.87, which is statistically significant.

CONCLUSION

MRI-CBCT fused images can significantly improve the accuracy and inter-examiner reliability in the evaluation of clinically diagnosed cases with internal derangement.

Temporomandibular joint pathologies: pictorial review

In this pictorial review, an introductory paragraph emphasizes the significance of some anatomical aspects for optimal imaging of the temporomandibular joint (TMJ). The most frequent pathologies: internal derangement (ID) and osteoarthritis (OA) are comprehensively discussed and illustrated. Less common conditions: ID and OA-like changes in children and adolescents, idiopathic condylar resorption, inflammatory arthritis, and juvenile idiopathic arthritis are briefly discussed. A short paragraph on differential diagnostics in young patients is included followed by a brief comment on expansile lesions that occasionally may occur in the TMJ.

Correlation between TMJ Space Alteration and Disc Displacement: A Retrospective CBCT and MRI Study

This study aims to determine if a large anterior and reduced posterior/superior joint space is highly predictable for disc displacement. From patients with temporomandibular disorders symptoms, fifty-two experimental joints and fourteen control joints were included. The cone beam computed tomography (CBCT) images were used to calculate posterior-to-anterior (P-A) and superior-to-anterior (S-A) joint space ratios, while disc position was determined using magnetic resonance imaging (MRI). One-way analysis of covariance test and receiver operating characteristics analysis were carried out. The results showed that among the 52 experimental joints, 45 were diagnosed as disc displacement and 7 as normal disc positions (N). All 14 control joints showed normal disc positions. The P-A ratio was 1.46 ± 0.21, 0.99 ± 0.23, and 0.86 ± 0.30 in the control, N, and DD groups, respectively (p < 0.001). The S-A ratio was 1.80 ± 0.27, 1.44 ± 0.33, and 1.08 ± 0.35 in the control, N, and DD groups, respectively (p < 0.001). When an altered P-A ratio and/or S-A ratio are observed on the CBCT, the diagnosis of disc displacement is quite predictable with high sensitivity and specificity.

Temporomandibular disorders-review of evidence-based management and a proposed multidisciplinary care pathway

Temporomandibular disorders (TMDs) are a prevalent but complex group of conditions that cause orofacial pain. Temporomandibular disorders are recognized as one of the most common chronic pain conditions, alongside back pain and headache disorders. Given the competing theories surrounding what causes TMDs and limited high-equality evidence on optimally treating TMDs, clinicians often encounter challenges in developing an effective management plan for patients. Furthermore, patients will often seek advice from multiple health care providers from varying specialties, seeking curative management, often resulting in inappropriate treatments and no improvement in pain symptoms. Throughout this review, we explore the existing evidence base surrounding the pathophysiology, diagnosis, and management of TMDs. An existing United Kingdom-based multidisciplinary care pathway for the management of TMDs is described herein, highlighting the benefits of a multidisciplinary approach to patient care for TMDs.

Examination for the Factors Involving to Joint Effusion in Patients with Temporomandibular Disorders Using Magnetic Resonance Imaging

BACKGROUND

This study investigated the factors involving joint effusion in patients with temporomandibular disorders.

METHODS

The magnetic resonance images of 131 temporomandibular joints (TMJs) of patients with temporomandibular disorders were evaluated. Gender, age, disease classification, duration of manifestation, muscle pain, TMJ pain, jaw opening disturbance, disc displacement with and without reduction, deformation of the articular disc, deformation of bone, and joint effusion were investigated. Differences in the appearance of symptoms and observations were evaluated using cross-tabulation. The differences in the amounts of synovial fluid in joint effusion vs. duration of manifestation were analyzed using the Kruskal-Wallis test. Multiple logistic regression analysis was performed to analyze the factors contributing to joint effusion.

RESULTS

Manifestation duration was significantly longer when joint effusion was not recognized (p < 0.05). Arthralgia and deformation of the articular disc were related to a high risk of joint effusion (p < 0.05).

CONCLUSIONS

The results of this study suggest that joint effusion recognized in magnetic resonance imaging was easily observed when the manifestation duration was short, and arthralgia and deformation of the articular disc were related to a higher risk of joint effusion.

Magnetic resonance imaging texture analysis for quantitative evaluation of the mandibular condyle in juvenile idiopathic arthritis

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease that affects the joints and other organs, including the development of the former in a growing child. This study aimed to evaluate the feasibility of texture analysis (TA) based on magnetic resonance imaging (MRI) to provide biomarkers that serve to identify patients likely to progress to temporomandibular joint damage by associating JIA with age, gender and disease onset age.

METHODS

The radiological database was retrospectively reviewed. A total of 45 patients were first divided into control group (23) and JIA group (22). TA was performed using grey-level co-occurrence matrix (GLCM) parameters, in which 11 textural parameters were calculated using MaZda software. These 11 parameters were ranked based on the p value obtained with ANOVA and then correlated with age, gender and disease onset age.

RESULTS

Significant differences in texture parameters of condyle were demonstrated between JIA group and control group (p < 0.05). There was a progressive loss of uniformity in the grayscale pixels of MRI with an increasing age in JIA group.

CONCLUSIONS

MRI TA of the condyle can make it possible to detect the alterations in bone marrow of patients with JIA and promising tool which may help the image analysis.

MRRead-A Novel Approach to Training Residents in Magnetic Resonance Image Temporomandibular Joint Interpretation

PURPOSE

The purpose of our study was to create an online, web-based training module that would instruct a group of participants in the interpretation of a magnetic resonance image (MRI) of the temporomandibular joint (TMJ) scan in a logical, step-wise manner to locate and identify all relevant features of internal derangement. The investigator's hypothesis was that implementing the MRRead TMJ training module would improve the participants' competency in the interpretation of MRI TMJ scans.

METHODS

The investigators designed and implemented a single-group prospective cohort study. The study population was composed of oral and maxillofacial surgery interns, residents, and staff. Subjects eligible for study inclusion were oral and maxillofacial surgeons of any level, between 18 and 50 years of age, that completed the MRRead training module to completion. The primary outcome variable was the difference between the pretest and post-test scores of the participants, and the frequency of missing internal derangement findings before and after the course. Secondary outcomes of interest were subjective data gathered from the course, including participant feedback as well as subjective evaluation of the training module and perceived benefit, as well as the learner's self-reported confidence level in interpreting MRI TMJ scans on their own before and after completion of the course. Descriptive and bivariate statistics were used.

RESULTS

The study sample consisted of 68 subjects, aged 20 to 47 (M = 29.1) years. When comparing the results of the exams precourse and post course, the overall frequency of missed features of internal derangement decreased from 19.7 to 5.9, and the total score overall increased from 8.5 to 68.6%. Regarding secondary outcomes, the majority of participants indicated that they agree or strongly agree with a number of positive subjective questions asked. In addition, there was a statistically significant increase in the participants' comfort levels in the interpretation of MRI TMJ scans.

CONCLUSION

The results of this study confirm the hypothesis that completing the MRRead training module (www.MRRead.ca) improves competency and comfort among participants in the interpretation of MRI TMJ scans and their identification of features of internal derangement correctly.

Effects of osseous structure based on three-dimensional reconstructive imaging evaluation in the assessment of temporomandibular joint disc position

OBJECTIVES

This pilot morphological study aimed to investigate the association between anterior disc displacement (ADD) and the status of the mandibular condyle and articular fossa.

MATERIALS AND METHODS

Thirty-four patients were divided into a normal articular disc position group and an ADD with and without reduction group. Images reconstructed were used to determine multiple group comparisons of these three different types of disc position, and the diagnostic efficacy for the morphological parameters with significant group difference was analyzed to assess.

RESULTS

The condylar volume (CV), condylar superficial area (CSA), superior joint space (SJS), and medial joint space (MJS) all exhibited obvious changes (P < 0.05). Additionally, they all had a reliable diagnostic accuracy in differentiating between normal disc position and ADD with an AUC value from 0.723 to 0.858. Among them, the CV, SJS, and MJS (P < 0.05) had a significantly positive impact on the groups by analysis of multivariate logistic ordinal regression model.

CONCLUSIONS

The CV, CSA, SJS, and MJS are significantly associated with different disc displacement types. The condyle in ADD exhibited altered dimensions. These could be promising biometric markers for assessing ADD.

CLINICAL RELEVANCE

The morphological changes of mandibular condyle and glenoid fossa were significantly influenced by the status of disc displacement, and condyles with disc displacement had three-dimensionally altered condylar dimensions, irrespective of age and sex.

Role of Dynamic 3 Tesla MRI in the Evaluation of Temporomandibular Joint Dysfunction

INTRODUCTION

The internal derangement of the temporomandibular joint (TMJ) is the most common type of dysfunction. Internal derangement can be divided into anterior and posterior disc displacement. Anterior disc displacement is the most common type, which is further classified into anterior disc displacement with reduction (ADDWR) and without reduction (ADDWoR). Temporomandibular joint dysfunction (TMD) symptoms are pain, reduced mouth opening, and joint sound. The main aim of this study was to correlate the clinical findings and magnetic resonance imaging (MRI) diagnosis of TMD in symptomatic and asymptomatic TMJs.

METHODS

This prospective observational study was conducted in a tertiary care hospital on a 3T Philips Achieva MRI machine with 16-array channel coils after obtaining approval from the institutional ethical committee. A total of 60 TMJs of 30 patients were included in the study. After the clinical examination of each patient, an MRI of both right and left TMJs was done. In patients with unilateral TMD, the asymptomatic side was used as the asymptomatic joint, and the affected side as the symptomatic joint. Asymptomatic patients without any symptoms of TMD were used as controls for bilateral TMD cases. MRI with high-resolution specific serial sections was obtained in both open- and closed-mouth positions. A p-value of <0.05 was considered a statistically significant agreement between clinical and MRI diagnoses of internal derangement.

RESULTS

Out of a total of 30 clinically asymptomatic TMJs, only 23 were normal on MRI. On MRI, 26 TMJs showed ADDWR and 11 showed ADDWoR. The most common shape of the disc was biconcave and the displacement was anterior in symptomatic joints. The most common type of articular eminence shape was sigmoid in ADDWR and flattened in ADDWoR. Agreement between clinical and MRI diagnosis in this study was 87.5% (p < 0.001).

CONCLUSION

 The study concluded substantial agreement between clinical and MRI diagnosis of TMJ internal dysfunction and suggests that the diagnosis of the internal dysfunction can be made clinically but the exact position, shape, and type of disc displacement can be assessed precisely with the help of MRI.

Temporomandibular joint: from anatomy to internal derangement

The temporomandibular joint can be affected by various conditions, such as joint dysfunction, degenerative changes, inflammatory processes, infections, tumors, and trauma. The aim of this pictorial essay is to help radiologists identify and describe the main findings on magnetic resonance imaging evaluation of the temporomandibular joint, given that the correct diagnosis is essential for the appropriate treatment of patients with temporomandibular joint disorders.

Kinematic magnetic resonance imaging for the evaluation of active motion of the mandibular condyle in patients with temporomandibular joint disorders

PURPOSE

To explore the mandibular condylar movements in patients with temporomandibular joint (TMJ) disorders using kinematic magnetic resonance imaging (MRI).

METHODS

We retrospectively recruited patients who were clinically diagnosed with internal derangement of the TMJ and referred to our center for MRI examination. The TMJ discs were categorized into normal disc (ND), anteriorly displaced disc (ADD), and disc with destruction (DD) groups using static images obtained in the closed-mouth view. The difference between the "open-mouth" and "closed-mouth" views on kinematic MRI was used to calculate the condylar translation and rotation. Two radiologists consensually performed the image readings and measurements. One-way analysis of variance and chi-squared test were used to compare the variables in the three groups. Pearson's correlation and general linear models were used to evaluate the correlation and differences between condylar translation and rotation in the three groups.

RESULTS

This study included 98 TMJs from 54 patients. Twenty-six, 49, and 23 TMJs were classified as ND, ADD, and DD, respectively. Condylar rotation and translation demonstrated a significant correlation in all TMJs examined (r = 0.635, p < 0.001), with similar coefficients for all groups. The mean condylar translation in the ND group was greater than that in the ADD and DD groups (ND versus ADD: p = 0.003; ND versus DD: p = 0.002). However, the change in condylar rotation was not affected by the disc status (ND as reference; DD∗condylar translation: coefficient = 0.341, p = 0.332; ADD∗condylar translation: coefficient = -0.100, p = 0.696).

CONCLUSIONS

Kinematic MRI studies revealed that TMJ condylar translation was correlated with its rotation for all disc statuses.

Comparison of magnetic resonance imaging findings in 880 temporomandibular disorder patients of different age groups: a retrospective study

BACKGROUND

Magnetic resonance imaging (MRI) findings of temporomandibular joint (TMJ) in temporomandibular disorder (TMD) patients of different ages are still unclear. The aim of this study was to analyze and compare the characteristics of MRI features of TMJs in different age groups.

METHODS

A total of 1760 TMJs from 880 patients were included in the study and divided into three groups: ≤ 18Y (n = 195, 14.89 ± 2.35Y); 19-30Y (n = 475, 24.09 ± 3.23Y); and > 30Y (n = 210, 41.73 ± 10.45Y). T2-weighted image (T2WI) of MRI was obtained to evaluate the relationship between age and disc morphology, the degree of disc displacement, joint effusion, joint movement and changes of condylar bone morphology. Data were analyzed by Pearson Chi square test and Spearman correlation coefficient.

RESULTS

There was no statistical difference between left and right sides in all age groups. Except condylar morphology (χ2 = 0.943, P = 0.624), there were significant differences in the distribution of disc morphology, disc position, joint effusion and joint motion among different age groups (χ2 = 24.450, χ2 = 24.829, χ2 = 19.855, χ2 = 39.259, respectively). There were significant differences in the distribution of the degree of anterior disc displacement, condyle morphology and joint effusion in different types of disc morphology among the different age groups (except for joint effusion in > 30Y), among which the first two were significantly correlated with the disc morphology.

CONCLUSIONS

The morphology and position of the articular disc changed significantly with age, but the proportion of abnormal condylar bone remained about 50%. The greater the degree of disc folding, the more prone to bone abnormalities. Trial registration This study was retrospectively registered on 28/03/2022 and endorsed by the Ethics committee (LCYJ2022014).

Promising minimally invasive treatment modalities for symptomatic temporomandibular joint disc displacement with reduction: a randomized controlled clinical trial

BACKGROUND

Pain and clicking are the primary complaints in patients suffering from temporomandibular joint disc displacement with reduction (DDwR), negatively affecting the patients' quality of life, making the treatment essential. This prospective randomized controlled trial (RCT) was conducted to evaluate the effectiveness of botulinum toxin type-A (BTX-A) and low level laser therapy (LLLT) in comparison to anterior repositioning appliance (ARA) for the treatment of DDwR.

METHODS

A total of 27 patients were randomly allocated to 3 groups; ARA (control group), BTX-A, and LLLT; with 9 patients each. All patients were evaluated before and 3 months after the treatment using a visual analogue scale (VAS) and magnetic resonance imaging (MRI).

RESULTS

At 3 months follow-up, all groups showed a significant reduction in pain assessed by VAS (P = 0.007). Measured on MRI, there was a significant improvement in disc position and joint space index (JSI) in BTX-A group (P < 0.001, P = 0.011) and LLLT group (P = 0.002, P = 0.017) in comparison to the control group (P = 0.087, P = 0.066) respectively. As for time of recovery, a statistically significant difference was observed in BTX-A group (P < 0.001) and LLLT (P < 0.001) group in comparison to ARA group, which showed the most prolonged duration for reduction of DDwR symptoms.

CONCLUSION

We concluded that BTX-A and LLLT could be considered effective alternative treatment modalities to ARA regarding reducing joint pain, clicking, and improving disc position in patients with symptomatic DDwR.

TRIAL REGISTRATION

This prospective double-blinded RCT has been registered at ClinicalTrials.gov with identification number: NCT05194488, 18/1/2022.

Synthesis of T2-weighted images from proton density images using a generative adversarial network in a temporomandibular joint magnetic resonance imaging protocol

Purpose

This study proposed a generative adversarial network (GAN) model for T2-weighted image (WI) synthesis from proton density (PD)-WI in a temporomandibular joint (TMJ) magnetic resonance imaging (MRI) protocol.

Materials and Methods

From January to November 2019, MRI scans for TMJ were reviewed and 308 imaging sets were collected. For training, 277 pairs of PD- and T2-WI sagittal TMJ images were used. Transfer learning of the pix2pix GAN model was utilized to generate T2-WI from PD-WI. Model performance was evaluated with the structural similarity index map (SSIM) and peak signal-to-noise ratio (PSNR) indices for 31 predicted T2-WI (pT2). The disc position was clinically diagnosed as anterior disc displacement with or without reduction, and joint effusion as present or absent. The true T2-WI-based diagnosis was regarded as the gold standard, to which pT2-based diagnoses were compared using Cohen's ĸ coefficient.

Results

The mean SSIM and PSNR values were 0.4781(±0.0522) and 21.30(±1.51) dB, respectively. The pT2 protocol showed almost perfect agreement (ĸ=0.81) with the gold standard for disc position. The number of discordant cases was higher for normal disc position (17%) than for anterior displacement with reduction (2%) or without reduction (10%). The effusion diagnosis also showed almost perfect agreement (ĸ=0.88), with higher concordance for the presence (85%) than for the absence (77%) of effusion.

Conclusion

The application of pT2 images for a TMJ MRI protocol useful for diagnosis, although the image quality of pT2 was not fully satisfactory. Further research is expected to enhance pT2 quality.

Effects of occlusal splint and exercise therapy, respectively, for the painful temporomandibular disorder in patients seeking for orthodontic treatment: a retrospective study

OBJECTIVE

To evaluate the effect of hard stabilization splints (HSS), counselling and exercise therapies, respectively, for the painful temporomandibular disorder (TMD) in patients seeking for orthodontic treatment through magnetic resonance imaging (MRI) and clinical examination.

MATERIALS AND METHODS

Eighty-seven TMD patients were divided into two groups according to their therapies: the HSS group (n = 43) comprising of patients treated with HSS, counselling and masticatory muscle exercises; the control group (n = 44) comprising of patients treated with counselling and masticatory muscle exercises alone. All patients had orthodontic therapies after the first treatment phase. The joint pain and clicking of all patients were recorded via clinical examination. MRIs of HSS groups were taken before (T₀), after the first phase (T₁), and after the orthodontic treatment (T₂). Parameters indicating the condyles and articular discs were evaluated. Clinical symptom (pain and clicking) changes among T₀, T₁ and T₂ time point were detected in the two groups respectively. The significant differences between HSS and control groups, as well as between male and female were tested at T₁ and T₂. Position changes of condyles and discs in HSS group among T₀, T₁ and T₂ were detected in male and female respectively.

RESULTS

After the first treatment phase, there was no difference in the decrease of facial pain between the two group, as well as between male and female in the two groups (P > 0.05). Clicking decreasing was not statistically significant. After the whole orthodontic periods, the TMJ pain relapsed in female of the control group, and the number of female's pain joints was more than male's (P < 0.05). In the HSS group, the posterosuperior movements of discs and the anteroposterior movements of condyles were recorded in closing position (P < 0.05). After the whole orthodontic periods, female's disc-condyle angles increased, the discs to HRP distance decreased and condyles to VRP distance increased when compared with the data of T₁ (P < 0.05).

CONCLUSIONS

For the orthodontic patients with painful TMD, HSS combined with counselling and exercise therapies before orthodontic treatment could provide pain relief. HSS is helpful to improve the position and relation of discs and condyles. In addition, male's prognosis is better than female's in terms of stability.

Quantitative volume and area assessment of masticatory muscles through magnetic resonance imaging in patients with temporomandibular joint disorders

OBJECTIVE

To compare volume and surface area measurements of the lateral pterygoid (LPM), medial pterygoid (MPM), and masseter muscles (MM) as calculated on magnetic resonance imaging (MRI) based on the position of the temporomandibular joint disk, mouth position, and patient sex, and to calculate the correlations of the measurements among the muscles.

STUDY DESIGN

Measurements of muscle volume and area were performed on the MRIs of 51 patients. Wilcoxon, Kruskal-Wallis, and Mann-Whitney U tests were used to calculate the significance of differences in measurements. The Spearman correlation coefficient calculated the correlation of measurements among the muscles. The significance of difference was established at P < .05.

RESULTS

Volume and area of the left MPM in patients with disk displacement without reduction (DDWOR) were larger than in patients with normal disk position (P ≤ .040). MM volumes were smaller with DDWOR than with DD with reduction bilaterally (P ≤ .031). The volume and area of LPM and MM were significantly different between closed and open mouth positions (P < .001). Differences in volume and area between females and males were significant for all muscles in volume (P ≤ .021) and for MPM and MM in area (P ≤ .021). Significant positive correlations were found among all muscles for volume and area.

CONCLUSION

Volume and area measurements of the masticatory muscles varied according to disk and mouth position and patient sex and exhibited significant positive correlations.

Evaluation of the relationship between temporomandibular joint disorders and tinnitus with computed tomography

PURPOSE

This study aimed to radiographically determine tinnitus and joint disorders by evaluating glenoid fossa depth and the horizontal angle of the ramus mandible in patients with isolated temporomandibular joint disorder and temporomandibular joint disorder with tinnitus by computed tomography (CT).

METHODS

In total, eighty two patients with temporomandibular disorders (TMDs) (forty two patients with tinnitus; forty patients without tinnitus) were evaluated using CT. CT images were analysed according to glenoid fossa depth and the horizontal angle of the ramus.

RESULTS

A total of 82 cases 43 (52.4%) female and 39 (47.6%) male were included. The distribution of gender was not significantly different between the TMD patients and the TMD-tinnitus patients (p >0.05). The mean age of the patients with isolated TMD was 31.70 ± 9.68 years, and the mean age of the patients with TMD-tinnitus was 34.07 ± 11.72 years. Comparisons were made of the right and left glenoid fossa depths of the patients with TMD and TMD-tinnitus, respectively. There was a statistically significant difference between the right glenoid fossa depths (p = 0.016) also there was also a statistically significant difference between the left glenoid fossa depths (p = 0.049).

CONCLUSION

Our study revealed that decreased glenoid fossa depth may be associated with an increased incidence of tinnitus in TMD patients by the way temporomandibular joint and ear can affect each other in diseases such as tinnitus due to their close anatomical relationship.

The Impact of Wearing a Face Mask during the COVID-19 Pandemic on Temporomandibular Joint: A Radiological and Questionnaire Assessment

Aim  Several health problems have been reported to be triggered or facilitated by prolonged mask usage during the coronavirus disease 2019 (COVID-19) pandemic. While wearing a face mask, people tend to push their jaws forward and downward in a repetitive manner to hold their masks in the right position; these jaw motions may induce temporomandibular joint disorder (TMD). In this study, we aimed to investigate these repetitive jaw movements while wearing face masks and their effects on TMD.

Patients and Methods  Patients who applied with TMD signs between June 2020 and May 2021 were evaluated prospectively. A survey using a questionnaire was conducted to define patients with TMD that caused only by mask-related repetitive jaw movements. Demographic data (age and gender), mean duration of daily mask usage, mask type, and magnetic resonance imaging results were recorded.

Results  Prolonged daily mask usage (≥8 hours/day) was significantly higher in patients with mask-related habits (group a) with a rate of 40.4% ( p ≈ 0.001). Also, in this group, the disc displacement with reduction rate (54.6%) was higher compared with other groups ( p ≈ 0.010). On the contrary, patients with no underlying risk factor (group c) showed an unexpected high osteoarthritis rate ( p ≈ 0.029).

Conclusions  In this study, we demonstrate that correcting the position of a face mask by repetitive jaw movements can increase the occurrence of TMD. Informing individuals wearing face masks about the risk of TMD and the importance of choosing the appropriate mask size according to the face shape are important issues to be addressed in the near future.

Correlation of MRI and arthroscopic findings with clinical outcome in temporomandibular joint disorders: a retrospective cohort study

BACKGROUND

Arthroscopy is a minimally invasive diagnostic tool and treatment strategy in patients suffering from temporomandibular disorders (TMD) when conservative treatment fails. This study aimed to find specific variables on pre-operative MRI or during arthroscopy that could predict success of arthroscopic lysis and lavage.

METHODS

This retrospective analysis compared pre-operative maximum interincisal opening (MIO), pain and main complaint (pain, limited MIO or joint sounds) with results at short-term and medium-term follow-up (ST and MT respectively). Different variables scored on MRI or arthroscopy were used to make a stepwise regression model, subsequently a combined analysis was conducted using variables from both MRI and arthroscopy.

RESULTS

A total of 47 patients (50 joints) met the inclusion criteria. The main complaint improved by 62 and 53% at ST and MT respectively. The absolute or probable absence of a crumpled disc scored on MRI predicted success at ST and MT (p = 0.0112 and p = 0.0054), and remained significant at MT in the combined analysis (p = 0.0078). Arthroscopic findings of degenerative joint disease predicted success at ST (p = 0.0178), absolute or probable absence of discal reduction scored during arthroscopy significantly predicted success in the combined analysis at ST (p = 0.0474).

CONCLUSION

To improve selection criteria for patients undergoing an arthroscopic lysis and lavage of the TMJ, future research might focus on variables visualized on MRI. Although more research is needed, disc shape and in particular the absolute or probable absence of a crumpled disc might be used as predictive variable for success.

[Development of a program for automatic collection and archiving of clinical data of patients with dysfunction of the temporomandibular joint]

OBJECTIVE

Development of a program for the automatic collection and archiving of clinical patients with TMJ dysfunction.

MATERIAL AND METHODS

Based on the clinical examination of 50 patients aged 18 to 30 years with temporomandibular joint dysfunction and the presence of an articular disc dislocation verified by magnetic resonance imaging, 80 signs were identified and terminologically formalized and were divided into 13 groups.

RESULTS

This was the basis for the development of a detailed questionnaire for this contingent of patients, which the authors consider as the primary source of systematized data for processing in the program for automatic collection and archiving of clinical data. For graphical (animation) support for patient questioning, a library of "virtual patient" graphic files has been created, which includes static and dynamic animation explanations of the questions.

CONCLUSION

An algorithm for optimizing the patient interrogation system based on the principle of excluding irrelevant units has been developed and implemented in the program.

Magnetic Resonance Imaging Evaluation of Closed-Mouth TMJ Disc-Condyle Relationship in a Population of Patients Seeking for Temporomandibular Disorders Advice

Objective

To characterize the closed-mouth temporomandibular joint (TMJ) disc-condyle relationship in a population of individuals who sought hospital services for temporomandibular disorders (TMD).

Methods

Two hundred and twenty-four TMJ magnetic resonance images (MRIs) of 112 patients were assessed in all spatial planes to classify disc position with respect to the condyle in a closed-mouth position.

Results

Disc displacement (DD) was present in 62.1% and superior disc position in 29.9% of the patients. Position could not be determined in 8% of the cases. Among DD, pure anteriorized position was the most common condition (34.4%), with different combined translational and rotational displacements in all the other joints (27.7%).

Conclusion

There is a wide biological variability in disc position in closed mouth among patients seeking for TMD advice. Getting deeper into the correlation with clinical symptoms is recommended to refine the potential relevance of any diagnostic and management strategies based on the imaging evaluation of TMJ disc position.

MRI of Temporomandibular Joint Disorders: Recent Advances and Future Directions

Temporomandibular joint disorders (TMDs) are a prevalent disease covering pain and dysfunction of temporomandibular joints and masticatory muscles, which can be detrimental to quality of life. Magnetic resonance imaging (MRI) is a powerful and noninvasive tool for the imaging and understanding of TMD. With the recent technical development of dynamic and quantitative MRI techniques, including diffusion-weighted imaging, T₂ mapping, and ultrashort/zero echo time, it is now feasible in TMD imaging and has been preliminarily investigated with promising results. In this review we will discuss the recent advances of MRI techniques in TMD and its future directions, and hope to highlight the scientific potential and clinical value of novel MRI techniques in diagnosing and treating TMD. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 3.

Knee orthopedics as a template for the temporomandibular joint

Although the knee joint and temporomandibular joint (TMJ) experience similar incidence of cartilage ailments, the knee orthopedics field has greater funding and more effective end-stage treatment options. Translational research has resulted in the development of tissue-engineered products for knee cartilage repair, but the same is not true for TMJ cartilages. Here, we examine the anatomy and pathology of the joints, compare current treatments and products for cartilage afflictions, and explore ways to accelerate the TMJ field. We examine disparities, such as a 6-fold higher article count and 2,000-fold higher total joint replacement frequency in the knee compared to the TMJ, despite similarities in osteoarthritis incidence. Using knee orthopedics as a template, basic and translational research will drive the development and implementation of clinical products for the TMJ. With more funding opportunities, training programs, and federal guidance, millions of people afflicted with TMJ disorders could benefit from novel, life-changing therapeutics.

Real-time assessment of temporomandibular joint using HASTE sequences: feasibility and comparison with standard static sequences

OBJECTIVE

To test real-time MRI (rtMRI) using HASTE sequences in patients with suspected internal disk derangement (IDD) of temporomandibular joint (TMJ) and to compare these sequences with standard static sequences.

METHODS AND MATERIALS

99 TMJ were studied with both standard sequences (fat-saturated proton density) and HASTE sequences with high temporal resolution. Image quality was assessed using a 4-point Likert scale. Two radiologists analysed both standard and rtMRI sequences separately, randomly and blinded (by a third operator) to patients' names in order to assess inter-observer repeatability. One of the radiologists performed the analysis twice for assessing intra-observer repeatability. The same radiologists evaluated randomly and blinded to the previous assessment both the sequences and decided in consensus which was the most credible. Qualitative scores were compared using Friedman's test while concordance between radiologists and sequences was evaluated using the concordance correlation coefficient.

RESULTS

At image quality analysis, mean score was 3.41 for static MRI and 3.82 for rtMRI, with a statistically significant difference in favour of rtMRI (p < 0.0001). Inter-rater concordance between operator 1 (Op1) and operator 2 (Op2) with regard to the same sequence was high for both static and rtMRI sequences (0.824 and 0.888, respectively). Inter-rater variability of Op1 and Op2 between static and rtMRI sequences was lower (0.647 for Op1 and 0.633 for Op2). Among 71 discordances between sequences, 60 were judged in favour of rtMRI, while 11 were in favour of static MRI.

CONCLUSION

rtMRI with HASTE sequences is a robust technique and provide additional information in assessing IDD compared to static sequences.

Quantitative assessment of temporomandibular disc and masseter muscle with shear wave elastography

PURPOSE

To assess the normal stiffness values of temporomandibular joint disc (TMJ) and masseter muscle by shear wave elastography (SWE) in a healthy adult population. This may be helpful in diagnosing and understanding the mechanism of temporomandibular disorders (TMD).

METHODS

This prospective study evaluated a total of 160 healthy adult volunteers (77 males, 83 females). The stiffness values of anterior, intermediate and posterior parts of the TMJ disc and masseter muscle were measured. Study cohort was classified into four groups based on age. Additionally, we investigated the changes in mean shear wave elasticity (kPa) and shear wave velocity(m/s) values of disc parts and masseter muscle in closed and open mouth positions, and the correlation of these SWE values with age and gender.

RESULTS

Mean stiffness values of the disc were 37.02 ± 23.75 kPa and 3.28 ± 1.09 m/s in the anterior part, 30.47 ± 18.89 kPa and 2.97 ± 1.04 m/s in the intermediate part, 22.61 ± 13.97 kPa and 2.55 ± 0.88 m/s in the posterior part. Stiffness values showed significant decrease in the posterior part compared to the rest of the disc both in males and females. No significant differences in mean stiffness values of masseter muscle related to mouth position, age or gender.

CONCLUSION

This study provides the normative quantitative elasticity values of disc and masseter muscle which could be a reference point for upcoming studies. Disc elasticity values are higher in women than men. Maybe this is one of the reason why TMD is more common in women. TMJ disc stiffness was significantly lower in the posterior part. SWE is a useful imaging method that can be used with routine ultrasonography in evaluation of the TMJ disc and masticatory muscles .

Actual applications of magnetic resonance imaging in dentomaxillofacial region

Magnetic resonance imaging (MRI) is a versatile imaging modality utilized in various medical fields. Specifically used for evaluation of soft tissues, with non-ionizing radiation and multiplanar sections that has provided great guidance to diagnosis. Nowadays, use of MRI in dental practice is becoming more pervasive, especially for the evaluation of head-and-neck cancer, detection of salivary gland lesions, lymphadenopathy, and temporomandibular joint disorders. Understanding the basic principles, its recent advances, and multiple applications in dentomaxillofacial region helps significantly in the diagnostic decision making. In this article, the principle of MRI and its recent advances are reviewed, with further discussion on the appearance of various maxillofacial pathosis.

Mapping research trends of temporomandibular disorders from 2010 to 2019: A bibliometric analysis

BACKGROUND

Because of various clinical manifestations and complicated courses, temporomandibular disorders (TMDs) are difficult to treat. Current knowledge about this disease remains insufficient for precise treatment after diagnosis.

OBJECTIVES

The objective of this study is to obtain and map the overall literature trends and most cited keywords in TMDs research.

METHODS

Many indicators, including annual number of publications, country distribution, global cooperations, author contributions, original journals, cited references and keywords, were calculated and evaluated using VOSviewer v.1.6.13, which visualised many results, from the WoSCC database.

RESULTS

A total of 3121 papers on TMDs research were retrieved from 2010 to 2019. The United States produced the most articles published, but the most productive institution was the University of Sao Paulo (Brazil). Researchers and institutions conducting TMDs research have shown a very widespread and close connection. TMDs have been studied worldwide by many research centres. Professor Svensson P was the most published researcher in TMDs research and the Journal of Oral Rehabilitation published the most TMDs research articles. The top cited references mainly presented diagnostic criteria of TMDs. The most cited keywords formed clusters: (a) Anatomical factor of TMDs, (b) Symptoms of TMDs and (c) RDC/TMD, the risk factors, biopsychosocial factors and epidemiology of TMDs.

CONCLUSIONS

The research results provide very valuable data for a thorough understanding of the research status of TMDs and demonstrated international cooperation.

Shear wave elastography of temporomandibular joint disc and masseter muscle stiffness in healthy children and adolescents: a preliminary study

OBJECTIVES

Shear wave elastography (SWE) are promising techniques in diagnosing temporomandibular joint (TMJ) disc and masseter muscle disorders. To investigate normative stiffness values of the TMJ disc and masseter muscle by SWE in children and adolescents.

METHODS

This prospective study evaluated 123 TMJ discs and masseter muscles in 123 subjects. The stiffnesses of anterior, middle, and posterior parts of the disc and the masseter muscle were measured. This study investigated differences in mean elasticity [kilopascal (kPa)] and velocity [metre/second (m/s)] values of the different disc parts and the masseter muscle in closed and open mouth positions, and the correlations of these SWE values with age, body mass index (BMI), height, and weight of the subjects.

RESULTS

The median stiffness disc values of all participants were 28.7 kPa (elasticity) and 3.07 m/s (velocity) for the anterior, 29.10 kPa and 3.07 m/s for the middle, and 23.2 kPa and 2.77 m/s for the posterior parts. Posterior stiffness was significantly lower than other body regions in all subjects and across all age groups. The mean stiffness values of the muscle were 16.96 ± 9.01 kPa and 2.33 ± 1.2 m/s for the closed mouth, and 28.7 ± 10.2 kPa and 3.23 ± 1.32 m/s for the open mouth.

CONCLUSION

The stiffness of the TMJ disc was significantly lower in the posterior part than in the anterior or middle parts. The mean stiffness was significantly higher in the open mouth than in the closed mouth position. Neither elasticity nor velocity were associated with age, height, weight, or BMI.

Functional changes of the lateral pterygoid muscle in patients with temporomandibular disorders: a pilot magnetic resonance images texture study

BACKGROUND

Texture features were the intrinsic properties of the human tissues and could efficiently detect the subtle functional changes of involved tissue. The pathologic changes of the lateral pterygoid muscle (LPM) were significantly correlated with the temporomandibular disc displacement. However, the occult functional changes of LPM could not be detected by the naked eye on the medical images. The current study was aimed to evaluate the functional changes of the LPM in the patients with temporomandibular disorders (TMDs) using texture analysis.

METHODS

Twenty-nine patients with TMD were performed with magnetic resonance (MR) imaging on a 3.0T MR scanner, who were consecutively recruited from the TMD clinic of Hainan Hospital of Chinese People's Liberation Army General Hospital from February 2019 to September 2019. The patients were classified into three groups according to the disc displacement: disc without displacement (DWoD), disc displacement with reduction (DDWR) and disc displacement without reduction (DDWoR). The gray-level co-occurrence matrix method was applied with the texture analysis of LPM on the axial T2-weighted imaging. The texture features included angular second moment, contrast, correlation, inverse different moment, and entropy. One-way analysis of variance was used for grouped comparisons and receiver operating characteristics (ROC) curve analysis was applied to evaluate the diagnostic efficacy of the texture parameters.

RESULTS

Texture contrast of LPM presented significantly lower in DDWoR (46.30 [35.03, 94.48]) than that in DWoD (123.85 [105.06, 143.23]; test statistic = 23.05; P < 0.001). Texture entropy of LPM showed significant differences among DWoD (7.62 ± 0.33), DDWR (6.76 ± 0.35), and DDWoR (6.46 ± 0.39) (PDWoD-DDWR < 0.001, PDWoD-DDWoR < 0.001, and PDDWR-DDWoR = 0.014). Area under the ROC curve (AUC) demonstrated that texture entropy had an excellent diagnostic accuracy for DWoD-DDWR (AUC = 0.96) and DWoD-DDWoR (AUC = 0.98).

CONCLUSION

The texture contrast and entropy could identify the altered functional status of LPM in patients with TMD and could be considered as the effective imaging biomarker to evaluate the functional changes of LPM in TMD.

Temporomandibular Joint Disorders: A Pictorial Review

Temporomandibular joint (TMJ) disorders are commonly encountered in the general population but often ignored or unrecognized. The detection and characterization of lesions has drastically improved over the years due to technological advances in cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI). However, adequate knowledge of the normal imaging appearance on different imaging modalities as well as the broad variety of pathology is required to provide a proper radiologic assessment. This pictorial review focuses on TMJ pathology and its appearance on CBCT and MRI. A short overview of the technical aspects and normal anatomy are provided to round out this complete summary on the subject.

Overexpression of MMPs, cytokines, and RANKL/OPG in temporomandibular joint osteoarthritis and their association with joint pain, mouth opening, and bone degeneration: A preliminary report

OBJECTIVE

This study aimed to determine the expression of distinct matrix metalloproteinases, cytokines, and bone resorptive factors in temporomandibular joint osteoarthritis (TMJ-OA) patients and their association with joint pain, mouth opening, and subchondral bone degeneration.

MATERIALS AND METHODS

Twelve patients affected with TMJ-OA (n = 5), disk displacement without reduction (DDWoR) (n = 3), or disk displacement with reduction (DDWR) (n = 4) were selected. Joint pain was quantified by using visual analog scale, mouth opening was quantified at the maximum pain-free aperture, and bone degeneration was quantified using joint imaging. Synovial fluid samples were collected and immediately processed for cell and synovial fluid recovering. From cells, the MMP-1, MMP-2, MMP-8, MMP-13, IL-6, IL-23, and TNF-α expression was quantified by qPCR. From synovial fluid, the RANKL and OPG levels were quantified by ELISA.

RESULTS

Higher levels of MMP-1, MMP-8, MMP-13, IL-6, IL-23, TNF-α, and RANKL/OPG ratio were detected in TMJ-OA compared with DDWoR and DDWR patients (p < .05). Joint pain significantly correlated with TNF-α levels (r = .975, p = .029). Besides, imaging signs of bone degeneration significantly correlated with RANKL/OPG ratio (r = .949, p = .042). Conversely, mouth opening did not correlate with any of the analyzed mediators.

CONCLUSION

During TMJ-OA, a pathological response characterized by the overexpression of TNF-α and RANKL/OPG could be involved in joint pain and subchondral bone degeneration.

MRI characteristics of the asymptomatic temporomandibular joint in patients with unilateral temporomandibular joint disorder

OBJECTIVE

To determine the association between unilateral temporomandibular joint disorder (TMD) and the presence of imaging abnormalities in the contralateral, asymptomatic joint.

METHODS

MRI studies of 219 subjects with symptoms of unilateral TMD were examined for signs of disc displacement, osteoarthritis, disc deformation, and effusion in both temporomandibular joints (TMJ). The Chi-Square test and stepwise logistic regression analysis were performed.

RESULTS

Disc displacement, osteoarthritis, disc deformation, and effusion were more common on the symptomatic side. However, in the category of disc displacement with a reduction in open mouth position (DDWR), the difference was not significant between the symptomatic and the asymptomatic TMJs. Stepwise logistic regression showed that the presence of any imaging abnormality other than DDWR was related to osteoarthritis and disc deformity on the symptomatic side. On the other hand, the presence of any MRI abnormality (including DDWR) on the asymptomatic side was related only to the presence of osteoarthritis on the symptomatic side.

CONCLUSIONS

Unilateral symptomatic TMD is related to the presence of imaging abnormalities on the contralateral, asymptomatic side, suggesting that the development and progression of joint changes in symptomatic and contralateral asymptomatic TMJs are interrelated.

Diagnosing mandibular asymmetry using posteroanterior cephalograms in patients with unilateral and bilateral degenerative joint disease

Objectives:

The purpose of this study was to evaluate the possible differences in facial asymmetry between bilateral degenerative joint disease (BDJD) and unilateral degenerative joint disease (UDJD) when compared to asymptomatic controls.

Materials and Methods:

Posteroanterior cephalograms of 61 pre-orthodontic treatment patients (21 BDJD, 20 UDJD, and 20 controls) were evaluated (young adults, between 12 and 25 years of age) to investigate the inclination of the frontal occlusal plane (FOP) and frontal mandibular plane (FMP) to determine vertical asymmetry. Mandibular dental midline shift (DMS) and mandibular midline shift (MMS) were studied to determine transverse asymmetry. FOP, FMP, MMS, and DMS were compared pairwise between study groups, with multiple comparisons justified by Tukey–Kramer procedure. Correlation analyses were performed to evaluate the relationship between the measures. Mantel–Haenszel Chi-square test was used to evaluate the association between groups and symptom severity.

Results:

The findings suggest that severity of the vertical mandibular displacement was associated with significant differences between BDJD and control patients, and between UDJD groups and control patients. However, they were no significant differences found between UDJD and BDJD patients, and this may be attributable to a different pattern of load on the ipsilateral and contralateral sides of the TMJ when they were compared to the controls. Moreover, the higher values of FOP and FMP correlated with the mandibular displacement being notably greater when the asymmetry was >3°. A similar tendency of a higher prevalence of mandibular displacement with a higher value of DMS and MMS was observed.

Conclusion:

Clinical implications of this study apply to patients with asymmetry in vertical and transverse dimensions. These patients should be evaluated for dental, skeletal (condylar changes), and soft-tissue changes before orthodontic and/or orthognathic treatment planning.

Temporomandibular joint imaging: current clinical applications, biochemical comparison with the intervertebral disc and knee meniscus, and opportunities for advancement

Temporomandibular disorders encompass multiple pathologies of the temporomandibular joint that manifest as middle/inner ear symptoms, headache, and/or localized TMJ symptoms. There is an important although somewhat limited role of imaging in the diagnostic evaluation of temporomandibular disorders. In this manuscript, we provide a comprehensive review of TMJ anatomy, outline potentially important features of TMJ disc ultrastructure and biochemistry in comparison with the intervertebral disc and knee meniscus, and provide imaging examples of the TMJ abnormalities currently evaluable with MRI and CT. In addition, we provide an overview of emerging and investigational TMJ imaging techniques in order to encourage further imaging research based on the biomechanical alterations of the TMJ disc.

Imaging of the temporomandibular joint

Temporomandibular disorders are common, especially in young to middle-aged women, and most settle with supportive treatment. Imaging is indicated for the small percentage of cases that do not respond to conservative management and when the diagnosis is no doubt. The temporomandibular joint (TMJ) is a bilateral synovial articulation between the mandible and skull base. It has an intra-articular disc dividing the joint into superior and inferior compartments and the articular surfaces are lined with fibrocartilage. The normal imaging anatomy of the TMJ is described and illustrated. Different movements occur in each joint compartments: a hinge movement in the inferior joint space and translation or gliding in the superior joint space. Internal derangement is the commonest disorder affecting the TMJ and is most commonly due to disc displacement, followed by osteoarthritis and inflammatory arthritides. The imaging findings, primarily on magnetic resonance imaging (MRI) and computed tomography (CT), of internal derangement and less common disorders of the joint, are reviewed and illustrated. Optimal imaging protocols are discussed with detailed reporting guidelines.

Evaluation of styloid chain calcification related to temporomandibular joint disc displacement: a retrospective cohort study

OBJECTIVES

The present study aimed to evaluate any relationship between elongated styloid process (ESP) and temporomandibular joint disc displacement (TMJD).

STUDY DESIGN

A retrospective cohort study.

SETTING

Dentomaxillofacial Radiology division of Erciyes University Dental Hospital.

PARTICIPANTS

Ninety-four temporomandibular joints (TMJs) of 47 patients were allocated in this study. Intervention-disease: Two experienced dentomaxillofacial radiologists have interpreted all CBCT and MR images. Patients who referred with TMJ disorders were classified according to temporomandibular joint's disc status as normal disc position (ND), displacement with reduction (DWR) and displacement without reduction (DWoR).

METHODS

Main outcome measures: Interpretation of styloid chain calcification pattern and styloid processes length measured linearly on reconstructed sagittal slices of CBCT. Randomization: Cone beam computed tomography (CBCT) and magnetic resonance (MR) images of 154 patients who were admitted between September 1, 2012 and September 1, 2019. Only 47 of them fulfilled the study requirements. Blinding: Single blind of the outcome measurements and interpretations of MR images.

RESULTS

Total 94 TMJs of 47 patients disc status groups were analyzed and defined as DWoR (n = 25), DWR (n = 32), and ND (n = 37). On multivariate analysis, no statistical significant differences were found between groups in terms of styloid process lengths. Mean SP length and standard deviation of disc status groups (DWoR, DWR, and ND) are 35.5 (± 9.8) mm, 34.6 (± 9.2) mm, and 38.3 (± 8.9) mm, respectively. When patients were grouped individually according to their post-MRI diagnosis, the mean styloid process length in the non-temporomandibular joint disc displacement (non-TMJD) patients (47.9 ± 10.8) was significantly higher than the TMJD patients (36.1 ± 9.3). In this study, there is no intervention to cause any harm or side effects.

CONCLUSION

Our results indicate that styloid-stylohyoid syndrome may be misdiagnosed with temporomandibular joint disorder (TMD).

TRIAL REGISTRATION

Clinical Trials NCT04280107.

Characteristics of patients with temporomandibular joint osteoarthrosis on magnetic resonance imaging

INTRODUCTION

Temporomandibular joint (TMJ) dysfunction is a common condition that is best evaluated with magnetic resonance (MR) imaging. The aim of this study was to investigate the characteristics of the patients with TMJ osteoarthrosis on MR imaging.

METHODS

The MR images of 206 TMJs of 103 patients with temporomandibular disorders (TMD) were evaluated retrospectively in this study. The relationship between osteoarthrosis and age, gender, TMJ pain and MR imaging findings, such as disc displacement with or without reduction and TMJ effusion, was analysed.

RESULTS

The patients with TMJ osteoarthrosis (mean: 51.6 years) were significantly older than those without osteoarthrosis (mean: 44.8 years, P = 0.027). The incidence of the patients with TMJ osteoarthrosis was significantly different between with (10.0 %) and without reduction (57.0 %, P < 0.001). Logistic multivariate regression analysis demonstrated that disc displacement without reduction was significant in patients with TMJ osteoarthrosis (odds ratio = 12.285, P < 0.001).

CONCLUSIONS

This study suggests that characteristics of the patients with TMJ osteoarthrosis on MR imaging include older and disc displacement without reduction.

Advanced Ultrasound Screening for Temporomandibular Joint (TMJ) Internal Derangement

Purpose

To present an advanced ultrasound (US) technique and propose its use as a screening diagnostic tool for temporomandibular joint (TMJ) internal derangement.

Materials and Methods

The technique is based on maintaining the US probe parallel to the articular disc, rather than traditional axial and coronal views, with the position described relative to a clock face. Validation was achieved by direct comparison with magnetic resonance imaging (MRI). A total of 61 patients, with age ranging from 13 to 67 years, were prescreened for TMJ pain and internal derangement, underwent US imaging for screening, and MRI evaluation for final diagnosis.

Results

29 of the 61 patients had disc pathology on MRI. US screening produced no false positive results and only 6 false negative results, corresponding to a sensitivity of 79% and specificity of 100%. Half of the false negative cases involved disc pathology with a medial component to the disc displacement.

Conclusion

US is both a sensitive and a specific screening tool for TMJ dysfunction when used by an appropriately trained operator, with the exception of medially displaced discs. If TMJ assessment is found to be abnormal, the patient should be referred for MRI, and any patient scheduled for surgery must have the diagnosis confirmed by MRI. If a component of medial disc displacement is suspected, MRI should be performed despite a normal screening US.

Association of volume and voxel intensity of the articular disc and lateral pterygoid muscle in migraine patients: a study with magnetic resonance imaging

Objectives: To compare the volume and voxel intensity of articular disc and lateral pterygoid muscle (LPM) between a group of migraine patients and a control group (those without history of headache) by using magnetic resonance imaging (MRI).Patients and methods: MRI scans of 17 migraine patients and 15 healthy controls subjects were analysed and processed, using ITK-SNAP software, by a single investigator, for calculation of volumes and voxel intensity of articular disc and superior and inferior head of LPM.Results: There were statistically significant differences between migraine patients and controls regarding the volume and voxel intensity of articular disc and inferior head of LPM, increasing in migraine patients. Intra-rater was highly consistent and reproducible (intra-class correlation coefficient [ICC] = 1).Conclusions: Higher voxel intensity in disc and inferior head of LPM of MRI scans was linked to the increased volume of articular disc, inferior head of LPM and migraine.

Painful clicking jaw: a pictorial review of internal derangement of the temporomandibular joint

Temporomandibular joint disorders are a common cause of chronic musculoskeletal pain worldwide. Among these, internal disc derangement is the most frequent type of disorder. Internal derangement is defined as an abnormal positional and functional relationship between the disc and articulating surfaces. Common clinical symptoms include pain and clicking.

Imaging plays a key role in diagnosing temporomandibular joint disorders. It is important for the radiologist to detect early imaging signs of internal derangement, thereby avoiding the evolution of this condition to degenerative joint disease. The aim of this article is to familiarise the reader with the spectrum of imaging findings that are encountered at different stages of the disease.

MRI Changes in the Temporomandibular Joint after Mandibular Advancement

PURPOSE

Esthetic dental and skeletal component correction can affect the temporomandibular joint (TMJ). Arthrogenic TMJ dysfunction can be present in the joint at the outset or it can develop during the treatment or later. The aim of the present study was to examine the changes found on magnetic resonance imaging (MRI) studies of the TMJ in patients with skeletal Class II malocclusion who had undergone combined orthodontic and bilateral sagittal split ramus osteotomy (BSSRO) advancement. Our objective was to measure the changes in the disc position, condylar translation, secondary bony changes, and joint effusion on MRI before and after treatment.

MATERIALS AND METHODS

An analytical, single-surgeon, single-institution, retrospective radiological (MRI) study was designed. We included patients who had undergone combined orthodontic and BSSRO advancement from 2011 to 2018. All 36 patients were examined using a 1.5-Tesla MRI unit (Siemens Symphony, Erlangen, Germany) with a 6 × 8-cm diameter surface coil, which allowed for simultaneous imaging of both TMJs.

RESULTS

Analysis using the Wilcoxon signed rank test revealed statistically significant differences in the pre- and post-treatment groups in the changes in the position of the disc from anterior disc displacement with reduction (ADDWR) to the normal position (P = .008), condylar translation from excessive to normal (P = .046), and an increase in secondary bony changes (P = .005).

CONCLUSIONS

Combined orthodontic and orthognathic movement in the treatment of skeletal Class II malocclusion can increase secondary bony changes, improve the disc position in ADDWR cases, and control excessive translation of the TMJ. No improvement was noted in the position of the disc in those with anterior disc displacement without reduction, hypomobility and joint effusion.