Imaging of the temporomandibular joint: An update

Automated pediatric TMJ articular disk identification and displacement classification in MRI with machine learning

OBJECTIVE

To evaluate the performance of an automated two-step model interpreting pediatric temporomandibular joint (TMJ) magnetic resonance imaging (MRI) using artificial intelligence (AI). Using deep learning techniques, the model first automatically identifies the disk and the TMJ osseous structures, and then an automated algorithm classifies disk displacement.

MATERIALS AND METHODS

MRI images of the TMJ from 235 pediatric patients (470 joints) were reviewed. TMJ structures were segmented, and the disk position was classified as dislocated or not dislocated. The UNet++ model was trained on MRI images from 135 and tested on images from 100 patients. Disk displacement was then classified by an automated algorithm assessing the location of disk centroid and surfaces for bone landmarks.

RESULTS

The mean age was 14.6 ± 0.1 years (Female: 138/235, 58 %), with 104 of 470 disks (22 %) anteriorly dislocated. UNet++ performed well in segmenting the TMJ anatomical structures, with a Dice coefficient of 0.67 for the disk, 0.91 for the condyle, and a Hausdorff distance of 2.8 mm for the articular eminence. The classification algorithm showed disk displacement classification comparable to human experts, with an AUC of 0.89-0.92 for the distance between the disk center and the eminence-condyle line.

CONCLUSION

A two-step automated model can accurately identify TMJ osseous structures and classify disk dislocation in pediatric TMJ MRI. This tool could assist clinicians who are not MRI experts when assessing pediatric TMJ disorders.

CLINICAL SIGNIFICANCE

Automated software that assists in locating the articular disk and surrounding structures and classifies disk displacement would improve the TMJ-MRI interpretation and the assessment of TMJ disorders in children.

Three-dimensional volumetric analysis of the temporomandibular joint space using a standard conical object

OBJECTIVE

The objective was to present a novel method for the assessment of the temporomandibular joint space volume (TMJSV) in cone beam computed tomography (CBCT) examinations with TMJ region landmarks. The significance of differences in measurements of mandibular head width (MHW) and volume (MHV) as well as TMJSV was calculated comparing right vs. left sides and males vs. females.

STUDY DESIGN

CBCT images from 50 Angle Class I adults were evaluated using 3D image software. MHW and MHV were obtained from each TMJ. The representative TMJSV was found through Boolean subtraction using a standard conical object in .stl format. Paired t-tests were used to compare right and left sides. The Pearson correlation coefficient was used to assess the correlation between numerical variables. Student t-tests were used to compare MHW, MHV, and TMJSV between males and females. P < .05 indicated significant difference.

RESULTS

The right and left mean MHW, MHV, and TMJSV values were 19.46 and 19.47 mm, 1431.51 and 1401.39 mm3, and 475.51 and 461.13 mm3, respectively, with no significant differences between sides (P ≥ .381). Correlation of these measurements with ipsilateral and contralateral values was moderate to strong (.70 - .89). Males presented higher mean values for all measurements (P ≤ .023).

CONCLUSIONS

The results are comparable to those of other studies, indicating the reliability of our method as a nuanced analysis of the intricate TMJ anatomy.

Temporomandibular joint assessment in MRI images using artificial intelligence tools: where are we now? A systematic review

OBJECTIVES

To summarize the current evidence on the performance of artificial intelligence (AI) algorithms for the temporomandibular joint (TMJ) disc assessment and TMJ internal derangement diagnosis in magnetic resonance imaging (MRI) images.

METHODS

Studies were gathered by searching 5 electronic databases and partial grey literature up to May 27, 2024. Studies in humans using AI algorithms to detect or diagnose internal derangements in MRI images were included. The methodological quality of the studies was evaluated using the Quality Assessment Tool for Diagnostic of Accuracy Studies-2 (QUADAS-2) and a proposed checklist for dental AI studies.

RESULTS

Thirteen studies were included in this systematic review. Most of the studies assessed disc position. One study assessed disc perforation. A high heterogeneity related to the patient selection domain was found between the studies. The studies used a variety of AI approaches and performance metrics with CNN-based models being the most used. A high performance of AI models compared to humans was reported with accuracy ranging from 70% to 99%.

CONCLUSIONS

The integration of AI, particularly deep learning, in TMJ MRI, shows promising results as a diagnostic-assistance tool to segment TMJ structures and classify disc position. Further studies exploring more diverse and multicentre data will improve the validity and generalizability of the models before being implemented in clinical practice.

Evaluation of the Articular Disc Using the Magnetic Resonance Cartigram in Asymptomatic and Symptomatic Temporomandibular Disorders

Objectives  The study is aimed to perform magnetic resonance (MR) cartigram of the articular disc in patients with asymptomatic and symptomatic temporomandibular disorders (TMD). Materials and Methods  Thirty-nine volunteers were divided into three groups: 16 symptomatic TMD, 16 asymptomatic TMD, and 7 controls. The articular disc was divided into three segments (anterior, middle, and posterior) and analyzed using morphological magnetic resonance imaging (MRI) and T2 mapping sequences. T2 relaxation values were measured and assessed by an experienced radiologist and two observers. The T2 values in the discs were compared between the control, asymptomatic, and symptomatic groups using the Kruskal-Wallis test. The right and left discs were compared using the Wilcoxon signed rank test. Inter-examiner reliability among different examiners was evaluated. Results  The controls had the highest T2 values compared with the other groups. The comparison among the right and left sides of all the groups revealed statistically significant results in the anterior portion in the asymptomatic group and the middle portion in the symptomatic group ( p  < 0.05). The inter-examiner reliability coefficients among the three examiners were consistently high, with values of 0.921, 0.920, and 0.930. Conclusion  Our study found the T2 relaxation time span was shorter than that reported in previous studies, which could be attributed to the early stage of cartilage deterioration in the individuals with TMD inferring treatment at this phase may be eventually effective with a good prognosis.

Role of artificial intelligence in magnetic resonance imaging-based detection of temporomandibular joint disorder: a systematic review

This systematic review aimed to evaluate the application of artificial intelligence (AI) in the identification of temporomandibular joint (TMJ) disc position in normal or temporomandibular joint disorder (TMD) individuals using magnetic resonance imaging (MRI). Database search was done in Pub med, Google scholar, Semantic scholar and Cochrane for studies on AI application to detect TMJ disc position in MRI till September 2023 adhering PRISMA guidelines. Data extraction included number of patients, number of TMJ/MRI, AI algorithm and performance metrics. Risk of bias was done with modified PROBAST tool. Seven studies were included (deep learning = 6, machine learning = 1). Sensitivity values (n = 7) ranged from 0.735 to 1, while specificity values (n = 4) ranged from 0.68 to 0.961. AI achieves accuracy levels exceeding 83%. MobileNetV2 and ResNet have revealed better performance metrics. Machine learning demonstrated the lowest accuracy 74.2%. Risk of bias was low (n = 6) and high (n = 1). Deep learning models showed reliable performance metrics for AI based detection of temporomandibular joint disc position in MRI. Future research is warranted with better standardisation of design and consistent reporting.

Is Ultrasonography an Effective Method for Diagnosing Degenerative Changes in the Temporomandibular Joint?

BACKGROUND

The accurate diagnosis of degenerative joint diseases (DJDs) of the temporomandibular joint (TMJ) presents a significant clinical challenge due to their progressive nature and the complexity of associated structural changes. These conditions, characterized by cartilage degradation, subchondral bone remodeling, and eventual joint dysfunction, necessitate reliable and efficient imaging techniques for early detection and effective management. Cone-beam computed tomography (CBCT) is widely regarded as the gold standard for evaluating osseous changes in the TMJ, offering detailed visualization of bony structures. However, ultrasonography (US) has emerged as a promising alternative, offering a non-invasive and radiation-free option for assessing TMJ disorders. This study aims to evaluate the diagnostic accuracy of US in identifying degenerative changes in the TMJ, with CBCT serving as the definitive diagnostic reference. By analyzing the sensitivity, specificity, and predictive values of US in detecting key degenerative markers-such as subchondral erosion, osteophytes, and joint space narrowing-this investigation seeks to assess its utility as a screening tool and its potential integration into clinical workflows.

METHODS

Forty adult patients presenting temporomandibular joint disorders were included in our cross-sectional study. Each patient underwent a clinical examination and was subjected to cone-beam computed tomography (CBCT) and ultrasonography (US). A statistical analysis was performed to compare the imaging results from CBCT and US.

RESULTS

The results are summarized in three tables. The first table presents a comparative analysis of radiological outcomes in patients with temporomandibular joint disorders using different imaging techniques. CBCT demonstrated higher sensitivity in detecting osteophytes in the right mandibular head (27.50% vs. 7.50%, p = 0.027) and higher detection rates for erosions, though without a significant advantage over US. The second table analyzes the consistency of diagnostic results between CBCT and US. A moderate agreement was observed for detecting normal bone structures, with AC1 values of 0.58 for the right and 0.68 for the left mandibular head (p < 0.001). The third table evaluates the diagnostic accuracy of US compared to CBCT. US demonstrated a positive predictive value (PPV) of 90% for detecting normal conditions, indicating its high reliability as a screening tool for normal findings. US demonstrates higher effectiveness in ruling out certain issues due to its high specificity and negative predictive value. However, its lower sensitivity in detecting abnormalities may lead to both false-positive and false-negative results.

CONCLUSIONS

US holds significant promise as a screening modality for detecting normal anatomical features of the temporomandibular joint, its limitations in identifying more complex degenerative changes necessitate a cautious and integrated approach to TMJ diagnostics.

Unlocking the Temporomandibular Joint: CT, MRI, and Arthroscopic Correlation

The temporomandibular joint constitutes a synovial connection between the mandible and the skull base and plays a pivotal role in functions such as jaw movement, chewing, and verbal and emotional expression. Temporomandibular joint dysfunction is observed in about 30% of the population, with a higher prevalence in young to middle-aged women. Interestingly, a majority of individuals affected do not report pain, and only 5%-10% of symptomatic cases necessitate therapeutic intervention. The most common temporomandibular joint disorder manifests as pain in the masticatory muscles and is referred to as myofascial syndrome. However, articular disorders are also very common, usually due to disk displacement and degenerative or inflammatory arthropathies. Less frequently, the temporomandibular joint may be affected by a range of congenital and acquired conditions such as trauma and neoplasms. Imaging becomes necessary for the small percentage of patients who do not respond to conservative management or when there is uncertainty in the diagnosis. A comprehensive understanding of the normal imaging appearance of the temporomandibular joint as well as the wide range of potential pathologic conditions is essential for conducting an accurate radiologic assessment. Moreover, collaboration among multidisciplinary teams and the correlation of imaging findings with arthroscopic observations are crucial to advancing the diagnosis and treatment of temporomandibular joint dysfunction. ©RSNA, 2024 Supplemental material is available for this article.

Morphological description of the temporomandibular joint ligaments in domestic pigs

The temporomandibular joint (TMJ) ligaments play crucial roles in its function or dysfunction. The objective of this study was to describe the macro and microscopic morphology of these ligaments in domestic pigs, aiming to: (1) expand knowledge about the species; (2) provide anatomical references for advancing veterinary therapy and utilizing pigs as animal models in craniofacial research. Heads of young Sus scrofa domesticus were dissected to identify TMJ ligaments. Fragments of these ligaments were collected and processed for subsequent histological analysis with Haematoxylin and eosin staining. The results were qualitatively described. Pigs exhibited a TMJ reinforced by three individualized capsular ligaments: a lateral ligament, attaching to the ventral margin of the zygomatic process of the temporal bone and the lateral margin of the mandibular neck; a caudomedial ligament, attaching to the retroarticular process of the squamous part of the temporal bone and the caudomedial margin of the mandibular neck and a caudolateral ligament, attaching to the ventral margin of the base of the zygomatic process of the temporal bone and the caudal margin of the mandibular neck. The lateral ligament exhibited a greater constitution of dense irregular connective tissue, while the caudomedial and caudolateral ligaments showed a greater constitution of dense regular connective tissue. It is concluded that the TMJ of pigs presents one more ligament than horses, cattle, dogs, cats and what has been described for pigs themselves. We believe these results may contribute to the improvement of veterinary clinical and surgical therapy overall, as well as provide essential morphological information for a better interpretation and application of interspecies results in craniofacial research using pigs as an experimental model, as in the case of humans.

Association between Clinical Manifestations in Temporomandibular Joint Disorders and Corresponding Radiographic Findings

Background: Temporomandibular disorders are common conditions characterized by discomfort within the temporomandibular joints, acoustic changes, and restricted mandibular movement. Accurate diagnosis and subsequent treatment rely heavily on clinical examination, but it is often necessary to add radiological examinations to the diagnostics. Magnetic Resonance Imaging (MRI) is the gold standard for visualizing the disc, while cone-beam computed tomography (CBCT) is primarily used for evaluating condylar morphology. Ultrasound (US) serves as a real-time imaging modality for soft tissues. The objective of the present study was to explore the association between clinical manifestations observed in patients with temporomandibular joint disorders and corresponding radiographic findings. Methods: A total of 63 adult patients (51 female and 12 male) with temporomandibular joint disorders were included in this cross-sectional study. Each patient underwent a clinical examination, followed by appropriate radiological examinations (MRI, CBCT, or US). The level of statistical significance was set at an alpha of 0.05. The Shapiro-Wilk test assessed the normality of numerical variables. The Wilcoxon rank sum test compared two independent groups with non-normally distributed data. Relationships between categorical variables were evaluated using the Pearson chi-square test or Fisher's exact test. The Kendall tau (τ) method analyzed the correlation between two binary variables. Results: The analysis included 63 patients with TMD, predominantly females (80.95%). Ages ranged from 18 to 74 years with a median of 39 years. In the CBCT study, we observed rarefied changes in the left bone structures in patients with bruxism (p = 0.010). MRI and ultrasound imaging revealed changes in patients with limited jaw opening: erosions in the right mandibular head on ultrasound (p = 0.008) and abnormal right bone structures on MRI (p = 0.009). In CBCT, asymmetry in the left joint space was correlated with a high incidence of right side muscle tension (p = 0.004). Additionally, both CBCT and ultrasound showed a correlation between muscle tension and erosion (p = 0.040 in ultrasound, p = 0.020 in CBCT). Acoustic changes, when compared with radiological imaging, were evident in all three studies, like temporomandibular joint pain or palpation. Conclusions: Our study compared three radiographic imaging methods with clinical examinations to assess their correlation with clinical symptoms. Each imaging technique provided unique insights depending on the specific symptoms presented. The observed correlations varied, highlighting the unique contributions of each modality to the diagnostic process. This underscores the importance of employing multiple diagnostic approaches for a thorough assessment of the temporomandibular joint. However, a limitation of our study is the small sample size and the uneven distribution of participants among the groups. Additionally, not all patients underwent every imaging modality.

Association between clinical symptoms and MRI image findings in symptomatic temporomandibular joint (TMJ) disease: A systematic review

To evaluate the association between clinical signs and symptoms of temporomandibular joint (TMJ) and magnetic resonance image (MRI) findings in patients with temporomandibular disorders (TMD). Relevant articles on humans over 18 years of age were obtained from five databases (Ovid MEDLINE, PubMed, Scopus, Web of Science, and Google Scholar) up to August 2022. Risk of bias assessment was completed using the Joanna Briggs Institute critical appraisal tools. The GRADEpro (Grading of Recommendations, Assessment, Development, and Evaluation) instrument was applied to assess the level of evidence across studies in a GRADE Summary of Findings table. In total, 22 studies were included in this systematic review. Of these, 11 studies highlighted that joint pain was positively associated with particular MRI findings: joint effusion, bone marrow edema, disk displacement with/without reduction, and condylar erosion. Masticatory muscle pain was found to have a strong positive correlation with disk displacement in four studies. Five studies found no significant association between MRI findings and masticatory muscle pain. Range of motion and MRI findings were examined in six studies. Limited mouth opening was found to be correlated with disk displacement in five studies. Of the 11 studies evaluating the correlation between joint noise and MRI findings, eight reported a significant association between disk displacement and TMJ noise. The results suggested that patients with joint pain and limited range of motion may benefit from MRI. Patients exhibiting primarily muscle pain are unlikely to benefit clinically from MRI. Future studies with improved quality are warranted.

Efficacy of the transcutaneous electrostimulation in treatment dysfunctions of the TMJ associated with occlusion distortions

BACKGROUND

The study evaluation of the effectiveness the method of electrostimulation in treatment TMJ associated with occlusion disorders with the use of a patches by the company "Aganyan''.

METHODS

The study included 54 patients with temporomandibular dysfunction syndrome who had previously undergone endodontic dental treatment. In patients temporomandibular disorders (TMD) determined on the basis of Diagnostic criteria for temporomandibular disorders(DC/TMD).All patients had occlusion disorders due to errors after dental filling restoration. To diagnose the TMJ, a CT scan was used. The complex therapy also included therapy and with the use of a patches by the company "Aganyan''. The wearable patch includes a flexible substrate, a binder an adhesive layer, with an electrode foil attached to it. Patients applied one patch behind each TMJ. The patches were applied for eight hours every third day for three months. All the patients were given full-fledged endodontic treatment and restoration of the crown part, taking into account anatomical features.

RESULTS

The dynamics of the complex treatment of patients diagnosed with TMJ dysfunction syndrome showed that after treatment, the clinical symptoms gradually decreased and disappeared at the end of treatment. CT scan a year after treatment showed a normal ratio of TMJ elements. Сomplex treatment was effective in 87% of patients, after 3-5 months gradually decreased pain, noise in the joints, restriction of opening and closing of the mouth disappeared. Patients recovered their chewing functions, psycho-emotional state.

CONCLUSION

The results of the studies revealed a positive effects for the complex treatment dysfunctions syndrome TMJ the using the patches by the company "Aganyan" through electrical stimulation with low intensity.

Observational study investigating the relationship between maxillomandibular characteristics and temporomandibular disc conditions in female patients with a skeletal class III pattern

OBJECTIVES

The objective of this study was to analyze the relationship between maxillomandibular characteristics and the severity of temporomandibular disc displacement in female patients with a skeletal class III (SKIII) pattern.

METHODS

Fifty-seven samples were included in the study. The evaluation of articular disc conditions was conducted using magnetic resonance imaging, while 25 cephalometric variables from lateral and postero-anterior (P-A) cephalograms were measured to determine their maxillomandibular characteristics. The samples were categorized into three groups based on the articular disc conditions: (1) normal disc position (NDP), (2) disc displacement with reduction (DDwR), and (3) disc displacement without reduction (DDwoR). The relationship between the maxillomandibular characteristics and disc conditions was examined through both basic statistical analysis and multivariate analysis using principal component analysis (PCA).

RESULTS

The Kruskal-Wallis and Dunn-Bonferroni tests revealed a significant difference between the groups in terms of the deviation of mandibular characteristics observed on the P-A cephalogram. The DDwoR group exhibited significantly larger menton deviation, ramal height asymmetry index, and total mandibular length asymmetry index compared to the NDP and DDwR groups. Moreover, the PCA successfully extracted all cephalometric variables into eight principal components. Among them, only the principal component related to mandibular asymmetry was able to differentiate the SKIII samples with DDwoR from the other groups.

CONCLUSIONS

The findings of this study highlight a significant relationship between mandibular asymmetry and the severity of disc displacement, particularly DDwoR, in female patients with a SKIII pattern.

Magnetic resonance imaging evaluation of the disc morphology of temporomandibular joint in patients with severe hemophilia

OBJECTIVES

This study aimed to assess the morphological differences in the articular disc (AD) between hemophilic patients and healthy individuals of the control group for further association with signs and symptoms.

METHODS

Fourteen severe hemophilic patients had their AD evaluated by magnetic resonance imaging (MRI). The morphological findings were compared to those of a control group consisting of 14 healthy individuals. MRI was used to evaluate all the components of the temporomandibular (TMJ), including the AD, resulting in sequential T1-weighted parasagittal images. All the images were acquired with teeth in maximum intercuspation position.

RESULTS

Morphological alterations showed significant statistical differences (P-value = 0.0068), whereas no statistical differences were found in the other variables, including TMJ pain, headache, bruxism and mouth opening limitation. In the group of non-hemophilic individuals, only two (14.29%) presented AD with non-biconcave features, whereas in the group of hemophilic patients, nine (64.29%) presented AD with a morphology other than biconcave.

CONCLUSIONS

In patients with severe hemophilia, there seems to be a pattern of morphological alterations in the articular disc over time. The standard biconcave morphology of AD tends to change into other ones, particularly biplanar, hemiconvex and folded.

Diagnostic efficacy of quantitative ultrasonography for anterior disc displacement of the temporomandibular joint

Background

Ultrasonography has been applied as an alternative method in the assessment of temporomandibular joint (TMJ) pathology including anterior disc displacement (ADD). However, a concrete screening or diagnostic method which is feasible in clinical practice has not yet been established. The study aimed to establish a quantitative ultrasonographic method and determine its diagnostic efficacy for ADD of the TMJ.

Methods

A total of 75 joints were allocated to either the normal disc position (NDP) group or the ADD group using magnetic resonance imaging (MRI) as the reference standard. Longitudinal scans of the lateral articular compartment were obtained by a 14-MHz L-shaped linear array transducer. The width of the lateral joint space (LJS), the upper lateral joint space (ULJS), and the lower lateral joint space (LLJS), as well as the position of the lateral articular disc edge (ADE), were investigated by stepwise logistic regression analysis to identify significant indicators of ADD and to build a diagnostic model. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were computed at the optimal cut-off value.

Results

MRI detected 25 joints in the NDP group and 50 joints in the ADD group. Correlation analysis indicated that all 4 variables were associated with ADD. With the best performance of the area under the receiver operating characteristic (ROC) curve (AUC) of 0.939, LJS and ULJS were identified as predictors of ADD and subsequently adopted to build a diagnostic model by stepwise logistic regression. The optimal cut-off value of the 2-variable regression model for diagnosing ADD was 0.800, with a sensitivity of 82%, specificity of 96%, PPV of 97.6%, NPV of 72.7%, and an accuracy of 86.7%.

Conclusions

The quantitative ultrasonographic diagnostic method showed promising diagnostic efficacy. It has the potential to be used for ADD screening in future clinical practice.

Orofacial Pain and Dentistry Management: Guidelines for a More Comprehensive Evidence-Based Approach

Orofacial pain represents one of the most common health problems that negatively affects the activities of daily living. However, the mechanisms underlying these conditions are still unclear, and their comprehensive management is often lacking. Moreover, even if pain is a common symptom in dentistry, differential diagnostic procedures are needed to exclude other pain origins. Misinterpretation of the pain origin, in fact, can lead to misdiagnosis and to subsequent mismanagement. Pain in the orofacial area is the most common reason for patients to visit the dentist, but this area is complex, and the pain could be associated with the hard and soft tissues of the head, face, oral cavity, or to a dysfunction of the nervous system. Considering that the origins of orofacial pain can be many and varied, a thorough assessment of the situation is necessary to enable the most appropriate diagnostic pathway to be followed to achieve optimal clinical and therapeutic management.

Recent Advances in Temporomandibular Joint Surgery

Temporomandibular disorders (TMDs) affect a high percentage of children and adults worldwide. Surgery may be indicated in severe or recalcitrant cases. Several recent advancements in TMD and temporomandibular joint (TMJ) surgery have elevated understanding and the ability to treat affected patients. We discuss recent advances in TMD epidemiology, juvenile idiopathic arthritis (JIA) of the TMJ, and surgical techniques and technologies. Technical advancements have been identified in TMJ arthroscopy, the treatment of TMJ subluxation and dislocation, and extended prosthetic total TMJ reconstruction (eTMJR). Overall, this review provides valuable insights into significant recent advancements in TMJ disorders and their surgical management.

A New Mechanical Mouth Opener for Dynamic Magnetic Resonance Imaging of the Temporomandibular Joint

(1) Background: During the magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ), it is necessary to scan the joints in the closed- and open-jaw position, as well as in the maximally open-jaw position. In order to examine both joints in these positions, an MRI compatible mouth opener is required, which allows the articular surfaces to maintain their position stably. (2) Methods: In this study, we included 200 patients aged 18 to 65, with various levels of clinical severity. The mouth opener is made of polymethyl methacrylate and used for dynamic imaging of TMJ. It is in the form of an arrow, with incisures on upper and lower surfaces 1 mm apart and these match possible variations in jaw opening. All the patients were scanned with mouth opener and, immediately after this scanning, with syringe (20 ccm) as a standard device used for mouth opening in clinical setting. (3) Results: A total of 200 MR examinations of TMJs were performed and the mechanical mouth opener was successfully applied without artifacts in all patients. The mouth opener device proved to be adequate in case of MRI of the TMJ for different ranges of mouth opening with the proper protocol for provoked imaging, because the incisures are located at a distance of 1 mm and no objective artifacts were observed in any examination that degraded the diagnostic quality of the examination. (4) Conclusions: The design of the acrylate mouth opener is precisely defined, and it has a purpose in the MRI diagnosis of TMJ disorders.

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.

Arthroscopic management of synovial chondromatosis with skull base perforation: A case report and literature review

OBJECTIVE

Synovial chondromatosis (SC) of the temporomandibular joint (TMJ) is a synovial membrane disease characterized by the formation of cartilaginous nodules (CN), that may erode the skull base. Historically, cases with skull base involvement have been treated with open surgery. We report a case of TMJ SC with skull base perforation treated and repaired via minimally invasive TMJ arthroscopy and describe the advanced endoscopic operative maneuvers performed.

CASE REPORT

A 34-year-old male presented with a 4-year history of malocclusion and right TMJ arthralgia. Clinical examination demonstrated malocclusion and direct pressure loading pain. Advanced imaging revealed glenoid fossa erosion and numerous homogenous hypointense lesions within an effusion. The initial surgical plan included diagnostic TMJ arthroscopy followed by conversion to open arthroplasty. Endoscopic operative maneuvers allowed for the accomplishment of the surgical goals, completely arthroscopically. Histopathology confirmed SC, and the patient remains on observation, with relief of symptoms.

CONCLUSION

Advanced arthroscopy is a viable treatment option for select cases of TMJ SC with skull base involvement that allowed for access to the joint space, retrieval of biopsy specimens and CN, and repair of the skull defect.

The efficacy of orofacial myofunctional therapy in oral dysphagia accompanying temporomandibular dysfunction

OBJECTIVE

Patients with temporomandibular dysfunction (TMD) may develop oral-stage dysphagia (OD) in the chronic phase.

METHODS

This study investigated the effect of orofacial myofunctional therapy (OMT) in individuals with TMD-related OD. Fifty-one patients aged 18-65 years with TMD-related OD were separated into three groups using a simple randomization method: the control group (n = 12) underwent patient education and a home-exercise program; additionally, to an exercise program the manual therapy (MT) group (n = 19) received MT; and the OMT group (n = 20) received the OMT program. MT and OMT were applied in two sessions per week for 10 weeks. The patients were re-evaluated after treatment and at 3 months.

RESULTS

The OMT group showed the most improvement in jaw functionality, swallowing-related quality of life, pain, and dysphagia (p < .05).

DISCUSSION

OMT was superior to MT and exercises alone in reducing dysphagia and improving the swallowing-related quality of life.

Exploring the Validity of an Optoelectronic Integrated Cone Beam Computed Tomography Jaw Tracking System

Jaw motion tracking functionalities of cone beam computed tomography (CBCT)-scanners can visualize, record, and analyze movements of the mandible. In this explorative study, the validity of the 4D-Jaw Motion module (4D-JM) of the ProMax 3D Mid CBCT scanner (Planmeca, Helsinki, Finland) was tested in vitro. The validity of the 4D-JM was accepted if values differed less than 0.6 mm (three voxels sizes) from the gold standard. Three dry human skulls were used. CBCT scans, the gold standard, were taken in eight jaw positions and exported as three-dimensional (3D) models. Individualized 3D-printed dental wafers ensured the correct positioning of the mandible. Jaw positions were recorded with the 4D-JM tracking device and exported as 3D models. The coordinates of six reference points for both superimposed 3D models were obtained. The differences in the x, y and z-axis and the corresponding vector differences between gold standard 3D models and 4D-JM models were calculated. For the mandible 10% and for the maxilla 90% of the vector differences fell within 0.6 mm of the gold standard. With an increasing vertical jaw opening, larger differences between the gold standard and the 4D-JM 3D models were found. The smallest differences of the mandible were observed on the x axis. In this study, the 4D-JM validity was not acceptable by the authors' predefined standards.

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.

Temporomandibular Joint Imaging

Prescriptions for imaging studies for temporomandibular disorders are based on the patient's complaint, history, and clinical findings. Appropriate selection criteria and justification for imaging examinations must be followed. Because the temporomandibular joint is composed of both hard and soft tissues, different studies are prescribed based on the clinically suspected condition. Current imaging modalities include panoramic radiographs, cone-beam computed tomography, and MRI. The entire examination must be interpreted, and the findings recorded in the patient record. No one imaging modalities is suitable for all patients. An oral and maxillofacial radiologist should be consulted when the interpretation of the study is beyond the scope of the practitioner.

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.

Positional Features of the Mandibular Condyle in Patients with Facial Asymmetry

OBJECTIVE

To describe the position of the mandibular condyle, the size of the joint spaces and the condylar angulation in patients with facial asymmetry (FA), and to classify these results according to the type of FA and compare them with a reference group without FA. Materials and Methods/Patients: An observational, cross-sectional, descriptive study using computed tomography (CT) was conducted on a sample of 133 patients with a clinical diagnosis of FA derived from the following entities: hemimandibular elongation (HE) (n = 61), hemimandibular hyperplasia (HH) (n = 11), condylar hyperplasia in its hybrid form (HF) (n = 19), asymmetric mandibular prognathism (AMP) (n = 25), glenoid fossa asymmetry (GFA) (n = 9) and functional laterognathism (FL) (n = 8). Likewise, a group of 20 patients without clinical or tomographic characteristics of FA was taken and their complete cone beam tomography (CBCT) scans were analyzed. The quantified variables were joint spaces (anterior, middle and posterior), angle of the condylar axis and condylar position. All measurements were performed using the free, open-source Horos software.

RESULTS

Most of the subjects without FA had a right middle condylar position (55%), while in the patients with FA the anterior condylar position predominated. On the left side, the most frequent condylar position was anterior, including the group without FA, except in the HH group. Considering the measurements of the anterior, middle and posterior joint space (mm) on the right side (anterior JS: 1.9 mm, middle JS: 2 mm and posterior JS: 2.8 mm) and on the left side (anterior JS: 2.7 mm, middle JS: 2.1 mm and posterior JS: 2.6 mm) of the subjects without FA, compared to those with FA, the latter presented smaller distances in all diagnoses and only for the right posterior JS (1.9 mm) in HH, was not significant. The condylar axis of the AF group showed significant differences with smaller angles for the left side in those diagnosed with HE (65.4°) and HH (56.5°) compared to those without AF (70.4°).

CONCLUSIONS

The condylar position of patients with FA tends to be anterior, both on the right and left sides, while for cases without FA it is middle and anterior, respectively. Patients with FA have smaller joint spaces (mm) compared to patients without FA, with the exception of HH for the right posterior JS.

Findings in ancient Egyptian mummies from tomb KV64, Valley of the Kings, Luxor, with evidence of a rheumatic disease

OBJECTIVE

In 2011, a spectacular find was made in the Valley of the Kings, Egypt - a well-known archaeological site, where pharaohs were buried during the New Kingdom (ca. 1500-1100 BCE). A team from the University of Basel's Kings' Valley Project discovered a tomb (KV64) containing two mummies that were buried in different time episodes (unidentified elite burial, 18th dynasty, and Nehemesbastet, 22nd dynasty).

METHOD

Anthropological investigations of the mummies were performed using portable X-ray and photographic documentation.

RESULTS AND CONCLUSION

The first burial was an adult individual with bilateral pathological changes at the temporomandibular joints (TMJs), most likely of inflammatory origin, possibly psoriatic arthritis. Investigations of the second burial revealed an intact body of a younger female individual.

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.

Do TMJ MRI diagnosis support clinical examination diagnosis following DC/TMD criteria?

PURPOSE

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) has been validated as a clinical diagnostic guideline with high-sensitivity and -specificity in identifying TMDs. The purpose of this study was to evaluate the agreement between DC/TMD diagnoses and magnetic resonance imaging (MRI) diagnoses in patients with TMD.

METHODS

A prospective cohort study was conducted on patients with TMD. The predictor variable was the clinical diagnosis of TMD based on DC/TMD criteria. The outcome variable was the MRI diagnosis of TMD. The diagnoses used for both the predictor variable and the outcome variable were the same. They were normal, disc displacement with reduction (DDWR), DDWR with intermittent locking, disc displacement without reduction (DDWOR) with limited opening, DDWOR without limited opening, degenerative joint disease, and subluxation. Age and gender of the patients and number of joints evaluated were covariates. Each subject had clinical examination performed by two independent Oral and Maxillofacial Surgeons. All subjects had a bilateral temporomandibular joint (TMJ) MRI performed which was evaluated by a radiologist. The correlation between the clinical and MRI diagnoses was calculated using Cohen's kappa value with a P value of <.05 considered significant.

RESULTS

A total of fifty patients (100 TMJs) were enrolled with 38 females and 12 males. The mean ages were 31.92 and 31.75 years, respectively, with a total of 100 TMJs analyzed. Internal derangement was clinically identified in 76% of the joints and with MRI in 69% of joints. The Cohen's kappa value between DC/TMD and MRI diagnoses was found to be κ = 0.720 (P < .01). The respective sensitivity and specificity in determining disc position clinically for DDWR was 1 and 0.96; for DDWR with intermittent locking 0.78 and 0.91; for DDWOR with limited opening 0.9 and 0.98; for DDWOR without limited opening 1 and 0.9; for degenerative joint disease 0.63 and 0.97 and for subluxation 0.28 and 1.00.

CONCLUSION

The DC/TMD clinical examination performed well in all types of disc displacement but is less reliable in detecting the presence of degenerative disc diseases and subluxation.

Recent Advances in Animal Models, Diagnosis, and Treatment of Temporomandibular Joint Osteoarthritis

Temporomandibular joint osteoarthritis (TMJOA) is a gradual degenerative jaw joint condition. Until recent years, TMJOA is still relatively unrecognized and ineffective to be treated. Appropriate animal models with reliable detection methods can help researchers understand the pathophysiology of TMJOA and find therapeutic options. In this study, we summarized common animal models of TMJOA created by chemical, surgical, mechanical, and genetical approaches. The relevant pathological symptoms and induction mechanisms were outlined. In addition, different pathological indicators, furthermore, emerging therapeutic regimens, such as intra-articular drug delivery and tissue engineering-based approaches to treat TMJOA based on these animal models, were summarized and updated. Understanding the physiology and pathogenesis of the TMJOA, together using various ways to diagnose the TMJOA, were elaborated, including imaging techniques, molecular techniques for detecting inflammatory cytokines, histochemical staining, and histomorphometry measures. A more reliable diagnosis will enable the development of new prevention and more effective treatment strategies and thereby improve the quality of life of TMJOA patients. Impact statement Temporomandibular joint osteoarthritis (TMJOA) affects 8 to 16 percent of the population worldwide. However, TMJOA is still relatively unrecognized and ineffective to be treated in the clinic. Appropriate animal models with reliable diagnostic methods can help researchers understand the pathophysiology of TMJOA and find therapeutic options. We herein summarized common animal models of TMJOA and various ways to diagnose the TMJOA. More importantly, emerging therapeutic regimens to treat TMJOA based on these animal models were summarized. With the aid of strategies listed, more effective treatment strategies will be developed and thereby improve the life quality of TMJOA patients.

Craniofacial Morphology of Temporomandibular Disorder Patients with Different Disc Positions: Stratifying Features Based on Sex and Sagittal Skeletal Pattern

Disc displacement (DD) appears in the majority of temporomandibular disorder (TMD) patients. The correlation between craniofacial morphology and different disc positions has been underlined, while the craniofacial morphological differences based on sex and sagittal skeletal pattern stratification have been insufficiently studied. In this study, 304 patients with TMD complaints were included and classified into normal position, disc displacement with reduction (DDwR) and disc displacement without reduction (DDwoR) groups according to magnetic resonance imaging. A total of 24 cephalometric measurements, covering the cranial base, vertical relationship, sagittal relationship, mandible position and morphology, and dental relationship, were assessed using lateral cephalograms. A stratified analysis was performed based on the sex and sagittal skeletal pattern. Overall, DD patients had distinctive craniofacial morphological features. The posterior cranial base length and mandibular arc angle were statistically different only in females, while the Y-axis angle, occlusal plane angle and sella nasion point A angle (SNA) might be unique features in males. Skeletal class II had the most statistically different measurements compared to the others. Differences in the Frankfort mandibular incisor angle (FMIA) and saddle angle were especially displayed in skeletal class III patients. The sex and skeletal sagittal pattern could affect the morphological differences in TMD patients with different disc positions.

Nonsurgical Management of Temporomandibular Joint Arthropathy

Arthropathy is a broad diagnostic term for any pathologic condition afflicting one or more joints of the body. Temporomandibular joint (TMJ) arthropathy is an umbrella term that may be applied to mechanical dysfunction or disease of one or both TMJs. This article provides evidence-based recommendations for conducting a patient evaluation, initiating a diagnostic workup, formulating an assessment, and instituting various nonsurgical modalities for the treatment of TMJ arthropathies.

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.

Static mandibular condyle positions studied by MRI and condylar position indicator

We compared mandibular condyle positions as determined by magnetic resonance imaging (MRI) and a mechanical device, the condylar position indicator (CPI). Both methods assessed 3 mandibular positions in 10 asymptomatic males and 10 asymptomatic females, aged 23 to 37 years, free from temporomandibular disorders: maximum intercuspation, bimanually manipulated centric relation, and the unguided neuromuscular position. Bite registrations were obtained for bimanual operator guidance and neuromuscular position. 3 T MRI scans of both temporomandibular joints produced 3D data of the most superior condylar points in all 3 mandibular positions. Using mounted plaster casts and the same bite registrations, an electronic CPI displayed 3D data of its condylar spheres in these positions. The results showed interclass correlation coefficients ranging from 0.03 to 0.66 (95% confidence intervals from 0 to 0.8) and significantly different condyle positions between both methods (p = 0.0012, p < 0.001). The implications of the study emphasize that condyle position is unpredictable and variable. Its exact knowledge requires radiological imaging and should not rely on CPI assessments.

The Role of Ultrasound in Temporomandibular Joint Disorders: An Update and Future Perspectives

Temporomandibular joint (TMJ) disorder is the second most common chronic pain condition affecting the general population after back pain. It encompasses a complex set of conditions, manifesting with jaw pain and limitation in mouth opening, influencing chewing, eating, speaking, and facial expression. TMJ dysfunction could be related to mechanical abnormalities or underlying inflammatory arthropathies, such as rheumatoid arthritis (RA) or juvenile idiopathic arthritis (JIA). TMJ exhibits a complex anatomy, and thus a thorough investigation is required to detect the TMJ abnormalities. Importantly, TMJ involvement can be completely asymptomatic during the early stages of the disease, showing no clinically detectable signs, exposing patients to delayed diagnosis, and progressive irreversible condylar damage. For the prevention of JIA complications, early diagnosis is therefore essential. Currently, magnetic resonance imaging (MRI) is described in the literature as the gold standard method to evaluate TMJ. However, it is a high-cost procedure, not available in all centers, and requires a long time for image acquisition, which could represent a problem notably in the pediatric population. It also suffers restricted usage in patients with claustrophobia. Ultrasonography (US) has emerged in recent years as an alternative diagnostic method, as it is less expensive, not invasive, and does not demand special facilities. In this narrative review, we will investigate the power of US in TMJ disorders based on the most relevant literature data, from an early screening of TMJ changes to differential diagnosis and monitoring. We then propose a potential algorithm to optimize the management of TMJ pathology, questioning what would be the role of ultrasonographic study.

Is scoliosis related to mastication muscle asymmetry and temporomandibular disorders? A cross-sectional study

OBJECTIVE

Patients with adolescent idiopathic scoliosis (AIS) may face motor control problems and health disability barriers during mandibular movements and chewing. However, studies investigating the extent of these disadvantages, and possible associated factors are quite limited in patients with AIS. This study was conducted to gain a deeper perspective on the effect of AIS on temporomandibular disorders (TMD) and to contribute to the small amount of data on this subject.

METHODS

Twenty-nine patients with AIS and 29 age- and sex-matched asymptomatic controls participated in this cross-sectional study. Cobb's method was used to measure scoliosis curves. In both groups, the volume of the masseter muscle was determined on magnetic resonance imaging, and Helkimo and Fonseca anamnestic indexes were used to evaluate temporomandibular joint (TMJ).

RESULTS

It was observed that the TMD symptoms were higher in the AIS group (22.6- Helkimo and 1.2 - Fonseca) than the asymptomatic group (13.6 - Helkimo and 0.7 - Fonseca). There was no significant asymmetry in masseter volume in patients with AIS, however the volume of the masseter muscles was smaller in the AIS group (R = 14.6/L = 13.6) compared to the control group (R = 16.1/L = 16.2).

CONCLUSIONS

The study results indicate that spinal curvatures affect the anatomical, biomechanical, and kinesiological features of the masticatory system, and individuals with AIS may experience more chewing problems than asymptomatic individuals. Examining musculoskeletal properties of masticatory system can provide information about the limitation of the TMJ in patients with AIS.

Controversial Aspects of Diagnostics and Therapy of Arthritis of the Temporomandibular Joint in Rheumatoid and Juvenile Idiopathic Arthritis-An Analysis of Evidence- and Consensus-Based Recommendations Based on an Interdisciplinary Guideline Project

Introduction: Due to potentially severe sequelae (impaired growth, condylar resorption, and ankylosis) early diagnosis of chronic rheumatic arthritis of the temporomandibular joint (TMJ) and timely onset of therapy are essential. Aim: Owing to very limited evidence the aim of the study was to identify and discuss controversial topics in the guideline development to promote further focused research. Methods: Through a systematic literature search, 394 out of 3771 publications were included in a German interdisciplinary guideline draft. Two workgroups (1: oral and maxillofacial surgery, 2: interdisciplinary) voted on 77 recommendations/statements, in 2 independent anonymized and blinded consensus phases (Delphi process). Results: The voting results were relatively homogenous, except for a greater proportion of abstentions amongst the interdisciplinary group (p < 0.001). Eighty-four percent of recommendations/statements were approved in the first round, 89% with strong consensus. Fourteen recommendations/statements (18.2%) required a prolonged consensus phase and further discussion. Discussion: Contrast-enhanced MRI was confirmed as the method of choice for the diagnosis of TMJ arthritis. Intraarticular corticosteroid injection is to be limited to therapy-refractory cases and single injection only. In adults, alloplastic joint replacement is preferable to autologous replacement. In children/adolescents, autologous reconstruction may be performed lacking viable alternatives. Alloplastic options are currently still considered experimental.

Normal Variants of the Oral and Maxillofacial Region: Mimics and Pitfalls

A normal variant is defined as an incidental, often asymptomatic, imaging finding that mimics a true pathologic condition. Given the complex anatomy and wide variety of normal variants in the oral and maxillofacial region, a thorough understanding of commonly encountered normal variants in this region is essential to avoid misinterpretation and unnecessary further imaging or interventions. Moreover, familiarity with normal variants that are known to become symptomatic at times is necessary to facilitate further workup and guide the treatment plan. Intraoral radiography and panoramic radiography, which are unique to oral and maxillofacial radiology, provide two-dimensional (2D) images. Hence, the overlapping of structures or the displacement of the tomographic layer on images can confuse radiologists. It is crucial to understand the principle of 2D imaging to avoid being confused by ghost images or optical illusions. In addition, understanding the normal development of the maxillofacial region is essential when interpreting maxillofacial images in children or young adults because the anatomy may be quite different from that of mature adults. Knowledge of changes in the jaw bone marrow and each tissue's growth rate is essential. It is also necessary to know when the tooth germ begins to calcify and the tooth erupts for diagnostic imaging of the maxillofacial region. The authors describe imaging findings and clinical manifestations of common normal variants in the oral and maxillofacial region, divided into four parts: the maxilla, mandible, tooth, and temporomandibular joint, and discuss the imaging approach used to differentiate normal variants from true pathologic conditions. Online supplemental material is available for this article. ^©RSNA, 2022.

Diagnostic use of computerized axiography in TMJ disc displacements

Application of paraclinical methods for investigating the temporomandibular joint (TMJ) has been a subject of constant controversy due to the absence of universally-accepted criteria and lack of consensus regarding their usage. Compared with medical imaging, which provides a structural analysis of the TMJ, axiography involves the functional recording of condylar movements. The aim of the present study was to explore the diagnostic value of computerized axiography for TMJ disc displacements using MRI as the reference standard. The present study included 33 (66 TMJs) patients clinically diagnosed with TMJ disc displacements. On the same day, all patients underwent clinical examination and computerized axiography measurements using Cadiax Compact^® II before undergoing MRI (1.5 T) 1-7 days later. The characteristics of the diagnostic parameters, namely sensitivity, specificity, positive and negative predictive values, accuracy, Youden index and the 95% confidence intervals (CI), were all computed. Compared with MRI, computerized axiography yielded a sensitivity of 85.11%, specificity of 94.74%, positive predictive value of 97.56%, negative predictive value of 72% and a diagnostic accuracy of 87.88% for any disc displacements. This suggests that computerized axiography can confer high sensitivity, specificity and accuracy for the diagnosis of TMJ disc displacements. However, axiographic analysis has no diagnostic significance in TMJ function if not associated with clinical examination.

Clinical Practice Guideline: The Diagnosis and Treatment of Rheumatoid Arthritis and Juvenile Idiopathic Arthritis of the Temporomandibular Joint

BACKGROUND

Involvement of the temporomandibular joint can be shown in 40-90% of patients with rheumatoid arthritis and juvenile idiopathic arthritis (JIA), although it is often asymptomatic. Restricted jaw mobility and jaw pain can be found in approximately 20% of patients with JIA (prevalence: 70 per 100 000 persons). Early diagnosis and treatment of the underlying disease are essential for a good outcome, but uniform, consensus-based management is still lacking.

METHODS

The clinical practice guideline is based on the findings of a systematic literature review in multiple databases and a Delphi procedure to obtain consensus on the recommendations.

RESULTS

Most of the identified studies were retrospective. Patients with JIA should undergo clinical screening with a structured examination protocol once per year in childhood and adolescence, and thereafter as well if the temporomandibular joint is involved. The diagnosis of chronic rheumatoid arthritis of the temporomandibular joint is established with contrastenhanced magnetic resonance imaging. Conservative treatment (antirheumatic basal therapy, local measures) is unsuccessful in less than 10% of patients. In such cases, arthroscopy and arthrocentesis can be used for temporary symptom relief and functional improvement. Intraarticular corticosteroid injections should be given only once, and only in otherwise intractable cases. In severe cases where all other options have been exhausted (<1%), open surgical treatment can be considered, including alloplastic joint replacement.

CONCLUSION

Oligosymptomatic and asymptomatic cases are common even with radiologic evidence of marked joint damage. The possibility of rheumatic involvement of the temporomandibular joint must be kept in mind so that serious complications can be avoided. Regular clinical evaluation of the temporomandibular joint is recommended, particularly for patients with juvenile idiopathic arthritis.

Relationship of Malocclusions with Disorders of the Temporomandibular Joint in Children of CALI-Colombia

OBJECTIVE

 The aim of this study was to determine the relationship of malocclusion with the presence and severity of temporomandibular disorders (TMDs) in children.

MATERIALS AND METHODS

 A clinical examination was performed in 87 patients (from 4 to 14 years of age) who attended the dentistry clinics of Universidad del Valle.

RESULTS

 The 77 patients studied had malocclusions; 55 patients had TMD and 67.3% were female. The most frequent symptom of TMD was articular unilateral noise with 33.8%, followed by pain in at least one masticatory muscle with 26%. TMJ pain was observed in 24.7% of the patients. There was a statistically significant relationship between the presence and severity of TMD with type of dentition and transverse malocclusion, respectively.

CONCLUSION

 The presence of TMD in children with malocclusion presented in a high frequency. TMD depends on the type of dentition and its severity is dependent on transverse malocclusion.

Temporomandibular Joint Space Dimensions among Saudi Patients with Temporomandibular Disorders: MRI-Based Retrospective Study

INTRODUCTION

The temporomandibular joint is a complex synovial joint in the body. It is the area in which the mandible articulates with the cranium. The temporomandibular joint space is located between the articular eminence and the glenoid fossa of the temporal bone at the base of the skull and the condylar process of the mandible. This interarticular space is divided into superior joint space (1.2 ml) and inferior joint space (0.9 ml) by the articular disc. The purpose of this study is to detect and evaluate the variations in the temporomandibular joint space among patients having temporomandibular joint disorders.

MATERIALS AND METHODS

In this retrospective study, 60 magnetic resonance imaging scans were evaluated at King Faisal Specialist Hospital in Riyadh, Saudi Arabia, between the years 2006 and 2016. Measurements were done in sagittal view in three areas: anterior, central, and posterior areas. However, coronal view readings were recorded in two different areas: medial and lateral joint spaces. All measurements were recorded at the highest point of the condyle that is perpendicular to the opposing bone. The SPSS program was used for statistical analysis.

RESULTS

The central joint space values were higher than the anterior and posterior joint spaces in both coronal and sagittal views. We also found that joint spaces among male patients were higher than female patients (right side P=0.015 and left side P=0.006). It is worth mentioning that the number of temporomandibular joint disorder female patients was more than the number of male temporomandibular joint disorder patients (52 females versus 24 males). Additionally, patients who were older than 55 years old had wider joint spaces than patients who were younger than 25 years old.

CONCLUSION

The central joint space value was the highest among the other joint spaces on both views of magnetic resonance imaging, and the values of joint spaces among males were larger than those of females on sagittal magnetic resonance imaging. Patients with elderly temporomandibular joint disorders showed larger joint spaces than young patients. This study spotlights the importance of magnetic resonance imaging evaluation in temporomandibular joint disorder patients for a better understanding of the clinical evolution of temporomandibular disorders.

Can dynamic magnetic resonance imaging replace static magnetic resonance sequences in evaluation of temporomandibular joint dysfunction?

Background

Static MRI was used as an effective tool for diagnosis of temporomandibular joint dysfunction instead of invasive techniques such as arthroscopy and arthrography. The purpose of this study was to detect whether dynamic MRI can be used instead of static MRI in diagnosis of TMJ dysfunction or not.

Results

According to disc displacement, anterior disc displacement was detected in 29 joints (36.25%) by both static and dynamic MRIs, and medial and lateral disc displacements were detected only by static MRI. Regarding disc mobility, dynamic MRI detects stuck disc in 4 joints versus 2 joints detected by static MRI (p value 0.008). Condylar translation was abnormal in 18 joints (22.5%) by static MRI and in 26 joints (32.5%) by dynamic MRI (p value < 0.001). The detection rate of articular disc for dynamic MRI was 87.5% versus static MRI 92.5% (p value 0.038), and the detection rate of condylar head for dynamic MRI was 97.5% versus static MRI 100% (p value 0.012).

Conclusion

Dynamic MRI cannot replace static MRI in evaluation of TMJ dysfunction; both of them support each other for accurate diagnosis and better image quality.

The Frequency of Communication Between the Synovial Compartments of the Equine Temporomandibular Joint: A Contrast-Enhanced Computed Tomographic Assessment

Background: There is conflicting evidence regarding communication between the two compartments of the equine temporomandibular joint (TMJ). Understanding the inter-relationship between TMJ compartments is critical for diagnostic and clinical management purposes. Objective: To determine the frequency of communication between the discotemporal joint (DTJ) and the discomandibular joint (DMJ) of the equine TMJ in horses free of overt disease. Study Design: A randomized, blinded, controlled cadaveric study. Methods: Equine cadaver heads (n = 20), with no reported history of potential TMJ disease, were collected and stored frozen until use. Horses were randomized to the treatment group, such that Group A horses (n = 10) underwent arthrocentesis of the left DTJ and the right DMJ compartments, while Group B (n = 10) underwent arthrocentesis of the left DMJ and the right DTJ compartments of the TMJ, for a total of 40 joints. Computed tomography (CT) imaging was performed before, and after, intra-articular injection of contrast media in each head. Two observers, blinded to the treatment group, independently interpreted CT images. Results: Communication between synovial compartments occurred in the left TMJ of two horses. Arthroscopic evaluation revealed that both horses had a perforation of the intra-articular disc in the region of the caudomedial fibrous expansion. Mild anterior displacement of the abnormal disc in the joint of one horse was demonstrated using magnetic resonance imaging (MRI). Main Limitations: Sample size, the use of owner provided animals' history, and frozen specimens. Conclusions: No physiological communication was present between the DTJ and the DMJ in the equine TMJ of the cases studied, regardless of which compartment underwent arthrocentesis. Two joints had pathological communications. These results suggest that diagnostic, and medical, treatment of intra-articular disease may be most effective when both joint compartments are injected. Furthermore, this study illustrates the value of contrast enhancement while imaging the equine TMJ.

Radiographic changes in the temporomandibular joint related to medication in rheumatic diseases

OBJECTIVES

The purpose of this study was to assess radiographical changes on temporomandibular joint (TMJ) in relation the autoimmune rheumatic diseases and the medicines that treat this diseases with cone beam computed tomography(CBCT).

METHODS

65 people with rheumatoid diseases were included in the study and divided into five subgroups according to drugs they used. Condyle height (CH), anteroposterior dimension (APD), mesiolateral dimension (MLD) and superior joint space (SJS) were measured in order to evaluate mandibular condyle dimensions. Further, were evaluated in terms of osteoarthritic changes such as erosion, flattening, osteophyte and subchondral cyst in the mandibular condyle. TMJ measurements were compared between study-control groups and subgroups by using Student's t-test, Mann-Whitney-U test, one-way analysis of variance (ANOVA) and Kruskal-Wallis test. The association between osteoarthritic features, rheumatoid status was tested by using χ2 test. Observers were blinded to all groups. Cohen κ values (0853-0945) and Spearman's correlation coefficient (0.959-0.997) indicated high interexaminer reliability.

RESULTS

Condylar dimentions were significantly lower in CH and SJS in rheumatic diseases group (p < 0.001), however APD (p = 0,681) and MLD (p = 0,757) was not different significantly. Osteoarthritic changes such as erosion (p < 0.001), flattening (p = 0.005), osteophyte (p = 0.001) and subchondral cyst (p = 0.001) were significantly higher in the patient group. None of the parameters were different significantly according to subgroups determined according to drugs used(p > 0.05).

CONCLUSIONS

Degenerative changes may cause decrease in condyle size and changes in condyle position. It is a process that can continue despite the use of antirheumatic or immunosuppressive drugs. All of these can become the source of possible TMJ problems.

COL5A1 RS12722 Is Associated with Temporomandibular Joint Anterior Disc Displacement without Reduction in Polish Caucasians

Numerous reports describe the association between the single-nucleotide polymorphism (SNP) rs12722 and rs13946 in the COL5A1 gene and injuries, such as Achilles tendon pathology, anterior cruciate ligament (ACL) injuries, and tennis elbow. Hence, there were no studies investigating COL5A1 and temporomandibular joint (TMJ) pathology. The aim of this study is to evaluate the relationship between COL5A1 rs12722 and rs13946 SNPs and TMJ articular disc displacement without reduction (ADDwoR). In this case-control study, the study group consisted of 124 Caucasian patients of both sexes. Each patient had a history of ADDwoR no more than 3 months prior. The control group comprised 126 patients with no signs of TMD according to DC/TMD. Genotyping of the selected SNPs was performed by real-time PCR using TaqMan probes. The significance of the differences in the distribution of genotypes was analyzed using Pearson’s chi-square test. Logistic regression modeling was performed to analyze the influence of the 164 investigated SNPs on ADDwoR. The COL5A1 marker rs12722 turned out to be statistically significant (p-value = 0.0119), implying that there is a difference in the frequencies of TMJ ADDwoR. The distribution of rs12722 SNPs in the study group TT(66), CC(27), CT(31) vs. control group TT(45), CC(26), CT(51) indicates that patients with CT had an almost 2.4 times higher likelihood of ADDwoR (OR = 2.41) than those with reference TT (OR = 1), while rs13946 genotypes were shown to be insignificant, with a p-value of 0.1713. The COL5A1 rs12722 polymorphism is a risk factor for ADDwoR in the Polish Caucasian population.

Ultra short time to Echo (UTE) MRI for cephalometric analysis-Potential of an x-ray free fast cephalometric projection technique

OBJECTIVES

A novel magnetic resonance imaging (MRI) scan protocol is presented on the basis of ultra-short time to echo (UTE). By this MRI cephalometric projections (MCPs) can be acquired without the need of post processing in one shot. Different technical parameterizations of the protocol are performed. Their impact on the performance of MCPs is evaluated in comparison to the gold standard-the lateral cephalometric radiography (LCR) for cephalometric analysis (CA) in orthodontics.

METHODS

Seven MCPs with various scan parameters influencing the scan duration and one LCR are used from one subject. 40 expert assessors performed CA for 14 predefined cephalometric landmarks. Relative metric distances and absolute angular measurements were calculated. Statistical analysis is presented and the deviations are highlighted to demonstrate the potential of the method for further analysis.

RESULTS

The MCPs are acquired in 5-154 seconds, depending on resolution and contrast. Mean relative distances were 2.4-2.7 mm in MCPs and 1.6 mm in LCR, which demonstrate the accuracy and level of agreement of the expert assessors in identifying anatomical landmarks. In comparison to other studies, the presented MCP performed similar in angular analysis and demonstrated on average deviation of 1.2° ±1.1° in comparison to LCR. Despite the point articulare (Ar) and the related gonial angle the calculate distances and angles show outcomes in the range of ±2°/2mm.

CONCLUSIONS

MCPs can be acquired much faster in comparison to other techniques known from literature for CA. This study demonstrated the potential of the new method and showed first feasible results. Further research is needed to analyze the performance on a broad range of patients.

Automatic Segmentation of Mandible from Conventional Methods to Deep Learning-A Review

Medical imaging techniques, such as (cone beam) computed tomography and magnetic resonance imaging, have proven to be a valuable component for oral and maxillofacial surgery (OMFS). Accurate segmentation of the mandible from head and neck (H&N) scans is an important step in order to build a personalized 3D digital mandible model for 3D printing and treatment planning of OMFS. Segmented mandible structures are used to effectively visualize the mandible volumes and to evaluate particular mandible properties quantitatively. However, mandible segmentation is always challenging for both clinicians and researchers, due to complex structures and higher attenuation materials, such as teeth (filling) or metal implants that easily lead to high noise and strong artifacts during scanning. Moreover, the size and shape of the mandible vary to a large extent between individuals. Therefore, mandible segmentation is a tedious and time-consuming task and requires adequate training to be performed properly. With the advancement of computer vision approaches, researchers have developed several algorithms to automatically segment the mandible during the last two decades. The objective of this review was to present the available fully (semi)automatic segmentation methods of the mandible published in different scientific articles. This review provides a vivid description of the scientific advancements to clinicians and researchers in this field to help develop novel automatic methods for clinical applications.

The Airway Volume Related to the Maxillo-Mandibular Position Using 3D Analysis

Objective

The aim of this research was to compare three cephalometric analyses and their correlation with the airway volume in subjects with different skeletal classes using 2D and 3D images. Study Design. Cross-sectional descriptive study. Material and Method. Steiner, McNamara, and Ricketts analyses and the airway volume were compared in 115 subjects who were candidates for orthognathic surgery under diagnosis using cone beam computed tomography (CBCT); 46 males (40%) and 69 females (60%) were included. The sagittal positions of the maxilla and mandible, the angulation of the mandibular plane, the sagittal positions of the upper and lower incisors, measurements of the largest or shortest airway area, and the volume were compared using Spearman's test considering a p value < 0.05.

Results

Differences were observed between the Steiner and McNamara techniques for the sagittal position of the maxilla (p = 0.01). For mandibular angulation, there was a greater difference between values for Steiner and Ricketts techniques (p = 0.001). In the upper incisor, the results for McNamara and Ricketts techniques were significantly different (p = 0.004). Analysing the airway, subjects with a class II skeletal pattern had a smaller volume than those with a class III pattern (p = 0.034).

Conclusion

It may be concluded that skeletal class II patients have a significantly smaller airway volume than class III patients. The skeletal parameter does not always relate to the airway volume; however, the high mandibular angle could be related to the airway conditions.