The Role of Imaging in the Diagnosis of Temporomandibular Joint Pathology

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.

Temporomandibular Joint Disorders and Pain Confounders: An Awareness Study

OBJECTIVES

Temporomandibular disorders (TMD) are the most common nonodontogenic cause of orofacial pain, leading to morbidity and impairment. TMD presents a diagnostic challenge due to many aetiologies that exhibit comparable symptoms and refer pain to the temporomandibular joint (TMJ) region. Patients may be referred to dental specialists without accounting for all pain sources. This study aims to identify radiographic confounders (RCs) that can be mistaken for TMD in patients undergoing TMJ assessment using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

A review of 369 CBCT oral maxillofacial radiology reports of the TMJ acquired between July 2020 and June 2023 was completed. Pertinent RCs were classified as endodontic lesions, impacted dentition, sinus pathologies, root fractures, soft tissue calcifications, and others. The chi-squared test assessed the significance of the relationship between RCs and patient variables.

RESULTS

A total of 283 RCs were identified in 202 of the 369 cases (54.7%). The most frequent findings included sinus abnormalities (32.5%), endodontic lesions (15.2%), impacted dentition (12.7%), and elongated/calcified stylohyoid process (9.2%). Significant associations were found between sinus pathologies with TMD signs (P = .009) and gender (P = .001).

CONCLUSION

Our results indicate that RCs that mimic TMD-related symptoms are prevalent in patients referred for TMJ CBCT imaging.

CLINICAL RELEVANCE

Clinicians should be aware of these RCs when diagnosing complaints related to the TMJ. We recommend clinicians first obtain dental clearance and investigate all other potential sources of a patient's complaint before initiating referrals to avoid unnecessary costs and delays in patient care.

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.

Jawbone measurements of edentulous sites related to implant planning using magnetic resonance imaging compared to cone beam computed tomography: An ex vivo study

AIM

To compare measurements on images obtained by magnetic resonance imaging (MRI) and cone beam CT (CBCT) for height, width, and area in alveolar bone sites in human jaw specimens.

MATERIAL AND METHODS

Forty edentulous alveolar posterior sites in human cadaver specimens were imaged using CBCT scanners, and with zero-echo-time MRI (ZTE-MRI). Semi-automatic volume registration was performed to generate representative coronal sections of the sites related to implant planning. ZTE-MRI sections were also presented after grayscale inversion (INV MRI). Three observers measured bone height, bone width 5 mm from the alveolar crest, and bone area stretching from the width measurement to the top of the alveolar crest in the images. Interobserver agreement was assessed by intra-class correlation coefficients (ICC). The measurements were analyzed using two-way repeated measures ANOVA factoring observer and image type.

RESULTS

ICC was >0.95 for bone height, width, and bone area. No significant differences among observers (p = 0.14) or image type (p = 0.60) were found for bone height. For bone width, observer (p = 0.14) was not a significant factor, while ZTE-MRI produced width estimates that were significantly different and systematically smaller than CBCT-based estimates (p ≤ 0.001). Observer (p = 0.06) was not a significant factor regarding the bone area measurements, contrary to the imaging type where ZTE-MRI led to significantly smaller area estimates than CBCT (p ≤ 0.001).

CONCLUSION

Bone height measurements were essentially equivalent using CBCT and MRI. This was found regardless of grayscale choice for the MRI. However, ZTE-MRI resulted in smaller estimates of bone width and area.

Morphological analysis of the temporomandibular joint in patients with anterior disc displacement

This study aims to investigate the morphological characteristics of the temporomandibular joint (TMJ) in the patients with anterior disc displacement with reduction (ADDwR) and the alterations after occlusal splint treatment. Thirty ADDwR patients and ten asymptomatic subjects were recruited. Thirteen parameters were adopted, along with automatic computation and presentation of the joint space to characterize the TMJ morphologies. Statistical results showed that morphological discrepancies between the patients and the asymptomatic subjects were ubiquitous. The adjustment of condyle position through occlusal splint treatment can result in joint spaces widening and has positive effects on mitigating the conditions of ADDwR.

Imaging signs of temporomandibular joint osteoarthritis in an urban population of 65-year-olds: A cone beam computed tomography study

BACKGROUND

Symptoms of osteoarthritis (OA) in the temporomandibular joint (TMJ) may vary and possible causes should be further explored, such as prevalence and characteristics of imaging features.

OBJECTIVES

Investigate prevalence, gender differences and characteristics of imaging signs of TMJ-OA by cone beam computed tomography (CBCT) in a population-based sample of 65-year-old Oslo citizens.

MATERIALS AND METHODS

159 (86 women, 73 men) individuals randomly recruited from a cohort of 460 Oslo citizens were examined with CBCT. The TMJs were categorised as with imaging signs of OA, no OA or indeterminate for OA.

RESULTS

CBCT signs of TMJ-OA were found in 35% of the 159 participants: 47% of the women and 22% of the men. CBCT signs of TMJ-OA were unilateral in two-thirds of the TMJs and characterised by articular surface flattening and condylar osteophytes. In almost all joints with bone erosive findings, bone productive findings were also found. Participants with and without CBCT signs of TMJ-OA showed no significant difference in TMD pain screener. Fourteen of the 159 participants (9%) had pain-related TMD and 12 (8%) had been in contact with health care services due to TMD.

CONCLUSIONS

CBCT signs of TMJ-OA was common in this study group of 65-year-old Oslo citizens, found in every second woman and every fifth man. Articular surface flattening and bone productive changes, in particular condylar osteophytes, were the most frequent imaging features. Despite the high frequency of CBCT signs of TMJ-OA, few of the participants had pain-related TMD.

Bibliometric Analysis of Research on Temporomandibular Joint and Occlusion from 2000 to 2022

Purpose

This study conducted a bibliometric analysis that comprehensively described publications on temporomandibular joint and occlusion from 1 January 2000 to 31 October 2022, aiming to reveal hotspots and predict future research trends.

Methods

A total of 2985 articles and reviews were retrieved from Web of Science Core Collection (WoSCC). Excel 2019, VOSviewer and CiteSpace software were used for visualizing analysis of research trends, authors, journals, institutions, countries, keywords and cited references.

Results

Both the annual publication counts and citation times increased significantly. Wang MQ was the most active author. Moreover, Manfredini D and Okeson JP were the most influential two. Journal of Oral Rehabilitation was the core journal. University of Sao Paulo was the most productive institutions. "Temporomandibular disorders" (TMDs), "temporomandibular joint" and "occlusion" were the top 3 keywords with the most frequencies. Keywords and references with burst showed that the causes of TMDs, diagnosis and treatments for TMDs as well as bruxism may be hotspots currently and in the future.

Conclusion

In this study, the research trends, the most productive and influential authors, journals, institutions, countries, in addition to keywords and cited references with burst in the field of temporomandibular joint and occlusion were revealed by a bibliometric analysis, which could help scholars to understand recent hotspots and future trends.

Artificial intelligence for detecting temporomandibular joint osteoarthritis using radiographic image data: A systematic review and meta-analysis of diagnostic test accuracy

In this review, we assessed the diagnostic efficiency of artificial intelligence (AI) models in detecting temporomandibular joint osteoarthritis (TMJOA) using radiographic imaging data. Based upon the PRISMA guidelines, a systematic review of studies published between January 2010 and January 2023 was conducted using PubMed, Web of Science, Scopus, and Embase. Articles on the accuracy of AI to detect TMJOA or degenerative changes by radiographic imaging were selected. The characteristics and diagnostic information of each article were extracted. The quality of studies was assessed by the QUADAS-2 tool. Pooled data for sensitivity, specificity, and summary receiver operating characteristic curve (SROC) were calculated. Of 513 records identified through a database search, six met the inclusion criteria and were collected. The pooled sensitivity, specificity, and area under the curve (AUC) were 80%, 90%, and 92%, respectively. Substantial heterogeneity between AI models mainly arose from imaging modality, ethnicity, sex, techniques of AI, and sample size. This article confirmed AI models have enormous potential for diagnosing TMJOA automatically through radiographic imaging. Therefore, AI models appear to have enormous potential to diagnose TMJOA automatically using radiographic images. However, further studies are needed to evaluate AI more thoroughly.

Magnetic resonance imaging and fractal analysis findings in temporomandibular joints with disk perforation

OBJECTIVE

This study compared magnetic resonance imaging (MRI) findings and fractal dimension (FD) values in the temporomandibular joints (TMJs) of study patients with disk perforation vs control patients.

STUDY DESIGN

Of 75 TMJs examined with MRI for characteristics of the disk and condyle, 45 were included in the study group and 30 in the control group. MRI findings and FD values were compared for significance of differences between the groups. The frequency of subclassifications was analyzed for differences between the two forms of disk configuration and grades of effusion. Mean FD values were analyzed for differences among subclassifications of MRI findings and between groups.

RESULTS

Examination of MRI variables revealed that the study group had significantly greater frequencies of flattened disks, disk displacement, flattening and combined defects in condylar morphology, and grade 2 effusion (P = .001) Joints with perforated disks had a large percentage of normal disk-condyle relationships (73.3%). Significant differences were discovered between biconcave and flattened disk configuration in the frequencies of internal disk status and condylar morphology. FD values of all patients varied significantly among the subclassifications of disk configuration, internal disk status, and effusion. Mean FD values were significantly lower in the study group with perforated disks (1.07) compared with the control group (1.20, P = .001).

CONCLUSIONS

MRI variables and FD can be useful in investigating intra-articular TMJ status.

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.

Comparison of symptoms, signs, gender, and magnetic resonance images of temporomandibular joint disorder patients

OBJECTIVE

To compare patients' complaints, clinician's examination findings, and magnetic resonance imaging (MRI) findings by considering gender.

METHODS

Temporomandibular joint (TMJ) pain, difficulty in mouth opening, masseter tenderness, deviation, clicking sound, bruxism, restriction, normal occlusion and normal mouth opening symptoms, and findings of temporomandibular disorder (TMD) patients who came to the author's outpatient clinic were recorded. These recordings were compared with MRI.

RESULTS

In the study, symptoms, signs, and MRIs of 276 TMD patients were analyzed, including gender. No difference was observed in terms of symptoms, signs, or MRI results for either gender. MRI findings were correlated with restriction and normal mouth opening in both groups (p < 0.05). Normal MRI findings were observed in 52.5% of the MRI results.

CONCLUSION

Except for normal mouth opening and limitation, MRI findings did not provide a significant result. Therefore, careful detection of symptoms and signs rather than MRI helps in diagnosis.

sEMG and Vibration System Monitoring for Differential Diagnosis in Temporomandibular Joint Disorders

The stomatognathic system represents an important element of human physiology, constituting a part of the digestive, respiratory, and sensory systems. One of the signs of temporomandibular joint disorders (TMD) can be the formation of vibroacoustic and electromyographic (sEMG) phenomena. The aim of the study was to evaluate the effectiveness of temporomandibular joint rehabilitation in patients suffering from locking of the temporomandibular joint (TMJ) articular disc by analysis of vibrations, sEMG registration of masseter muscles, and hypertension of masticatory muscles. In this paper, a new system for the diagnosis of TMD during rehabilitation is proposed, based on the use of vibration and sEMG signals. The operation of the system was illustrated in a case study, a 27-year-old woman with articular dysfunction of the TMJ. The first results of TMD diagnostics using the k-nearest neighbors method are also presented on a group of fifteen people (ten women and five men). Vibroacoustic registration of temporomandibular joints, sEMG registration of masseter muscles, and functional manual analysis of the TMJ were simultaneously assessed before employing splint therapy with stomatognathic physiotherapy. Analysis of vibrations with the monitoring of sEMG in dysfunctions of the TMJ can lead to improve differential diagnosis and can be an objective way of monitoring the rehabilitation process of TMD.

Imaging of the Temporomandibular Joint

Temporomandibular disorder (TMD) is a common musculoskeletal condition that causes pain and disability for patients and imposes a high financial burden on the healthcare system. The most common cause of TMD is internal derangement, mainly secondary to articular disc displacement. Multiple other pathologies such as inflammatory arthritis, infection, and neoplasm can mimic internal derangement. MRI is the modality of choice for evaluation of the TMJ. Radiologists need to be familiar with the normal anatomy and function of the TMJ and MR imaging of the internal derangement and other less common pathologies of the TMJ.

TMJ contrast enhancement in CBCT images using a new algorithm

Magnetic resonance imaging (MRI) is considered the gold standard to reliably diagnose inflammation in the temporomandibular joint (TMJ) of patients with juvenile idiopathic arthritis (JIA). However, even MRI imaging is dependent on the familiarity of the radiologist with the normal appearance of the TMJ; therefore, new approaches are needed. Our purpose here is to improve imaging quality of cone beam computed tomography (CBCT) as a tool to help in the diagnosis of JIA in the TMJ. We have designed and applied a filter (the Stacking Enhancement Filter) over a stock of CBCT images from the TMJs of two patients with JIA. We then made a visual comparison of the results with archival images from MRI of the same patients, to show that the filter substantially improves the visual quality of the image. The work on the image contrast and the increase of the difference of appearance between tissues of different densities (all the anatomical structures that are present within the joint) leads to an improvement of the resulting images of the TMJ without the use of a chemical contrast agent. We conclude that CBCT could be used as a filter tool for the analysis of the TMJs affected by arthritis. Our image processing technique yields images that possible improve the range of use of CBCT.

Relationship between Clinical Symptoms and Magnetic Resonance Imaging in Temporomandibular Disorder (TMD) Patients Utilizing the Piper MRI Diagnostic System

Clinical problems of the temporomandibular joint (TMJ) and the masticatory musculature are both included in the term temporomandibular disorder (TMD). The purpose of the present study was to examine the pathology of the joints of patients diagnosed with TMD utilizing the dedicated Piper MRI-based classification, and to link these pathologies with various symptoms while considering their severity. In total, 64 patients with clinical TMD were examined. Symptoms were recorded using a questionnaire. The clinical examination included diagnosing the occlusion in centric relation, which was followed by a standardized MRI. It was confirmed that, although they occurred in a high percentage in all classes, muscle pain and occlusal interference are not indicators of TMJ damage. The results indicate that the progressive degradation of the TMJ, represented by qualification to the higher Piper classes, is associated with an increase in TMJ pain only up to a certain stage. For the highest Piper classes, the joint pain occurs in a smaller percentage of patients, but sounds are more frequent.

Exploration of MRI T2 Mapping Image Application in Articular Disc Displacement of the Temporomandibular Joint in Adolescents

Purpose

To explore the application of magnetic resonance imaging (MRI) T2 mapping technique in clinical practice through morphological and quantitative analysis of T2 mapping sequences in adolescents with temporomandibular disorders (TMDs) and control groups comprising healthy participants.

Patients and Methods

A total of 45 and 63 patients, who had articular disc displacement with and without reduction, respectively, were assigned to the experimental groups, and 57 participants with normal articular discs of the temporomandibular joint were considered as the control group. All participants in the three groups underwent MRI. T2 mapping was performed in the oblique sagittal plane. The regions of interest (ROIs) for the T2 relaxation time maps of the disc were selected manually. The performance of morphological and structural changes and quantitative parameters in MRI T2 mapping image artifacts were statistically compared.

Results

In the control group, the mean T2 value was 39.284 ±5.634 ms, in the group of disc displacement with reduction, the mean T2 value was 33.634 ±4.235 ms, and in the group of disc displacement without reduction, the mean T2 value was 30.982 ±3.205 ms. The T2 mapping values of the experimental groups, together with different morphological structures, were significantly lower than were those of the control group.

Conclusion

MRI T2 mapping enables a more accurate evaluation of TMD severity. Sequentially, it helps provide a more reliable medical imaging basis for classifying diagnosis and evaluation in clinical practice.

Histopathology of the temporomandibular joint disc: Findings in 30 samples from joints with degenerative disease

Aim

The aim of this study is to show the anatomical and histological features of the displaced temporomandibular joint (TMJ) disc in joints with degenerative disease.

Methods

This study was performed on a total of 30 TMJ discs extracted from 22 patients, who underwent surgical discectomy after failure of conservative non‐surgical treatment regimens to control pain and/or limited range of motion. All joints had imaging signs of an anteriorized disc position and degenerative joint disease. Samples of the extracted discs were stored in formalin, cut into 3 micron‐thick sections imbedded in paraffin and processed with hematoxylin‐eosin.

Result

All the samples present irreversible morphologic and histological alterations. The macroscopical evaluation showed that 14 discs were worn and fragmented in several parts, and one disc was perforated. Morphological alterations with deformation and degenerative signs were shown in all discs, which were all severely worn and compromised. Histologically, various alterations were found, such as pre‐fibrous sclerosis with myxoid degeneration and collagen deposits (N = 25), an increase in fibro‐hyaline and fibrous tissues, with loss of elasticity (N = 25), scattered calcifications (N = 15), and synovial inflammation with microvascular proliferation and increased cellularity, presence of lymphocytes, histiocytes and plasma cells (N = 18). After the intervention, all patients reported decreased pain levels and showed improved function at 6 months.

Conclusion

These observations suggest that degenerative joint disease is accompanied by a anteriorized discs featuring abnormal macroscopical and histological changes. From a clinical viewpoint, this may suggest that, when treatment escalation leads to consider TMJ surgery, total discectomy is the most reasonable approach.

Correlation between MRI-diagnosed joint effusion and demographic, clinical, imaging, and arthroscopic findings of the temporomandibular joint

Our study aimed to evaluate the diagnostic accuracy of MRI in cases of joint effusion and documented its relationship with clinical and arthroscopic findings. A cross-sectional study was carried out, using the following selection criteria: clinical, radiological, and MRI-based diagnosis of joint pathology; joint pain; and indication for minimally invasive management with arthroscopy. Arthroscopic analysis, included synovitis, adhesions, chondromalacia, and disc perforations. These variables were recorded and compared with MRI findings of effusion. Data were analyzed using chi-square and Fisher's exact tests. In total, 44 temporomandibular joints were studied, of which 38 corresponded to women; 21 cases were diagnosed as Wilkes IV-V, with effusion found in all of them. The presence of effusion was significantly related to synovitis (p = 0.031) and adherences (p = 0.042). Pain was significantly related to the presence of effusion (p = 0.002), Wilkes advanced stages (p = 0.006), synovitis (p = 0.031), and adherences (p = 0.004). Regarding maximum mouth opening, there was no significant correlation with the variables studied, aside from gender and Wilkes classification. There was a significant correlation between the presence of joint effusion detected by MRI and clinical and arthroscopic findings. This suggests that effusion diagnosed by magnetic resonance has a significant value. Therefore, an adequate presurgical examination should be considered before submitting the patient to an invasive diagnostic procedure.

Radiographic Interpretation in Oral Medicine and Hospital Dental Practice

Oral medicine practice includes the diagnosis and nonsurgical treatment of oral and orofacial diseases and oral manifestations of systemic conditions. Oral medicine specialists in medical and dental settings often require imaging in assessment and treatment of these conditions. This article reviews imaging that may be used in practice, particularly as relevant for facial pain, bone conditions, and salivary gland disease. It reviews imaging that may be considered in a hospital setting for assessment of admitted patients, patient evaluation before surgical procedures, and provision of dentistry in a hospital setting for patients who cannot submit to treatment in an outpatient setting.

Microenvironment in subchondral bone: predominant regulator for the treatment of osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease in the elderly. Although OA has been considered as primarily a disease of the articular cartilage, the participation of subchondral bone in the pathogenesis of OA has attracted increasing attention. This review summarises the microstructural and histopathological changes in subchondral bone during OA progression that are due, at the cellular level, to changes in the interactions among osteocytes, osteoblasts, osteoclasts (OCs), endothelial cells and sensory neurons. Therefore, we focus on how pathological cellular interactions in the subchondral bone microenvironment promote subchondral bone destruction at different stages of OA progression. In addition, the limited amount of research on the communication between OCs in subchondral bone and chondrocytes (CCs) in articular cartilage during OA progression is reviewed. We propose the concept of 'OC-CC crosstalk' and describe the various pathways by which the two cell types might interact. Based on the 'OC-CC crosstalk', we elaborate potential therapeutic strategies for the treatment of OA, including restoring abnormal subchondral bone remodelling and blocking the bridge-subchondral type H vessels. Finally, the review summarises the current understanding of how the subchondral bone microenvironment is related to OA pain and describes potential interventions to reduce OA pain by targeting the subchondral bone microenvironment.

Recent advances on TMDCs for medical diagnosis

Transition metal dichalcogenides (TMDCs), such as MoS₂ and WS₂, have attracted much attention in biosensing and bioimaging due to its excellent stability, biocompatibility, high specific surface area, and wide varieties. In this review, we overviewed the application of TMDCs in biosensing and bioimaging. Firstly, the synthesis methods and surface functionalization methods of TMDCs were summarized. Secondly, according to the working mechanism, we classified and gave a detailed account of the latest research progress of TMDC-based biosensing for the detection of the enzyme, DNA, and other biological molecules. Then, we outlined the recent progress of applying TMDCs in bio-imaging, including fluorescence, X-ray computed tomographic, magnetic response imaging, photographic and multimodal imaging, respectively. Finally, we discussed the future challenges and development direction of the application of TMDCs in medical diagnosis. Also, we put forward our view on the opportunity of TMDCs in the big data of modern medical diagnosis.

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.

The importance of multisection sagittal and coronal magnetic resonance imaging evaluation in the assessment of temporomandibular joint disc position

OBJECTIVES

The aim of this study was to evaluate diagnoses of temporomandibular (TMJ) disc displacement by comparing evaluations done on the basis of central sagittal scans only, the most often used in temporomandibular disorder (TMD) patients, with a multisection evaluation done with both sagittal and coronal scans.

MATERIALS AND METHODS

Multisection MRI analysis of 382 TMJs was conducted in 191 patients with disc displacement according to RDC/TMD criteria. Disc position in the intercuspal position (IP) was assessed two times using two different methods. The first method involved a TMJ disc position evaluation on the central slide in the oblique sagittal plane only. In the second method, the TMJ disc position was assessed on all oblique sagittal and coronal images. McNemar's χ² test was used to evaluate the differences between the sensitivities of two methods.

RESULTS

The first method (central oblique sagittal scans assessment) identified 148 TMJs (38.7%) with normal disc position compared with 89 TMJs (23.3%) with normal disc position found by the second method (all oblique sagittal and coronal scans assessment). The sensitivity of analysis in both planes was significantly higher than in the sagittal plane only (p < 0.001).

CONCLUSIONS

The multisection analysis in the sagittal and coronal plane allows to distinguish the correct disc position from disc displacement and thus improve evaluation of TMJ internal derangement.

CLINICAL RELEVANCE

The multisection sagittal and coronal images should be recommended as a standard in MRI of the TMJ disc displacement in patients with TMD to avoid false-negative diagnoses.

Improvement of bone-erosive temporomandibular joint (TMJ) abnormalities in adolescents undergoing non-surgical treatment: a longitudinal study

OBJECTIVES

To investigate the longitudinal changes of the imaging temporomandibular joint (TMJ) characteristics in young patients with TMJ-related symptoms and treated with non-surgical methods. The severity of self-reported symptoms at follow-up was also investigated.

METHODS

A cone beam CT (CBCT)/CT follow-up examination [median follow-up 4.1 (1.3-6.4) years] was performed in 22 patients with erosive TMJ abnormalities [baseline median age 16 (12-18) years]. Imaging characteristics were analyzed and the changes between the examinations were categorized as (A) improvement, (B) no change, or (C) worsening. Severity of follow-up symptoms was evaluated using Jaw Functional Limitation Scale (JFLS-8) and Graded Chronic Pain Scale (Grade 0-IV). Analyses were performed separately for left and right TMJ. Findings at baseline and follow-up were compared using McNemar test to account for dependencies. Changes in proportions of hard tissue findings between examinations were assessed using Wilcoxon signed ranks test.

RESULTS

A significant reduction in the proportion of patients with erosive abnormalities was found [59.1%, 95% CI (36.4-79.3) %]. Baseline erosions improved in 9/12 (75%) right and 14/15 (93%) left TMJs. About half repaired; developed an intact cortical outline. Number of joints with osteophytes increased (right: p < 0.04, left: p < 0.003). New osteophytes were mostly found in joints with erosive findings. Low or no limitation of jaw function (Jaw Functional Limitation Scale) was found in 12/22 (55%) and no or low intensity of pain (Graded Chronic Pain Scale Grade 0 or I) in 19/22 (86%) at follow-up.

CONCLUSION

We found a high potential for repair of erosive TMJ abnormalities. However, the patient series was small. The majority of patients assessed their symptom severity at follow-up as low.

Incidental findings in a consecutive series of digital panoramic radiographs

Purpose

The aim of this study was to determine the prevalence of incidental findings (IFs) on digital dental panoramic radiographs (DPRs) of asymptomatic patients attending a general dental practice.

Materials and Methods

This was a retrospective study of 6,252 consecutive digital (photostimulatable phosphor) DPRs of patients who visited a Canadian general dental practice for a complete new patient examination. The IFs were grouped into dental-related anomalies, radiopacities and radiopacities in the jaws, changes in the shape of the condyles, and other findings in the jaws, such as tonsilloliths and mucosal antral pseudocysts. Their prevalence was determined.

Results

Thirty-two percent of the DPRs showed at least 1 IF. The highest prevalence was found for dental-related anomalies (29% of all DPRs), of which impacted teeth were the most prevalent finding (24% of all DPRs), followed by idiopathic osteosclerosis (6% of all DPRs). A lower prevalence was noted for tonsilloliths (3%), and the prevalence of root tips, mucosal antral pseudocysts, and anomalies in condylar shape was approximately 1% each.

Conclusion

The observed prevalence of 32.1% for IFs of any type underscores the need for a dental practitioner to review the entire DPR when a patient presents for an initial dental examination (or check-up) or for dental hygiene. Only a single IF (a central giant cell granuloma) provoked alarm, as it was initially considered malignant. Similarly, impacted teeth and suspected cysts need careful evaluation upon discovery to determine how they may be optimally managed.

Shear Wave Elastography in the Evaluation of Temporomandibular Joint Disorders

We aimed at verifying the usefulness of shear wave elastography in determining the temporomandibular disc stiffness in patients with a temporomandibular disorders (TMDs). The study included 37 patients with confirmed TMDs and 208 healthy volunteers. Patients presented with significantly greater stiffness of the intermediate zone of the disc (region of interest [ROI] 1) and significantly lower stiffness of its anteriorly displaced portion (ROI 3). A receiver operating characteristics analysis indicated that a decrease in the stiffness in ROI 3 less than 8.667 KPa provided 100% sensitivity, 97.3% specificity, 100% positive predictive value (PPV) and 99.5% negative predictive value (NPV) in distinguishing between patients with TMDs and without. Whereas an increase in ROI 1 stiffness to at least 54.33 KPa provided high specificity and NPV, both the sensitivity and the PPV of this predictor equaled zero. Findings suggest that a decrease in anteriorly dislocated disc stiffness less than 8.667 kPa can accurately identify patients with TMDs.

Standardizing the Clinical Orofacial Examination in Juvenile Idiopathic Arthritis: An Interdisciplinary, Consensus-based, Short Screening Protocol

OBJECTIVE

To develop a consensus-based, standardized, short (< 3 min) clinical examination protocol to assess the multidimensional, orofacial manifestations of juvenile idiopathic arthritis (JIA).

METHODS

The study was conducted by a multidisciplinary task force from the Temporomandibular Joint Juvenile Arthritis Working Group (TMJaw). The study used an acknowledged sequential approach involving (1) a global multidisciplinary online questionnaire study, (2) a systematic literature review and consensus meetings to identify items for inclusion, (3) pilot testing of included items, (4) test of reliability in 22 subjects with JIA by 4 examiners, (5) test of construct validity in a case-control study involving 167 subjects, and (6) establishment of final recommendations.

RESULTS

Six items were recommended for the final examination protocol: (1) clinician-assessed pain location, (2) temporomandibular (TMJ) joint pain on palpation (open and closed mouth), (3) mandibular deviation at maximal mouth opening (≥ 3 mm), (4) maximal unassisted mouth opening capacity, (5) frontal facial symmetry, and (6) facial profile. All recommended items showed acceptable reliability and construct validity. The average mean examination time was 2 min and 42 s (SD ± 38.5 s).

CONCLUSION

A consensus-based, short clinical examination protocol was developed. The protocol takes less than 3 min to complete and provides information about orofacial symptoms, TMJ dysfunction, and dentofacial deformity. The standardized examination protocol is applicable to routine clinical care, as well as future research studies.

Effect of arthrocentesis on the clinical outcome of various treatment methods for temporomandibular joint disorders

Background

We evaluated the improvement of pain and the increase in mouth opening after temporomandibular joint arthrocentesis and the possible association with various factors such as previous splint treatment, medication, and diagnosis.

Results

We studied 57 temporomandibular joint disorder patients who underwent arthrocentesis at Korea University Anam Hospital. These patients (24 males and 33 females, aged between 15 and 76 years) underwent arthrocentesis that was performed by one surgeon. The degree of mouth opening (assessed using the maximum mouth opening: MMO) and pain (assessed using the visual analog scale: VAS) were assessed pre- and post-arthrocentesis. The study also investigated whether treatment modalities other than arthrocentesis (medication and appliance therapy) were performed. Statistical analysis revealed that there was a significant difference in mouth opening and pain after temporomandibular joint arthrocentesis. Preoperative appliance therapy affected the results of arthrocentesis, but it was not statistically significant. With regard to pain relief, preoperative diagnosis did not show a significant difference. However, with regard to maximum mouth opening, patients with disc displacement without reduction with limited mouth opening (closed lock) showed the highest recovery (11.13 mm).

Conclusion

The average of MMO increase after arthrocentesis was 9.10 mm, and patients with disc displacement without reduction with locking (closed lock) showed most recovery in maximum mouth opening and it was statistically significant. The average pain relief of patients after arthrocentesis was 3.03 in the VAS scale, and patients using anterior repositioning splint (ARS) preoperatively showed the most pain relief.

Early growth response 1 reduction in peripheral blood involving condylar subchondral bone loss

OBJECTIVES

To detect whether early growth response 1 (EGR1) in peripheral blood leucocytes (PBLs) indicates temporomandibular joint (TMJ) osteoarthritis (OA) lesions.

MATERIALS AND METHODS

Egr1 mRNA expression levels in PBLs were detected in eight malocclusion patients without temporomandibular disorder (TMD) signs and 16 malocclusion patients with clinical TMD signs with (eight) or without (eight) imaging signs of TMJ OA. Twelve 6-week-old rats were randomized to a control group and a unilateral anterior crossbite (UAC) group and were sampled at 4 weeks. The Egr1 mRNA expression levels in PBLs and protein expression levels in different orofacial tissues were measured.

RESULTS

Patients with TMD signs with/without TMJ OA diagnosis showed lower Egr1 mRNA expression levels in PBLs than patients without TMD signs. The lower Egr1 mRNA expression was also found in the PBLs of UAC rats, which were induced to exhibit early histo-morphological signs of TMJ OA lesions. In subchondral bone of UAC rats, EGR1 protein expression was decreased, co-localization of EGR1 with osterix or dentin matrix protein-1 was identified, and the number of EGR1 and osterix double-positive cells was reduced (all p < .05).

CONCLUSION

Egr1 reduction in PBLs potentially indicates subchondral bone OA lesions at an early stage.

CBCT characteristics and interpretation challenges of temporomandibular joint osteoarthritis in a hand osteoarthritis cohort

OBJECTIVES

To characterise osteoarthritis (OA) in the temporomandibular joints (TMJs) by means of cone beam CT in a hand OA population, and identify interpretation challenges.

METHODS

The TMJs of 54 individuals (mean age 71.3) recruited from the "The Oslo hand OA cohort", independently of TMJ-related symptoms, were examined with cone beam CT (ProMax MidCBCT). Images were analysed for bone change characteristics and each joint was diagnosed with either OA, no OA or as indeterminate for OA. The image analysis criteria developed for the Research Diagnostic Criteria for Temporomandibular Disorders were used. Frequencies of bone changes, joint diagnoses and severity grades (1-2) were calculated, as well as κ values for observer agreement.

RESULTS

In the OA joints, the most frequent bone changes occurred in the condyle: flattening (79%), osteophyte (72%) and subcortical sclerosis (70%). The most frequent changes in the fossa/eminence were flattening (57%), erosion (49%) and subcortical sclerosis (47%). 53 (49%) of the 108 joints were diagnosed with TMJ OA (68 % Grade 2), 29 joints (27%) with no OA, and 26 joints (24%) were indeterminate for OA. Inter- and intraobserver agreement showed mean κ values of 0.67 and 0.62, respectively.

CONCLUSIONS

TMJ changes were common in elderly with hand OA and characterised by bone productive changes. The radiologic features indicated a late stage TMJ OA. Interpretation challenges related to subtle changes were identified and are reflected by the rather low observer agreement. The diagnosis of TMJ OA should be based on evident and clear abnormalities only.