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Objectives: This study aimed to examine the relationship between computed tomography (CT) values of the condylar surface in the coronal plane, condylar morphology and the disc positions in the temporomandibular joint (TMJs) in patients with deformities before and after orthognathic surgery.  MATERIALS AND METHODS: The maximum CT values (pixel values) on the condylar surface, condylar thickness, condylar width, condylar angle, condylar height, and joint space were measured. TMJ disc position was classified into five types (anterior type, fully covered type, posterior type, anterior disc displacement with [AW] and without reduction [AWO]), using magnetic resonance imaging (MRI), before and 1 year after surgery. Statistical analysis was performed to assess differences between groups and between the pre- and postoperative values.  RESULTS: We enrolled 142 TMJs from 71 female patients diagnosed with jaw deformities. Disc position classification did not change after surgery in all TMJ. Significant differences were observed between anterior displacement (AW and AWO) and other types (fully covered type and posterior type) in the lateral CT value and condylar angle before and 1 year after surgery (P < 0.05).  CONCLUSIONS: This study demonstrated a strong relationship between condylar surface CT values in the coronal plane and condylar angle with TMJ disc position classification., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethics approval: This retrospective cohort study was performed in accordance with the Declaration of Helsinki and was approved by the Ethical Committee of the University of Yamanashi. Receipt number 1125, November/20/2013. Consent to participate: Informed consent was obtained from all individual participants included in the study. Consent to publish: The authors affirm that the human research participants provided informed consent for the publication of the images in Figures., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Chondroitin and glucosamine sulphates (CGS) are considered structure-modifying drugs and have been studied in the prevention, delay or reversal of structural morphological changes in joints caused by osteoarthritis., Objective: The aim of the present study was to investigate the action of CGS on the progression of chemically induced osteoarthritis in the temporomandibular joint (TMJ) of rabbits by evaluating the serum levels of tumour necrosis factor (TNF-α) and collagen in the articular discs., Materials and Methods: A sample of 36 male rabbits was divided into three groups: control (CG), osteoarthritis (OG) and treatment (TG). The disease was induced by intra-articular injection of sodium monoiodoacetate (10 mg/mL) in the OG and TG groups bilaterally. After 10 days, the TG animals received subcutaneous injection of chondroitin sulphates and glucosamine (7.5 mg/kg) and the OG and CG received saline solution (50 μL). Euthanasia times were subdivided into 40 and 100 days. Collagen quantification was performed by biochemical and histological analysis and for the quantification of serum levels of TNF-α, an enzyme immunoassay was used., Results: The TG showed an increase in the collagen area of the articular disc when compared to the CG and the OG. The increase collagen concentration in the discs did not show a statistically significant difference between the groups. Post-treatment TNF-α levels were significantly lower in TG compared to OG., Conclusions: The results indicate that CGS treatment delayed the degeneration of the collagen in the TMJ articular disc and reduced serum TNF-α levels, indicating a preventive effect on OA progression., (© 2024 John Wiley & Sons Ltd.)

Objective: Anterior disc displacement (ADD) has been used to establish temporomandibular joint disorder (TMD) models. Based on whether preserve of the retrodiscal attachment, the modelling methodologies include ADD with dissecting the retrodiscal attachment (ADDwd) and ADD without dissecting the retrodiscal attachment (ADDwod). This article aims to determine which model better matches the micromechanical and microstructural progression of TMD., Methods: Through meticulous microscopic observations, the microstructure and micromechanical deformation of the TMJ discs in ADDwd and ADDwod rabbit models were compared at 2 and 20 weeks., Result: Scanning electron microscopy and transmission electron microscopy showed that collagen fibres became slenderized and straightened, collagen fibrils lost diameter and arrangement in the ADDwd group at 2 weeks. Meanwhile, nanoindentation and atomic electron microscopy showed that the micro- and nano- mechanical properties decreased dramatically. However, the ADDwod group exhibited no significant microstructure and micromechanical deformations at 2 weeks. Dissection of the retrodiscal attachment contribute in the acceleration of disease progression at the early stage, the devastating discal phenotype remained fundamentally the same within the two models at 20 weeks., Conclusion: ADDwod models, induced stable and persistent disc deformation, therefore, can better match the progression of TMD. While ADDwd models can be considered for experiments which aim to obtain advanced phenotype in a short time., (© 2024 John Wiley & Sons Ltd.)

Objective: To assess the association between three-dimensional inclination of the osseous structures of temporomandibular joints (TMJ) and the risk of disc displacement (DD)., Methods: The 120 TMJs of 60 patients were evaluated. According to magnetic resonance images, disc position was classified as normal, anterior DD with reduction (ADDWR) and without reduction (ADDWoR) and as normal, medial DD (MDD), and lateral DD (LDD) on the sagittal and coronal views, respectively. Condyle and eminence inclinations were measured using cone beam computed tomography., Results: Smaller horizontal condylar inclination was associated with ADDWoR ( p < 0.05). Larger coronal condylar inclination was associated with ADDWR ( p < 0.05) and LDD ( p < 0.05). There was no association between sagittal eminence inclination and DD ( p < 0.05)., Conclusion: Medial condylar rotation in the axial view may be associated with ADDWoR. The condyle head horizontally inclined in the coronal view may be associated with ADDWR and LDD.

Objective: To observe the dynamic changes of the temporomandibular joint (TMJ) disc in joint movement under different Angle's classification, providing reference for understanding joint functional movement and providing a basis for more accurate clinical imaging diagnosis. Methods: A total of 30 patients (13 males and 17 females) with temporomandibular disorders who were admitted to Beijing Friendship Hospital, Capital Medical University and General Hospital of the People's Liberation Army from January 2022 to April 2024 were enrolled. Thirty adults (13 males and 17 females) with different Angle's classification, with an average age of (34.4±8.5) years, were subjected to dynamic imaging of their TMJ from the closed position to the maximum opening position, and then to the closed position using MRI. The position and morphological changes of the articular discs were observed. Results: The results showed that volunteers with no displacement of the articular disc in class Ⅰ, Ⅱ, and Ⅲ relationships had different shapes of the articular disc during open and closed mouth movements. However, in the maximum opening position, the articular disc were all located directly below the maxillary nodules, and their shape is double concave. In terms of irreversible anterior displacement of the articular disc, in class Ⅰ Angle, the posterior zone of the disc contacts the anterior inclined plane of condyle from the maximum opening position back to the front of the closing position. In class Ⅱ, the posterior zone of the disc contacts the anterior inclined plane of condyle from the beginning of opening position to maximum opening position. In class Ⅲ, the posterior zone of the disc is always in contact with the anterior inclined plane of condyle throughout the entire movement process. And among them, the articular disc presents a forward displacement state at the closing position, its morphology undergoes folding phenomenon. When the openness is 2.5 cm, the articular disc moves up to a certain extent, and is closer to the anterior inclined plane of condyle, and its shape is also partially changed. When the openness is 4.3 cm, the shape of the articular disc, located between the anterior inclined plane of the joint node and the posterior inclined plane of the condyle, is typical double concave, which is sufficient to show that the articular disc is reversible when maximum opening position is reached. In terms of reversible anterior disc displacement, in class Ⅰ Angle, the posterior zone of the disc contact with the anterior inclined plane of condyle at the beginning of the opening position and the end of the closing position. In classⅡ Angle, the posterior zone of the articular disc is not in contact with the anterior inclined plane of condyle. In class Ⅲ Angle, the posterior zone of the articular disc contact with the anterior inclined plane of condyle at the end of the closing position. Conclusions: Multi level dynamic MR imaging data of the temporomandibular joint can dynamically observe the movement of the temporomandibular joint, intuitively and accurately display the position and shape of the articular disc during movement, and can serve as a useful supplement to static conventional MR imaging of the TMJ. The patient's TMJ needs to reach the maximum opening position in order to determine whether the joint disc displacement can be reversible or not.

Objective: Anterior disc displacement (ADD) is a common clinical issue and may cause osteoarthritis (OA). However, the research of protein changes in synovial fluid as disease development marker and potential treatment clue is still insufficient., Materials and Methods: We conducted the high-resolution mass spectrometry (MS) of synovial fluid collected from 60 patients with normal disk position to ADD and ADD with osteoarthritis (OA). The proteins with significant changes among the 3 groups were analyzed by biological information and further validated by in primary rat condyle chondrocytes and OA animal model., Results: FGL2, THBS4, TNC, FN1, OMD etc. were significantly increased in ADD without OA (p < 0.05), which reflected the active extracellular matrix and collagen metabolism. FGFR1, FBLN2, GRB2 etc. were significantly increased in ADD with OA group (p < 0.05), which revealed an association with apoptosis and ferroptosis. Proteins such as P4HB, CBLN4, FHL1, VIM continuously increase in the whole disease progress (p < 0.05). Both the in vitro and in vivo results are consistent with protein changes detected in MS profile., Conclusion: This study firstly provides the expression changes of proteins from normal disc condyle relationship toward ADD with OA, which can be selected and studied further as disease progress marker and potential treatment targets., (© 2024 Wiley Periodicals LLC.)

Objectives: This study aimed to propose a new method for the automatic diagnosis of anterior disc displacement of the temporomandibular joint (TMJ) using MRI and deep learning. By using a multistage approach, the factors affecting the final result can be easily identified and improved., Methods: This study introduces a multistage automatic diagnostic technique using deep learning. This process involves segmenting the target from MR images, extracting distance parameters, and classifying the diagnosis into 3 classes. MRI exams of 368 TMJs from 204 patients were evaluated for anterior disc displacement. In the first stage, 5 algorithms were used for the semantic segmentation of the disc and condyle. In the second stage, 54 distance parameters were extracted from the segments. In the third stage, a rule-based decision model was developed to link the parameters with the expert diagnosis results., Results: In the first stage, DeepLabV3+ showed the best result (95% Hausdorff distance, Dice coefficient, and sensitivity of 6.47 ± 7.22, 0.84 ± 0.07, and 0.84 ± 0.09, respectively). This study used the original MRI exams as input without preprocessing and showed high segmentation performance compared with that of previous studies. In the third stage, the combination of SegNet and a random forest model yielded an accuracy of 0.89 ± 0.06., Conclusions: An algorithm was developed to automatically diagnose TMJ-anterior disc displacement using MRI. Through a multistage approach, this algorithm facilitated the improvement of results and demonstrated high accuracy from more complex inputs. Furthermore, existing radiological knowledge was applied and validated., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology and the International Association of Dentomaxillofacial Radiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Temporomandibular joint (TMJ) disorder (TMD) is a chronic progressive disease that is commonly seen in clinical settings. TMJ disc degeneration is an important manifestation of TMD, and further aggravates the progression of TMD. However, treatments on TMJ disc degeneration are very limited till now. In this study, we first observed the effects of bone marrow stem cells (BMSC) conditioned medium on functions of TMJ disc fibroblasts. Then BMSC-derived small extracellular vesicles (BMSC-EVs) were isolated and exposed to TMJ disc fibroblasts. RNA-sequencing was used to further investigate the mechanisms. BMSC-EVs were finally injected into a rat model with TMD. Results showed that in the transwell co-culture system, the medium derived from BMSC reduced inflammation and enhanced chondrogenesis in TMJ disc fibroblasts. BMSC-EVs promoted proliferation, migration, and chondrogenic differentiation of TMJ disc fibroblasts, and inhibited apoptosis and inflammatory responses. Local injection of BMSC-EVs into the TMD model alleviated TMJ disc degeneration. Therefore, BMSC-EVs were a potentially effective, sustainable and clinically translational-promising option for TMJ disc degeneration, and further reduce the progression of TMD., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: Temporomandibular disorders (TMD) may include conditions involving the temporomandibular joint and/or masticatory muscles. Approximately 20 % of patients are refractory to first-line therapies. This study aims to evaluate the effects and safety of incobotulinumtoxinA in the treatment of refractory TMD due to disk dislocation., Material and Methods: A quasi-experimental one-arm prospective study was conducted. Target population included individuals with a diagnosis of TMD due to disk dislocation. Patients were treated with electromyography or ultrasound guided injection of incobotulinumtoxinA in the masticatory muscles (20 U into each masseter and pterygoideus lateralis). Pain was assessed using the pain numerical rating scale, maximum unassisted mouth opening was measured in mm, and adverse events were registered at baseline, week 4, week 12 and week 24 post-treatment. Statistical analysis used the Wilcoxon test for the comparison of paired samples and the Mann-Whitney U test for independent samples, considering a p-value ≤ 0.05 as significant., Results: 51 patients with 75 painful temporomandibular joints due to disk dislocation (38 with reduction and 37 without) were included. A significant reduction in pain from a pre-treatment mean of 6.08/10 to a post-treatment mean of 2.04/10 (week 4), 3.18/10 (week 12), and 3.65/10 (week 24) was observed (p < 0.001). A significant decrease in maximum unassisted mouth opening from a pre-treatment mean of 36.45 mm to a post-treatment mean of 32.29 mm at week 4 was observed (p < 0.001)., Discussion: Botulinum toxin injection of the masticatory muscles is safe and seems equally effective in reducing pain in patients with refractory TMD due to disk dislocation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Objectives: Extracellular matrix components play a significant role in maintaining tissue integrity and pathological processes of the temporomandibular joint (TMJ). This study aimed to evaluate the influence of a soft diet on the mRNA expression of proteoglycans and glycosaminoglycans (GAGs) linked to proteoglycan core proteins in rat TMJ discs., Methods: Thirty 4-week-old male Wistar rats were assigned to one of two groups: a control group fed a regular pellet diet and a soft diet group fed a powdered diet for 4 weeks. The mRNA expression levels of 12 proteoglycans in TMJ discs were evaluated using real-time polymerase chain reaction (PCR). In addition, histomorphometric and biochemical analyses were performed to evaluate the thickness and deoxyribonucleic acid (DNA), GAG, and water content of the TMJ discs., Results: The TMJ disc thickness in the anterior, intermediate, and posterior bands decreased significantly in the soft diet group. The GAG content decreased significantly in the soft-diet group, whereas no significant differences in DNA content or water content ratio were observed between the groups. Real-time PCR indicated that the expression levels of aggrecan, versican, biglycan, decorin, fibromodulin, lumican, and chondroadherin decreased in the soft diet group. The expression levels of all versican isoforms decreased in the soft diet group., Conclusions: These results indicate that the biomechanical environment of the TMJ caused by a soft diet is closely related to the expression of proteoglycans in TMJ discs, which may eventually increase the fragility of the TMJ discs., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest related to this study., (Copyright © 2024 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.)

Objectives: This study aimed to verify the accuracy of clinical protocols for the diagnosis of disc displacement (DD) compared with MRI, considering examiners' calibration., Methods: PubMed, Cochrane (Central), Scopus, Web of Science, LILACS, Embase, Science Direct, Google Scholar, and DANS EASY Archive databases were searched. Two reviewers independently screened and selected the studies. A meta-analysis was conducted using the R Statistical software. Results are shown using sensitivity and specificity, and 95% confidence intervals., Results: Of the 20 studies included in the systematic review, only three were classified as low risk of bias. Seventeen studies were included in the meta-analysis. Compared to MRI, clinical protocols showed overall sensitivity and specificity of 0.75 (0.63-0.83) and 0.73 (0.59-0.84) for DD diagnosis, respectively. For DD with reduction, sensitivity was 0.64 (0.48-0.77) and specificity was 0.72 (0.48-0.87). For DD without reduction, sensitivity was 0.58 (0.39-0.74) and specificity 0.93 (0.83-0.97). Only 8 studies reported examiner calibration when performing clinical and/or MRI evaluation; nevertheless, calibration showed a tendency to improve the diagnosis of DD., Conclusion: The sensitivity and specificity of clinical protocols in the diagnosis of DD are slightly below the recommended values, as well as the studies lack calibration of clinical and MRI examiners. Examiner calibration seems to improve the diagnosis of DD., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology and the International Association of Dentomaxillofacial Radiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: The authors retrospectively studied the relationship between the morphology and position of the articular disc in magnetic resonance imaging (MRI) and the morphology and position of the condyle in cone beam computed tomography (CBCT), with the purpose for providing reference for clinical diagnosis and treatment of temporomandibular disorders (TMD)., Methods: Patients with both CBCT and MRI imaging data were studied retrospectively, excluding TMJ tumour, fracture, severe condylar morphological abnormalities, non-intercuspal position, and poor quality images. A total of 744 temporomandibular joints (TMJs) from 372 patients were included, with the mean age of 25.94±11.04Y (75 males and 297 females). T2-weighted image (T2WI) of MRI imagings were used to evaluate disc morphology and disc displacement, while CBCT was obtained to evaluate the condylar bone and sagittal condylar position. Data were analysed by Pearson Chi square test and Spearman correlation coefficient., Results: THE DISTRIBUTION OF 744 TMJS IS AS FOLLOWS: 1) DISC MORPHOLOGY: contracture (37.1 %) > biconcave (32.9 %) > irregular (18.5 %) > lengthened (11.4 %); 2) disc position: ADDWoR (48.3 %) > NA (26.9 %) > ADDWR (21.6 %) > PDDWR (2.8 %) > PDDWoR (0.4 %); 3) condylar position: concentric (43.7 %) > posterior (37.6 %) > anterior (18.7 %); 4) condylar bone: normal (63.4 %)> abnormal (36.6 %). There were significant differences in the distribution of disc morphology and disc position between the sex (P < 0.05). There were significant differences in the distribution of disc position and condylar morphology amongst the age groups (P < 0.05). There were significant differences in the distribution of disc position, condylar position and condylar morphology amongst disc morphology (P < 0.05), and there were positive correlation between disc position(r = 0.703, P = 0.000), the score of condyle (r = 0.478, P = 0.000) and disc morphology respectively. There were significant differences in the distribution of disc position and condylar position amongst condylar morphology (P < 0.05). There was a positive correlation between disc position and condyle morphology (r = 0.413, P = 0.000), and a negative correlation between condyle position and condyle morphology (r=-0.152, P = 0.000). There were significant differences in the distribution of disc position amongst condylar position (P < 0.05), but there was no linear correlation (P = 0.159)., Conclusions: The mutual distribution of disc morphology, disc position, condylar morphology and condylar position was statistically significant. Disc displacement did not necessarily lead to condylar bone changes, but 92.7 % TMJs with condylar bone abnormalities had disc displacement., Trial Registration: This study was retrospectively registered on 28/03/2022 and endorsed by the Ethics committee (LCYJ2022014)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Objective: To investigate the morphological and positional temporomandibular joint (TMJ) characteristics of different temporomandibular disorders (TMDs)., Methods: One hundred forty-three TMD patients were divided into three groups: Group 1: Myalgia (M), Group 2: Disc displacement with reduction (DDWR), and Group 3: Disc displacement without reduction (DDWOR). Three-dimensional positional and dimensional parameters of the TMJ, including mandibular fossa, condyle, and TMJ spaces were evaluated using cone beam computed tomography (CBCT). The significance level was p < 0.05., Results: Mandibular condyles were significantly positioned in more vertical, posterior, and medial directions, with the reduced condylar width in the DD groups ( p < 0.001). Anterior joint space was significantly higher in the DDWR group than the myalgia group; the superior joint spaces were more reduced in DD groups than the myalgia group., Conclusion: Patients diagnosed with disc displacement showed significantly different condylar positions and joint spaces compared to the myalgia group in a skeletally comparable sample.

Objective: To evaluate the clinical effectiveness and stability of open suture versus micro-screw anchored disc reduction and fixation in treating disc displacement without reduction in the anterior temporomandibular joint., Methods: A total of 38 patients (51 sides) with anterior disc displacement without reduction (ADDwR) of the TMJ treated in our hospital from August 2021 to January 2023 were selected, including 19 cases in group A (23 sides) treated with open temporomandibular joint disc reduction and anchorage, and 19 cases in group B (28 sides) treated with temporomandibular joint disc reduction and suture. The Magnetic Resonance Imaging (MRI) data of the two groups before and after operation were compared to evaluate the effective rate of articular disc reduction, the change of articular disc length, The Maximal Interincisal Opening (MIO) and Numeric Rating Scale (NRS) were measured before and after operation., Results: In group A, the MRI effective rate 6 months after disc reduction was 95.65 % (22/23), the disc length gain was 1.74 mm, MIO was 40.32±5.067 mm, and NRS was 0.47±0.697. The MRI effective rate 6 months after disc reduction in group B was 100 % (28/28). The disc length gain was 1.78 mm, MIO was 41.58±3.746 mm, and NRS was 0.00. There was no significant difference between the two groups (P > 0.05)., Conclusions: TMJ disc reduction and suture and open TMJ disc anchorage can effectively reduce the TMJ disc. The TMJ disc stability is high at 6 months after operation, and the pain and mouth opening can be improved, which is worthy of further promotion in clinical practice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Objectives: To analyse the correlation between temporomandibular joint (TMJ) disc perforation and degenerative joint changes (DJC) on cone-beam computed tomography (CBCT) and related factors., Study Design: A total of 238 female patients with anterior disc displacement without reduction (ADDwoR), accounting for 348 affected joints, requiring TMJ disc open anchorage surgery were included in the study conducted from June 2021 to August 2022. Following TMJ disc open anchorage surgery, patients were divided into two groups: disc perforation (DP) and disc non-perforation (DNP). CBCT was utilised to assess different grades of condyle and articular eminence degenerative changes, and comparisons were made between the two groups regarding DJC and clinically relevant factors., Results: In comparison with the DNP group, the DP group exhibited statistically significant differences in mid- and late-stage condyle bone degenerative changes and bone alterations of the articular eminence (odds ratio [OR] = 7.822; 95% CI [4.438-13.785]; p < 0.001 and OR = 5.575; 95% CI [3.128-9.936]; p < 0.001). Additionally, persistent joint sounds (OR = 1.932; 95% CI [1.011-3.691]; p = 0.046) and longer disease duration (OR = 4.901; 95% CI [2.395-10.028]; p < 0.001) demonstrated statistically significant differences. However, no significant differences were observed between the two groups in terms of age, joint pain and limited mouth opening., Conclusions: Bone degeneration changes in TMJ CBCT images are a high possible risk factor for DP. With an escalation in the degree of condyle degeneration, the risk of DP may increased correspondingly. Persistent joint sounds and extended duration of the disease were also confirmed to be noteworthy clinical risks of DP., (© 2024 John Wiley & Sons Ltd.)

Background: Aberrant occlusion and aging are two main risks for temporomandibular joint (TMJ) degeneration., Objective: To assess the combined impact of occlusion and age on TMJ disc., Methods: To avoid the confounding impact of gender, presently, 126 female C57BL/6J mice, 63 youngsters, 6-week old and 63 adults, 28-week old, were used. An experimental bilateral anterior crossbite (BAC) relation was created by installing metal tubes onto the mandibular incisors. Mice were sacrificed at 3, 7 and 11 weeks (n = 9). Additionally, the installed tubes were removed at 7 weeks in removal groups and the TMJs were sampled after another 4 weeks (n = 9). Disc changes were detected by histomorphology, immunohistochemistry, and western blot assays., Results: Disc deformation was obvious in BAC groups. The typical change was hyperplasia at the posterior region of the disc where there was significant infiltration of inflammatory cells. Expressions of the inflammatory markers, including tumour necrosis factor-α and interleukin-1β, and the catabolic markers, including fibronectin (FN), FN N-terminal fragments, and vascular endothelial growth factor-A, were all increased. The changes were more obvious in adults than in youngsters. Removal of BAC attenuated inflammatory and catabolic changes in the youngsters, but the inflammatory markers recovered little in the adults., Conclusion: TMJ disc responds to BAC by degeneration and inflammation, and respond to BAC removal by rehabilitation. Adult discs show severer degeneration responses to BAC and a lower level of anti-inflammatory capability to BAC removal than the youngster's discs. Animals cannot be equated with humans. The human disc response to occlusion changes worth further exploration., (© 2024 John Wiley & Sons Ltd.)

Objective: The objective of this prospective study was to assess possible changes in the position and shape of the temporomandibular joint (TMJ) articular disc in patients treated with two protocols of rapid maxillary expansion (RME) and face mask (FM) therapy., Methods: A sample of 88 patients with Class III or Class III subdivision malocclusions, aged between 6 and 13 years, were consecutively selected and divided into three groups (G): G1-34 patients were treated with RME, followed by FM therapy; G2-34 patients were treated using RME according to modified alternate rapid maxillary expansion and constriction (ALT-RAMEC) protocol, followed by FM therapy. These treated groups were randomly (1:1 allocation ratio) distributed according to the two treatment protocols. G3 - Control Group - 20 untreated patients were followed. Magnetic resonance imaging (MRI) TMJs were obtained before (T1) and after (T2) a treatment period or follow-up. McNemar test, Fisher's exact test and intra- and inter-observer concordance (K) were performed (p ≤ .05)., Results: There were no statistically significant differences in the baseline cephalometric variables at T1 between the groups. There were statistically significant differences between the groups (p < .001) in relation to the disc shape in T1, since G1 (8 TMJs -11.76%) presented higher occurrences of altered forms in comparison with G2 (no changes). No significant differences were observed in disc position CM and OM (G1 - p > .999; G2 - p = .063; G3 - p = .500) and shape (G1 - p > 0.999; G2 - p = .250; G3 - not calculable), between T1 × T2, in any of the groups studied., Conclusion: The two treatment protocols did not have adverse effects on the position and shape of the TMJ disc, in a short-term evaluation., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: The objective of the study was to investigate the relationship between types of disc displacement (DD) diagnosed by magnetic resonance imaging (MRI), and the risk (presence or absence) and severity of condylar erosion (CE) graded using cone-beam computed tomography (CBCT) in adult Temporomandibular disorders (TMD) patients., Methods: A total of 353 TMD patients (283 females, 70 males) underwent MRI scans to categorise DD as normal (NA), anterior displacement with reduction (ADDR), or anterior displacement without reduction (ADDNR). CE severity was graded on a scale of 0-3 (absence, mild, moderate or severe) using CBCT. To establish the plausibility and cut-off points for CE diagnosis, the severity of CE was then further divided into three classifications: Grade 0 versus 1 + 2 + 3; Grades 0 + 1 versus 2 + 3; Grades 0 + 1 + 2 versus 3. Logistic regression analysis was performed, adjusting for age, gender and joint correlation., Results: ADDNR significantly increased the risk of CE compared with NA (OR = 10.04, 95% CI: [6.41, 15.73]) and showed a significant increase in CE severity across all classifications (ORs = 10.04-18.95). The effects of ADDNR were significant in both genders (p < .001) and had a greater impact in females. ADDR was predominantly associated with mild CE., Conclusions: ADDNR significantly increased the risk and severity of CE independent of gender when compared to NA, whereas ADDR was mainly associated with mild CE. Slight cortical discontinuity may represent a subclinical diagnosis requiring further investigation., (© 2024 John Wiley & Sons Ltd.)

The aim of this study was to evaluate the reliability of magnetic resonance imaging (MRI) in detecting disc perforations in the temporomandibular joint (TMJ), and to establish diagnostic criteria for this purpose. The retrospective analysis included patients who had undergone preoperative MRI and TMJ arthroscopy at the same hospital. Direct and indirect signs of disc abnormalities on MRI were compared with arthroscopic findings of disc perforation. Out of 355 joints evaluated in 185 patients, arthroscopy confirmed disc perforations in 14.7% of cases. Several MRI findings were significantly associated with disc perforation, including anterior disc displacement without reduction (ADDwoR), signal alterations in the mid-disc area, disc deformity (SAMD), retrocondylar disc fragments, osteophytes, condylar bone marrow degeneration (CBMD), and joint effusion in both joint spaces (ESJS-EIJS). Regression analysis revealed that SAMD, osteophytes, and CBDM were strongly associated with disc perforation. The ROC curve showed that MRI had an AUC = 0.791, with a sensitivity of 88.5% and a specificity of 61.5%. Two diagnostic methods, one based on three findings (osteophytes, ADDwoR, and SAMD) and one based on two direct signs (ADDwoR and SAMD), yielded high sensitivity and specificity values of 80.4% and 69.8%, and 84.3% and 62.5%, respectively. In conclusion, MRI demonstrated acceptable accuracy in the detection of TMJ disc perforations, with specific diagnostic criteria offering high sensitivity and specificity. Significant MRI indicators of disc perforation included SAMD, osteophytes, and CBDM. This study provides valuable information on the use of MRI as a diagnostic tool for TMJ disc perforations., Competing Interests: Declaration of competing interest The authors have no conflicts of interest or financial ties to disclose., (Copyright © 2024 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Failures in orthognathic surgery are associated with different factors, including those related to untreated or undiagnosed preoperative temporomandibular joint (TMJ) disorders. This systematic review aimed to assess potential alterations in the condylar head following orthognathic surgery. A systematic search for randomised controlled trials and retrospective studies was performed. For inclusion in the review, studies had to meet the following eligibility criteria according to the PICO framework: Patients: patients with orthognathic deformity and temporomandibular dysfunction (or temporomandibular osteoarthritis); Intervention: patients submitted to orthognathic surgery concomitantly with TMJ disjunction; Control: patients undergoing only orthognathic surgery with or without presurgical data; and Outcome: changes in temporomandibular joint position and volume. Nine studies met all the inclusion criteria and were selected for qualitative analysis. The results of this review show that simultaneous articular disc repositioning and orthognathic surgery provide better results in patients with preoperatively diagnosed condylar osteoarthritic changes. In conclusion, condylar remodelling (resorption/deposition) and its extent are determined by the direction of condylar displacement during surgery. Other factors such as age are also associated with the development of condylar resorption., (Copyright © 2024 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Segmentation of the temporomandibular joint (TMJ) disc and condyle from magnetic resonance imaging (MRI) is a crucial task in TMJ internal derangement research. The automatic segmentation of the disc structure presents challenges due to its intricate and variable shapes, low contrast, and unclear boundaries. Existing TMJ segmentation methods often overlook spatial and channel information in features and neglect overall topological considerations, with few studies exploring the interaction between segmentation and topology preservation. To address these challenges, we propose a Three-Branch Jointed Feature and Topology Decoder (TFTD) for the segmentation of TMJ disc and condyle in MRI. This structure effectively preserves the topological information of the disc structure and enhances features. We introduce a cross-dimensional spatial and channel attention mechanism (SCIA) to enhance features. This mechanism captures spatial, channel, and cross-dimensional information of the decoded features, leading to improved segmentation performance. Moreover, we explore the interaction between topology preservation and segmentation from the perspective of game theory. Based on this interaction, we design the Joint Loss Function (JLF) to fully leverage the features of segmentation, topology preservation, and joint interaction branches. Results on the TMJ MRI dataset demonstrate the superior performance of our TFTD compared to existing methods., Competing Interests: Declaration of competing interest None Declared., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: This study compared temporomandibular joint (TMJ) magnetic resonance imaging (MRI) findings between bruxism and control groups with unilateral TMJ pain as well as the TMJ MRI findings for the painful and non-painful sides of individuals in the two groups., Methods: Clinical and MRI findings of patients seen at Uşak University, Dentistry Faculty, Department of Oral and Maxillofacial Surgery for unilateral TMJ pain between 2017 and 2020 were analyzed. Bruxism was diagnosed based on clinical findings and patient history. The MRI variables were disc/condyle relationship (normal, disc displacement with reduction, or disc displacement without reduction), disc structure (normal and abnormal), condyle degeneration type (normal, moderate, or severe), and joint effusion (absent or present). Pain was recorded based on a visual analog scale (VAS) numbered between 0 and 10. Statistical analyses were performed using IBM SPSS. The data were distributed non-normally according to the results of Kolmogorov-Smirnov tests. The Mann-Whitney U test was used to compare age and VAS. Chi-square tests were used to compare categorical variables. Statistical significance was defined as p < 0.05., Results: This study assessed the MRI records of 558 cases of TMJ pain. No significant differences in disc/condyle relation, disc structure, condyle structure, or effusion were observed between the control and bruxism groups ( p > 0.05). However, a significant difference in TMJ MRI findings was observed between the painful and non-painful sides of each individual in the control and bruxism groups ( p = 0.001, p < 0.001 and p = 0.004, p < 0.001, respectively)., Conclusion: The results of this study established a relationship between the painful side for each patient and TMJ MRI findings. In particular, individuals with bruxism had a higher rate of TMJ internal derangement and effusion on the painful side.

Objectives: Temporomandibular disorders (TMDs) are common and may cause persistent functional limitations and pain. Magnetic resonance imaging (MRI) at 1.5 and 3 T is commonly applied for the evaluation of the temporomandibular joint (TMJ). No evidence is available regarding the feasibility of modern low-field MRI for the assessment of TMDs. The objective of this prospective study was to evaluate the image quality (IQ) of 0.55 T MRI in direct comparison with 1.5 T MRI., Materials and Methods: Seventeen patients (34 TMJs) with suspected intraarticular TMDs were enrolled, and both 0.55 and 1.5 T MRI were performed on the same day. Two senior readers independently evaluated the IQ focusing on the conspicuity of disc morphology (DM), disc position (DP), and osseous joint morphology (OJM) for each joint. We analyzed the IQ and degree of artifacts using a 4-point Likert scale (LS) at both field strengths. A fully sufficient IQ was defined as an LS score of ≥3. Nonparametric Wilcoxon test for related samples was used for statistical comparison., Results: The median IQ for the DM and OJM at 0.55 T was inferior to that at 1.5 T (DM: 3 [interquartile range {IQR}, 3-4] vs 4 [IQR, 4-4]; OJM: 3 [IQR, 3-4] vs 4 [IQR 4-4]; each P < 0.001). For DP, the IQ was comparable (4 [IQR 3-4] vs 4 [IQR 4-4]; P > 0.05). A sufficient diagnostic IQ was maintained for the DM, DP, and OJM in 92% of the cases at 0.55 T and 100% at 1.5 T. Minor image artifacts (LS score of ≥3) were more prevalent at 0.55 T (29%) than at 1.5 T (12%)., Conclusions: Magnetic resonance imaging of the TMJ at 0.55 T yields a lower IQ than does MRI at 1.5 T but maintains sufficient diagnostic confidence in the majority of patients. Further improvements are needed for reliable clinical application., Competing Interests: Conflicts of interest and sources of funding: R.H., M.M., M.K., and M.U. are members of the speakers bureau of Siemens Healthcare GmbH. F.W.R. outside the current work (for the last 36 months) was a consultant to Grünethal GmbH, Shareholder Boston Imaging Core Lab (BICL), LLC. All other authors have no affiliation with any organization with a direct or indirect financial interest in the subject discussed in the article. This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: To investigate the correlation between the osseous structure of temporomandibular joint (TMJ) and three different status of anterior disc location, so that it could guide the clinical diagnosis further. Methods: Fifty-two patients [46 females and 6 males, with an age of (27.8±8.3) years] who treated with MRI and cone beam CT, were recruited from the Temporomandibular Joint Specialist Clinic, The First Affiliated Hospital of Xinjiang Medical University, between March 2018 to December 2021. According to the radiographic findings of the level of anterior disc displacement (ADD) in TMJ, patients were divided into three groups: normal articular disc position (NADP, n =28 TMJs), anterior disc displacement with reduction (ADDWR, n =28 TMJs), and anterior disc displacement without reduction (ADDWoR, n =28 TMJs). In the light of the reconstructed three-dimensional model, ten representative morphological parameters including condylar volume (CV), condylar superficial area (CSA), fossa volume (FV), fossa superficial area (FSA), the proportion of the condylar volume in the articular fossa (CV%), the proportion of the condylar superficial area in the articular fossa (CSA%), superior joint space (SJS), anterior joint space (AJS), posterior joint space (PJS), and medial joint space (MJS), were measured respectively under one-way analysis of variance (ANOVA), Kruskal-Wallis H test and receiver operator characteristic curve(ROC curve) analyses. Results: CV and CSA values varied significantly in the pathological progression from normal location to irreversible anterior displacement in TMJ. For CV value, NADP group [(1 834.90±667.67) mm 3 ]>ADDWR group [(1 747.34±369.42) mm 3 ]>ADDWoR group [(1 256.29±418.27) mm 3 ] [ t =4.31, P (NADP-ADDWoR) <0.001; t =3.66, P (ADDWR-ADDWoR) <0.001], for CSA value, NADP group [(859.27±216.01) mm 2 ]>ADDWR group [(838.23±118.82) mm 2 ]>ADDWoR group [(669.14±150.26) mm 2 ] [ t =4.27, P (NADP-ADDWoR) <0.001; t =3.80, P (ADDWR-ADDWoR) <0.001]. The difference of SJS value in NADP group [(2.22±0.88) mm], ADDWR group [(1.94±0.64) mm] and ADDWoR group [(1.45±0.57) mm], was statistically significant [ t =4.11, P (NADP-ADDWoR) <0.001; t =2.63, P (ADDWR-ADDWoR) =0.010]. The results of MJS in NADP group [(5.03±1.41) mm], ADDWR group [(3.86±1.32) mm], and ADDWoR group [(4.91±1.65) mm] were significantly different [ t =3.00, P (NADP-ADDWR) =0.004; t =2.63, P (ADDWR-ADDWoR) =0.009]. As calculated by the ROC curve analysis, CV, CSA and SJS showed that (AUC CV =0.77, AUC CSA =0.76; AUC SJS =0.76) for the NADP and ADDWoR groups, and (AUC CV =0.80; AUC CSA =0.80; AUC SJS =0.72) for the ADDWR and ADDWoR groups. While the diagnostic accuracy of MJS for the comparison in NADP versus ADDWR and ADDWR versus ADDWoR was respectively AUC (NADP-ADDWR) =0.73, and AUC (ADDWR-ADDWoR) =0.69. Conclusions: CV, CSA, SJS, and MJS were significantly associated with the different disc displacement status, and the condyle in TMJ ADD exhibited three-dimensionally altered dimensions. They could be considered as promising biometric markers to diagnose the ADD status.

Purpose: The objective of this study was to analyze the effect of TMJ disc position on condylar bone remodeling after arthroscopic disc repositioning surgery., Methods: Nine patients with anterior disc displacement without reduction (ADDWoR, 15 sides) who underwent arthroscopic disc repositioning surgery were included. Three-dimensional (3D) reconstruction of the articular disc and the condyle in the closed-mouth position was performed using cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) data. Then, the CBCT and MRI images were fused and displayed together by multimodal image registration techniques. Morphological changes in the articular disc and condyle, as well as changes in their spatial relationship, were studied by comparing preoperative and 3-month postoperative CBCT-MRI fused images., Results: The volume and superficial area of the articular disc, as well as the area of the articular disc surface in the subarticular cavity, were significantly increased compared to that before the surgical treatment（P < 0.01）. There was also a significant increase in the volume of the condyle (P < 0.001). All condyles showed bone remodeling after surgery that could be categorized as one of two types depending on the position of the articular disc, suggesting that the location of the articular disc was related to the new bone formation., Conclusions: The morphology of the articular disc and condyle were significantly changed after arthroscopic disc repositioning surgery. The 3D changes in the position of the articular disc after surgery tended to have an effect on condylar bone remodeling and the location of new bone formation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Disc perforation (DP) is a severe type of Temporomandibular Disorder (TMD). DP may induce changes in the internal stresses of the temporomandibular joint (TMJ). Herein, this study attempts to investigate the biomechanical effects of different positions and sizes of DP on the TMJ using a biomechanical approach, to explore the mechanical pathogenesis of TMD., Methods: Eleven three-dimensional finite element (FE)models of the TMJ were constructed based on CBCT imaging files of a patient with DP on the left side. These models included the disc with anterior displacement and discs with different locations and sizes of perforations on the affected disc. FE methods were conducted on these models., Results: Anterior displacement of the disc leads to a significant increase in the maxim von Mises stress (MVMS) in both TMJs, with the affected side exhibiting a more pronounced effect. DP occurring at the posterior band and the junction between the disc and the bilaminar region has a greater impact on the MVMS of both TMJs compared to perforations at other locations. As the size of the perforation increases, both sides of the TMJs exhibit an increase in the magnitude of MVMS., Conclusions: Unilateral disc anterior displacement results in an increased stress on both TMJs. Unilateral DP further affects the stress on both sides of the TMJs. TMD is a progressive condition, and timely intervention is necessary in the early stages to prevent the worsening of the condition., (© 2023. The Author(s).)

Objective: To investigate the arthroscopic temporomandibular joint disc reduction on the outcome of orthodontic patients with anterior disc displacement without reduction. Methods: From January 2012 to December 2021, forty treated orthodontic patients with anterior disc displacement without reduction (unilateral/bilateral) and no obvious articular cartilage absorption were selected from Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The patients were (17.5±3.8) years old (12-25 years old), including 8 males and 32 females. Twenty patients who had completed arthroscopic temporomandibular joint disc reduction were included in the control group, and twenty patients with untreated temporomandibular joint disc were included in the experimental group. Model measurement (including overjet, etc.), cephalometric analysis (including ANB angle, which was formed by subspinale, nasion and supramental, etc.) and temporomandibular joint magnetic resonance imaging (including measurement of the condyle height of the displacement sides) were used to compare the difference of two groups. Objective grading system was used to evaluate the efficacy of orthodontic treatment. Results: The overjet of the experimental group and the control group after orthodontic treatment was (2.19±0.76) and (1.92±0.94) mm, respectively. Both two groups achieved ideal overjet with no statistical difference ( t= 1.02, P= 0.314). The ANB angle difference before and after treatment in the control group (-1.97°±2.87°) was greater than that in the experimental group (0.09°±1.82°), and the difference was statistically significant ( t= 2.72, P= 0.010). The variation of condyle height before and after treatment was (0.30±1.11) mm in the experimental group and (0.82±1.25) mm in the control group, with no statistical significance ( t= 1.80, P= 0.076). The post-treatment objective grading system scores of the experimental group and the control group were 21.00 (16.00, 24.00) and 21.00 (17.00, 25.00), respectively, which had no statistical difference ( U =0.24, P= 0.808). Conclusions: In orthodontic patients with anterior disc displacement without reduction and no obvious articular cartilage absorption, whether displaced discs are repositioned after arthroscopic surgery has no significant effect on the orthodontic treatment outcome.

Background: Temporomandibular joint (TMJ) disc repositioning through open suturing (OSu) is a new disc repositioning method. Its result for adolescents with condylar resorption and dentofacial deformities combined with and without postoperative occlusal splints (POS) has not been well studied., Objective: This study was to evaluate and compare the effects of OSu with and without POS in the treatment of TMJ anterior disc displacement without reduction (ADDwoR) in adolescent skeletal Class II malocclusion., Methods: A total of 60 adolescents with bilateral ADDwoR were enrolled in this study. They were randomly allocated into two groups: OSu with and without POS. Magnetic resonance imaging (MRI) and lateral cephalometric radiographs were used to measure changes in condylar height and the degree of skeletal Class II malocclusion from before operation and at 12 months postoperatively. Changes in these indicators were compared within and between the two groups., Results: After OSu, both groups exhibited significant improvements in condylar height and occlusion at the end of 12 months follow-up (P < 0.05). The group of OSu with POS had significantly more new bone formation (2.83 ± 0.75 mm vs. 1.42 ± 0.81 mm, P < 0.001) and improvement in dentofacial deformity than the group of OSu only (P < 0.05). The new bone height was significantly correlated with POS (P < 0.001), the changes of SNB (P = 0.018), overjet (P = 0.012), and Wits appraisal (P < 0.001)., Conclusion: These findings indicated that OSu can effectively stimulate condylar regeneration and improve skeletal Class II malocclusion in adolescents with bilateral ADDwoR. The results are better when combined with POS., Trial Registration: This trial was prospectively registered on the chictr.org.cn registry with ID: ChiCTR1900021821 on 11/03/2019., (© 2023. BioMed Central Ltd., part of Springer Nature.)

The temporomandibular joint (TMJ) disc complex (i.e., the TMJ disc and its six attachments) is crucial to everyday functions such as mastication and speaking. The TMJ can be afflicted by many conditions, including disc displacement and defects. Pathologies of the TMJ disc complex most commonly present first as anterior disc displacement, which the field hypothesizes may implicate the two posterior attachments. As a result of anterior disc displacement, defects may develop in the lateral disc complex. Tissue engineering is poised to improve treatment paradigms for these indications of the TMJ disc complex by engineering biomimetic implants, but, first, gold-standard design criteria for such implants should be established through characterization studies. This study's objective was to characterize the structural, mechanical, biochemical, and crosslinking differences among the two posterior attachments and the lateral disc in the Yucatan minipig, a well-accepted TMJ animal model. In tension, it was found that the posterior inferior attachment (PIA) was significantly stiffer and stronger by 2.13 and 2.30 times, respectively, than the posterior superior attachment (PSA). It was found that collagen in both attachments was primarily aligned mediolaterally; however, the lateral disc was much more aligned and anisotropic than either attachment. Among the three locations, the PSA exhibited the greatest degree of heterogeneity and highest proportion of fat vacuoles. The PIA and lateral disc were 1.93 and 1.91 times more collagenous, respectively, by dry weight (DW) than the PSA. The PIA also exhibited 1.78 times higher crosslinking per DW than the PSA. Glycosaminoglycan per DW was significantly higher in the lateral disc by 1.48 and 5.39 times than the PIA and PSA, respectively. Together, these results establish design criteria for tissue-engineering of the TMJ disc complex and indicate that the attachments are less fibrocartilaginous than the disc, while still significantly contributing to the mechanical stability of the TMJ disc complex during articulation. These results also support the biomechanical function of the PIA and PSA, suggesting that the stiffer PIA anchors the disc to the mandibular condyle during articulation, while the softer PSA serves to allow translation over the articular eminence. Impact Statement Characterization of the temporomandibular joint (TMJ) disc complex (i.e., the disc and its attachments) has important implications for those aiming to tissue-engineer functional replacements and can help elucidate its biomechanical function. For example, the findings shown here suggest that the stiffer posterior inferior attachment anchors the disc during articulation, while the softer posterior superior attachment allows translation over the articular eminence.

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 than MRI in detecting the presence of degenerative disc diseases and subluxation., (Copyright © 2023 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: To explore the correlation between the attachment type of lateral pterygoid muscle (LPM) and the position of temporomandibular joint (TMJ) disc in patients with temporomandibular disorders (TMD) by using wireless amplified magnetic resonance imaging detector (WAND) coupled with conventional head and neck joint coil for high resolution imaging of TMJ. Methods: Eighty-five patients with TMD diagnosed by oral and maxillofacial surgeons of Guizhou Provincial People's Hospital from October 2019 to January 2022 were collected. A total of 160 TMJ were included. There were 16 males and 69 females, aged (32.7±14.2) years. All patients were scanned with open, closed oblique sagittal and coronal WAND coupled head and neck coils with bilateral TMJ. Based on TMJ and LPM high resolution imaging, to explore the correlation between LPM attachment types and the position of TMJ disc in TMD patients, and to evaluate the potential clinical value of LPM attachment types in TMD patients. χ 2 test and Pearson correlation analysis were used to evaluate the correlation between LPM attachment type and TMJ disc location. Results: There were three types of LPM attachment: type Ⅰ in 51 cases [31.9% (51/160)], type Ⅱ in 77 cases [48.1% (77/160)] and type Ⅲ in 32 cases [20.0% (32/160)]. There was a significant correlation between the type of LPM attachment and the position of articular disc ( χ 2 =28.20, P =0.002, r =0.776). There was no statistical significance between the type of LPM attachment and the reversible displacement of articular disc ( χ 2 =0.24, P =0.887, r =0.825). Conclusions: There is a correlation between the attachment type of LPM and the position of the disc in TMD patients. WNAD coupled with conventional head and neck joint coil TMJ high resolution scan can provide reliable imaging evidence for TMD patients in evaluating the type of LPM attachment and the location of disc.

The objective of this study was to measure the association between the disk position and condylar alteration in patients diagnosed with anterior disk displacement (ADD) of temporomandibular joint (TMJ). A retrospective cross-sectional study was designed, dividing into 4 groups: normal articular disk position (NADP) of unilateral ADD patients (n=10), ADD with reduction (ADDwR, n=16), ADD without reduction (ADDwoR, n=24), and healthy volunteers (HV, n=30) based on magnetic resonance imaging and cone-beam computed tomography. After morphologic parameters were calculated from 3-dimensional reconstructive images, differences in parameters with respect to ADD status were tested with analysis of variance and Fisher least significant difference multiple comparisons were performed. Condylar volume of ADDwR, ADDwoR, NADP, and HVs were 1768.29±404.19, 1467.13±438.20, 1814.48±753.60, and 1914.66±476.48 mm, respectively, showing a significant downward trend from healthy disk to a displaced one ( P <0.05). Same trend also found in condylar superficial area, with the condylar superficial area of the ADDwR, ADDwoR, NADP, and HVs were 842.56±138.78 mm, 748.52±157.42 mm, 842.87±263.00 mm, and 892.73±164.19 mm, respectively. From NADP to ADDwR to ADDwoR, superior joint space (SJS) was declined, [SJS (NADP) (2.10±0.91 mm) > SJS (ADDwR) (1.85±0.61 mm) > SJS (ADDwoR) (1.50±0.50 mm), P =0.034]; medial joint space was significantly associated with the different disk displacement types ( P(HV-ADDwR) =0.001; P(HV-ADDwoR) =0.021; P(NADP-ADDwR) =0.022; P(ADDwR-ADDwoR) =0.001). Our findings suggest that condylar volume and superficial area, and superior and medial joint space, albeit with a small sample size, are significantly associated with different disk displacement types, detection of which might therefore be worth exploring for assessing ADD., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)

Objectives: Morphologic study is a common approach in the field of anterior disc displacement (ADD) pathology; however, analysis based on 3D reconstructive imaging has not been investigated. This study investigated the association between ADD and the status of the mandibular condyle and articular fossa., Method and Materials: Thirty-four patients were divided into a normal articular disc position (NADP) group, an ADD with reduction (ADDwR) group, and an ADD without reduction (ADDwoR) group. Images reconstructed were used to determine multiple grouped comparisons of these three different types of disc position, and the diagnostic efficacy for the morphologic parameters with significant grouped difference was analyzed to assess., Results: The condylar volume and condylar superficial area of the NADP, ADDwR, and ADDwoR groups exhibited obvious changes (P < .05). A multivariate logistic ordinal regression model showed that the condylar volume (odds ratio [OR], 1.011; regression coefficient [RC] = .011, P = .018), superior joint space (OR, 8.817; RC = 2.177; P < .001), and medial joint space (OR, 1.492; RC = 0.400; P = .047) had a significantly positive impact on the groups., Conclusion: The mandibular condyle and articular fossa in temporomandibular joint ADD exhibited altered dimensions. The condylar volume, condylar superficial area, superior joint space, and medial joint space could be considered as promising biometric markers for assessing ADD, and were investigated in this current pilot study. (Quintessence Int 2023;54:156-166; doi: 10.3290/j.qi.b3512027).

The aim of this study was to assess the various outcomes of arthroscopic discopexy compared to the natural course of anterior disc displacement (ADD) longitudinally in the same patients. A retrospective review was performed of 108 patients (152 joints) who experienced the natural course of ADD for a period of time and then underwent arthroscopic discopexy. The outcome was evaluated clinically and by magnetic resonance imaging. The natural course of ADD showed significant deterioration in pain, diet, and quality of life, and also a significant reduction in inter-incisal opening (all P < 0.001), while significant improvements in all clinical parameters were observed at the final postoperative follow-up (all P < 0.001, compared to the last preoperative visit). During the natural course, there was a significant shortening of condylar height, mandibular height, and disc length, and an increase in disc displacement distance (all P < 0.001). Postoperative follow-up revealed the restoration of condylar height and mandibular height, and all discs were significantly repositioned with an increased disc length (unfolded) (all P < 0.001). Bearing in mind the assumption of a low evidence base due to bias resulting from the retrospective non-double-blinded study design and the variable duration of the natural disease course prior to surgery, this study found that the natural course of ADD led to degenerative changes in the joint structures and clinical symptoms, whereas arthroscopic discopexy led to a restoration of the bony structures and the alleviation of clinical symptoms., (Copyright © 2022 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Disc displacement without reduction is a common disorder of the temporomandibular joint, causing clinical symptoms and sometimes condylar degeneration. In some cases, bone regeneration is detected following disc-repositioning procedures. Until now, however, systems-wide knowledge of the protein levels for condylar outcome with disc position is still lacking. Here, we performed comprehensive expression profiling of synovial fluid from 109 patients with disc displacement without reduction using high-resolution data-independent acquisition mass spectrometry and characterized differences in 1,714 proteins. Based on magnetic resonance imaging, samples were divided into groups with versus without condylar absorption and subgroups with versus without new bone. For the proteomic analysis, 32 proteins in groups presented with statistical significance (>2-fold, P < 0.05). Pathways such as response to inorganic substances, blood coagulation, and estrogen signaling were significantly expressed in the group with bone absorption as compared with pathways such as regulation of body fluid levels, vesicle-mediated transport, and focal adhesion, which were enriched in the group without bone absorption. In subgroup analysis, 45 proteins of significant importance (>2-fold, P < 0.05) were associated with pathways including would healing, glycolysis and gluconeogenesis, and amino acid metabolism. Combined with clinical examination, molecules such as acetyl-CoA carboxylase beta (ACACB) and transforming growth factor beta 1 (TGFB1) were related to features such as visual analog scale and maximum interincisal opening ( P < 0.05). In addition, 7 proteins were examined by Western blotting, including progesterone immunomodulatory binding factor 1 (PIBF1), histidine-rich glycoprotein (HRG), and protein kinase C and casein kinase substrate in neurons 2 (PACSIN2). In conclusion, this study provides the first proteome analysis of condylar absorption at disc displacement without reduction and postoperative new bone formation after disc reposition. Integrated with clinical data, this analysis provides an important insight into the proteomics of condylar modification at disc position.

Purpose: The aim of this study was to evaluate the lateral pterygoid muscle (LPM) area, attachment type, signal intensity and presence of arthrosis, effusion in the temporomandibular joint (TMJ) by magnetic resonance imaging (MRI) according to the position of the articular disc., Methods: The study included a total of 126 TMJs belonging to 69 patients over the age of 18 years who had MRI due to TMJ complaints. The position of the articular disc, the area, attachment type, and signal intensity of the LPM, the presence of arthrosis on the condyle surface, and the presence of effusion in the joint space were evaluated., Results: The attachment type of the LPM did not show a statistically significant difference according to the position of the articular disc. The groups were not statistically different in terms of LPM intensity. Although the distribution of the LPM area was found to be low in the anterior disc displacement with reduction (R+DD) group and high in the anterior disc displacement without reduction (R-DD) group. It was determined that the rate of arthrosis at the condyle head was significantly higher in the R-DD group compared to the normal disc position group. The incidence of effusion was found significantly higher in the R-DD and R+DD groups than joints with normal disc position., Conclusions: Pathological changes in LPM and TMJ can be detected by MRI. In the group with R-DD, the rate of arthrosis at the condyle head, effusion, LPM area, and intensity of the Sup. LPM were higher., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Background: This study aimed to quantify the morphological changes of temporomandibular joint (TMJ) discs after disc repositioning surgery using the three-dimensional (3D) modeling., Methods: Thirty patients who diagnosed with unilateral ADDwoR were included to compare the morphological differences between ADDWoR discs and normal discs, and fifteen patients who experienced unilateral or bilateral disc repositioning surgery were included to analyze the morphological changes before and after disc repositioning surgery. Disc 3D reconstruction and analyses were performed using magnetic resonance imaging (MRI) data., Results: In the unilateral ADDwoR patients, volume, superficial area, length, and maximum longitudinal-sectional area of the ADDwoR disc were significantly smaller compared with the non-affected discs. However, there was no significant difference in width and cross-sectional areas between ADDwoR discs and non-affected discs. In patients who subjected to disc repositioning surgery, disc volume, superficial area, length, width and maximum longitudinal-sectional area of TMJ discs were markedly increased 6 months after surgery., Conclusions: This study demonstrated that the TMJ discs tended to be morphologically smaller in volume and shorter in length under ADDwoR status. Importantly, the ADDwoR discs tended to morphologically recover toward non-affected discs after 6 months follow-up following TMJ disc repositioning surgery., (© 2022. The Author(s).)

The aim of this systematic review was to evaluate the effectiveness of different temporomandibular joint arthroscopic discopexy techniques. The systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and an electronic search was performed using MEDLINE (PubMed), The Cochrane Library, ScienceDirect databases using a combination of the terms ''discopexy,'' ''disc recapture,'' ''disc fixation,'' and ''temporomandibular joint'' to identify clinical trials published from 2010. In total, 493 records were screened, of which only 9 fulfilled the inclusion criteria and were included in qualitative data synthesis. The results of clinical findings evaluation showed that arthroscopic discopexy statistically significantly improved levels of pain (VAS) and maximum interincisal opening whereas magnetic resonance imaging evaluation showed disc position improvement of up to 90% to 100%. In conclusion, this review provides the evidence of the potential benefits of arthroscopic disc fixation in the treatment of patients with internal derangements : reduced pain, increased maximum interincisal opening, and improved disc position evaluated by magnetic resonance imaging, whereas disc fixation using suturing techniques seems to be the most appropriate method., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)

Background: To investigate morphological features of the mandibular condyle and its association with anterior temporomandibular disc displacement on sagittal oblique MRI plane., Methods: One hundred and twenty patients with temporomandibular MRI examination were retrospectively involved in the study. Patients aged less than 18 years and those with severe osteoarthritis, posterior disk displacement, tumor, abscess, history of a rheumatic disease, facial trauma, and motion artifacts on images were excluded. Three radiologists evaluated all images in consensus. Temporomandibular disc locations were classified as normal, anteriorly displaced with reduction (ADr), and anteriorly displaced without reduction (ADwr) on sagittal oblique T1-weighted images. Condylar shapes were classified as flat, rounded, and angled, and condyle anteroposterior width (c-APW) was measured on these images in closed-mouth position., Results: Ninety six discs were in normal position (40%), 70 discs were ADr (29%), and 74 discs were ADwr (31%). Eighty-four condyles were flat (35%), 100 condyles were rounded (42%), and 56 condyles were angled (23%). Mean c-APW was 7 mm in normal joints, 5.9 mm in ADr, and 5.8 mm in ADwr joints, and it was smaller in joints with anterior disc displacement (p < 0.001). In normal joints, flat and rounded type condylar shape was more common and almost equally prevalent (44% and 43%); however, rounded type was more common among ADr (%47) and angled type was more common among ADwr joints (36%) (p = 0.008). Patients with anterior disc displacement were significantly younger from normal cases and anterior disc displacement was more common among female sex., Discussion: Mandibular condyle shape alterations and condyle size on sagittal oblique MRI plane are associated with anterior disc displacement. Angled shape was more common among ADwr joints. Joints with anterior disc displacement had smaller c-APW than normal joints.

The aim of this research was to assess possible relationships between petrotympanic fissure (PTF) characteristics, malleus position, and temporomandibular joint disorders (TMD). A retrospective study was performed, including patients with TMD. Magnetic resonance imaging (MRI) and cone-beam computed tomography (CBCT) examination were used to evaluate temporomandibular joint (TMJ) disc position and condylar bone changes. Fifty-eight TMJs from twenty-nine patients (23:6 females: males) were assessed. Erosive changes (DDR-disc displacement with a reduction of 6 (24%), DDwR-disc displacement without a reduction of 8 (61.5%) vs. normal disc position 3 (15%), p = 0.012) and condyle osteophytes production (DDR 6 (24%), DDwR 9 (69.2%) vs. normal condyle 7 (35%), p = 0.012) were more frequent in subjects with disc displacement compared to normal disc position; malleus was closer to PTF in cases with erosive changes (median 2.15 interquartile range: (1.85-2.75) vs. 2.75 (2.25-3.15), p = 0.029) as well as those with condylar osteophytosis (2.25 (1.91-2.75) vs. 2.75 (2.33-3.32), p = 0.015); the PTF length was higher in cases with condylar osteophytosis compared to those without (4.45 (3.50-4.77) vs. 3.67 (3.34-4.28), p = 0.039). The disc position and disc shape were not related to PTF or malleus position. Malleus position and PTF dimensions were not associated with the PTF type. In cases with erosive changes and condylar osteophytosis, malleus was closer to PTF.

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., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Nasser Raqe Alqhtani et al.)

Aim: Temporomandibular disorders (TMD), in particular disc displacement, are recognised to have a multifactorial aetiology. Ligamentous laxity has been suggested as a potential risk factor for TMD. Ligamentous laxity can lead to generalised joint hypermobility (GJH) involving multiple joints, including the temporomandibular joint (TMJ). The aim of this work is to evaluate the correlation between GJH and disc displacement (DD) assessed on magnetic resonance images (MRI) of the TMJ in adolescent patients., Materials: The study was included 40 adolescent patients (10-16 years), divided into two groups, a Study Group (SG), composed of 20 subjects with GJH, and a Control Group (CG), composed of 20 subjects without GJH. The GJH was assessed by the Beighton test with a threshold value of ≥ 4. The severity of the TMD was determined using the Fonseca Questionnaire and a clinical evaluation of the type of TMD. The condylar-discal relationship and the condylar mobility of the TMJ were evaluated by MRI. Pearson's χ2 Test was performed for the analysis of the statistical correlation., Conclusion: This study suggests that adolescents with GJH have a greater risk of developing TMJ disc displacement, especially disc displacement without reduction.

The temporomandibular joint (TMJ) disc is a fibrocartilaginous tissue located between the condyle of the mandible and glenoid fossa and articular eminence of the temporal bone. Damage or derangement of the TMJ disc can require surgical removal (discectomy) to restore function. Removal of the TMJ disc, however, leaves the joint space vulnerable to condylar remodeling and degradation, potentially leading to long-term complications. No consistently effective clinical option exists for repair or replacement of the disc following discectomy. This study investigates the use of an acellular scaffold composed of extracellular matrix (ECM) derived from small intestinal submucosa (SIS) as a regenerative template for the TMJ disc in a porcine model. Acellular SIS ECM scaffolds were implanted following discectomy and allowed to remodel for 2, 4, 12, and 24 weeks postimplantation. Remodeling of the implanted device was assessed by longitudinal magnetic resonance imaging (MRI) over the course of 6 months, as well as gross morphologic, histologic, biochemical, and biomechanical analysis (tension and compression) of explanted tissues (disc and condyle) at the time of sacrifice. When the scaffold remained in the joint space, longitudinal MRI demonstrated that the scaffolds promoted new tissue formation within the joint space throughout the study period. The scaffolds were rapidly populated with host-derived cells and remodeled with formation of new, dense, aligned fibrocartilage resembling native tissue as early as 1 month postimplantation. De-novo formation of peripheral muscular and tendinous attachments resembling those in native tissue was also observed. The remodeled scaffolds approached native disc biochemical composition and compressive modulus, and possessed 50% of the tensile modulus within 3 months postimplantation. No degradation of the condylar surface was observed. These results suggest that this acellular bioscaffold fills a medical need for which there is currently no effective treatment and may represent a clinically relevant "off-the-shelf" implant for reconstruction of the TMJ disc.

The objective of this retrospective study was to introduce and evaluate an arthroscopic discopexy for closure of retrodiscal tissue perforations. A total of 112 patients (135 joints) receiving an arthroscopic discopexy for management of retrodiscal tissue perforations between January 2016 and September 2019 were included. Pre- and postoperative visual analogue scale (VAS) pain scores and maximum inter-incisal opening (MIO), as well as magnetic resonance imaging (MRI) data, were collected and analysed. Success was recorded when the disc position was >11 o'clock, VAS pain score <3, and MIO>25 mm. For patients with a condyle deformity, postoperative bone remodelling was also recorded. The VAS pain score decreased from 3.04 ± 2.66 preoperatively to 0.88 ± 1.13 at 12 months postoperatively (P < 0.001) and MIO increased from 33.90 ± 7.39 mm to 35.19 ± 6.14 mm (P = 0.029). MRI evaluation revealed that 133 discs were successfully repositioned back on top of the condyle. Among these, 11 joints were associated with either VAS pain score ≥3 or MIO ≤25 mm. Therefore, a success rate of 90.4% (122/135) was achieved at 12 months postoperative. Bone remodelling was detected in 72 joints. Arthroscopic discopexy is a minimally invasive and effective treatment for retrodiscal tissue perforations that achieves the purpose of simultaneously restoring the intra-articular structures and relieving clinical symptoms., (Copyright © 2021 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Measuring bone density (BD) is a common method of determining bone quality; however, the relationship between condylar BD and the occurrence of temporomandibular joint (TMJ) disorders has not been investigated. To address this knowledge gap, we aimed to investigate condylar BD in terms of TMJ disk displacement (TMJ DD) using computed tomography (CT) and magnetic resonance imaging (MRI). We classified TMJ MRI results according to the position of the disk: normal disk position (Normal), anterior disk displacement with reduction (ADDR), and anterior disk displacement without reduction (ADDNR). After retrospectively evaluating 86 female condyles, we determined the total, cortical, and trabecular BD in the upper-joint portion of the condyle and the whole condyle using CT data. To standardize condylar BD, we calculated the BD ratios by dividing the condylar BD by the cervical axis BD. The Kruskal-Wallis test analyzed the differences in BD measurements in the TMJ DD patient groups and showed significant between-group differences in condylar BD. The total and trabecular BD was significantly higher in ADDNR condyles than in Normal or ADDR condyles (Normal = ADDR < ADDNR). However, there was no significant difference in the cortical BD among the three TMJ DD groups. The BD ratios showed a similar tendency with condylar BD. These results suggest that increased condylar BD - specifically total and trabecular BD - may be significantly associated with ADDNR condyles. Our findings will help clinicians determine the course of treatment for patients with disk-related TMJ disorders., (Copyright © 2021 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.)

Purpose: The aim of this study was to investigate the clinical characteristics of disc perforation (DP) of temporomandibular joint (TMJ) at different ages. METHODS：Patients with TMJ disc perforation admitted to the Department of Trauma and Temporomandibular Joint Surgery Stomatological Hospital of Wuhan University, from April 2012 to May 2021 were included in this study. They were divided into 6 groups according to different ages. Clinical and CBCT radiographic features were analyzed. Clinical features included maximal interincisal opening, pain, clicking，and occlusal changes. Imaging features included condylar absorption flattening, hyperplasia or osteophyte formation, sclerosis, subchondral cysts, depression defects, and blurred anterior slope. The clinical and imaging characteristics of patients in different age groups were statistically analyzed. SPSS 26.0 software was used for statistical analysis, and Chi-square test was used to compare the distribution of clinical symptoms and imaging features in patients of different ages., Results: A total of 368 patients were collected, including 24 males, with an average age of 27.63±15.90 years. There were 344 females with an average age of 32.61±15.61 years. The incidence of pain was 21.31%, occlusal change was 50.82%, and condylar absorption flat was 50.82% in the 10-19 age group. The incidence of pain in 20-29 age group was 31.06%, occlusal change was 53.42%, and condylar absorption flattening was 45.34%. In 50-59 age group, the incidence of pain was 83.33%, occlusal changes were 2.38%, and hyperplasia or osteophyte formation was 47.62%. In age group ≥60 years old, the incidence of pain was 82.86%, occlusal changes were 2.86%, and hyperplasia or osteophyte formation was 60%., Conclusions: In terms of clinical features, patients under 40 years old are more likely to have occlusal changes, while patients over 40 years old are most likely to have joint pain. Radiographically, patients under 40 years old are mainly characterized by bone loss in the condyle, while patients over 40 years old are mainly characterized by condylar hyperplasia.

Objective: The objective of the study is to determine the role of Lateral Pterygoid Muscle LPM in the articular disc displacement ADD, which is considered controversial due to the variations in the pattern of insertion of the Superior Lateral Pterygoid Muscle SPLM., Background: It is well understood that the superior head of the lateral pterygoid muscle has only a single insertion pattern among individuals, in which the muscle is attached to the articular disc and capsule. However, recent findings in many studies have shown a noticeable variation in the insertion pattern of the upper LPM., Methods: MRI examinations were collected at King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia. Scans of 61 patients (41 females, 20 males; mean age 33 years old) with symptoms of temporomandibular dysfunction were reviewed retrospectively. The direction of their articular disc displacement was evaluated through sagittal and coronal views in both open and closed mouth positions., Results: There was no statistical significance found between the LPM attachment types and TMJ disc position. The chi-square test also showed no significant difference between the type of LPM attachment and the condylar location. Forty-five percent of the articular discs were located between the articular eminence and the glenoid fossa. The majority of the disc displacement was in the anterior direction., Conclusion: There was no statistically significant association found between the type of LPM attachments and the direction of disc displacement., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Value of ultrasonography method in the diagnosis of temporomandibular disorders and patient management monitoring is underestimated. Application of ultrasonography in the diagnosis of patients with temporomandibular disorders in many countries is limited. The main advantage and feature of the method is the ability to conduct examination in dynamics (during the function). Its safety and availability allow applying the method often and at different stages of diagnosis and treatment. So, ultrasonography fully satisfies the needs of primary diagnosing. MRI remains the recognized «gold standard» for the diagnosis of temporomandibular disorders. A case report which is presented, demonstrates the relevance and scope of diagnostic information obtained by ultrasonography, and their verification and clarification with the use of magnetic resonance imaging. Upon comparing the results of USG and MRI described in the clinical case report, we can conclude that ultrasound is quite sensitive and specific in diagnosing anterior disc displacement and blocked movement of the head of the mandible.

This prospective clinical study aimed to establish a new classification system for TMJ internal derangement based on MRI in correlation with clinical findings contributing to a nonsurgical treatment protocol. A consecutive sample of 435 internal derangement patients was enrolled in the study. Clinical and MRI studies were used to establish the new classification system. A total of 747 joints were classified according to our staging system and received treatment according to the associated nonsurgical treatment protocol. The primary outcome variables were maximum voluntary mouth opening and visual analogue scale pain scores. The secondary outcome variable was joint sound. Statistical analysis of the differences between pretreatment and posttreatment measurements showed an increase in mouth opening throughout the study period (P < 0.001 at 12 m posttreatment). Statistical analysis of the VAS scores showed a statistically significant decrease in all study groups during all study periods, with P < 0.0001 at 12 months posttreatment. Statistical analysis of joint sounds showed significant improvement during all study periods. The new classification system is a simple, & reasonable including a detailed description of all the pathologic changes of the joint. The nonsurgical treatment protocol was Simple, effective and specific depending on the pathological changes in joint., (© 2021. The Author(s).)

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.