TMJ Disorders: Future Innovations in Diagnostics and Therapeutics

Minimum clinically important difference and substantial clinical benefit in patients with chronic temporomandibular disorders

BACKGROUND

Research on temporomandibular disorder (TMD) responsiveness is scarce and limited regarding patients' representativeness.

OBJECTIVE(S)

This study aimed to estimate minimum clinically important difference (MCID) and substantial clinical benefit (SCB) among a large and diverse patient population regarding sex and age.

METHODS

In this study, 162 patients participated from five hospitals. MCID and SCB in pain, functional disability and quality of life were examined with anchor-based methods. Patients' global impression of change was used as the anchor. Area under the curve (AUC) values were determined for testing accuracy. Changes from baseline and coefficient of variation by responsiveness status were calculated to explain the results of accuracy.

RESULTS

SCB was estimated to be 2.18 for the numeric rating scale (NRS) for pain (AUC: 0.80 [95% CI: 0.72-0.88]) in all patients and 2.50 in women (AUC: 0.81 [95% CI: 0.71-0.89]). The estimated SCB of NRS for discomfort (1.50) and Jaw Functional Limitation Scale for mastication (1.35) had wide CIs for AUCs. Likewise, the estimated MCIDs of NRS for pain (0.80) and NRS for discomfort (1.50) had wide CIs for AUCs. Among non-responders who did not achieve the MCID of NRS for pain, the coefficient of variation was very high for all outcomes other than the NRS for pain.

CONCLUSION

This study investigated the responsiveness of patients with TMD using a large and diverse patient sample. SCB in pain decrease can be used to assess the responsiveness of patients with TMD. Composite outcomes should be developed to estimate MCID.

Alendronate treatment rescues the effects of compressive loading of TMJ in osteogenesis imperfecta mice

BACKGROUND

Osteogenesis imperfecta (OI) is a genetic disorder of connective tissue caused by mutations associated with type I collagen, which results in defective extracellular matrix in temporomandibular joint (TMJ) cartilage and subchondral bone. TMJ is a fibrocartilaginous joint expressing type I collagen both in the cartilage and the subchondral bone. In the present study the effects of alendronate and altered loading of the TMJ was analyzed both in male and female OI mice.

MATERIALS AND METHODS

Forty-eight, 10-weeks-old male and female OI mice were divided into 3 groups: (1) Control group: unloaded group, (2) Saline + Loaded: Saline was injected for 2 weeks and then TMJ of mice was loaded for 5 days, (3) alendronate + loaded: alendronate was injected for 2 weeks and then TMJ of mice was loaded for 5 days. Mice in all the groups were euthanized 24-h after the final loading.

RESULTS

Alendronate pretreatment led to significant increase in bone volume and tissue density. Histomorphometrically, alendronate treatment led to increase in mineralization, cartilage thickness and proteoglycan distribution. Increased mineralization paralleled decreased osteoclastic activity. Our immunohistochemistry revealed decreased expression of matrix metallopeptidase 13 and ADAM metallopeptidase with thrombospondin type 1 motif 5.

CONCLUSION

The findings of this research support that alendronate prevented the detrimental effects of loading on the extracellular matrix of the TMJ cartilage and subchondral bone.

Structure-Mechanics Principles and Mechanobiology of Fibrocartilage Pericellular Matrix: A Pivotal Role of Type V Collagen

The pericellular matrix (PCM) is the immediate microniche surrounding resident cells in various tissue types, regulating matrix turnover, cell-matrix cross-talk and disease initiation. This study elucidated the structure-mechanical properties and mechanobiological functions of the PCM in fibrocartilage, a family of connective tissues that sustain complex tensile and compressive loads in vivo. Studying the murine meniscus as the model tissue, we showed that fibrocartilage PCM contains thinner, random collagen fibrillar networks that entrap proteoglycans, a structure distinct from the densely packed, highly aligned collagen fibers in the bulk extracellular matrix (ECM). In comparison to the ECM, the PCM has a lower modulus and greater isotropy, but similar relative viscoelastic properties. In Col5a1 +/- menisci, the reduction of collagen V, a minor collagen localized in the PCM, resulted in aberrant fibril thickening with increased heterogeneity. Consequently, the PCM exhibited a reduced modulus, loss of isotropy and faster viscoelastic relaxation. This disrupted PCM contributes to perturbed mechanotransduction of resident meniscal cells, as illustrated by reduced intracellular calcium signaling, as well as upregulated biosynthesis of lysyl oxidase and tenascin C. When cultured in vitro, Col5a1 +/- meniscal cells synthesized a weakened nascent PCM, which had inferior properties towards protecting resident cells against applied tensile stretch. These findings underscore the PCM as a distinctive microstructure that governs fibrocartilage mechanobiology, and highlight the pivotal role of collagen V in PCM function. Targeting the PCM or its molecular constituents holds promise for enhancing not only meniscus regeneration and osteoarthritis intervention, but also addressing diseases across various fibrocartilaginous tissues.

Evaluation of the efficacy of pharmacological treatment in patients with temporomandibular joint dysfunctions using ultrasonography

STATEMENT OF PROBLEM

Temporomandibular joint dysfunctions (TMDs) are complex problems affecting the temporomandibular joints (TMJs), masticatory muscles, or both. TMDs are considered muscle pain caused by contraction and ischemia in the masticatory muscles, but evaluation of the efficacy of pharmacological treatment is lacking.

PURPOSE

The purpose of this clinical study was to evaluate the changes in masticatory muscles, joint space, and main arteries supplying the TMJs after pharmacological therapy in patients with TMDs using ultrasonography (USG).

MATERIAL AND METHODS

The TMJ space, masseter and temporal muscles, temporal superficial artery (TSA), and facial artery (FA) were examined using USG in 30 participants with acute TMD pain before and after 10 days of symptomatic treatment with analgesic and myorelaxant. The bilateral masseter and temporal muscle thicknesses, joint space, and end-diastolic minimum velocity (Ved), minimum end-diastolic minimum velocity (Vmin), peak systolic maximum velocity (Vmax), pulsatility index (PI), and resistance index (RI) values of the TSA and FA were measured and compared before and after pharmacological treatment. The relationship between the masseter muscle thickness and the Ved and Vmin values of the TSA and FA before and after pharmacological treatment was analyzed using the paired sample t test; the relationship between the temporal muscle thickness, TMJ spaces, and Vmax, PI, and RI values of the TSA and FA was analyzed using the Wilcoxon signed-rank test (α=.05).

RESULTS

A significant difference was found between the right temporal muscle thickness before and after medication (P=.01), whereas no statistically significant difference was found in the left temporal muscle thickness (P>.05). A significant difference was found between pretreatment and posttreatment bilateral masseter thicknesses at rest (right P=.014; left P=.004). No statistically significant difference was found in the bilateral joint space or Vmax, Vmin, Ved, PI, and RI values of the TSA and FA before and after treatment (P>.05).

CONCLUSIONS

Pharmacological treatment in participants with acute TMD led to a reduction in masseter and temporal muscle thickness but did not significantly affect joint space and local blood flow. USG is a useful diagnostic tool in the diagnosis and follow-up of TMDs.

Evaluation of intra-articular injection of injectable platelet-rich fibrin, anterior repositioning splint and arthrocentesis in treatment of temporomandibular joint internal derangement

The current research paper was designed to assess the impact of an intra-articular injection of injectable platelet-rich fibrin (I-PRF) following arthrocentesis and the use of an anterior repositioning splint (ARS) as a proposed treatment approach for addressing symptomatic internal derangement of the temporomandibular joint (TMJ). This study comprised thirty patients who presented with bilateral disc displacement without reduction. The patients were evenly distributed into two groups: Group I underwent treatment involving ARS and arthrocentesis alone, while Group II underwent treatment with ARS, arthrocentesis, and the injection of I-PRF. Clinical assessment of all patients was done postoperatively in the following intervals; first week, first month, third month, and six months for maximum mouth opening (MMO), right and left lateral excursion, and pain score. Magnetic resonance imaging (MRI) assessment for all joints was done at the sixth month postoperatively. Both groups demonstrated improvement in MMO, lateral excursion, and pain. Significant statistical differences were observed in the mean values of MMO and Visual Analogue Scale (VAS), favouring the I-PRF group. MRI postoperatively showed no significant changes in disk position or morphology at the end of the sixth month. Administering an intra-articular I-PRF injection subsequent to arthrocentesis demonstrates effectiveness as a treatment approach for alleviating the signs and symptoms associated with internal derangement of the TMJ.

Effect of high voltage electrical stimulation in temporomandibular disorders: a randomized controlled trial

OBJECTIVE

To examine the effects of high voltage electrical stimulation (HVES) on pain intensity, maximum mouth opening (MMO), cervical mobility, head position, pressure pain thresholds (PPTs), bite force, joint sounds, and jaw muscle strength in individuals with temporomandibular disorders (TMDs).

METHODS

Thirty-four individuals with TMDs were randomly divided into the exercise group (EG) (n = 17) and the HVES group (HG) (n = 17). For 4 weeks, EG received exercise therapy alone, while HG received HVES (12 sessions in total, 3 days a week to anterior temporalis and masseter) in conjunction with exercise.

RESULTS

After the treatment, in both groups, pain intensity significantly decreased (p < .001); MMO (7.27 mm in HG and 3.61 mm in EG), cervical mobility, head position, PPTs, bite force, and jaw muscle strength significantly increased (p = .043 to < .001). Joint sounds significantly decreased in the HG (p = .008). Left bite force (p = .040) and left medial pterygoid PPT (p = .013) increased more in EG. The change in left bite force in EG over time was significant (p = .040; ηp2 = .126). The effect sizes of treatments were medium to large (from .527 to 1.602) for the evaluated parameters.

CONCLUSION

Although exercise alone was effective in many parameters evaluated, additional application of HVES provided further improvement for pain, MMO, cervical mobility, PPTs, jaw muscle strength and joint sounds. HVES can be routinely used in clinics for individuals with TMDs.

Correlation between temporomandibular joints and craniocervical posture in patients with bilateral anterial disc displacement

OBJECTIVE

To study the changes of temporomandibular joints and craniocervical posture in adult patients with bilateral anterior disc displacement, and to explore their correlation, which may provide some clinical value for clinical diagnosis and treatment planning.

METHODS

Ninety-eight adult patients were divided into 3 groups: 29 patients in bilateral disc normal position group (BN), 33 patients in bilateral Anterior Disc Displacement With Reduction group (ADDWR) and 36 patients in bilateral Anterior Disc Displacement Without Reduction group (ADDWoR). Dolphin and Uceph software were used to measure 14 items of temporomandibular joint and 11 items of craniocervical posture for comparison and correlation analysis between groups.

RESULTS

There were significant differences in bilateral joint space between three groups. Compared with the BN, the anteroposterior diameter of the condyle was significantly reduced, the condyle was significantly displaced posteriorly and superiorly in the ADDWR and ADDWoR, but the joint fossa width and joint fossa depth did not change significantly. Cervical curvature and inclination were greater in patients with anterior disc displacement than BN, indicating that the craniocervical posture of adult patients with anterior disc displacement was extended and protrusive.

CONCLUSION

Anterior disc displacement of the temporomandibular joint can displace the condyle upwards and posteriorly and reduce the anteroposterior diameter of condyle, and then make the condyle closer to the wall of articular fossa to induce joint symptoms. Additionally, craniocervical postural position is significantly affected, which may be related to compensate for the effects of airway space.

Temporomandibular Dysfunction and Voice-Related Quality of Life Impairment

OBJECTIVE

Muscle tension in the head and neck may co-occur with temporomandibular dysfunction (TMD) possibly leading to voice change. Several studies have reported a correlation between TMD and dysphonia. However, literature on TMD and voice-related quality of life (QOL) is scant. This study aimed to investigate the relationship between TMD and self-perceived voice-related QOL impairment.

METHODS

Patients from TMD clinic were prospectively surveyed on voice-related quality of life using the Voice Handicap Index (VHI) questionnaire. Patients were queried using paper and pen upon initial evaluation in dentistry clinic for temporomandibular disorders by a single dentist or dental assistant in the otolaryngology department.

RESULTS

A total of 53 patients completed the VHI. 80% of patients presenting to TMD clinic had VHI scores above zero, but most had minimal to mild impairment. Forty-two patients had scores between 1 and 86, (average 10.98); 11 patients had a score of zero (20.75%). Total average score: 8.70, range: 0-86, median: 4. Functional average score: 3.13, range: 0-29, median: 1. Physical average score: 3.58. range: 0-25, median: 2. Emotional average score: 1.98, range: 0-32, median: 0; these averages did not differ from historical controls.

CONCLUSION

The majority of patients presenting to TMD clinic also presented with some level of voice-related QOL impairment, although minimal and consistent with historical VHI controls. Data indicates that TMD disease may be primarily defined as functionally and physically uncomfortable. Incorporation of interdisciplinary care, with laryngology, speech pathology, physical therapy, counseling, and pain management may be warranted.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:315-317, 2024.

Efficacy of Arthrocentesis with and Without Sodium Hyaluronate Injection for Temporomandibular Joint Disorders: A Comparative Study

Aim

To evaluate the efficacy of arthrocentesis with and without sodium hyaluronate injection for internal derangement of temporomandibular joint.

Materials and Methods

Patients with clinically and radiographically confirmed cases of temporomandibular joint disorders were enrolled for this study. 20 patients were randomly allocated into two groups for arthrocentesis of TMJ with 10 patients in each group. In group 1, patients were treated with TMJ arthrocentesis followed by sodium hyaluronate injection, and in group 2, patients were treated with arthrocentesis alone. All the patients were treated under local anaesthesia. The patients were followed up at 1st week, 2nd week, 4th week and 12th week post operatively for maximum mouth opening, lateral mandibular movements, pain at rest and on mastication and the subjective efficacy of the treatment.

Results

By the end of twelfth week follow up, the mean mouth opening showed significant improvement in group 1, the right and left lateral movements showed better results in group 1 than in group 2, pain at rest and pain on mastication were mild in both the groups with subjective efficacy good in group 1 and moderate in group 2.

Conclusion

This study suggested that TMJ arthrocentesis with sodium hyaluronate injection had better clinical outcome compared to TMJ arthrocentesis alone for TMJ disorders.

Temporomandibular treatments are significantly efficient in improving otologic symptoms

Symptoms of temporomandibular disorders (TMD) could be present as otologic symptoms like earache and dizziness in some patients. In most cases, these symptoms are not recognized because otolaryngologists fail to diagnose TMD as a source of the problem. This investigation was conducted to evaluate the effect of TMD treatments on the otologic symptoms which after taking history and clinical examinations seemed to be related to TMD. In the present study, the patients who were complaining of otalgia, ear fullness, tinnitus, hearing loss, and dizziness were evaluated by an ear fellow. Forty patients who had no known otologic or other primary causes to explain their symptoms, were referred to the orofacial pain clinic with the possible diagnosis of TMD. If the diagnosis was confirmed by an orofacial pain specialist, a combination of TMD treatments was administered to each case and the patients were followed up. The results showed that following implementation of treatment protocols for TMD, more than 50% of the patients reported complete or partial recovery in the second follow-up (p < 0.05). The most common otologic symptom of the referred cases was earache, and the most common associated complaint was neck pain. All the patients had one or more parafunctional habits. This study showed that TMD treatments were significantly efficient in improving otologic symptoms partially or completely and the authors concluded that for the patients with otolaryngologic unexplained symptoms, an overhaul examination is needed to assess TMD as a possible cause of the patient complaint. It is recommended that in cases with unexplained otologic symptoms, otolaryngologists care more about the neck trigger points (TP) and ask about the patient's parafunctional habits. Otolaryngologists and dentists need to be aware of the risk of developing otologic symptoms caused by these habits or cervical TPs.

Prevalence of temporomandibular disorders in the Brazilian population: A systematic review and meta-analysis

This systematic review aimed to assess the prevalence of temporomandibular disorders (TMD) in the Brazilian population, with studies that used the RDC/TMD or DC/TMD as diagnostic tools. A total of 6365 people from 11 studies were included. Sample mean age ranged from 12 to 69.5 years. The pooled prevalence of TMD was 33.6% (95% CI 31.5-35.8; I2 = 37.2). Prevalence of TMD was higher in females (37.0%) than in males (29.3%). Our results indicate that TMD is a prevalent condition across Brazil's territories. The results from this meta-analysis can help calculate more accurate sample sizes for future studies.

Repair and remodeling of the mandibular head of the condylar process in four immature dogs

Spontaneous repair and remodeling of the mandibular head of the condylar process is a rarely reported outcome following condylectomy. This clinical report describes the spontaneous repair and subsequent remodeling of the mandibular head of the condylar process in four immature dogs that sustained traumatic injuries, necessitating surgical intervention through arthroplasty via partial or complete condylectomy, or caudal mandibulectomy. In subsequent evaluations, it was observed that all dogs exhibited clinically functional TMJs, as evidenced by an appropriate range of motion. These findings were corroborated by the owners' reports of the patient's normal eating and drinking abilities. Conventional and cone-beam computed tomography studies demonstrated the repair and remodeling of the osseous tissues of the mandibular head of the condylar process. Histopathology was unavailable to assess the novel tissues. No evidence of intraarticular or extraarticular ankylosis or osteoarthritic changes was observed.

Single-cell RNA sequencing reveals neurovascular-osteochondral network crosstalk during temporomandibular joint osteoarthritis: Pilot study in a human condylar cartilage

Purpose

Temporomandibular joint osteoarthritis (TMJ-OA) is one of the most complex temporomandibular disorders, causing pain and dysfunction. The main pathological feature of TMJ-OA is neurovascular invasion from the subchondral bone to the condylar cartilage. This study aimed to discover the cells and genes that play an important role in the neurovascular-osteochondral network crosstalk in human TMJ-OA.

Materials and methods

Condylar cartilages from patient with TMJ-OA were divided into OA group, and others from patients with benign condylar hyperplasia (CH) were used as control for further single-cell RNA-sequencing (scRNA-seq). Hematoxylin and eosin staining were performed. The cells and genes in the condylar cartilage were identified and analyzed by scRNA-seq.

Results

Histological analysis revealed blood vessel invasion and ossification in the TMJ-OA condylar cartilage. The scRNA-seq identified immune cells, endothelial cells, and chondrocytes in the TMJ-OA condylar cartilage. Macrophages, especially M1-like macrophages, contributed to the inflammation, angiogenesis, and innervation. CD31+ endothelial cells contributed to the bone mineralization. The TMJ-OA cartilage chondrocytes highly expressed genes related to inflammation, angiogenesis, innervation, and ossification. The hub genes contributing to these processes in the TMJ-OA chondrocytes included CTGF, FBN1, FN1, EGFR, and ITGA5.

Conclusion

Our study marks the first time scRNA-seq was used to identify the cells and genes in a human TMJ-OA condylar cartilage, and neurovascular-osteochondral network crosstalk during the human TMJ-OA process was demonstrated. Targeting the crosstalk of these processes may be a potential comprehensive and effective therapeutic strategy for human TMJ-OA.

Prevalence of Temporomandibular Disorders in Orthognathic Surgery patients: A systematic review conducted according to PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions

BACKGROUND

Orthognathic surgery is done to treat a variety of dentofacial abnormalities, but a wide gap still remains on how it can result in temporomandibular joint dysfunction (TMD). The primary goal of this review was to assess the effects of various orthognathic surgical techniques on the emergence or exacerbation of TMJ dysfunction.

METHODS

A comprehensive search was conducted across several databases using Boolean operators and MeSH keywords related to temporomandibular joint disorders (TMDs) and orthognathic surgical interventions, with no limitation on the year of publication. Two independent reviewers screened the identified studies based on predetermined inclusion and exclusion criteria, followed by a risk of bias assessment using a standardised tool.

RESULTS

Five articles were considered for inclusion in this review. A greater number of females opted for surgical options than their male cohorts. Three studies were of prospective design, 1 of retrospective and 1 of observational type. Mobility on lateral excursion, tenderness on palpation, arthralgia and popping sounds were the TMD characteristics that showed significant differences. Overall, orthognathic surgical intervention did not show an increase in TMD signs and symptoms as compared to nonsurgical counterparts.

CONCLUSION

Though orthognathic surgery reported greater cases of some TMD symptoms and signs as compared to the nonsurgical cohorts in four studies, the conclusive evidence is debatable. Further studies are recommended with a longer follow-up period and greater sample size to determine the impact of orthognathic surgery on TMJ.

Age-Related Gene and Protein Expression in Mouse Mandibular Condyle Analyzed by Cap Analysis of Gene Expression and Immunohistochemistry

INTRODUCTION

Aging, an inevitable physiological process, leads to morphological and histological degenerative changes in the mandibular condylar cartilage (MCC); however, the molecular mechanism has not yet been elucidated, and little information is available on age-related factors. Therefore, this study was designed to identify age-related factors by investigating the age-related differentially expressed genes (DEGs) and localization of their translated protein expression in the mandibular condyle.

METHODS

Mandibular condyles were collected from 10- and 50-week-old mice. Total RNA was extracted from the samples and then analyzed using cap analysis of gene expression (CAGE) to identify age-related DEGs. Gene ontology (GO) enrichment analysis was performed to determine which biological processes were most affected by aging in terms of gene expression using Metascape. The mandibular condyle samples were processed for histology to investigate morphological changes caused by aging and for immunohistochemistry to localize the protein expression encoded by age-related genes identified with CAGE. Semi-quantitative immunohistochemistry was performed to assess age-related extracellular matrix (ECM) protein levels in the MCC. The histological sections were also used for Alcian blue histochemistry to detect glycosaminoglycans (GAGs).

RESULTS

GO enrichment analysis revealed that the genes related to "extracellular matrix organization," including Acan, Col1a1, Col1a2, Col2a1, Mmp3, Mmp9, and Mmp13, were most differentially expressed in the aged mandibular condyle. Among these seven genes, Mmp3 was upregulated, and the others were downregulated with aging. Histological examination showed the age-related morphological and histological changes in the MCC. Immunohistochemical investigation showed the localization of matrix metalloproteinases (MMPs)-3, -9, and -13 and their substrate proteins, aggrecan, type I collagen, and type II collagen, in the mandibular condyle at 10 and 50 weeks, indicating different localizations between the young and the aged. In the aged MCC, semi-quantitative immunohistochemistry showed a significant decrease in the aggrecan protein level, and Alcian blue histochemistry showed a decrease in GAGs.

CONCLUSION

MMP-3, MMP-9, and MMP-13 contribute to the remodeling of the ECM of the MCC and subchondral bone during aging by degrading ECM proteins at specific times and sites under the regulation of their production and secretion.

Temporomandibular Joint Fibrocartilage Contains CD105 Positive Mouse Mesenchymal Stem/Progenitor Cells with Increased Chondrogenic Potential

Objective

A specific type of mesenchymal stem/progenitor cells (MSPCs), CD105+ is reported to aid in cartilage regeneration through TGF-β/Smad2-signalling. The purpose of this study was to identify and characterize CD105+ MSPCs in temporomandibular joint (TMJ) cartilage.

Materials and Methods

MSPCs were isolated from mouse TMJ condyle explants and evaluated for their clonogenicity and pluripotential abilities. MSPC were examined for CD105 antigen using immunohistochemistry and flow cytometry.

Results

Immunohistochemistry revealed presence of CD105+ MSPCs in the proliferative zone of condyle's cartilage. Only 0.2% of isolated MSPCs exhibited CD105, along with the stem cell surface markers CD44 and Sca-1. In CD105+ MSPCs, intracellular immunostaining revealed significantly higher (p < 0.05) protein levels of collagen type 1, 2, proteoglycan 4. Ability for chondrogenic differentiation was found to be significantly higher (p < 0.05) after 4 weeks compared to CD105- cells, using alcian blue staining. CD105+ cells were found to resemble an early MSPC subgroup with significantly higher gene expression of biglycan, proteoglycan 4, collagen type 2, Gli2, Sox5 (p < 0.001) and Sox9 (p < 0.05). In contrast, significantly lower levels of Runx2 (p < 0.05), Osterix, Trps1, Col10a1 (p < 0.01), Ihh (p < 0.001) related to chondrocyte senescence and commitment to osteogenic lineage, were observed compared to CD105- cells.

Conclusion

The study showed the existence of a CD105+ MSPC subgroup within TMJ fibrocartilage that may be activated to aid in fibrocartilage repair.

Dimensional and positional temporomandibular joint osseous characteristics in normodivergent facial patterns with and without temporomandibular disorders

OBJECTIVE

This study evaluated the dimensional and positional osseous temporomandibular joint features in normodivergent facial patterns with and without temporomandibular disorders.

METHODS

A total of 165 adult patients were divided into two groups: group 1 (n = 79 patients; 158 joints): temporomandibular disorders patients and group 2 (n = 86 patients; 172 joints): non-temporomandibular disorders patients. Three-dimensional positional and dimensional temporomandibular joint characteristics, including glenoid fossa, mandibular condyles, and joint spaces, were assessed by cone beam computed tomography.

RESULTS

The glenoid fossa positions in the three orthogonal planes and height showed statistical significance between the two studied groups. The temporomandibular disorders patients showed higher horizontal and vertical condyle inclinations while anteroposterior inclination was less, and the condyle was positioned more superior, anterior, and lateral in the glenoid fossa. The condyle width and length showed no significance between the two groups, while condyle height was smaller in temporomandibular disorders patients. Anterior and medial joint spaces increased while the superior and posterior joint spaces reduced in temporomandibular disorders patients.

CONCLUSION

There were significant differences between the patients with and without temporomandibular joint disorders in terms of mandibular fossa positions and height as well as condylar positions and inclinations in horizontal and vertical planes together with reduced condylar height and reduced posterior and superior joint spaces in the temporomandibular disorders patients.

CLINICAL RELEVANCE

The temporomandibular disorder is a multifactorial disorder in which one of these factors is the dimensional and positional characteristics of the temporomandibular joints; including or excluding this factor requires a comprehensive three-dimensional investigation of patients with TMD compared to the normal group under the condition that the facial pattern is average as a confounding factor.

Assessing change in functional outcomes and quality of life in myogenic temporomandibular disorders undergoing botulinum toxin injection: A before and after comparison

PURPOSE

This prospective study aimed to evaluate the changes in functional outcomes and quality of life after the injection of botulinum toxin (BTX) into the masticatory muscles for the management of myogenic temporomandibular disorders (TMDs).

MATERIALS AND METHODS

This study was conducted with 45 individuals who presented with clinically myogenic TMDs according to the Diagnostic Criteria for Temporomandibular Disorders. All patients received BTX injections in the temporalis and masseter muscles. The Oral Health Impact Profile-Temporomandibular Dysfunction (OHIP-TMD) questionnaire was used to evaluate the effects of treatment on quality of life. The OHIP-TMD, visual analogue scale (VAS), and maximum mouth opening (MMO) scores before and 3 months after BTX injection were evaluated.

RESULTS

The preoperative and postoperative assessments revealed a statistically significant reduction (p ≤ 0.001) in the average overall OHIP-TMD scores. A significant increase in the MMO scores and a significant decrease in the VAS scores were observed (p < 0.001).

CONCLUSIONS

The injection of BTX into the masticatory muscles is beneficial for improving the clinical and quality of life parameters in the management of myogenic TMD.

Comparative evaluation of the trabecular structure of the mandibular condyle, the levels of salivary cortisol, MMP-3, TNF-α, IL-1β in individuals with and without temporomandibular joint disorder

OBJECTIVE

Temporomandibular disorder (TMD) is still a challenge in terms of diagnosis and management. The aim of this study is to explore if the evaluation of salivary biomarkers and fractal dimension (FD) of mandibular condyle could be useful for interpreting early degenerative changes and the effectiveness of salivary cortisol in determining the stress levels of TMD patients.

MATERIALS AND METHODS

34 patients with TMD, and 34 healthy controls were included in this study. Saliva samples were obtained from all participants between 09:00-12:00 am. Salivary cortisol, IL-1β, TNF-α, and MMP-3 levels were evaluated with ELISA method. FD of the mandibular condyle was determined by means of box-counting method. Depression and anxiety were determined with PHQ-9 and GAD-7 questionnaires.

RESULTS

The salivary cortisol and depression/anxiety were higher in study group; however, not significant (p>0.05). FD of the study group was found significantly lower than the control group (p<0.01). Salivary TNF-α, IL-1β and MMP-3 levels were showed no significant difference between the two groups (p>0.05). There were no significant correlations between the evaluated parameters.

CONCLUSION

Salivary cortisol seems to be a non-invasive way of measuring physiological stress of TMD patients. Fractal analysis may be a useful tool in detecting early structural changes in mandibular condyle. Salivary TNF-α. IL-1β and MMP-3 have not a diagnostic value in terms of interpreting early degenerative changes.

Clinical aspects and outcomes in osteoarthritis

Osteoarthritis (OA) is the most prevalent type of arthritis worldwide, and its incidence significantly increases with age. It commonly affects the knees, hips, spine, big toes, and hands. OA can be identified through clinical examination, symptoms, and imaging methods. Its main symptoms include pain, stiffness, and limitations in joint movement. Examinations may reveal coarse crepitus, bony enlargement, and tenderness at the joint line. In severe cases of OA, rest pain, night pain, and deformity may occur. OA can lead to decreased physical activity, function, and quality of life due to symptoms such as pain and stiffness. To evaluate these impacts, patient-reported outcome measures (PROMs) are necessary. Various generic, disease-specific, and joint-specific PROMs have been developed and used in clinical practice to assess the outcomes of OA.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Therapy for Temporomandibular Disorders: 3D-Printed Splints from Planning to Evaluation

INTRODUCTION

This article describes the authors' digital workflow-based method for fabricating intraoral occlusal splints, from planning to the evaluation phase.

MATERIALS AND METHODS

In our protocol, first, we had a registration phase. This included taking digital impressions, determining the centric relation (CR) position with the deprogrammer Luci Jig, and using the digital facebow for measuring the individual values. The laboratory phase was next, which included planning and manufacturing with a 3D printer. The last phase was delivery, when we checked the stability of the splint and adjusted the occlusal part.

RESULT

The average cost is lower for a fully digital splint than for conventional methods. In terms of time, there was also a significant difference between the classic and digital routes. From a dental technical point of view, the execution was much more predictable. The printed material was very rigid and, therefore, fragile. Compared to the analog method, the retention was much weaker.

CONCLUSION

The presented method permits time-efficient laboratory production, and may also be performed chairside in a dental office. The technology is perfectly applicable to everyday life. In addition to its many beneficial properties, its negative properties must also be highlighted.

Comparison of imaging findings of 714 symptomatic and asymptomatic temporomandibular joints: a retrospective study

BACKGROUND

The correlation between temporomandibular disorders (TMD) and imaging features remains unclear. This study compared the cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) features in the temporomandibular joints (TMJs) with and without TMD symptoms.

METHODS

The participants were recruited from the TMJ Diagnosis and Treatment Center from March 2022 to September 2022. Condylar morphology and condylar position were evaluated by CBCT. Disc morphology, disc position, and joint effusion were evaluated by T2-weighted image of MRI. The Chi-Square test and binary logistic regression analysis were carried out.

RESULTS

Eighty-two patients with bilateral symptoms, 196 patients with unilateral symptoms, and 79 asymptomatic participants received MRI and CBCT examination. There were significant differences in the distribution of sex, age, condylar morphology, condylar position, disc morphology, disc position, and joint effusion in symptomatic and asymptomatic TMJs (P < 0.05), which showed a positive correlation with symptoms (P < 0.05). In multiple logistic regression, 19-30-year-age group, > 30-year-age group, abnormal condylar morphology, posterior condylar position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWoR) were found to be statistically significant (P < 0.05). The odds of having symptomatic TMJ were 1.952 higher in the 19-30-year-age group and 1.814 higher in the > 30-year-age group when compared to those aged ≤ 18-year-age group. The odds of having symptomatic TMJ were 2.360 higher in persons with abnormal condylar morphology when compared to those with normal condylar morphology. The odds of having symptomatic TMJ were 2.591 higher in persons with posterior condylar position when compared to those with the normal condylar position. The odds of having symptomatic TMJ were 2.764 higher in persons with DDWR and 4.189 higher in persons with DDWoR when compared to those with normal disc position. The area under the curve of the model was 0.736 ± 0.019 (95% CI 0.700-0.773, P = 0.000), which indicated that the model has a good fitting effect.

CONCLUSIONS

The imaging findings of TMJs were significantly different between symptomatic and asymptomatic TMJs. TMD is affected by multiple factors including > 19-year-age, abnormal condylar morphology, posterior condylar position, DDWR, and DDWoR, which could be risk factors for the development of TMD symptoms. Trial registration This study was retrospectively registered on 28/03/2022 and endorsed by the Ethics Committee of Affiliated Stomatology Hospital of Guangzhou Medical University (LCYJ2022014).

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Evaluation of the temporomandibular joint morphology and condylar position with cone-beam computerized tomography in patients with internal derangement

OBJECTIVES

To evaluate the relationship between internal derangement and morphological features of the temporomandibular joint by comparing joint morphology between patients with ID and control patients.

METHODS

The current study prospectively is evaluated the cone-beam computed images of 106 ID patients and 122 patients with asymptomatic joints; recorded angular and linear measurements. The relationships between these measurements and ID are investigated; the differences between the two groups using paired t tests.

RESULTS

There were significant differences in the values of articular slope and the condyle height/glenoid fossa depth (CH/GFD) ratio between patients in the ID and control groups (p < 0.05). There was also a relationship between these parameters and the gender of patients with ID. The condylar position was posterior in the ID group.

CONCLUSION

Posteriorly and superiorly located condyles with an increased CH/GFD ratio, condyles located eccentrically, and a steeper posterior slope may be risk factors for ID.

Anabolic Response of Intermittent Parathyroid Hormone and Alendronate on the Osteochondral Tissue of TMJ

OBJECTIVE

To characterize the effects of parathyroid hormone (PTH) and alendronate (Alend) on the osteochondral tissue of temporomandibular joint (TMJ).

MATERIALS AND METHODS

Ninety-six male and female transgenic reporter mice, 4 to 5 weeks old were divided into 6 groups: (1) Control group: Saline was injected daily for 14 days; (2) PTH: PTH was injected daily for 14 days; (3) Alend: Alend was injected every alternate days for 14 days; (4) Combined PTH and Alend: PTH was injected daily and Alend injected every alternate days for 14 days; (5) PTH then Alend: PTH was injected daily for 14 days followed by Alend injections in alternate days for 14 days; and (6) PTH wait Alend: PTH was injected daily for 14 days. There was a waiting period of 1 week before administration of Alend in alternate days for 14 days. Mice were injected with 5-ethnyl-2'-deoxyuridine (EdU), 48 and 24 hours prior to euthanization.

RESULTS

There was significant increase in bone volume and decrease in osteoclastic activity in groups in which Alend was administered after PTH in both gender. There was significant increase in cartilage thickness with PTH or Alend alone in females, whereas in males, PTH alone led to increase in cartilage thickness. Chondrocyte apoptosis was significantly decreased with PTH or Alend alone in both male and female. Matrix metallopeptidase 13, and aggreganase-2 (ADAMTS5) expression were significantly decreased with PTH and Alend alone in both gender.

CONCLUSION

PTH and Alend administration causes anabolic effects in the osteochondral tissue of TMJ.

Thread Embedding Acupuncture for Temporomandibular Disorder: Protocol for a Pilot Randomized Controlled Trial

Background

Temporomandibular disorder (TMD) affects multiple tissues of the temporomandibular joint complex and manifests as orofacial pain and functional disturbance. While thread embedding acupuncture (TEA) is used for the treatment of TMD in clinical practice, sufficient clinical evidence is lacking. This pilot trial will explore the feasibility of a confirmatory randomized controlled trial (RCT) by considering the efficacy, safety, and cost-effectiveness of TEA to address pain, function, and quality of life in patients with TMD.

Methods

This randomized, assessor-blinded, controlled trial will include two parallel arms. Thirty patients with TMD and temporomandibular joint pain more severe than 40 mm on the 100-mm visual analog scale (VAS) and aged 19-70 years will be recruited and randomly allocated to either TEA or usual care groups. The TEA group will receive treatment at 14 predefined acupoints once weekly for 4 weeks. The usual care group will receive physical therapy consisting of transcutaneous electrical nerve stimulation and infrared therapy. The average VAS score over the last week for temporomandibular pain after four sessions will be assessed as the primary outcome. Furthermore, maximum pain VAS, vertical opening movement, Graded Chronic Pain version 2, Jaw Functional Limitation Scale 20, Patient Global Impression of Change, Korean version of Beck's Depression Index, Short Form-12 Health Survey, EuroQol 5-Dimension 5-level, treatment expectation, rescue medication consumption, adverse events, and medical costs for economic evaluation will be measured and analyzed as secondary outcomes during four follow-up visits and after the termination of all sessions.

Conclusion

The results of this trial will help evaluate the feasibility of a confirmatory RCT considering efficacy, safety, and cost-effectiveness and verify the effect size required to determine an appropriate sample size.

Trial Registration Number

KCT0007421.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Superwettable and injectable GelMA-MSC microspheres promote cartilage repair in temporomandibular joints

Temporomandibular disorders (TMD) can be treated by promoting cartilage regeneration with biomaterials. However, there are deficiencies in the infiltration function of bone filler biological materials. In this study, stems cells were loaded onto gelatin methacryloyl (GelMA) hydrogel microspheres endowed with superwettable properties and TGF-β sustained-release function, which can quickly infiltrate the irregular surface of the temporomandibular joint (TMJ) bone defect area and accelerate cartilage healing. First, to improve cell adhesion and spreading function, the BMSCs-coated GelMA microspheres were endowed with superwetting property. At the same time, the swelling adsorption characteristics of gelatin microspheres could be used to load recombinant TGF-β within the microspheres, which could in turn promote the chondrogenic differentiation of multi-potent bone marrow mesenchymal stem cells. The SEM imaging demonstrated that BMSCs-coated GelMA microsphere has superwettable and superhydrophilic property, which enabled rapid adaptation to the bone defect surface morphology, which is conducive to tissue repair. Furthermore, the cartilage defect model showed that rBMSCs-coated GelMA microspheres promote temporomandibular joint arthritis repair. In conclusion, our study established that BMSC-coated GelMA microspheres endowed with superwetting properties, can colonize the bone defect repair site better with sustained release of growth factors, thus providing an innovative strategy for promoting cartilage regeneration.

UYKU BRUKSİZMİ OLAN MİYOFASYAL TEMPOROMANDİBULAR DİSFONKSİYON TANILI HASTALARDA MANUEL TEDAVİ İLE SPLİNT TEDAVİSİNİN KARŞILAŞTIRILMASI

Purpose: The aim of this study was to examine the effect of manual therapy on temporomandibular pain, range of motion, functionality level of the jaw, sleep quality, and patient satisfaction, and to compare the efficacy with splint therapy among female patients with myofascial temporomandibular dysfunction (M-TMD) accompanied by sleep bruxism (SB). Methods: A total of 29 female patients, aged 18-50 years, diagnosed with M-TMD were separated into two groups using a simple random sampling method as the manual therapy group (MT; n:15) and the splint therapy group (ST; n:14). All the patients were informed about bruxism and its effects and were given home exercises. The patients in the ST group were instructed to use a static splint for one month. The MT group patients received a total of 8 sessions, 45 minutes twice a week of treatment, including joint and soft tissue mobilizations to the temporomandibular joint (TMJ) and cervical region. Pain severity, symptoms, TMJ range of motion, jaw functionality, sleep quality, and patient satisfaction were evaluated. The evaluations were repeated after 4 weeks and compared with baseline values. Results: A statistically significant difference was determined in both groups in pain, TMJ range of motion, and sleep quality (p

Prevalence of Temporomandibular Disorder-Related Pain among Adults Seeking Dental Care: A Cross-Sectional Study

Objectives

Temporomandibular disorders (TMD) are a constellation of painful conditions that affect the craniofacial complex. The etiology and risk factors of these conditions have been extensively studied; however, the data available describing the epidemiology of TMD in the Middle East are scarce. We aimed to estimate the prevalence and risk factors of TMD-related pain in a sample population of dental school clinic patients.

Methods

This observational cross-sectional study used a translated and culturally adapted temporomandibular disorders pain screener, a part of the Diagnostic Criteria/Temporomandibular Disorders (DC/TMD) criteria instrument, and questions related to demographic characteristics and risk factors for TMD. Data were analyzed through chi-square and Mann–Whitney U tests using SPSS.

Results

The sample population included 199 participants (66% female and 34% male). The prevalence of TMD-related pain was 26.8% (n = 42); men and women did not differ statistically in their TMD-related pain. TMD-related pain cases differed significantly on the Center for Epidemiologic Studies Depression Scale (CES-D) and body pain scores compared with noncases.

Conclusion

The prevalence of TMD-related pain in the clinical sample population was high. Hence, the onus is on dental health services to screen and educate patients on TMD conditions regularly.

Lateral Cephalometric Analytical Uses for Temporomandibular Joint Disorders: The Importance of Cervical Posture and Hyoid Position

The temporomandibular joint disorder (TMD) is a syndrome that affects the masticatory muscles and temporomandibular joint (TMJ). Its pathophysiology is not yet fully known. Cephalometric analysis is used for routine evaluation regarding orthodontic treatment and other purposes. The aim of this study was to assess if using cephalometric analysis and TMJ conservative therapy to evaluate the hyoid bone position and the cervical posture reduced symptoms in adults with TMDs compared to no intervention. The authors conducted a systematic review of the literature (PubMed, Cochrane, Web of Science, Scopus, and Embase) for clinical studies of TMDs with conservative treatment and lateral cephalometric analysis of the hyoid and cervical posture. To assess the risk of bias for non-randomized clinical trials ROBINS-I tool was used. Out of 137 studies found, 6 remained to be included. Most of them found a link between TMD and lateral cephalometric analysis, but there was a high risk of bias. This review found a possible link between TMDs, the neck and cervical posture. There is a benefit reported regarding the use of the lateral cephalometry as a treatment, but more extensive prospective randomized clinical trials are necessary to be able to draw definitive conclusions.

Hypoxia-inducible factor expression is related to apoptosis and cartilage degradation in temporomandibular joint osteoarthritis

BACKGROUND

It remains unclear etiology of cartilaginous tissues in osteoarthritis (OA) lesions. In this study, we hypothesized the accumulation of hypoxia-inducible factor (HIF) and activated apoptosis relate to condylar cartilage degeneration in vivo.

METHODS

Malocclusion stress was applied for 2 weeks, 4 weeks and 8 weeks to induce an OA-like lesion animal model in rats. Histological analysis was performed by H&E staining and Safranin O/fast green staining. The expression levels of protein in condylar cartilage were examined by immunostaining to evaluate cartilage degeneration.

RESULTS

We found apparent histological phenotypes associated with degeneration in the occlusion disorder (OD) stress group. The OD group at 4 weeks and 8 weeks had obviously reduced expression of Aggrecan (Acan) and type II collagen (Col II) in cartilage. In contrast, the OD groups had higher levels of ADAM metallopeptidase with thrombospondin type 5 (ADAMTS5) and matrix metallopeptidase 13 (MMP13) in the condylar cartilage than the control group. Moreover, the OD group cartilage had prominent degenerative changes with reduced levels of hypoxia inducible factor 1 alpha (HIF1α) and increased levels of hypoxia inducible factor 2 alpha (HIF2α) and the apoptosis factor Caspase3 in condylar cartilage at 8 weeks.

CONCLUSION

Thus, abnormal hypoxic conditions inducing Occlusion disorder stress results in cartilage degeneration. opposite expression patterns of HIF1α and HIF2α could be involved in the pathogenesis of condylar cartilage degeneration and chondrocyte apoptosis. HIF2α may provide a potential negative feedback mechanism for HIF1α during cartilage damage.

The role of SLRPs and large aggregating proteoglycans in collagen fibrillogenesis, extracellular matrix assembly, and mechanical function of fibrocartilage

PURPOSE

Proteoglycans, especially small leucine rich proteoglycans (SLRPs), play major roles in facilitating the development and regulation of collagen fibers and other extracellular matrix components. However, their roles in fibrocartilage have not been widely reviewed. Here, we discuss both SLRP and large aggregating proteoglycan's roles in collagen fibrillogenesis and extracellular matrix assembly in fibrocartilage tissues such as the meniscus, annulus fibrosus (AF), and TMJ disc. We also discuss their expression levels throughout development, aging and degeneration, as well as repair.

METHODS

A review of literature discussing proteoglycans and collagen fibrillogenesis in fibrocartilage was conducted and data from these manuscripts were analyzed and grouped to discuss trends throughout the tissue's architectural zones and developmental stage.

RESULTS

The spatial collagen architecture of these fibrocartilaginous tissues is reflected in the distribution of proteoglycans expressed, suggesting that each proteoglycan plays an important role in the type of architecture presented and associated mechanical function.

CONCLUSION

The unique structure-function relationship of fibrocartilage makes the varied architectures throughout the tissues imperative for their success and understanding the functions of these proteoglycans in developing and maintaining the fiber structure could inform future work in fibrocartilage replacement using tissue engineered constructs.

Morphologic and histologic characterization of sheep and porcine TMJ as large animal models for tissue engineering applications

Objective

The aim of this study was to compare and characterize the structural and ultrastructural organization of the temporomandibular joint (TMJ) between two large animal models for use in the development of tissue engineering strategies.

Materials and methods

Whole TMJs from sheep and pigs were evaluated with micro-computed tomography (μCT) for morphology and quantitative analyses of bone parameters. Histological examination was performed on the TMJ disc and its attachments to investigate regional distribution of collagen, elastin, and glycosaminoglycans (GAGs).

Results

μCT analyses demonstrate higher bone mineral density (BMD) in the temporal fossa compared to the mandibular condyle in both species, with this variable being significantly higher in sheep than pig. Quantitative morphometry of the trabecular condyle reveals no statistical differences between the species. Histology demonstrates similar structural organization of collagen and elastin between species. Elastin staining was nearly twofold greater in sheep than in the pig disc. Finally, Safranin-O staining for GAGs in the TMJ disc was localized to the intermediate zone in the sheep but was absent from the porcine disc.

Conclusions

Our findings show some important differences in the pig and sheep TMJ μCT variables and histology and composition of the disc and discal attachment. These disparities likely reflect differences in masticatory and TMJ functional loading patterns between the two species and provide insights into large animal models towards human applications.

Clinical relevance

As with the established pig model, the sheep is a suitable large animal model for TMJ research such as regenerative strategies, with specific considerations for design parameters appropriate for human-analog applications.

An updated view on Temporomandibular Joint degeneration: insights from the cell subsets of mandibular condylar cartilage

The high prevalence of temporomandibular joint osteoarthritis (TMJOA), which causes joint dysfunction, indicates the need for more effective methods for treatment and repair. Mandibular condylar cartilage (MCC), a typical fibrocartilage that experiences degenerative changes during the development of TMJOA, has become a research focus and therapeutic target in recent years. MCC is composed of four zones of cells at various stages of differentiation. The cell subsets in MCC exhibit different physiological and pathological characteristics during development and in TMJOA. Most studies of TMJOA are mainly concerned with gene regulation of pathological changes. The corresponding treatment targets with specific cell subsets in MCC may provide more accurate and reliable results for cartilage repair and TMJOA treatment. In this review, we summarized the current research progress on the cell subsets of MCC from the perspective of MCC development and degeneration. We hope to provide a reference for further exploration of the pathological process of TMJOA and improvement of TMJOA treatment.

Is there any differences in magnetic resonance imaging findings of painful temporomandibular joint between patients with and without vertigo?

Background/Aim: Temporomandibular disorder (TMD) is an umbrella term and consists of pathological situations about temporomandibular joint (TMJ) internal structure, masticatory muscle and associated structures. Otalgic complaints are included in the group of complaints within TMJ associated structures and are frequently seen with TMD. The aim of this study is to evaluate the magnetic resonance imaging findings (MRI) of patients who had unilateral pain in the preauricular region, diagnosed with vertigo. Material and Methods: The present retrospective and cross-sectional clinical study was carried out on patients presenting with preauricular pain referred to XXX University Faculty of Dentistry Department of Oral and Maxillofacial Surgery between 2018 and 2020. There were 2 groups as vertigo and health groups. MRI findings were the primary predictor variables, while pain was the primary outcome variable, recorded on a visual analog scale (VAS). Results: 120 patients were included in the study. The patients included in both groups are between 19 and 65 years of age and there is no significant statistical difference between mean ages of the groups (p>0.05). The VAS values varies between 6 and 9 in both groups. There is no significant statistical difference between mean VAS values of the groups (p>0.05). On the painful side there is no significant difference between the groups in terms of disc/condyle relation (p>0.05). On the other hand moderate effusion (61.4%) was significantly higher in the healthy group while severe effusion (54%) was significantly higher in the vertigo group (p<0.01). Conclusions: Although both groups had the same pain scale, it was observed that the vertigo group had more dramatic MRI findings in terms of disc/condyle relation and presence of effusion. This study is the first to evaluate the disc/condyle relation and the presence of effusion through MRI in vertigo patients diagnosed with TMD.

Evaluation of wear behaviour of various occlusal splint materials and manufacturing processes

OBJECTIVES

To investigate the volumetric and vertical loss of occlusal splints manufactured by conventional (heat-cure), subtractive (CAD/CAM) and additive (3D-printing) methods.

METHODS

Six occlusal splint materials were investigated (n = 126), using three manufacturing methods: heat-cured, CAD/CAM and 3D-printed built-in three different printing angles (0°,45°and 90°). Block-on-ring wear testing was performed with extracted human molars as the antagonist. All samples were tested with an applied force of 49N at 1 Hz and 60RPM in artificial saliva at 37 °C for six and 12 months. Scanning electron microscopy images were analysed to evaluate the wear on the tooth enamel and in the splint material. Volumetric and vertical wear loss were statistically analysed.

RESULTS

The lowest volumetric and vertical loss was observed in CAD-CAM materials (6.44 ± 1.77 mm³ and 48.3 ± 7.14 μm) with no statistical significance to the heat-cured material (17.22 ± 9.23 mm³ and 148 ± 121.1 μm) after 12 months (p < 0.172). The mean volumetric loss of 3D printed materials ranged from 0.25 ± 0.15 mm³ to 0.29 ± 0.1 4mm³ with no statistical difference, whereas, the differences in vertical loss from 131.63 ± 44.1 μm to 493 ± 79.19 μm were statistically significant (p < 0.001). The highest vertical loss was observed in the KeySplint Soft 3D printed at 90° (385.35 ± 82.37 μm), whereas FreePrint Splint 2.0 with a build angle of 0° had the highest volumetric loss (204.59 ± 25.67 mm³).

CONCLUSION

CAD-CAM material had the highest wear resistance followed by heat-cured material.KeySplint Soft and FreePrint Splint 2.0 3D printed materials would be preferred for patients that do not have severe bruxing episodes. No significant wear of human enamel after six and 12 months was observed under SEM for any tested materials.

Depth-dependent patterns in shear modulus of temporomandibular joint cartilage correspond to tissue structure and anatomic location

To fully understand TMJ cartilage degeneration and appropriate repair mechanisms, it is critical to understand the native structure-mechanics relationships of TMJ cartilage and any local variation that may occur in the tissue. Here, we used confocal elastography and digital image correlation to measure the depth-dependent shear properties as well as the structural properties of TMJ cartilage at different anatomic locations on the condyle to identify depth-dependent changes in shear mechanics and structure. We found that samples at every anatomic location showed qualitatively similar shear modulus profiles as a function of depth. In every sample, four distinct zones of mechanical behavior were observed, with shear modulus values spanning 3-5 orders of magnitude across zones. However, quantitative characteristics of shear modulus profiles varied by anatomic location, particularly zone size and location, with the most significant variation in zonal width occurring in the fibrocartilage surface layer (zone 1). This anatomic variation suggests that different locations on the TMJ condyle may play unique mechanical roles in TMJ function. Furthermore, zones identified in the mechanical data corresponded on a sample-by-sample basis to zones identified in the structural data, indicating the known structural zones of TMJ cartilage may also play unique mechanical roles in TMJ function.

BMP2 Is Required for Postnatal Maintenance of Osteochondral Tissues of the Temporomandibular Joint

OBJECTIVE

Bone morphogenetic protein 2 (BMP2) plays important roles in cartilage growth and development. Paradoxically, elevated levels of BMP2 leads to hypertrophic differentiation and osteoarthritis of cartilage. We examined the in vivo loss of BMP2 in cells expressing aggrecan of the mandibular condyle and knee.

DESIGN

Three-week-old BMP2 flox/flox-CreER-positive mice and their Cre-negative littermates were treated with tamoxifen and raised until 3 or 6 months. We also investigated the direct effects of BMP2 on chondrocytes in vitro. Cells from the mandibular condyle of mice were treated with recombinant human BMP2 (rhBMP2) or rhNoggin (inhibitor of BMP2 signaling).

RESULTS

Conditional deletion of BMP2 caused breakage of the cartilage integrity in the mandibular condyle of mice from both age groups, accompanied by a decrease in cartilage thickness, matrix synthesis, mineralization, chondrocyte proliferation, and increased expression of degeneration markers, while the effects at articular cartilage were not significant. In vitro results revealed that rhBMP2 increased chondrocyte proliferation, mineralization, and differentiation, while noggin induced opposite effects.

CONCLUSIONS

In conclusion, BMP2 is essential for postnatal maintenance of the osteochondral tissues of the mandibular condyle.

Assessments of Muscle Thickness and Tonicity of the Masseter and Sternocleidomastoid Muscles and Maximum Mouth Opening in Patients with Temporomandibular Disorder

The purpose of this study was to compare the muscle thickness and tone of the masseter and sternocleidomastoid (SCM) muscles and maximum mouth opening (MMO) in subjects with and without temporomandibular disorders (TMD), and perform a correlation comparison on the results of the TMD group. Sixty patients were allocated to the TMD group (n = 30) or the non-TMD group (n = 30). Ultrasound imaging, myotonometer, and vernier calipers were used to determine the related changes in muscle thickness and muscle tone in masseter and SCM, and MMO, respectively. The TMD group revealed a significant decrease than the non-TMD group in the muscle thickness of masseter and SCM, respectively (p < 0.001), with a significant increase in frequency (p < 0.001) and stiffness (p < 0.001) in the masseter muscle tone, with a significant increase in frequency (p < 0.001) and stiffness (p = 0.005) in the SCM muscle tone, a significant decrease in the MMO (p < 0.001). There was a moderate negative correlation between the relaxed state of masseter muscle thickness and stiffness of SCM muscle tone (r = −0.40, p = 0.002), and a moderate negative correlation between the relaxed state of SCM muscle thickness and frequency of SCM muscle tone (r = −0.42, p = 0.001). There was a moderate negative correlation between the clenching state of SCM muscle thickness and the frequency of SCM muscle tone (r = −0.47, p < 0.001). In addition, a moderate negative correlation between MMO and frequency of SCM muscle tone (r = −0.44, p < 0.001). The muscle thickness was decreased, and the muscle tone was increased in the masseter and SCM muscle, respectively. Additionally, MMO was decreased in patients with TMD compared with non-TMD.

Association between Self-Reported Bruxism, Peripartum Depression and Myogenous Temporomandibular Disorders among Postpartum Women in Turkey

Background/Aim: It is possible to find studies in the literature evaluating the relationship among self-reported bruxism, psychological factors, and myogenous temporomandibular disorder. In addition, the relationship between these issues has not yet been clarified. The objective of this study was to evaluate the association between peripartum depression, self-reported bruxism, and myogenous temporomandibular disorders among postpartum women in Turkey.

Material and Methods: This study included 220 women, whom were asked about their bruxism behaviour during day and during sleep. Besides, all of them assessed with Short-Form Fonseca’s Anamnestic Index for myogenous temporomandibular disorder and the Edinburgh postnatal depression scale for peripartum depression.

Results: The results showed that, self-reported bruxism was observed at a statistically significantly higher rate (94.3%) in peripartum depression group. 86.5% of the patients with self-reported bruxism had myogenous temporomandibular disorder (p<0.001). As a result, 80.0% of the patients with peripartum depression had myogenous temporomandibular disorder (p<0.001).

Conclusions: In conclusion, a significant relationship has been found between peripartum depression and self-reported bruxism, self-reported bruxism and myogenous temporomandibular disorder, and peripartum depression and myogenous temporomandibular disorder. The present study is the first to evaluate the relationship between peripartum depression, self-reported bruxism, and myogenous temporomandibular disorder so it could be considered as a pilot attempt, and further studies using more representative samples are encouraged.

Electroacupuncture for Temporomandibular Disorders: A Systematic Review of Randomized Controlled Trials

Although electroacupuncture (EA) is an effective treatment for pain relief, there has been no systematic review of EA treatment for temporomandibular disorder TMD. This systematic review aimed to evaluate the efficacy and safety of EA in TMD management. We searched 14 databases until April 2021 for randomized controlled trials (RCTs) evaluating the effects of EA on TMDs. Eleven RCTs with 667 patients that used three acupuncture points (ST6, ST7, and LI4) were included. Two RCTs reported significant effects of EA plus microwave treatment compared with EA treatment alone on the total effectiveness rate (TER) for TMD. Further, two studies reported that compared with ultrashort wave alone, EA plus ultrashort wave had a significant effect on the TER for TMD and visual analog scale. All RCTs did not report adverse events. Our findings demonstrated the positive potential of EA in TMD management. However, there was weak evidence regarding EA use for TMD management given the poor quality and small sample sizes of the included studies. In the future, well-designed RCTs are required. It is necessary to investigate clinical trials and systematic reviews to compare the effectiveness and safety of EA and acupuncture for TMD.

The hierarchy of different treatments for myogenous temporomandibular disorders: a systematic review and network meta-analysis of randomized clinical trials

The best treatment modality for the management of painful temporomandibular disorders of muscular origin (M-TMD) with predictable outcomes based on solid evidence is still not well defined. Thus, the aim of this network meta-analysis (NMA) was to identify the best treatment for adult patients with M-TMD. An electronic search was undertaken from the inception of each database to August 2018, to identify randomized clinical trials (RCTs), which are comparing two or more of the following treatment modalities in patients with M-TMD: counseling therapy; occlusal appliances; manual therapy; laser therapy; dry needling; intramuscular injection of local anesthesia (LA) or botulinum toxin-A (BTX-A); muscle relaxants; hypnosis/relaxation therapy; oxidative ozone therapy; and placebo or no treatment. Primary outcome variables were the reduction of pain and mechanical sensitivity. The secondary outcome was the maximal mouth opening (MMO). The quality of evidence was rated according to Cochrane's tool for assessing risk of bias. Standardized mean difference was used to analyze via frequentist network meta-analysis (NMA), using STATA software. 52 RCTs were included in this NMA. At the most follow up moments, manual therapy, counseling therapy, occlusal splints therapy, and needling using BTX-A or LA as well as dry needling significantly decreased post-treatment pain intensity in M-TMDs, when compared to placebo.  At short term (≤5 months), the four highest-ranked treatments for post-treatment pain reduction were manual therapy (83.5%, low quality evidence), ozone therapy (75.7%, very low quality evidence),counseling  therapy (71.2%, moderate quality), and occlusal appliances  (71.7%,moderate quality evidence). When intermediate term (≥6 months)was considered, BTX-A (85.8%, very low quality evidence) , counseling therapy(80%, low quality evidence), occlusal appliances  (62.8%, low quality evidence) and hypnosis (50.6%, very low quality evidence) were the four highest-ranked treatments.  This NMA reveals that manual therapy can be considered the most effective treatment for M-TMD, followed by counseling treatment, intramuscular injection of LA, and occlusal appliances  . However, considering the limitations of the studies included, and the scarce of strong evidence, the present findings should be interpreted cautiously.

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

Purpose

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

Patients and Methods

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

Results

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

Conclusion

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