Temporomandibular joint anterior disc displacement with reduction in a young population: Prevalence and risk indicators

Comparing microstructural and micromechanical deformation of the TMJ disc in two anterior disc displacement models

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.

Application of panoramic radiographs in the diagnosis of temporomandibular disorders

To evaluate the feasibility of temporomandibular disorder (TMD) diagnosis with panoramic radiography, and provide standardized data for artificial intelligence-assisted diagnosis by measuring the differences in the condylar and mandibular ramus heights. A total of 500 panoramic radiographs (219 male and 281 female participants) of healthy individuals were examined. The panoramic machine compatible measurement software, SCANORA 5.2.6, was used to measure the bilateral condylar height and mandibular ramus height, and SPSS 27.0 was used to calculate the left- and right-side differences in condylar height and mandibular ramus height of healthy individuals. Magnetic resonance images of the temporomandibular joint region obtained from 46 outpatients in the Stomatology Department were selected along with their corresponding panoramic radiographs. The left- and right-sided differences were measured and compared with the magnetic resonance imaging results. The measurement data are expressed as mean ± standard deviation (mm). t Tests were used to analyze data from healthy male and healthy female groups. The findings revealed that while there was no significant difference (P > .05) in the height of the condyle between men and women, there was a significant difference (P  < .05) in the height of the mandibular ramus. In healthy population, the difference in height between the left and right condyle was 1.09 ± 0.99 mm. The difference in height of mandibular ramus in men was 1.26 ± 0.85 mm and that in women was 1.19 ± 0.87 mm. For the diagnosis of TMD, the sensitivity of panoramic radiographs was 94.74% (36/38), specificity was 75.00% (6/8), and diagnostic accuracy was 91.30% (42/46). The height of the right and left lateral condyles was not identical in healthy individuals, resulting in a discernible height discrepancy. In addition, the height of the mandibular ramus varied. By considering the left-right lateral height differences identified in this study along with clinical examination, it is possible to employ this metric as a preliminary screening tool for patients with TMD. Further, the use of panoramic radiographs for initial TMD screening is both viable and significant.

Heterogeneous Characteristics of the CD90+ Progenitors in the Fibrocartilage of Different Joints

OBJECTIVE

This study aimed to isolate and compare the mesenchymal stem cell characteristics of CD90+ cells from different fibrocartilage tissues in the temporomandibular joint (TMJ), the knee joint, and the intervertebral joint to further understand the similarities and differences of these 4 fibrocartilage tissues.

METHODS

CD90+ cells were isolated from TMJ disc, condylar cartilage, meniscus, and intervertebral disc by using magnetic-activated cell sorting. Cellular assays including 4.5-ethynyl-2'-deoxyuridine labeling, multilineage differentiation, colony formation, and cell migration were conducted to compare their mesenchymal stem cell characteristics. Immunofluorescent staining was performed for observing the expression of actively proliferating CD90+ cells within the tissues. H&E staining and Safranine O staining were used to compare the histological features.

RESULTS

The CD90+ cells derived from these 4 fibrocartilage tissues exhibited comparable cell proliferation abilities. However, the cells from the TMJ disc displayed limited multilineage differentiation potential, colony formation, and cell migration abilities in comparison with the cells from the other fibrocartilage tissues. In vivo, there was relatively more abundant expression of CD90+ cells in the TMJ disc during the early postnatal stage. The limited EDU+ cell numbers signified a low proliferation capacity of CD90+ cells in the TMJ disc. In addition, we observed a significant decrease in cell density and a restriction in the synthesis of extracellular proteoglycans in the TMJ disc.

CONCLUSION

Our study highlights the spatial heterogeneity of CD90+ cells in the fibrocartilages of different joint tissues, which may contribute to the limited cartilage repair capacity in the TMJ disc.

Morphologic Analysis of Condyle among Different Disc Status in the Temporomandibular Joints by Three-dimensional Reconstructive Imaging: A Preliminary Study

OBJECTIVES

Morphological study is a common approach in the field of anterior disc displacement (ADD) pathology; however, analysis based on three-dimensional reconstructive imaging has not been investigated. This study investigated the association between ADD and the status of the mandibular condyle and articular fossa.

METHODS

Thirty-four patients were divided into three groups: normal articular disc position (NADP), anterior disc displacement with reduction (ADDwR), and anterior disc displacement without reduction (ADDwoR). Multiple grouped comparisons of three different disc statuses were performed by Kruskal-Wallis H test and variance analysis respectively. Receiver-operating characteristic curve was plotted to assess the diagnostic efficacy of the morphological parameters. Multivariate logistic regression analysis was used to investigate the interfering factors of ADD.

RESULTS

The condylar volume (CV) and condylar superficial area (CSA) in the NADP, ADDwR, and ADDwoR groups exhibited obvious changes (P < 0.05). Both CV and superior joint space (SJS) presented a good diagnostic accuracy for NADP-ADDwoR [area under the curve (AUC)_CV = 0.813; AUC_SJS = 0.855)], and ADDwR-ADDwoR (AUC_CV = 0.858; AUC_SJS = 0.801). CSA presented a good diagnostic accuracy for ADDwR-ADDwoR (AUC = 0.813). A multivariate logistic ordinal regression model showed that the CV [odds ratio (OR) = 1.011; regression coefficient (RC) = 0.011, P = 0.018], SJS (OR, 8.817; RC = 2.177; P < 0.001), and medial joint space (MJS) (OR, 1.492; RC = 0.400; P = 0.047) had a significantly impact on the groups.

CONCLUSION

CV, CSA, SJS, and MJS were significantly associated with the different disc status, and the condyle in ADD exhibited 3-dimensionally altered dimensions. They could be considered as promising biometric markers to assess the ADD.

Temporomandibular joints disorders (TMDs) prevalence and their relation to anxiety in dental students

Background: Temporomandibular joint disorders (TMDs) are very common disorders affecting the population and causing pain. Researchers have reported a high prevalence of TMDs among university students due to increased distress. The aims of this study were to determine the frequency of TMDs in Umm al-Qura University (UQU) dental students using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), and to examine the relationship between anxiety, bruxism, and TMDs among those students. Methods: The DC/TMD pain screener questionnaire was completed by dental students. Students who reported TMD pain or had at least one positive TMD symptom were invited to the dental clinic for a full TMJ evaluation. History of bruxism was documented and an ultra-brief tool for detecting anxiety and depression (Patient Health Questionnaire-4 PHQ) was completed by all students. Results: A total of 240 students responded to the TMD pain screener in which 119 reported at least one TMJ symptom. Only 93 dental students presented to clinical examination in which 64.5% (n=60) of them had temporomandibular joint disorders. Disc displacement with reduction and local myalgia (38.7% & 32.25%, respectively) were the most frequent diagnosis. A total of 29% (n=27) of students had more than one diagnosis. Overall, 41 participants (44.09%) reported a positive response to the anxiety scale and (n=38) 40% of participants reported parafunctional habits. Both the history of bruxism and anxiety were significantly related to TMDs (P=0.0002) and also significantly higher in women of higher academic years (P≤0.01). Conclusions: This study found a high prevalence of TMDs among UQU dental students. Disc displacement with reduction was the most prevalent disorder. Bruxism and anxiety were associated with painful TMDs.

Outcomes of Treatment with Manipulative Reduction Combine with the Disc-condyle Repositioning Splint in Acute Anterior Disc Displacement without Reduction

ABSTRACT

In this report, the authors describe a case of the acute anterior disc displacement without reduction treated by manipulative reduction combined with the disc-condyle repositioning splint to improve the limited mouth opening and relieve the pain, including diagnostic images and treatment performed.

Is the Temporomandibular Joints' Reciprocal Clicking Related to the Morphology and Position of the Mandible, as Well as to the Sagittal Position of Lower Incisors?-A Case-Control Study

The number of patients diagnosed with temporomandibular joint (TMJ) internal derangements, who are seeking orthodontic treatment, is increasing. The aim of the study was to assess the relationship between the presence of TMJ reciprocal clicking and the morphology and position of the mandible, and position of lower incisors, examined on the lateral cephalograms. Fifty patients diagnosed with reciprocal clicking in at least one of the TMJs and 55 patients with no symptoms of TMJ dysfunction were included in the study. Cephalometric analysis was used for the assessment of: skeletal class, sagittal and vertical position of the mandible, angle of the mandible, inclination of the mandibular ramus and the mandibular corpus, as well as for the assessment of the position of the mandibular incisors. The statistical significance level was set at p = 0.05. There were no statistically significant differences between the examined groups regarding the sagittal and vertical position of the mandible, as well as regarding the sagittal position of the mandibular incisors. Presence of TMJ reciprocal clicking is not associated with the position and the morphology of the mandible, as well as with the sagittal position of the mandibular incisors. Patients with early stages of TMJ internal derangements do not present any significant changes in Cephalometrics. Patients diagnosed with TMJ internal derangements before orthodontic treatment require an interdisciplinary approach to the treatment, including physiotherapy.

Prevalence of temporomandibular joint disorders: a systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review was to evaluate the prevalence of temporomandibular joint disorders (TMJD) among the general population.

MATERIALS AND METHODS

Five main electronic databases and three grey literature were searched to identify observational studies in which TMJD was diagnosed using the research diagnostic criteria (RDC/TMD) or diagnostic criteria (DC/TMD). The studies were blindly selected by two reviewers based on eligibility criteria. Risk of bias (RoB) was assessed using the Joanna Briggs Institute Critical Appraisal Checklist, and the "R" Statistics software was used to perform meta-analyses.

RESULTS

From 2741 articles, 21 were included. Ten studies were judged at low RoB, seven at moderate, and four at high. The TMJD investigated were as follows: arthralgia, disk displacement (DDs) with reduction (DDwR), DDwR with intermittent locking, DDs without reduction (DDwoR) with limited opening, DDwoR without limited opening, degenerative joint disease (DJD), osteoarthritis, osteoarthrosis, and subluxation. The main results from prevalence overall meta-analyses for adults/elderly are as follows: TMJD (31.1%), DDs (19.1%), and DJD (9.8%). Furthermore, for children/adolescents are as follows: TMJD (11.3%), DDs (8.3%), and DJD (0.4%). Considering the individual diagnosis meta-analyses, the most prevalent TMJD is DDwR for adults/elderly (25.9%) and children/adolescents (7.4%).

CONCLUSIONS

The overall prevalence of TMJD was approximately 31% for adults/elderly and 11% for children/adolescents, and the most prevalent TMJD was DDwR.

CLINICAL RELEVANCE

Knowledge about the frequency of TMJD can encourage dentists to consider appropriate strategies for early and correct diagnosis and, if need be, correct management.

Relationship between Age-Dependent Body Constitution and Temporomandibular Joint Sounds in Adolescents

To date, risk factors for temporomandibular joint (TMJ) sounds are still not completely understood, and anatomical factors are suspected to influence their occurrence. This study aimed to evaluate the impact of body constitution on temporomandibular joint sounds of adolescents. 10- to 18-year-old participants of the LIFE Child Study were examined for TMJ sounds, and physical parameters such as body height, body weight, and general laxity of joints were measured. Odds ratios (OR) for associations of TMJ sounds and standard deviation scores (SDS) of body height and body weight were calculated by using binary logistic regression, including cofactors such as age and number of hypermobile joints. The OR for TMJ sounds and SDS of body height was 1.28 (95% confidence interval (CI) 1.06; 1.56) in females when the age-adjusted height value was above 0. SDS of body weight indicated significant ORs for TMJ sounds in males with values of 0.81 (95% CI 0.70; 0.94). No correlation was detected for SDS values and TMJ crepitus. Tall female adolescents seem to be more prone to TMJ clicking sounds, while their occurrence seems less likely in male adolescents with higher body weight.

Temporomandibular Joints' Morphology and Osteoarthritic Changes in Cone-Beam Computed Tomography Images in Patients with and without Reciprocal Clicking-A Case Control Study

Background: Patients referred for orthodontic treatment often present symptoms of temporomandibular joints’ disorders (TMD), predominantly clicking. The objective was to analyze the morphology of the temporomandibular joints in cone-beam computed tomography (CBCT) images based on the presence of reciprocal clicking before orthodontic treatment. Methods: 105 participants took part in the study. 210 temporomandibular joints (TMJs) were allocated into one of two groups regarding the presence of reciprocal clicking. Morphology of condyle’s head, glenoid fossa, and articular eminence as well as condylar head position in the glenoid fossa and osteoarthritic changes in the area of the condylar head were examined for each TMJ in the CBCT images. Statistical analysis was performed with STATISTICA version 12.0. The following tests were performed: U-Mann Whitney, Kruskal-Wallis, t-Student, and chi-square. The statistical significance level was p = 0.05 for all the measurements included. Results: Significantly smaller condylar A-P dimension (p = 0.040) characterized temporomandibular joints with reciprocal clicking. Condyles were substantially more often positioned posteriorly (p = 0.043) and were significantly more often accompanied by subcortical cysts and pathologic osteoarthritic bone changes (p < 0.001). Conclusions: The early stages of internal derangements stay with alterations in morphology and position of TMJs as well as with the presence of osteoarthritic changes.