Temporomandibular joint in juvenile idiopathic arthritis: magnetic resonance imaging measurements and their correlation with imaging findings

Causal Links Between Bone Diseases and Temporomandibular Disorders

INTRODUCTION AND AIMS

Epidemiological observational studies have explored the link between bone joint-related diseases and temporomandibular disorders (TMD), but inconsistent conclusions have emerged due to various limitations. This study aims to investigate the causal relationship between bone joint-related diseases and TMD using Mendelian randomization (MR).

METHODS

We utilized a two-sample MR design, applying pooled genome-wide association study (GWAS) data from six subtypes of bone and joint diseases and TMD. Primary analysis was conducted using the inverse-variance weighted (IVW) method, complemented by weighted median (WM), weighted mode, and MR-Egger regression to assess causal relationships. Additionally, we performed reverse causality analyses and applied sensitivity analyses, including MR-PRESSO, MR-Egger, Cochran's Q, and leave-one-out methods to evaluate result robustness, explore heterogeneity, and identify potential biases.

RESULTS

MR genetic prediction analyses indicated that bone and joint-related diseases increase the risk of TMD, with specific odds ratios (OR) for ankylosing spondylitis (AS: OR 1.36, 95% CI: 1.04-1.77, P = .026), rheumatoid arthritis (RA: OR 1.08, 95% CI: 1.03-1.13, P = .001), and osteoporosis (OR 1.0751, 95% CI: 1.0047-1.1505, P = .036). Conversely, reverse MR analysis revealed a positive genetic link from TMD to RA (RA: OR 1.12, 95% CI: 1.02-1.23, P = .018). MR-Egger regression showed no influence of horizontal pleiotropy, and MR-PRESSO detected no outliers. The leave-one-out analysis confirmed the results' stability.

CONCLUSIONS

The findings demonstrate a positive, causal association between TMD risk and AS, RA, and osteoporosis. Moreover, TMD patients exhibit an increased risk of developing RA.

CLINICAL RELEVANCE

Understanding these relationships aids in better diagnosis and management of TMD and its association with bone joint diseases, potentially guiding clinical interventions.

Classification of the temporomandibular joint disc displacement without reduction using MRI in the mouth-opening position

OBJECTIVES

This study aimed to analyze the positional characteristics of the temporomandibular joint (TMJ) disc in patients with anterior disc displacement without reduction (ADDWoR) using magnetic resonance imaging (MRI).

MATERIALS AND METHODS

2,827 MRI images from 2,168 ADDWoR patients were collected and categorized into two groups: without limited opening (WoLO) group and with limited opening (WLO) group. The position of TMJ disc and their distribution characteristics in these two groups were analyzed from the oblique sagittal planes of MRI.

RESULTS

The disc positions were classified into 11 types based on oblique sagittal MRI images during maximum mouth opening. Anterior displacement was the most common in both groups, with 39.65% in WoLO and 41.96% in WLO. Anteroinferior displacement and anteroinferior displacement in the lateral part were also prevalent, particularly in the WLO group. While the MRI imaging features of superior displacement did not appear in the WLO group, due to mouth opening limitation. The effect of masticatory muscles and condylar excursion during mouth opening play a crucial role in the displacement of TMJ disc.

CONCLUSIONS

ADDWoR patients of WoLO group primarily manifest disc anterior displacement, anteroinferior in the lateral part, and anteroinferior displacement. ADDWoR patients of WLO group are more likely to exhibit disc anterior displacement and anteroinferior displacement, without the manifestation of superior displacement.

CLINICAL RELEVANCE

The position of the anterior displaced disc can guide treatment strategies, conservative treatment alleviating restricted mouth opening for anteroinferior displacement patients, or controlling excessive mouth opening to relieve ligamentous laxity for anterosuperior displacement patients.

Magnetic resonance imaging texture analysis for quantitative evaluation of the mandibular condyle in juvenile idiopathic arthritis

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease that affects the joints and other organs, including the development of the former in a growing child. This study aimed to evaluate the feasibility of texture analysis (TA) based on magnetic resonance imaging (MRI) to provide biomarkers that serve to identify patients likely to progress to temporomandibular joint damage by associating JIA with age, gender and disease onset age.

METHODS

The radiological database was retrospectively reviewed. A total of 45 patients were first divided into control group (23) and JIA group (22). TA was performed using grey-level co-occurrence matrix (GLCM) parameters, in which 11 textural parameters were calculated using MaZda software. These 11 parameters were ranked based on the p value obtained with ANOVA and then correlated with age, gender and disease onset age.

RESULTS

Significant differences in texture parameters of condyle were demonstrated between JIA group and control group (p < 0.05). There was a progressive loss of uniformity in the grayscale pixels of MRI with an increasing age in JIA group.

CONCLUSIONS

MRI TA of the condyle can make it possible to detect the alterations in bone marrow of patients with JIA and promising tool which may help the image analysis.