PO:26:097 | Ultrasound evaluation of temporomandibular disorders: comparative analysis between inflammatory and degenerative patterns in patients with and without rheumatological pathologies

Beatrice Maranini¹, Stefano Mandrioli², Fabio Fabbian³, Tommaso Bianchi¹, Manlio Galiè², Marcello Govoni¹ | ¹UO di Reumatologia, Dipartimento di Scienze Mediche, Università di Ferrara; ²UO di Chirurgia Maxillo-Facciale, Dipartimento Testa-Collo, Università di Ferrara; ³Dipartimento di Scienze Mediche, Università di Ferrara, Italy

Background. Temporomandibular disorders (TMD) encompass a heterogeneous group of conditions with varying etiologies, either inflammatory or degenerative, that affect the temporomandibular joint (TMJ). Differentiating these mechanisms is crucial for targeted treatment, especially in patients with underlying rheumatologic diseases, where TMJ involvement may reflect systemic activity. The aim of this prospective, cross-sectional study is to evaluate the usefulness of ultrasound (US) in identifying inflammatory or degenerative alterations of the TMJ, comparing the results between patients with known inflammatory rheumatic diseases (arthritis, connective tissue diseases, and vasculitis), primary fibromyalgia, and symptomatic individuals without known rheumatologic conditions.

Materials and Methods. A total of 312 subjects (272 patients + 40 healthy controls) were subjected to standardized TMJ clinical and ultrasound evaluation between 2018 and February 2025. The sample was divided into two groups: Group A, consisting of patients without inflammatory rheumatic disease + healthy controls (asymptomatic for TMD) + primary fibromyalgia (n = 110); and Group B, consisting of patients with inflammatory arthropathy or connective tissue disease (n = 202). Clinical signs and symptoms related to TMD were recorded for each subject included in the study. The ultrasound parameters analyzed included more specifically inflammatory characteristics (joint effusion, synovial hypertrophy, and Doppler signal -PD-), and degenerative-mechanical features (condylar surface irregularities, enthesophytes, erosions, joint space narrowing, calcifications, and disc dislocations).

Results. Inflammatory ultrasound findings—such as synovitis, joint effusion, and PD signal—were significantly more frequent in Group B (p < 0.05). Physical examination alone did not reliably differentiate inflammatory involvement from mechanical involvement in the TMJ (66.4% vs. 33.6%, p = 0.634) (Figure 4). Degenerative findings, such as cortical irregularities, enthesophytes, and cartilage thinning, were also more frequent in Group B, although similar results were observed in Group A patients, likely due to possible chronic mechanical stress factors (e.g., bruxism). Unexpectedly, a PD signal was detected in some cases of fibromyalgia. Multivariate analysis identified joint erosions and cartilage thinning as the only ultrasound lesions significantly correlated with clinical TMJ symptoms. These results support US as a useful tool for distinguishing between inflammatory and mechanical alterations and for detecting subclinical TMJ joint involvement.

Conclusions: US is confirmed as a valuable non-invasive tool for assessing different patterns of TMD, including at the TMJ level, complementing clinical evaluation and improving diagnostic accuracy.