Effects of Biologics on Temporomandibular Joint Inflammation in Juvenile Idiopathic Arthritis

Objective This prospective study investigates the efficacy of biologics in combination with methotrexate or leflunomide on juvenile idiopathic arthritis (JIA)- related temporomandibular joint (TMJ) arthritis measured by magnetic resonance imaging (MRI)-based inflammation score and deformity score. Methods A prospective single center observational cohort study of 18 consecutive patients were performed between September 2018- April 2023. Inclusion criteria were: 1) Diagnosis of JIA, 2) MRI-verified TMJ arthritis leading to treatment with tumor necrosis factor inhibitor (TNFi), 3) MRI at 6 and 24 months after treatment initiation, 4) clinical follow-up contemporary with the MRI by a pediatric rheumatologist and an orthodontist. Results We included 18 patients (89% females). At time of first MRI median age was 13.2 years (IQR 11.3-16.9), median disease duration was 7.8 years (IQR 3.4-11.1) and 4 received MTX/leflunomide. During the observation period, significant improvements were observed in TMJ movement pain (p=0.01), morning stiffness (p=0.004), opening capacity (p=0.03) and maximal incisal opening (p=0.006). The inflammation score decreased significantly from median 2 (IQR 1-3) at baseline to median 1(IQR 0-2) at 24 months, p=0.009. In 17 out of 36 TMJs (48%), the deformity score improved or remained stable and no significant increase in the median score was observed. Conclusion This is the first prospective observational study with evidence to support that the orofacial signs, symptoms and MRI-derived inflammation score in TMJ arthritis can be reduced by treatment with TNFi.