Mandibular Mobility as a Marker for Temporomandibular Joint Arthritis in Juvenile Idiopathic Arthritis—A Cross-Sectional Observational Study

<b>Background/Objectives:</b> This study aims to evaluate the functional characteristics of the temporomandibular joint (TMJ) in patients diagnosed with juvenile idiopathic arthritis (JIA). Specifically, it seeks to determine the prevalence of TMJ involvement and its impact on clinical symptoms and functional limitations. <b>Methods:</b> A total of 40 patients diagnosed with JIA according to the International League of Associations for Rheumatology criteria were included. Exclusion criteria encompassed systemic diseases unrelated to JIA, prior craniofacial surgery, and trauma. Participants were divided into two groups: those with TMJ arthritis (n = 23) and those without (n = 17). Clinical assessments were conducted using the Helkimo anamnestic index (Ai) and dysfunction index (Di) to evaluate TMJ-related symptoms. <b>Results:</b> The Ai revealed that most patients reported no or only mild subjective symptoms. Overall Di distributions did not differ significantly between groups, although mandibular mobility was more impaired in the TMJ arthritis group. A moderate correlation (r = 0.4) was observed between Ai and Di. <b>Conclusions:</b> This pilot study indicates that impaired mandibular mobility may suggest TMJ involvement in JIA. Given the study's limitations, such as being a single-center study with a small sample size and using a CBCT-based classification, further multicenter studies utilizing validated pediatric protocols are necessary to reinforce these preliminary findings.