Temporomandibular joint damage in juvenile idiopathic arthritis: Diagnostic validity of diagnostic criteria for temporomandibular disorders

Background : Diagnostic Criteria reported in the expanded taxonomy for Temporomandibular Disorders include a standardised clinical examination and diagnosis (DC/TMD 3.B) of temporomandibular joint (TMJ) damage in patients with juvenile idiopathic arthritis (JIA), however their validity is unknown. Objectives: to assess the validity of DC/TMD 3.B for the identification of TMJ damage in JIA - patients, using magnetic resonance imaging (MRI) as gold standard; to investigate the relation between clinical findings and TMJ damage. Methods: 50 consecutive JIA -patients, (9 -16 years) were recruited. DC/TMD 3.B were compared with TMJs MRI (100 TMJs) performed maximum at 1 month from the visit. The severity of TMJ damage was scored in 4 grades. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), logistic regression models with Odds Ratio of DC/TMD 3.B and clinical findings respect to MRI were calculated. Results: The DC/TMD 3.B were inadequate in the identification of TMJ damage (sensitivity=0.15, specificity=0.92, PPV=0.85, NPV=0.28, P=0.350). Chin deviation and TMJ crepitus were associated with worse TMJ damage (P=0.006; P=0.034). Reduced mouth opening (OR=3.91, P=0.039) and chin deviation (OR=13.7, P=0.014) were associated with the presence of TMJ damage. Combining “Pain ” (History of pain, TMJ pain, Pain during movements) and “Function ” (TMJ crepitus, Reduced mouth opening, Chin deviation) clinical findings the sensitivity and the specificity were 0.88 and 0.54. Conclusion: DC/TMD 3.B present a low sensitivity to diagnose TMJ damage. Chin deviation, reduced mouth opening and TMJ crepitus are associated with TMJ damage. We suggest combining “Pain” and“Function” findings for the evaluation of TMJ damage in JIA-patients