Evaluating Temporomandibular Disorder Severity: A Four-Dimensional Model.

Background: This study developed and tested a multi-dimensional model for evaluating the severity of temporomandibular disorders (TMDs) based on the five core symptoms (5Ts) of the Diagnostic Criteria for TMDs (DC/TMD).

Methods: Study participants were sourced from a university hospital. The 5Ts screener was expanded to include the dimensions of duration, frequency, intensity, and interference with daily activities (5Ts-4D). The 5Ts-4D, along with the Graded Chronic Pain Scale (GCPS), Jaw Functional Limitation Scale-8 (JFLS-8), and Oral Health Impact Profile for TMDs (OHIP-TMD), was administered to individuals with no (NT), intra-articular (IT), pain-related (PT), and combined (CT) TMDs as determined using the DC/TMD methodology and diagnostic algorithms. Reliability and validity testing were carried out thereafter (α = 0.05).

Results: Among the 324 participants, 13.6% had NT, while 42.9%, 15.7%, and 27.8% were diagnosed with IT, PT, and CT, respectively. The 5Ts-4D demonstrated good internal consistency (Cronbach's alpha = 0.83-0.95) and moderate-to-good test-retest reliability (ICC = 0.51-0.97) across various symptom-dimension combinations. It also showed robust known-group differences (PT, CT, IT>NT) and convergent validity, with strong correlations between global TMD severity, JFLS-8, and OHIP-TMD (r_s = 0.68-0.78).

Conclusions: The 5Ts-4D, with its strong reliability and robust validity, holds promise as a straightforward tool for evaluating TMD symptoms and severity, thereby contributing to more effective management of TMD patients.