The reliability and minimal detectable change of common tests and measures for temporomandibular disorders

Temporomandibular disorders are a source of orofacial pain. Understanding clinimetric properties of evaluation procedures is necessary for assessing impairments and determining response to interventions.

Reliability, minimal detectable change (MDC₉₅), and 95% limits of agreement of TMJ examination procedures were investigated.

Occlusion (central incisor alignment, overjet, overbite), mandibular dynamics (maximal incisor opening, laterotrusion, protrusion active range of motion (AROM)), auscultation, tenderness, and joint play were measured on 50 asymptomatic adults (30 females), mean age 24.8. The inter-rater reliability assessment used an intra-session design. Participants returned 24-48 h later for intra-rater assessments. Intraclass correlation coefficients (ICC) and Kappa values were used to determine reproducibility.

Intra-rater reliability for occlusion and AROM was ICC _3,1 ≥ 0.75, whereas interrater reliability was ICC _2,1 ≥ 0.68. Kappa values for inter-rater agreement of joint mobility was K = .18, whereas auscultation and palpation were K ≥ 0.48. Intra-rater Kappa values were ≥ 0.24, with lateral pterygoid region palpation having poor agreement. The MDC₉₅ for occlusion was 1 mm, whereas AROM ranged from 3 to 6 mm. Mean AROM differences between raters were -1.16, -0.42, -0.18, and -0.8 mm for maximal incisor opening, left and right laterotrusion, and protrusion, respectively.

AROM and occlusion measurements may be used with confidence; however, poor agreement for joint mobility measurements and lateral pterygoid region palpation must be recognized. When re-assessing measurements, a 3-6 and 1-mm change in AROM and occlusion, respectively, is required to be 95% certain change is not due to error. Future symptomatic population research is needed (250/250).