Temporomandibular joint disorders’ impact on pain, function and disability

Abstract

Aims: To determine the association between more advanced stages of temporomandibular joint intra-articular disorders (“TMJ intraarticular status”), representing a transition from normal joint structure to TMJ disc displacement with and without reduction (DDwR and DDwoR) to degenerative joint disease (DJD), and patient-reported outcomes of jaw pain, function, and disability (“TMD impact.”) Methods: This cross-sectional study included 614 cases from the Validation Project with at least one temporomandibular disorder (TMD) diagnosis. TMJ intraarticular status was determined by three blinded, calibrated radiologists using magnetic resonance imaging and computed tomography as one of normal joint structure, DDwR, DDwoR, or DJD, representing the subject’s most advanced TMJ diagnosis. TMD impact was conceptualized as a latent variable consisting of (i) pain intensity (Characteristic Pain Index from the Graded Chronic Pain Scale [GCPS]), (ii) jaw function (Jaw Functional Limitation Scale); and (iii) disability (Disability Points from GCPS). A structural equation model (SEM) estimated the association of TMJ intraarticular status with the latent measure TMD impact as a correlation coefficient in all TMD cases (N=614) and in cases with a TMD pain diagnosis (N=500). Results: The correlations between TMJ intraarticular status and TMD impact were 0.05 (95% CI -0.04 to 0.13) for all TMD cases and 0.07 (95% CI -0.04 to 0.17) for cases with a pain diagnosis, which are neither statistically significant nor clinically relevant. Conclusion: Conceptualizing worsening of TMJ intra-articular disorders as four stages and characterizing impact from TMD as a composite of jaw pain, function, and disability, this cross-sectional study found no clinically significant association. Models of TMJ intraarticular status other than ours (normal structure → DDwR → DDwoR → DJD) should be explored.