Differential Associations of TMJ Disc Displacement and Muscle Disorders With Pain, Function, and Quality of Life in Temporomandibular Disorders

BackgroundTemporomandibular joint (TMJ) disc displacement has an unclear clinical importance in temporomandibular disorders (TMD), which has been shown to vary depending on the presence of concomitant muscle disorders.

ObjectiveDetermine differences in associations between disc displacement/muscle disorders and pain/function and quality of life (QoL).

MethodsClinical data from 100 TMD patients were analyzed. Patients were separated into disc displacement (DD) (n = 35), muscle disorder (MD) (n = 30), and DD+MD (n = 35) groups. Pain (visual analog scale [VAS]), function (Helkimo Index), and QoL (OHIP-14) scores were compared among groups using regression models adjusted for relevant covariates.

ResultsThe DD+MD group had significantly worse pain scores, functional limitation, and QoL (p < 0.001). DD was independently associated with pain and function (but not QoL) after controlling for covariates.

ConclusionTMJ DD is not an independent driver of pathology but is instead amplified in the presence of muscle disorders.