Cervical Muscle Tenderness in Temporomandibular Disorders and Its Associations with Diagnosis, Disease-Related Outcomes, and Comorbid Pain Conditions

Aims: To analyze cervical tenderness scores (CTS) in patients with various temporomandibular disorders (TMD) and in controls and to examine associations of CTS with demographic and clinical parameters. Methods: This case-control study included 192 TMD patients and 99 controls diagnosed based on a questionnaire and a clinical examination following the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) guidelines. CTS, adapted from the widely used total tenderness score, was the mean sum of the palpation scores from the suboccipital, sternocleidomastoid, and trapezius muscles. Depending on the variables, data were analyzed using Pearson chi-square, analysis of variance, t test, Bonferroni post hoc adjustment, and/or multivariate linear regression analyses. Results: CTS was higher in TMD patients compared to controls (P .001). Across TMD subgroups, CTS was notable only in those with a myogenous TMD diagnosis, but not in arthrogenous TMD (P = .014). CTS was positively associated with: female sex (P = .03), whiplash history, higher verbal pain scores, comorbid headaches, body pain, increased pain on mouth opening, and higher masticatory muscles tenderness scores (MTS) (P .001 for all). Sex (P .001), MTS (P .001), comorbid headache (P = .042), and pain on opening (mild: P = .031; moderate: P = .022) retained significant associations with CTS in the multivariate analysis, and these main effects were influenced by interactions with whiplash history and comorbid body pain. Conclusion: CTS differentiated between TMD patients and controls and between TMD diagnoses. Specific patient and pain characteristics associated with poor outcome in terms of CTS included effects of interactions between myogenous TMD, female sex, whiplash history, comorbid body pain and headaches, and pain on opening. It can therefore be concluded that routine clinical examination of TMD patients should include assessment of the cervical region. Keywords: cervical muscle tenderness, masticatory muscle disorders, muscle tenderness score, temporomandibular disorders