Neuropathic pain characteristics in patients with pain-related temporomandibular disorders.

In orofacial pain patients, pain-related temporomandibular disorders (TMD) and neuropathic pain (NP) can both be present. The aim of this cross-sectional study was to examine whether in patients with orofacial pain, associations can be found between (subdiagnoses of) pain-related TMD and NP. Participants were asked to fill in the questionnaires of the Diagnostic Criteria for TMD (DC/TMD) and a screening questionnaire for NP, the Douleur Neuropathique 4 (DN4). Complete data sets were collected from 355 participants with an orofacial pain complaint. First, univariate analyses were used to pre-screen the independent variables. Subsequently, multivariate binary logistic regression analysis was used to further assess the association between the independent variables, which were significant in the univariate analyses, and the dependent variable NP. From all 355 participants, 274 (77.2%) had pain-related TMD. 72 participants (20.3%) had a DN4 score ≥4, suggesting the presence of NP. A DN4 score ≥4 occurred in 62 (22.6%) of the 274 cases with pain-related TMD. In the univariate analyses, NP was found to be significantly associated with the presence of pain-related TMD (χ² = 4.088, p = 0.043), myalgia (χ² = 6.916, p = 0.009), and headache attributed to TMD (χ² = 13.366, p < 0.001). In the multivariate analysis, NP was only significantly associated with headache attributed to TMD (Odds Ratio = 2.37, 95% Confidence Interval: 1.30 to 4.34, p = 0.005). NP characteristics are associated with headache attributed to TMD. The results stress the need for including a NP assessment in diagnostic protocols for pain-related TMD.