Age and Gender, but Not Pain are Associated with Pressure Pain Thresholds in Patients with Temporomandibular Disorders: A Cross-Sectional Study

PURPOSE: This study aims to explore the association of pressure pain thresholds (PPTs) with age, gender, and pain in patients with temporomandibular disorders (TMD). PATIENTS AND METHODS: A total of 301 TMD patients (248 female and 53 male) were recruited and classified into the high and low age groups according to their median age of 26 years. Patients’ demographics, pain-related variables, TMD-related variables, and PPTs of both left and right temporomandibular joints (TMJs), masseter, and temporalis were collected. RESULTS: Pain duration and visual analog scale of pain (VAS) showed no significant correlations with PPTs (P>0.05). Multiple linear regression analysis revealed a significant positive association of PPTs of all six sites with males (β=0.41–0.72 kg·cm(−2), 95% CI (0.19–0.38, 0.74–0.99), P<0.001), as well as with the high age group [β=0.28–0.36 kg·cm(−2), 95% CI (0.07–0.20, 0.47–0.53), P<0.020]. Furthermore, PPTs of the left TMJ showed a significant negative association with left pain-related TMD (PT) [β=−0.21 kg·cm(−2), 95% CI (−0.38, −0.04), P=0.026], but PPTs of the remaining sites did not show a significant association with PT (P>0.05). Stratified analysis showed that PPTs in females were associated with the high age group [β=0.25–0.37 kg·cm(−2), 95% CI (0.04–0.20, 0.45–0.56), P<0.020] and that PPT of the left TMJ was associated with left PT [β=−0.21 kg·cm(−2), 95% CI (−0.39, −0.03), P=0.043]. The remaining PPTs did not show a significant association with PT (P>0.05). In males, PPTs did not show significant correlations with age, PT and VAS (P>0.05). CONCLUSION: PPTs in the orofacial region are associated with gender and age in TMD patients. Pain duration and intensity show no significant correlations with PPTs in TMD patients. Researchers and dentists should take age and gender into account when using PPTs as auxiliary diagnostic indicators for PT.