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

Yunhao Zheng,1 Rui Zhu,2 Chuqiao Xiao,3 Qiaoyu Cheng,3 Yifei Long,3 Xueman Zhou,3 Shilong Zhang,4 Jun Wang,3 Xin Xiong1,3 1Department of Temporomandibular Joint, West China Hospital of Stomatology, Sichuan University, Chengdu, People’s Republic of China; 2Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, People’s Republic of China; 3Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, People’s Republic of China; 4Department of Orthodontics, School and Hospital of Stomatology, Hebei Medical University & Hebei Key Laboratory of Stomatology, Shijiazhuang, People’s Republic of ChinaCorrespondence: Xin Xiong, National Clinical Research Center for Oral Diseases, State Key Laboratory of Oral Diseases, Department of Temporomandibular Joint, West China Hospital of Stomatology, Sichuan University, Chengdu, People’s Republic of China, Tel/Fax +86-28-85503898, Email drxiongxin@scu.edu.cnPurpose: 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.Keywords: pain sensitivity, temporomandibular disorders, pressure pain threshold, age, gender