Distributions of orofacial two-point discrimination threshold: A cross-sectional study in healthy population and patients with pain-related temporomandibular disorders.

OBJECTIVE: This study aimed to explore the distribution and difference of orofacial two-point discrimination threshold (2-PDT) between patients with pain-related Temporomandibular Disorders (TMDs) and healthy individuals. METHODS: This study included 58 pain-related TMDs patients and 58 healthy individuals. Demographics including the gender, age of participants were collected. Temporomandibular joint (TMJ), mandible, zygomatic and temporal 2-PDTs were examined for statistical analyses. RESULTS: Pain-related TMDs patients showed significantly higher 2-PDTs in all tested regions (p < 0.001). In gender subgroups of the control, males had significantly higher 2-PDTs than females in bilateral TMJ and temporal regions. In gender subgroups of patients, no statistical 2-PDT differences were found between males and females. Pain-related TMDs females had higher 2-PDTs than control females in all regions, which were also observed between pain-related TMDs males and control males (p < 0.001), except for temporal 2-PDTs. Only pain-related TMDs were significantly associated with orofacial 2-PDTs with beta coefficients varied from 3.5 to 7 (p < 0.001). The discrimination performance of 2-PDTs on pain-related TMDs was considered effective, while the TMJ 2-PDTs was the best single predictor (Area under curve: 0.833). CONCLUSION: Pain-related TMDs patients had weaker orofacial tactile acuity, which was consistent in gender subgroups, except for the temporal region of males. Healthy males had weaker tactile acuity compared to females in TMJ and temporal regions. No significant gender effect on orofacial tactile acuity was observed among male and female patients. The 2-PDTs of the tested sites, especially for TMJ, has the potential for further utilization in pain-related TMDs patients.