Abstract: Objective To compare and evaluate the difference of mechanical sensitivity mapping in the orofacial regions of the painful temporomandibular disorders (TMD) patients and healthy individuals with a quantitative palpometer. Methods Eighty TMD patients with pain in the unilateral masseter muscle or temporomandibular joint (TMJ) regions and 40 healthy controls were involved into this study. Both groups were palpated by quantitative palpometer on their bilateral masseter muscle and TMJ regions. Numerical rating scale (NRS)（0-50-100）was used to evaluate the pressure pain sensitivity of TMD patients and healthy control in test points. Shannon Entropy and Center of gravity (COG) were also calculated to compare the difference of mechanical sensitivity mapping in TMD patients and healthy control. Data were analyzed with Two-way analysis of variance (ANOVA) to find the difference of NRS score, Entropy and COG coordinates values over gender and test sides. Three-way ANOVA was used to analyze the difference of NRS score over gender, test site and test point within groups. Results The difference of Entropy in TMD patients were statistically significant on their pain side and healthy side (masseter muscle: P＜0.001; TMJ: P=0.006). TMD patients tend to have significant higher NRS scores in their painful side compared with their healthy side (masseter muscle: P＜0.001,TMJ: P＜0.001), but no significant difference of entropy and NRS scores were found in control (P≥0.071). Conclusion Significant differences of NRS scores and Entropy value of TMD patients’ pain side and healthy side indicate that mechanical sensitivity mapping with a simple quantitative palpometer can be used as an auxiliary tool to help professionals distinguish TMD patients from normal person, and it can also be used as an indicator to evaluate the effectiveness of treatment in TMD patients.

Key words: temporomandibular joint disorders, mechanical sensitivity mapping, palpometer