Ethnic Differences Regarding Tactile and Pain Thresholds in the Trigeminal Region

Abstract

The aim of the present study was to evaluate ethnic differences of the tactile detection threshold (TDT), the filament-prick pain detection threshold (FPT), the pressure pain detection threshold (PPT), and the pressure pain tolerance detection threshold (PTOL) in the orofacial region of symptom-free subjects. Twenty-two men and 22 women in Belgium and in Japan (age range from 20 to 31 years) participated. The TDT and the FPT were measured on the cheek skin (CS) overlying the masseter muscles (MM), on the maxillary gingiva (MG), and at the tip of the tongue (TT), using Semmes-Weinstein monofilaments. The PPT and PTOL were measured at the central part of the MM, using a pressure algometer. A general linear model was used in each case to capture ethnic and gender effects. Japanese women had the lowest TDT at CS, in contrast to Belgian men, who had the highest value; a significant ethnic and gender effect was found (P=.026 and P<.001, respectively). Similar results were found for FPT at CS with significant ethnic and gender effects (P<.001 for both). There was no significant ethnic effect regarding intra-oral TDT and FPT or regarding PPT and PTOL. Our findings clearly indicate that future studies of tactile and pain measurements need to standardize and control for gender and ethnicity. Further, a comprehensive evaluation of results from various stimulation modalities may better clarify the pain mechanisms and gender/ethnic characteristics, as well as comparisons between normal subjects and patients.