Clinical assessment of the pressure pain threshold in temporomandibular disorders

Part 1. Evaluation non-pain subjects using a new type of pressure pain meter

Abstract

Muscle and/or joint tenderness is defined as a patient report of pain on palpation, but there is less interobserver agreement for pain-related measures. The use of various types of pressure pain meter for determining the pressure pain threshold has demonstrated the strong validity and adequate reliability of pressure pain threshold measurement. However there is no agreement about sex dimorphism. The objective of this study was to establish the range of normal values for the pressure pain threshold of 46 non-pain volunteers (Men: 23, Women: 23), including positional variation and sex dimorphism. We used a new type of pressure pain meter that increased at constant rate of 0.5kg/sq. cm/sec for measurements.
The results showed that the pressure pain thresholds for men were significantly higher at all sites compared with that for women. The pressure pain threshold at the posterior margin of the ramus was significantly lower than the values measured at other points, and the pressure pain threshold at the mid-portion of the masseter was higher than that at the inferior portion of the masseter in both sexes. The variances for the pressure pain threshold were 0.75 to 1.21kg in men and 0.8 to 1.31kg in women in a range of 25-75%.
These results suggest that the new type pressure pain meter is useful for determining the pressure pain threshold value. Furthermore, the need to determine the appropriate pressure at each site according to the sex of the subject was shown. Furthermore, the inter-individual pressure pain threshold varied widely, so that determination of the normal range might be difficult without assessment of individual sensitivity to pain.