Absolute and relative facial pressure-pain thresholds in healthy individuals

To investigate and compare absolute pressure-pain threshold (PPT) levels and ratios between craniofacial test and reference sites during consecutive PPT recordings, as well as over a 6-month period, in healthy individuals. This study also investigated PPT differences between genders and the clinical usefulness of different reference sites in the craniofacial region.

Twelve female and 12 male healthy individuals participated in the first examination. Six months later, 9 females and all of the males returned for a second examination. An electronic algometer was used to make 5 consecutive recordings of PPTs with a 2-minute interval at 3 reference sites: mental protuberance (PRO), first metacarpal bone (MET), and frontal bone (FRO), as well as at 3 test sites: temporomandibular joint, masseter muscle, and temporalis muscle.

Absolute PPTs decreased significantly for all test sites during the 5 recordings, while they increased significantly between the examinations. No ratio with FRO as a reference site changed significantly. The males had significantly higher absolute PPTs than the females at PRO and FRO sites.

This study shows that absolute PPT levels in healthy individuals change significantly during consecutive PPT recordings, as well as over a 6-month period; this limits the usefulness of such measurements. This study also shows that the use of relative PPTs with the FRO as a reference site is useful, both for comparison between groups and for longitudinal studies.