Comparison of sensory and pain threshold in tooth pulp stimulation in normotensive man and essential hypertension

Recent studies indicate a diminished responsiveness to noxious stimuli in arterial hypertension in the experimental animal. A similar finding is also reported in the only study published to our knowledge on this subject in man. The aim of the study was to assess in humans the sensory and pain threshold by a non-invasive tooth pulp stimulation test (stepwise increased electrical stimuli delivered by a commercial pulp tester). Subjects had to report when they started to feel pulp stimulation and when this became painful. The data reported are the means of the measurements on four healthy teeth in each subject. Significantly higher values (expressed as relative units [RU]) were found in 28 non-treated essential hypertensives compared with 33 normotensive controls for sensory threshold (40.64 +/- 8.07 versus 29.96 +/- 6.82 RU, P < 0.0001) and for pain threshold (55.67 +/- 12.74 versus 42.08 +/- 12.58 RU, P < 0.001). Multivariate analysis of variance showed that this difference was apparently not related to age and sex. These data lend further support to the view that pain modulation may be altered in the hypertensive state in man.