24-HOUR NONINVASIVE BLOOD-PRESSURE MONITORING AND PAIN PERCEPTION

Although a hypertension-related hypalgesia has been described, the rel ation between pain perception and the 24-hour blood pressure trend is still unknown. The ambulatory blood pressure monitoring parameters and dental pain sensitivity were correlated in 67 male subjects. The pulp ar test (graded increase of test current of 0 to 0.03 mA) was performe d on three healthy teeth, and mean dental pain threshold (occurrence o f pulp sensation) and pain tolerance (time when the subjects asked for the test to be stopped) were evaluated. Three groups of subjects with normal (n=34), intermediate (n=13), and high (n=20) blood pressure va lues were identified according to ambulatory monitoring results. Pain threshold differed among the three groups (P<.02), being higher in the group with highest blood pressure. The groups of hypertensive subject s showed higher pain tolerance than the normotensive group (P<.02). Pa in threshold was correlated with 24-hour, diurnal, and nocturnal blood pressure values. Pain tolerance nocturnal diastolic and mean arterial pressure values. Systolic and diastolic blood pressure loads were sig nificantly associated with pain threshold, and diastolic load was also associated with tolerance. The blood pressure variability (SD) did no t relate to pain perception. The 24-hour arterial pressure was more cl osely associated with pain perception than the blood pressure values o btained before the pulpar lest. A close correlation between pain perce ption and 24-hour ambulatory blood pressure was demonstrated. The 24-h our mean blood pressure and loads, more than dynamic variations, were related to pain sensitivity, suggesting that the cardiovascular modula tion of pain perception may be influenced mainly by sustained levels o f arterial pressure.