Subjective sensation and objective neural discharges recorded from clinically nonvital and intact teeth.

The aim of this study was to compare subjective sensation with objective neural discharges recorded by microneurography. We examined human teeth that did not respond to pulp vitality testing, but that responded to cavity preparation for endodontic treatment (pathophysiological). Intact teeth and endodontically obturated teeth were used as controls. Pulpal blood flow in the clinical crown and histological examination were also used. Most teeth, both in normal and pathophysiological conditions, did not respond to all pulp vitality tests. Even when teeth in the pathophysiological group showed spike discharges evoked by pulp vitality tests or from spontaneous activity no sensation was elicited. These results confirmed the usefulness of microneurography for research on pulpal sensation and the significance of summation in the perception of sensation in chronically inflamed tooth pulp.