Sensation and responses elicited by electrical stimulation of human tooth pulp

Abstract

Quality of sensation elicited by electrical tooth pulp stimulation, and the correlation between the evoked EEG, and inhibition of the masseteric EMG, on the one hand, and the elicited sensation, on the other, were studied in respect to human subjects, and the following results were obtained.(1) Pre-pain was a sensation elicited by tooth pulp stimulation at a low intensity, while stimulation at higher intensities produced pain. These two sensations could be differentiated by the absence or presence of spatio-temporal summation, and their positive correlation with the early or late components of the evoked EEG as well as their threshold stimulus-intensities. Thus, it suggests that different mechanisms would be involved in the production of the two sensations.(2) The threshold intensity for pre-pain was approximately equivalent to that for an early component of the evoked EEG and an early phase of masseteric inhibition. In the range of stimulus-intensity for pre-pain, it showed a high positive linear correlation to the amplitude of an early component of the evoked EEG.On the other hand, in the range for pain, the stimulus intensity was more correlated to the late component than the early one. Therefore, it can be assumed that the evoked responses in cortical EEG and inhibition of the masseteric EMG to an electrical tooth pulp stimulation could be objective indices of the sensations elicited by tooth pulp stimulation.