The effects of stimulus polarity and electrode area on the threshold to monopolar stimulation of teeth in human subjects, with some preliminary observations on the use of a bipolar pulp tester

No consistent relationship was found between the threshold to electrical stimulation of human teeth and the area of electrode contact. The different patterns observed can be accounted for on the basis of different sites of initiation of nerve impulses. In some cases, the threshold increased progressively as the area of the electrode was increased and in these cases it appears that nerves were being stimulated in the dentine or superficial layers of the pulp. Bipolar stimulation gave thresholds which were similar to those obtained with monopolar cathodal stimulation and lower than those with monopolar anodal stimulation.