Electrical stimulation of the tooth pulp in the study of pain

Unit activity was recorded from bulbar neurons in the immobilized, lightly anesthetized cat following bipolar, electrical stimulation of the canine tooth pulp and the immediately proximal gingiva. When feasable, variations in neuronal responding were studied subsequent to the application of a topical anesthetic to the portion of the gingiva being stimulated. The results indicate that (1) stimulation of the pulp with insulated, embedded, dental electrodes does not excite receptors in adjacent, nondental tissue and (2) stimulation of the gingiva through insulated, concentric electrodes does not activate pulpal receptors in near-by teeth. In addition, the results corroborate previous demonstrations that current spread beyond the pulpal cavity is unlikely when appropriate stimulating procedures are used. Together, the data lend support to the position that electrical stimulation of the tooth pulp provides a unique means for the selective, parametric study of a known pain sensor.