Transmembrane Potentials of Odontoblasts

¹ Department of Physiology, Baylor University College of Dentistry, Dallas, Texas

Resting potentials and the electrical excitability of odontoblasts were determined by intracellular microelectrode measurements on both dog and human teeth. The mean resting potential of odontoblasts from freshly extracted human teeth was 32 millivolts. Extracted dog canine teeth yielded a mean value of 30 millivolts. Resting potentials of odontoblasts from dog canine teeth in situ had a mean value of 34 millivolts. Electrical stimuli applied to the dentino-enamel junction did not cause an active electrical response of the odontoblasts. Simultaneous measurements on the dental branches of the mandibular nerve were used to verify that a pulpal response had occurred. High thresholds of electrical stimulation at the dentino-enamel junction indicated an absence of any electrically excitable tissue in this region. It was therefore improbable that the odontoblast processes conveyed pain impulses from the dentin in a manner similar to that of nerve tissue.