Selective stimulation of human tooth-pulp with a new stable method: responses and validation

Introduction: The aims of this study were to establish a harmless technique for selective stimulation of nerves in human tooth-pulp during long experiments and to validate its use even with stimuli of high intensities. Methods: A custom-made veneer containing 2 silver wire-conductive cream electrodes was attached with cement to the labial surface of an upper central incisor tooth. A variety of stimulus intensities were applied, and sensory and reflex responses from jaw closing muscles were recorded. Results: In 15 participants, the stimuli evoked predominantly sharp or painful sensations and reflex inhibitions of activity in the jaw muscles. Stimulation of 3 non-vital teeth evoked no sensations or reflexes even at intensities that evoked maximal reflexes in vital teeth. The electrodes had reasonably stable resistances throughout experiments lasting up to 90min. Discussion: This method enables responses to low or high intensity stimulation of human pulpal nerves to be investigated in long experiments.