[Somatosensory evoked potentials by mechanical stimulation of tooth in humans]

We examined topographical analysis of the PM-SEP (periodontal mechanoreceptor-sensory evoked potential) inducing by mechanical stimulation of the tooth in eight subjects. Sensory evoked potential were recorded from various regions of the scalp by the mechanical stimulation of the normal tooth. Eleven electrodes were placed according to the International 10-20 system (T3, T4, C3, C4, T5, T6, F7, F8, Fz, Cz, Oz). The mechanical stimulation was applied to the right upper first incisor tooth. PM-SEPs were averaged 100 times following the mechanical stimulation of the tooth produced six waves of SEP at the ipsilateral temporal area (T4), but did not evoked any potential from the other regions. PM-SEP included I, II, III, IV, V and VI. The earliest latency (I wave) was approximately 11ms and latest latency (VI wave) was approximately 40 ms. These PM-SEP observed by intensity with 3 times of the threshold. In addition, the all components were abolished after local anesthesia of the periodontal ligament. These data suggests that the six waves of the PM -SEP were evoked the ipsilateral temporal region following mechanical stimulation of the tooth, and these regions were projected by afferent impulse from the periodontal mechanoreceptor.