Abstract
To determine whether cortical negative potential (hereafter referred to as CNP), which was recorded from the scalp (sites: T3, CZ and T4), preceding the right-side chewing is affected by input from the periodontal membrane, the CNP and pattern of the appearance of masseter electric discharge before the anesthetization of the apex of the tooth root and those after the anesthetization were compared.
1) CNP preceding the right-side chewing appeared at T4 early both before and after the anesthetization and showed a maximum amplitude immediately before masseter electric discharge. CNP duration and amplitude increased after the anesthetization as compared with those before the anesthetization.
2) The initial increase in electromyogram associated with chewing became sharper after the anesthetization than before the anesthetization.
From these findings, that the cerebral cortex is in a preparatory state at an early stage when the sensation in the periodontal membrane on the chewing side is blocked, and that, as a consequence, strong chewing is produced.
