Effect of periodontal stimulation on respiratory activity

Abstract

The effects of the application of force to a tooth on respiratory activity were investigated in anaesthetized rabbits. Three types of force stimuli were used: 1) continuous force (1kgf for 15s) to the upper incisor, 2) repetitive force (1kgf 80/min for 15s) to the upper incisor and 3) biting of a wooden stick during cortically induced rhythmic jaw movements. Each of the force stimuli elicited an augmenting respiratory reflex. This reflex was characterized by an increase in inspiratory activity (EMG activity in the diaphragm), a decrease in expiratory activity (EMG activity in middle pharyngeal constrictor), and an increase in the respiratory rate. This latter increase was caused primarily by a decrease in the duration of the expiratory phase. Inhibition of expiratory activity was greater with repetitive stimulation than with continuous stimulation. After electrical stimulation of the cortical masticatory area, stable respiratory rhythm became unstable. However, rhythmicity was re-established with repetitive periodontal stimulation in the form of rhythmic biting on a wooden stick.
These results suggest that the augmenting respiratory reflex mediated by periodontal mechanoreceptors affects respiration when biting may occur during mastication.