Our experiments on the reflex control of human mastication indicate the following: Periodontal mechanoreceptors actively contribute to chewing and also protect the teeth. Muscle spindles help develop bite force and also allow jaws to move smoothly. Mechanoreceptors reduce their sensitivity during chewing to weak mechanical stimuli to allow mastication to continue smoothly. They can however generate strong inhibitory effects if the stimulus is strong to protect the teeth and supporting tissues. These studies contribute to a better understanding of the neuronal circuitry of the masticatory system which may form a scientific background for future clinical applications.