Research into mastication.

An electronic method of recording displacement was used to study mandibular movement during mastication. The technique enables the parameters of muscle activity, the sound of tooth contact, the force developed between opposing teeth, and the displacement of the mandible to be recorded at the same time on a single U/V chart. Previous reports on mandibular movement using cine-photographic techniques were confirmed in relation to mastication, but additional information was obtained in relation to muscle activity in the final closing movements. It appears that tooth contact initiates a latent-silent period in masseter and temporalis which occurs before movement is arrested in the final intercuspal position. It is considered that the kinetic energy of the mandible on closing is reduced by the cessation of activity in these two muscles during the silent period and finally absorbed by the crushing of food during the terminal intercuspal slide to rest. A description of mastication is given and a theory advanced that this may be controlled by a central clock mechanism.