Question Which of the versatile complex functions of the stomatognathic system play a key role in human development? Background The stomatognathic system and its comprehensiveness and meaning for the entire organism is underestimated even by dentists. We usually only speak of the chewing organ and this concept alone seems to reduce our operating field to restoring the function of "chewing". However, the stomatognathic system has many other functions and plays a key role in the evolution from hominoids to homo sapiens as opposed to other organ systems. It consists of numerous structures that form a complex cypernetic regulatory circuit (Fig. 1a, Fig. 1b), which themselves show os¬seous, chondral, ligamentary, muscular, fascial, organic and neuronal connection with other systems.