[Homage to Pedro Planas].

It has been known since the time of Claude Bernard that the "function makes the organ" and ensures its development. However, it took Planas to discover that the masticatory function is the principal factor related to the development of the jaw! Nonetheless, this function only attains its objective if it is physiologically normal, grinding of food taking place by alternative laterality, which can only occur according to Gysi with a balanced occlusion, in conformity with Hanau's rules: opening-closing type mastication as a result of another type of occlusion leads to maxillo-alveolar sub-development and lack of sufficient space. Neuro-Occlusal Rehabilitation (N.O.R.) attempts to detect the type of mastication and occlusion at an early age, to correct it as from the age of 3 years by selective grinding in order to establish alternative laterality: true prophylaxis. If the grinding function is not adequate because it has been corrected too late, Planas appliances are used. Post-orthodontic stability is remarkable as the treatment uses natural and normal means of development.