[The use of growth prediction and V.T.O.: special concepts]

Growth induces very important modifications of the skeletal positions of the maxilla and the mandible and the precise position of the teeth is not foreseeable before an attempt to evaluate the situation the bones will be in by the end of the treatment has been made. Predictability factors are examined and a specific construction of V.T.O. is suggested. Then a new superposition is proposed which allows to determine the direction and range of teeth displacements.