Before bracket placement, in all dental crowns, a two reference coordinate designed by Andrews was drawn: the facial axis of the clinical crown Facial Axis Clinical Crown, FACC and its middle point, called Facial Axis Point Facial Axis Point, FAP Figure 3.
Previamente a la colocación de los brackets, se dibujó en cada una de las coronas dentales, una coordenada compuesta por dos referencias utilizadas por Andrews: el eje facial de la corona clínica Facial Axis Clinical Crown, FACC, y su punto medio, denominado punto facial axial Facial Axis Point, FAP Figura 3.