The class 1 appliances are divided in four types of arch shape. They are engaged in basal skeletal disharmonies, responsable for horizontal occlusal deficits, as transverse insufficiences, or vertical ones, as open or deep bites, where there aren’t alterations from class 2 and 3 dental classes. F MODEL Adapted shape to a complete cranial morphology with narrow palate and high and dental arches, frequently in the tall/thin subjects with oval facial contour. Cranial index: dolichocephalic 45-65mm