[The principal functional appliances. Characteristics and clinical indications]

The author present a review of the six most important functional appliances available now, showing the way of construction, his working and clinical applications. Appliances are extremely valid to rectify skeletric malocclusion of I, II, III class, with ipertonic perioral musculature and with a wrong position of the tongue in growing patient with the FMA under 25 degrees; must be done a correct diagnosis based on patient clinical exam, observation of the model of study and finally on the observation of radiographic exam.