In the last several years the use of aligners has been increasing, especially in adult patients and in those who demand higher aesthetics. In addition, aligners have certain advantages over the Edgewise appliance that relate to the ability to consume food without any restrictions, maintaintance of a normal oral hygiene protocol, mobility and comfort. Today, as a result of the advancement of biomechanics and the introduction of attachments and other biomechanical elements, almost all tooth movements are possible, and the only limitation are non co-operative patients. For this reason, this type of orthodontic therapy is considered to be the orthodontic treatment of the future. Diagnosis, as always in orthodontics, includes anamnesis, patient's chief complaint, extraoral and intraoral clinical examination, functional, model and radiological analysis. After adequate diagnostics, the following step is treatment planning, which is performed on a digital model by using special softwares. Finally, a stereolithographic approach is used to print the models which are used to fabricate a series of aligners with a pressure molding machine. Patients must wear the aligners all day excluding eating and drinking times. Aligners are changed every two weeks and the orthodontic treatment is completed in approximately the same time interval as fixed appliances. After concluding the active phase of orthodontic treatment, retention is obligatory. It follows the same protocol as therapy with fixed appliances.