As part of the 50th international orthodontic conference of the Austrian Society for Orthodontics, the author gave an overview presentation of the development of aligner orthodontics based on clinical treatments. According to this, for more than 20 years orthodontic therapy using serials produced polyurethan splints has increasingly established itself as a supplement or substitute for classic, removable appliances or multi-bracket appliances.In the early years, the area of indication was still very limited and considered exclusively for the treatment of adult patients, but the use of digital aligner technology is now also suitable for therapy in children and adolescents and for solving complex orthodontic treatment tasks.The decisive factor here is the unconditional compliance with the generally applicable, medical orthodontic standards from the diagnostics, the planning phase and including the personal treatment management with the well-founded specialist knowledge of the educated orthodontist.With data of the anatomical findings, considering the biomechanical basics, the suitability of the patient and the corresponding expertise of the doctor, not only moderate dentoalveolar malocclusion as crowding, but also significant vertical and sagittal deviations can generally be treated with clear aligners.However, the implementation of physical, translational tooth movements to achieve orthodontic space closure, as may be indicated when teeth are missing, remains a particular challenge.The possibilities and limits of aligner therapy are shown here using the example of a special spacing-situation that arose as a result of trauma caused by the loss of the central and lateral incisor in a ten-year-old boy. Particular attention is paid here to tooth movement over the upper midline, which has already been described several times in the literature but has not yet been comprehensively described in aligner orthodontics.
