[Orthodontics, stability, recurrence].

The stability of orthopedic treatments has been studied in many ways, but conclusions are very divergent. Usually, the methodology is not reproducible and unfavourable to compare the results. The structural analysis, described by Lautou, Dunglas and Vermelin, help to distinguish the skeletal from the dental effects, during treatments using activators. Clinical cases treated with activator appliances show that the relapse appears when the orthopedic response is poor and when the dento-alveolar compensations are strong.