No abstract

As a result of treatment with removable functional appliances, we observed locally different trends in root length increase in the posterior region in late-mixed and young adult dentitions, hence at a stage when root development had not concluded. The roots became longer during treatment with both the activator and bite-jumping appliance, but the maxillary first premolars' root development varied widely. This may be because the bite-jumping appliance's anchorage is right on the dentition, and the forces thus exert an immediate effect on the anchorage unit, particularly in the immediate vicinity of the protrusive bars in the maxilla. This led to certain groups of teeth to fail to achieve their entire potential length.