Long-term effects of activator (Andresen appliance) treatment. A clinical, biometric, cephalometric roentgenographic and functional analysis.

The purpose of this investigation was to analyse the long-term effects of activator treatment on the dental arches and arch relationships, the dento-facial skeleton and the function of the masticatory system. A follow-up study was performed on 112 patients treated 10-20 years previously with activators as the sole orthodontic appliance. In connection with activator treatment extractions of permanent teeth were performed on 66 patients while 46 patients were treated without tooth extractions. The investigation consisted of four separate portions (Parts I-IV).