Changes of facial hard tissue in patients with Angle Class IIdivision 1 malocclusion treated by activator

【Objective】To evaluate the facial hard tissue changes of patients with Angle Class Ⅱ division 1 malocclusion treated by activator and discuss the activator function.【Methods】30 patients on the growing stage with Angle Class Ⅱ division 1 malocclusion were treated by the Activator.17 cephalograms measurement indexes of every patients were traced on pre-and post-treatment to analyze the changes of the cephalograms.【Results】The indexes of the most patients tended to be normal after early treatment.The length of the mandibular increased,the upper incisors retracted and the overjet decreased.【Conclusions】The indexes of most patients with Angle Class Ⅱ division 1 malocclusion access to be normal after treatment.The length of the mandibular increased,but,second stage treatment was still required for some patients.