Objective To evaluate the effects of headgear- activat（or HGAC）combination appliances on bone and dentition of juveniles with Class Ⅱ division 1 malocclusion using Pancherz′s analysis approach. Methods Fifteen patients( 8 males of 10- 13 years old and 7 females of 9- 12 years old, average age was 11.2 years old, ANB≥5°, overjet≥6 mm, Class Ⅱ molar relation) were treated with HGAC appliance for more than 14 hours everyday and for total of 8 - 10 months cephalograms were taken before and after the treatment. The data was analyzed with Pancherz′s analysis and pare t te（st SPSS 11.5 software) . Results After the therapy, SNA and ANB angles re - duced, the change of SNB angle was trivial, pg/OLP was forward movement. The axial inclination of the lower incisors increased and of the upper incisor reduced. Overjet of the incisors was improved, in which skeletal factor was improved to 44.64% and dentition factor was 55.36%. The first molar on the mandible was forward movement. Molar relationship was also improved, in which skeletal factor was improved to 65.65%, and dentition factor was 34.35%. Conclusion HGAC can efficaciously treat Class Ⅱ division 1 malocclusion with maxillary protrusion, stimulate modification of the mandibular condyle and fossa, and promote the development of the mandibles. Dentition was improved more than skeletal on overjet, and skeletal was improved more than dentition on molar relationship.
