Comparison of skeletal changes between female adolescents and adults with hyperdivergent Class II Division 1 malocclusion after orthodontic treatment.

OBJECTIVE To compare the skeletal changes between female hyperdivergent adolescents and adults with Class II Division 1 malocclusion after orthodontic treatment. METHODS Thirty adolescent girls and 30 adult women both with hyperdivergent Class II Division 1 malocclusions were selected. The 2 groups were matched by both treatment period and treatment method. Cephalometric radiographs taken before and after treatment were traced and measured. Data were statistically examined. RESULTS After treatment, SNA decreased significantly in both groups. SNB remained unchanged in the adolescent group, while it decreased in the adult group. ANB decreased significantly only in the adolescent group and remained unchanged in the adult group. Obvious growth was found in the adolescent group. Ar-Gn, Ar-Go, N-Me and S-Go increased significantly in adolescents. In the adult group, N-Me and ANS'-Me increased after treatment, but with less magnitude than those in the adolescent group. All the angular measures (MP-SN, PP-SN, Ar- Go-Gn and N-S-Ba) remained quite stable in both the adolescent and adult groups. CONCLUSION Although obvious vertical growth was found in the female hyperdivergent adolescent Class II Division 1 group, no clockwise rotation of the mandible and no mandibular catch-up growth were found. Vertical growth of the mandible was helpful in maintaining the MP-SN angle with conventional orthodontic mechanism in the adolescent group.