Abstract:

Objective This study is aimed to evaluate the orthodontic treatment outcomes of patients with Angle Class Ⅱ division 1 malocculsion with vertical growth pattern; and provide experimental results to help to make orthodontic treatment plan and treatments. Methods 38 patients with Angle Class Ⅱ division 1 malocculsion with vertical growth pattern were included in our study. Their pre- and post-treatment cephalometric Xrays were measured. 39 cephalometric items of hard tissue of groups of adolescents and adults were measured before and after treatments, and the different of the measurements between the adolescent and the adult were studied. Results The changes of ANB angle, NA-PA, U1-FH, U1-NA, U1-Ptm, Spr-Ptm, Id-Go between the groups of adolescent and adult were statistically different. The measurements of Pog-Go, Cd-Go, S-Go, N-Me were all increased. While the OP-FH plane was decreased in the adolescent group, the OP-FH plane was increased in the adult group after orthodontic treatment, indicating the clockwise rotated of the adult occlussal plane. Conclusion The orthodontic treatment in adolescent expressed more bony effects, showing that the profiles of Angle Class Ⅱ of adolescents could be improved more than adults. The extrusions of the upper molars were basically within the beneficial range of amount. And with the mandibular ramus growth, these combined effects of molar extrusion and ramus growth could rotate the mandibular plane and occlussal plane anti-clockwisely which benefited to the corrections of Angle Class Ⅱ divison 1 malocclusions with vertical growth pattern and helped to maintain the stability of the treatment results. Our research also suggested that the most effective time to treat Angle Class Ⅱ division 1 malocclusion with vertical growth pattern was during the fast growth period time of adolescent.

Key words: vertical growth pattern, Angle Class Ⅱ division 1 malocclusion, orthodontic treatment, tooth extraction, changes of hard tissue, cephalometric analysis