Ye Cui, Du Xi, Zhao Qing, Tan Zhen
Department of Orthodontics, West China Stomatological Hospital, Sichuan, People's Republic of China.
J Craniofac Surg. 2012 Sep;23(5):1544-7. doi: 10.1097/SCS.0b013e31824f6454.
The aim of this study was to compare the effectiveness of 2-phase (a first phase with Twin Block therapy immediately followed by a second phase with fixed appliance therapy with nonextraction) and 1-phase (fixed appliance therapy with extraction of 4 first premolars) treatment of class II division 1 malocclusion.
Two groups of successfully treated subjects, aged 10 to 14 years with class II division 1 malocclusion, were evaluated: 2-phase group (n = 70) and 1-phase group (n = 76). Pretreatment and posttreatment lateral cephalograms were traced manually and subjected to Student t test.
In the 2-phase group, the forward positioning of the mandible (Pg-Olp) was less than that of the extraction group. The sagittal mandibular forward growth (Pg-Olp) was, on average, 2.39 ± 0.4 mm in the 2-phase group and 4.56 ± 2.51 mm in the 1-phase group (P = 0.008, P < 0.05). In the vertical plane, the increases in lower facial height and mandibular plane angle were greater in the 2-phase treatment. In the 2-phase group, the lower anterior teeth proclined (Ii-MP) by 7.3 ± 2 degrees, and in the extraction treatment group, it changed -4.1 ± 3.6 degrees. The 1-phase group contributed more sagittal orthopedic effects than did the 2-phase group.
The proclination of the mandibular incisors in the 2-phase group might restrain the mandibular bone from growing enough and cause the backward and downward rotation of the mandible.
本研究的目的是比较两期治疗（第一期采用 Twin Block 矫治器治疗，紧接着第二期采用不拔牙固定矫治器治疗）和一期治疗（拔除 4 颗第一前磨牙的固定矫治器治疗）对安氏 II 类 1 分类错牙合畸形的疗效。
对两组成功治疗的安氏 II 类 1 分类错牙合畸形患者进行评估，患者年龄在 10 至 14 岁之间：两期治疗组（n = 70）和一期治疗组（n = 76）。对治疗前和治疗后的头颅侧位片进行手工描图，并进行 Student t 检验。
在两期治疗组中，下颌骨的前徙量（Pg-Olp）小于拔牙组。两期治疗组下颌骨矢状向的平均前徙生长量（Pg-Olp）为 2.39±0.4mm，一期治疗组为 4.56±2.51mm（P = 0.008，P < 0.05）。在垂直平面上，两期治疗在下颌面部高度和下颌平面角的增加方面更大。在两期治疗组中，下前牙前倾（Ii-MP）了 7.3±2 度，而在拔牙治疗组中，其变化为-4.1±3.6 度。一期治疗组比两期治疗组产生了更多的矢状向矫形效果。
两期治疗组下颌切牙的前倾可能会抑制下颌骨充分生长，并导致下颌骨向后下旋转。
