Ji Guo-ping, Pan Xiao-gang, Shen Gang, Huang Ning
Department of Orthodontics, Ninth People's Hospital, School of Stomatology, Shanghai Second Medical University, Shanghai 200011, China.
Shanghai Kou Qiang Yi Xue. 2005 Aug;14(4):359-64.
The purpose of this study was to investigate the efficacy of Twin-block appliance on maxillofacial growth by using monozygotic twins.
6 pairs of non-high angle monozygotic twins aged 12.2 with class II division 1 malocclusion were selected from 32 pairs of twins. In the first year Twin A of each pair was functionally treated using Twin-block appliance; meanwhile, Twin B underwent non-extracted fixed treatment without any treatment procedure which might cause changes like functional appliances such as Class II elastics. The difference of the cephalometric changes of maxilla and mandible before and after treatment between Twin A and Twin B was compared using paired-t test.
Compared with those of Twin A after one year treatment, SNA, Cd-A and Cd-Go of Twin B had little chang (P>0.05), but Cd-S' reduced (P<0.05), Cd-Gn and SNB increased (P=0.01), (Cd-Gn)-(Cd-A) and ANB increased (P<0.05) significantly.
Twin-block appliance can stimulate forward mandibular growth and cause forward mandibular displacement, but has little effect on ramus height and maxillary growth.
本研究旨在通过单卵双胞胎探讨Twin-block矫治器对颌面生长的疗效。
从32对双胞胎中选取6对年龄为12.2岁、安氏II类1分类错牙合的非高角单卵双胞胎。在第一年，每对双胞胎中的A使用Twin-block矫治器进行功能矫治；同时，双胞胎B接受不拔牙固定矫治，不进行任何可能引起类似功能矫治器（如II类牵引）变化的治疗程序。使用配对t检验比较双胞胎A和双胞胎B治疗前后上颌骨和下颌骨头颅侧位片变化的差异。
与治疗一年后的双胞胎A相比，双胞胎B的SNA、Cd-A和Cd-Go变化不大（P>0.05），但Cd-S'减小（P<0.05），Cd-Gn和SNB增加（P=0.01），（Cd-Gn）-（Cd-A）和ANB显著增加（P<0.05）。
Twin-block矫治器可刺激下颌向前生长并导致下颌向前移位，但对下颌升支高度和上颌生长影响不大。
