Ruellas Antônio Carlos de Oliveira, Pithon Matheus Melo, dos Santos Rogério Lacerda
Federal University of Rio de Janeiro - UFRJ, Brazil.
Dental Press J Orthod. 2013 Mar-Apr;18(2):101-7. doi: 10.1590/s2176-94512013000200021.
To mechanically evaluate different systems used for incisors retraction.
Three different methods for incisors retraction using 0.019 x 0.025-in stainless steel wire were evaluated. The samples were divided into three groups: Group A (retraction arch with 7-mm high vertical hooks); Group G3 (elastic chain attached to the mini-implant and to the 3-mm stainless steel hook welded to the retraction arch); Group G6 (elastic chain attached to the mini-implant and to the 6-mm stainless steel hook welded to the retraction arch). A dental mannequin was used for evaluation in order to simulate the desired movements when the device was exposed to a heat source. The analysis of variance (ANOVA) and the Tukey test were used (p < 0.05).
The results demonstrated that Groups G3 and G6 exhibited less extrusion and less incisor inclination during the retraction phase (p < 0.05). With regard to incisor extrusion, statistically significant differences were observed between Groups A and G3, and between Groups A and G6 (p < 0.05). Regarding incisor inclination, statistically significant differences were observed between the three evaluated systems (p < 0.05).
Arches with 6-mm vertical hooks allow the force to be applied on the center of resistance of the incisors, thus improving mechanical control, when compared with the other two systems.
对用于切牙后移的不同系统进行力学评估。
评估了三种使用0.019×0.025英寸不锈钢丝进行切牙后移的不同方法。样本分为三组：A组（带有7毫米高垂直钩的后移弓）；G3组（弹性链连接微型种植体和焊接在后移弓上的3毫米不锈钢钩）；G6组（弹性链连接微型种植体和焊接在后移弓上的6毫米不锈钢钩）。使用牙科人体模型进行评估，以模拟装置暴露于热源时所需的移动。采用方差分析（ANOVA）和Tukey检验（p<0.05）。
结果表明，G3组和G6组在牙齿后移阶段表现出较少的牙伸长和较小的切牙倾斜度（p<0.05）。关于切牙伸长，在A组与G3组之间以及A组与G6组之间观察到统计学上的显著差异（p<0.05）。关于切牙倾斜度，在三种评估系统之间观察到统计学上的显著差异（p<0.05）。
与其他两种系统相比，带有6毫米垂直钩的弓允许将力施加在切牙的阻力中心上，从而改善力学控制。
