Ferreira Marcelo do Amaral, de Oliveira Fernando Torino, Ignácio Sérgio Aparecido, Borges Paulo César
Angle Orthod. 2005 May;75(3):368-77. doi: 10.1043/0003-3219(2005)75[368:EFDSFA]2.0.CO;2.
A new geometry of orthodontic retraction spring was experimentally studied through an electronic device (platform for measuring forces), using strain gauges that were adapted to cantilever beams. The sample consisted of 36 titanium-molybdenum springs, divided into three groups of 12 springs each. The springs were produced with different cross sections of 0.016 x 0.022 inch and 0.017 x 0.025 inch and with different angles between the extremities (120 degrees and 130 degrees). The springs were adapted to the platform in three different positions so that the force system developed by them could be known (horizontal forces, vertical forces, alpha-beta moments, and moment-to-force ratio M:F). The analysis of factorial variance and the Tukey honestly significant difference test were applied to verify the differences between the averages caused by three possible variation sources and the interactions between them. Regression analysis was also performed to obtain the spring rate. The results show the interactions between the three geometric variables, force magnitudes, and also the spring rates, which are compatible with the ones mentioned in the literature related to the subject. The spring rate was within the levels that are appropriate for clinical use (varying from beta = 33.1 gf/mm to beta = 43.9 gf/mm).
通过一种电子设备（测力平台），利用适配于悬臂梁的应变片，对一种新型正畸牵引弹簧的几何结构进行了实验研究。样本由36个钛钼合金弹簧组成，分为三组，每组12个弹簧。这些弹簧制作时采用了不同的横截面尺寸（0.016×0.022英寸和0.017×0.025英寸）以及两端之间不同的角度（120度和130度）。弹簧在三个不同位置适配于平台，以便了解它们所产生的力系统（水平力、垂直力、α-β力矩以及力矩与力的比值M:F）。应用析因方差分析和Tukey真实显著差异检验来验证由三个可能的变异源及其之间的相互作用所导致的平均值差异。还进行了回归分析以获得弹簧刚度。结果显示了三个几何变量、力的大小以及弹簧刚度之间的相互作用，这些与该主题相关文献中提及的结果相符。弹簧刚度处于适合临床使用的水平范围内（β值从33.1 gf/mm变化到43.9 gf/mm）。
