Alcock Joseph P, Barbour Michele E, Sandy Jonathan R, Ireland Anthony J
Division of Child Dental Health, Bristol Dental School, University of Bristol, Bristol, UK.
Dent Mater. 2009 Aug;25(8):1039-43. doi: 10.1016/j.dental.2009.03.003. Epub 2009 May 23.
The purpose of this research was to investigate the effects of decontamination and clinical exposure on the elastic moduli, hardness and surface roughness of two frequently used orthodontic archwires, namely 0.020in.x0.020in. heat activated (martensitic active) nickel titanium archwires and 0.019in.x0.025in. austenitic stainless steel archwires.
This study was a prospective clinical trial in which 20 consecutive patients requiring an archwire change as part of their course of orthodontic fixed appliance therapy, had either a nickel titanium or stainless steel archwire fitted as deemed clinically necessary. The effect of clinical use was determined by comparing distal end cuts of the "as received" archwires before and after decontamination, with the same retrieved archwires following clinical use and decontamination. Hardness, elastic modulus and surface roughness were determined using an atomic force microscope (AFM) coupled with a nanoindenter.
The results showed that the decontamination regimen and clinical use had no statistically significant effect on the nickel titanium archwires, but did have a statistically significant effect on the steel archwires. Decontamination of the steel wires significantly increased the observed surface hardness (p=0.01) and reduced the surface roughness (p=0.02). Clinical use demonstrated a statistically significant increase in the observed elastic modulus (p<0.001) and a decrease in surface roughness (p=0.001).
At present it is difficult to predict the clinical significance of these statistically significant changes in archwire properties on orthodontic tooth movement.
本研究旨在调查去污和临床使用对两种常用正畸弓丝弹性模量、硬度和表面粗糙度的影响，这两种弓丝分别是0.020英寸×0.020英寸热激活（马氏体活性）镍钛弓丝和0.019英寸×0.025英寸奥氏体不锈钢弓丝。
本研究是一项前瞻性临床试验，20例连续患者在正畸固定矫治器治疗过程中需要更换弓丝，根据临床需要安装镍钛或不锈钢弓丝。通过比较“收到时”弓丝在去污前后的远端切口，以及临床使用和去污后回收的相同弓丝，来确定临床使用的效果。使用与纳米压痕仪联用的原子力显微镜（AFM）测定硬度、弹性模量和表面粗糙度。
结果表明，去污方案和临床使用对镍钛弓丝没有统计学上的显著影响，但对不锈钢弓丝有统计学上的显著影响。钢丝去污显著提高了观察到的表面硬度（p=0.01）并降低了表面粗糙度（p=0.02）。临床使用显示观察到的弹性模量有统计学上的显著增加（p<0.001），表面粗糙度降低（p=0.001）。
目前，很难预测弓丝性能的这些统计学显著变化对正畸牙齿移动的临床意义。
