Norman Noraina Hafizan, Worthington Helen, Chadwick Stephen Mark
a Orthodontic Department , University of Manchester Dental Hospital , Higher Cambridge Street, M15 6JH , Manchester , UK.
b Faculty of Dentistry , Universiti Teknologi MARA , Malaysia.
J Orthod. 2016 Sep;43(3):176-85. doi: 10.1080/14653125.2015.1122260. Epub 2016 Feb 2.
To compare the clinical performance of nickel titanium (NiTi) versus stainless steel (SS) springs during orthodontic space closure.
Two-centre parallel group randomized clinical trial.
Orthodontic Department University of Manchester Dental Hospital and Orthodontic Department Countess of Chester Hospital, United Kingdom.
Forty orthodontic patients requiring fixed appliance treatment were enrolled, each being randomly allocated into either NiTi (n = 19) or SS groups (n = 21). Study models were constructed at the start of the space closure phase (T0) and following the completion of space closure (T1). The rate of space closure achieved for each patient was calculated by taking an average measurement from the tip of the canine to the mesiobuccal groove on the first permanent molar of each quadrant.
The study was terminated early due to time constraints. Only 30 patients completed, 15 in each study group. There was no statistically significant difference between the amounts of space closed (mean difference 0.17 mm (95%CI -0.99 to 1.34; P = 0.76)). The mean rate of space closure for NiTi coil springs was 0.58 mm/4 weeks (SD 0.24) and 0.85 mm/4 weeks (SD 0.36) for the stainless steel springs. There was a statistically significant difference between the two groups (P = 0.024), in favour of the stainless steel springs, when the mean values per patient were compared.
Our study shows that stainless steel springs are clinically effective; these springs produce as much space closure as their more expensive rivals, the NiTi springs.
比较镍钛（NiTi）弹簧与不锈钢（SS）弹簧在正畸关闭间隙过程中的临床性能。
双中心平行组随机临床试验。
英国曼彻斯特大学牙科医院正畸科和切斯特伯爵夫人医院正畸科。
招募40名需要固定矫治器治疗的正畸患者，每位患者随机分为NiTi组（n = 19）或SS组（n = 21）。在间隙关闭阶段开始时（T0）和间隙关闭完成后（T1）制作研究模型。通过对每个象限第一恒磨牙上犬牙尖端至近中颊沟进行平均测量，计算每位患者的间隙关闭率。
由于时间限制，研究提前终止。仅30名患者完成研究，每个研究组各15名。间隙关闭量之间无统计学显著差异（平均差异0.17 mm（95%CI -0.99至1.34；P = 0.76））。NiTi螺旋弹簧的平均间隙关闭率为0.58 mm/4周（标准差0.24），不锈钢弹簧为0.85 mm/4周（标准差0.36）。比较每位患者的平均值时，两组之间存在统计学显著差异（P = 0.024），支持不锈钢弹簧。
我们的研究表明不锈钢弹簧在临床上是有效的；这些弹簧与更昂贵的竞争对手NiTi弹簧产生的间隙关闭量相同。
