Nucera Riccardo, Lo Giudice Antonino, Matarese Giovanni, Artemisia Alessandro, Bramanti Ennio, Crupi Paolo, Cordasco Giancarlo
Department of Scienze Sperimentali Medico-Chirurgiche ed Odontostomatologiche, Section of Orthodontics and TMJ Disorder, University of Messina, Via Consolare Valeria, Messina, 98123, Italy.
Prog Orthod. 2013 Oct 1;14(1):35. doi: 10.1186/2196-1042-14-35.
During orthodontic treatment, a low resistance to slide (RS) is desirable when sliding mechanics are used. Many studies showed that several variables affect the RS at the bracket-wire interface; among these, the design of the bracket slot has not been deeply investigated yet. This study aimed to clarify the effect of different slot designs on the RS expressed by five types of low-friction brackets in vertical and horizontal active configurations of the wire.
Five low-friction brackets (Damon SL II, Ormco, Orange, CA, USA; In-Ovation, GAC International, Bohemia, NY, USA; Quick, Forestadent, Pforzheim, Germany; Time 2, AO, Sheboygan, WI, USA; Synergy, RMO, Denver, CO, USA) coupled with an 0.014-in NiTi thermal wire (Therma-Lite, AO) were tested in two three-bracket experimental models simulating vertical and horizontal bracket displacements. A custom-made machine was used to measure frictional resistance with tests repeated on ten occasions for each bracket-wire combination. Design characteristics such as the mesio-distal slot width, slot depth, and presence of chamfered edges at the extremities of the slot were evaluated on SEM images (SUPRA, Carl Zeiss, Oberkochen, Germany) and analyzed in relation to the data of RS recorded.
Time 2 was found to show the higher frictional forces (1.50 and 1.35 N) in both experimental models (p<0.05), while Quick and Synergy brackets showed the lower frictional values in the vertical (0.66 N) and in the horizontal (0.68 N) bracket displacements, respectively. With vertically displaced brackets, the increased mesio-distal slot width and the presence of clear angle at mesial and distal slot edges increase the values of RS. With brackets horizontally displaced, the RS expressed by the wire is influenced simultaneously by the depth of the slot, the mesio-distal slot width, and the presence of clear angle at the extremities of the slot base, the clip, or the slide.
In order to select the proper low-friction bracket system, clinicians should consider specific characteristics of slot design apart from the wire engaging method.
在正畸治疗中，使用滑动机制时，希望有较低的滑动阻力（RS）。许多研究表明，有几个变量会影响托槽-弓丝界面处的RS；其中，托槽槽沟的设计尚未得到深入研究。本研究旨在阐明不同槽沟设计对五种低摩擦托槽在弓丝垂直和水平主动配置下所表现出的RS的影响。
将五种低摩擦托槽（美国加利福尼亚州奥兰治市奥美科公司的Damon SL II；美国纽约州波希米亚市GAC国际公司的In-Ovation；德国普福尔茨海姆市福莱斯特登特公司的Quick；美国威斯康星州希博伊根市AO公司的Time 2；美国科罗拉多州丹佛市RMO公司的Synergy）与一根0.014英寸的镍钛热激活弓丝（AO公司的Therma-Lite）相结合，在两个模拟垂直和水平托槽位移的三托槽实验模型中进行测试。使用一台定制机器测量摩擦阻力，每个托槽-弓丝组合的测试重复进行十次。在扫描电子显微镜图像（德国奥伯科亨市卡尔蔡司公司的SUPRA）上评估槽沟的近远中宽度、槽沟深度以及槽沟末端是否有倒角等设计特征，并结合记录的RS数据进行分析。
发现在两个实验模型中，Time 2均显示出较高的摩擦力（分别为1.50 N和1.35 N）（p<0.05），而Quick托槽和Synergy托槽在垂直托槽位移（0.66 N）和水平托槽位移（0.68 N）中分别显示出较低的摩擦值。对于垂直位移的托槽，增加的近远中槽沟宽度以及近远中槽沟边缘有明显角度会增加RS值。对于水平位移的托槽，弓丝所表现出的RS同时受到槽沟深度、近远中槽沟宽度以及槽沟底部、夹子或滑动处末端是否有明显角度的影响。
为了选择合适的低摩擦托槽系统，临床医生除了考虑弓丝结扎方法外，还应考虑槽沟设计的具体特征。
