不同尺寸、不同摇椅曲度不锈钢方丝在Empower自锁托槽内摩擦力的实验分析

目的 研究不同尺寸、不同摇椅曲度(rocking chair curvature,RCC)不锈钢方丝（stainless steel,SS）在Empower自锁托槽(Empower self-ligating brackets,Empower SLB)内所产生的摩擦力差异。方法 选用由标准石膏模型翻制的标准牙〖HT5”，7”SS〗牙〖KG-*3〗合模型，并于干燥条件下在其上粘结Empower SLB及颊面管，分别测量按照在电镜下确定弓丝拉拔方向的两种尺寸SS(0.46 mm×0.64 mm、0.48 mm×0.64 mm)，4种不同RCC(0°、5°、10°、15°)，共8种弓丝-摇椅工况组合在滑动法关闭拔牙间隙时在Empower SLB内产生的摩擦力。结果 两种尺寸弓丝分别在尖牙至第二前磨牙区加载0°、5°、10°、15°的RCC，得出以下结果：①所有工况下动摩擦力稍小于最大静摩擦力；②相同RCC下，0.46 mm×0.64 mm SS 在自锁托槽内产生的滑动摩擦力小于0.48 mm×0.64 mm SS（P＜0.05)；③相同尺寸弓丝随RCC（0°、5°、10°、15°）增加，滑动摩擦力（0.46 mm×0.64 mm SS :0＜0.19 N＜0.35 N＜0.90 N；0.48 mm×0.64 mm SS:0＜0.26 N＜0.43 N＜1.00 N）逐渐增大（P＜0.05)。结论 SS在Empower SLB内的滑动摩擦力稍小于最大静摩擦力，弓丝尺寸越大、摇椅曲曲度越大，SS在自锁托槽内产生的摩擦力也越大。

An experimental study on frictional resistance of stainless steel archwires with different sizes and rocking chair curvature in Empower self-ligating brackets

Abstract: Objectives To study the friction forces of stainless steel(SS) archwires with different sizes and rocking chair curvature (RCC) in Empower self-ligating brackets (Empower SLB) so as to guide the orthodontists′ choice of the brackets and archwires.Methods The standard occlusal plaster model was selected as the study model,and it was bonded with the Empower SLB and buccal tubes in a dry condition.Then the frictional forces of two rectangular SS archwire sizes(0.46 mm×0.64 mm and 0.48 mm× 0.64 mm) with four RCC(0°,5°,10°,and 15°) which made 8 combinations were tested.Results According to the RCC of 0°,5°,10°,and 15° loaded by 2 rectangular stainless steel(SS) archwire sizes from the canines to the secondary premolar segment,(1) In all combinations,dynamic friction was slightly less than the maximum static friction; (2) With the same RCC,0.46 mm×0.64 mm SS had less frictional force than 0.48 mm×0.64 mm SS (P<0.05).(3) Archwires of the same size increased as RCC (0°,5°,10°,15°)increased,and the frictional force also gradually increased (0.46 mm×0.64 mm SS:0＜0.19 N＜0.35 N＜0.90 N; 0.48 mm×0.64 mm SS:0＜0.26 N＜0.43 N＜1.00 N.P<0.05).Conclusions The dynamic friction is slightly less than the maximum static friction in Empower SLB.The frictional force gradually increased with the growing of SS sizes and RCC.