Khambay Balvinder, Millett Declan, McHugh Siobhan
Unit of Orthodontics, Glasgow Dental School, 378 Sauchiehall Street, Glasgow G2 3JZ, Scotland, UK.
Eur J Orthod. 2005 Jun;27(3):302-8. doi: 10.1093/ejo/cji008.
The aims of this study were to determine the mean tensile force of four different elastomeric modules, the archwire seating force of different ligation methods, and its effect on frictional resistance. To determine the mean tensile force, each elastomeric module (purple, grey, Alastik, and SuperSlick) was extended by 5 mm using two hooks attached to a load cell using a Nene M3000 testing machine. To assess the median archwire seating force, a maxillary premolar bracket (3M Unitek) was welded to a sheet of stainless steel (SS) and glued to a Perspex block. The bracket base was removed and the cut continued into the Perspex below. A length of test wire was taken and bent to form a "U" shape, with the middle portion 20 mm in length. The free ends of the wire were secured to the load cell of the Nene testing machine. Two wire sizes were tested, 0.017 x 0.025 and 0.019 x 0.025 inch SS. The load cell was activated and the force with which the wire was displaced into the slot by the ligation method was measured. Four types of elastomeric module were tested together with a pre-formed 0.09 inch SS ligature. The experimental method used to determine the mean frictional force of each module and wire size was carried out using a method described previously. Statistically significant differences existed in the mean tensile forces and median archwire seating forces between the elastomeric modules. Grey modules with either size wire produced the lowest median archwire seating force, whereas SS ligatures produced the highest forces. SS ligatures with either wire produced the lowest mean frictional forces, whereas grey modules produced significantly higher mean frictional force (P < 0.01). The force with which the wire was seated into the bracket did not seem to be related to the subsequent amount of mean frictional force produced.
本研究的目的是确定四种不同弹性模块的平均拉伸力、不同结扎方法的弓丝就位力及其对摩擦力的影响。为了确定平均拉伸力，使用Nene M3000测试机，通过连接到测力传感器的两个钩子将每个弹性模块（紫色、灰色、Alastik和SuperSlick）拉伸5毫米。为了评估弓丝就位力的中位数，将一个上颌前磨牙托槽（3M Unitek）焊接到一块不锈钢板上，并粘接到一个有机玻璃块上。去除托槽底座，并将切口延伸到下面的有机玻璃中。取一段测试钢丝并弯曲成“U”形，中间部分长度为20毫米。钢丝的自由端固定到Nene测试机的测力传感器上。测试了两种钢丝规格，0.017×0.025英寸和0.019×0.025英寸的不锈钢丝。激活测力传感器，测量通过结扎方法使钢丝移入槽内的力。四种类型的弹性模块与预先形成的0.09英寸不锈钢结扎丝一起进行测试。用于确定每个模块和钢丝规格平均摩擦力的实验方法采用先前描述的方法进行。弹性模块之间的平均拉伸力和弓丝就位力中位数存在统计学上的显著差异。两种规格钢丝的灰色模块产生的弓丝就位力中位数最低，而不锈钢结扎丝产生的力最高。两种钢丝的不锈钢结扎丝产生的平均摩擦力最低，而灰色模块产生的平均摩擦力显著更高（P<0.01）。钢丝移入托槽的力似乎与随后产生的平均摩擦力大小无关。
