Rowan M B, Nicholls J I, Steiner J
Department of Restorative Dentistry, University of Washington, Seattle, WA 98195, USA.
J Endod. 1996 Jul;22(7):341-5. doi: 10.1016/S0099-2399(96)80214-7.
The torsional properties of stainless steel (SS) endodontic files (Flex-O-File; Maillefer/L. D. Caulk Co., Milford, DE) and recently developed nickel-titanium (NiTi) endodontic files (Quality Dental Products, Inc., Johnson City, TN) were compared. File sizes 15, 25, 35, 45, and 55 were subjected to torsional load in clockwise (CW) and counterclockwise (CCW) directions independently. Results showed that SS files had a significantly greater rotation to failure in the CW direction, whereas the NiTi files had a significantly greater rotation to failure in the CCW direction. Despite these differences in rotation to fracture, there was essentially no difference between the SS and NiTi instruments in the torque that it took to cause failure in both the CW and the CCW directions. Therefore, whereas the number of CW and CCW rotations to failure differed for the two instruments, the actual force that it took to cause that failure was the same.
比较了不锈钢（SS）根管锉（Flex - O - File；Maillefer/L.D. Caulk公司，米尔福德，特拉华州）和最近开发的镍钛（NiTi）根管锉（优质牙科产品公司，约翰逊城，田纳西州）的扭转性能。分别对15、25、35、45和55号锉进行顺时针（CW）和逆时针（CCW）方向的扭转载荷测试。结果表明，不锈钢锉在顺时针方向的断裂旋转角度显著更大，而镍钛锉在逆时针方向的断裂旋转角度显著更大。尽管在断裂旋转方面存在这些差异，但在顺时针和逆时针方向导致断裂所需的扭矩上，不锈钢和镍钛器械之间基本没有差异。因此，虽然两种器械断裂时的顺时针和逆时针旋转次数不同，但导致断裂的实际力是相同的。
