Dalton B C, Orstavik D, Phillips C, Pettiette M, Trope M
Department of Orthodontics, University of North Carolina School of Dentistry, Chapel Hill 27599, USA.
J Endod. 1998 Nov;24(11):763-7. doi: 10.1016/S0099-2399(98)80170-2.
The purpose of this study was to compare intracanal bacterial reduction on teeth instrumented with 0.04 tapered nickel-titanium (NiTi) rotary instrumentation to bacterial reduction when using a stainless-steel K-file step-back technique using sterile saline irrigation. Forty-eight patients with apical periodontitis were randomly assigned treatment type. The canals were sampled before, during, and after instrumentation. The samples were incubated anaerobically for 7 days at 37 degrees C, colony-forming unit numbers calculated, and a log transformation performed to normalize the counts. Teeth exhibiting apical periodontitis were uniformly infected, whereas vital control teeth were not. A similar and uniform reduction occurred with progressive filing, regardless of technique (p < 0.0001). There was no detectable difference in colony-forming unit count after NiTi rotary or stainless-steel hand instrumentation (p = 0.42). Neither technique could predictably render canals free of bacteria. The results of this study indicate NiTi rotary and stainless-steel hand K-file step-back instrumentation techniques were not significantly different in their ability to reduce intracanal bacteria.
本研究的目的是比较使用0.04锥度镍钛（NiTi）旋转器械进行根管预备时的根管内细菌减少情况与使用不锈钢K锉逐步后退技术并辅以无菌盐水冲洗时的细菌减少情况。48例根尖周炎患者被随机分配治疗类型。在根管预备前、预备过程中和预备后对根管进行取样。样本在37℃下厌氧培养7天，计算菌落形成单位数量，并进行对数转换以标准化计数。患有根尖周炎的牙齿均被感染，而对照活髓牙则未被感染。无论采用何种技术，随着逐步锉磨，细菌数量均出现相似且一致的减少（p < 0.0001）。在使用NiTi旋转器械或不锈钢手动器械预备后，菌落形成单位计数没有可检测到的差异（p = 0.42）。两种技术均无法可预测地使根管内无菌。本研究结果表明，NiTi旋转器械和不锈钢手动K锉逐步后退预备技术在减少根管内细菌的能力方面没有显著差异。
