不同器械及预备方法对单根管内感染物清除效果的比较

A comparative study of antimicrobial efficacy of three different instruments and mechanical preparation techniques in single infected root canals

目的:比较分析不同器械及方法机械预备后对单根管内细菌感染物的清除效果及其影响因素。方法:选择45个慢性根尖周炎的单根管患牙,随机分为3组,每组15个患牙,A组:手用不锈钢锉、步退法预备根管;B组:HERO642镍钛锉、标准冠下法预备根管;C组:Mtwo镍钛锉、改良冠向下法预备根管。各组预备过程中用无菌生理盐水冲洗,分别于预备前、预备后根管内取样、接种、培养,检测根管内细菌种类及数量的变化。结果:3组器械及方法机械预备后均可使根管内的细菌种类及数量明显减少(P<0.01),其中手用不锈钢根管锉、步退法及Mtwo旋转镍钛锉、改良冠向下法预备后根管内细菌的减少量均大于HERO 642旋转镍钛锉、标准冠下法,且差异有显著性(P<0.05),手用不锈钢根管锉、步退法预备后根管内细菌的减少量大于Mtwo旋转镍钛锉、改良冠向下法,但差异无显著性(P>0.05)。结论:机械预备可以大大减少根管内细菌量,但不能达到完全无菌,旋转镍钛器械、标准冠下法在提高根管内感染清除能力并无明显优势,机械预备应配合化学预备以提高根管治疗的成功率。

Objective： To compare and analyze the antimicrobial efficacy of three different mechanical preparation techniques in single infected root canals. Methods： Forty-five single root canals with chronic periapical periodontitis were selected. The specimens were divided into three groups randomly, 15 root canals per group. Group A： preparation with stainless steel K-files （step-back technique） , Group B： preparation with HERO 642 NiTi rotary files （crown-down technique） and Group C： preparation with Mtwo NiTi rotary files （modified crown-down technique）. The sterile normal saline was used as irrigation. Samples were taken before and after canal preparation. The difference of CFU was calculated as well as the bacterial species. Results ： All groups were effective to reduce bacteria within the infected root canals greatly （ P 〈 0.01 ）. Group A and Group C were statistically better than Group B （ P 〈0. 05 ）. Group A was more effective than Group C but there was no statistically difference between them （ P 〉0. 05 ）. Conclusion： Mechanical preparation can greatly reduce the intracanal bacteria, but can not obtain bacteria-free canals. The mechanical preparation must be aided by chemical irrigation to improve the success of root canal therapy.