根管预备尺寸对Er:YAG激光消毒效果的影响

目的 比较Er:YAG激光在不同根管预备尺寸情况下的消毒效果。方法 368颗离体上颌单直根管前牙，随机分为8组，机用K3镍钛锉预备至以下尺寸: A1组和B1组（#25/0.06）、A2组和B2组（#30/0.06）、A3组和B3组（#35/0.06）、A4组和B4组（#40/0.06）。高压灭菌后，A组接种粪肠球菌，B组接种白念菌。每组冲洗方法均为Er:YAG激光+3% NaOCl，Er:YAG激光+17% EDTA，Er:YAG激光+生理盐水，然后收集各组处理后根管壁表面微生物样本，进行微生物培养和计数，采用GraphPad Prism 5.02软件包分析各组绝对残留菌落数及菌落相对残留率。结果 Er:YAG激光对粪肠球菌与白念菌的消毒效果在预备尺寸为#40/0.06最佳，#35/0.06次之。#40/0.06、#35/0.06的消毒效果与#30/0.06、#25/0.06相比，差异显著（P＜0.05）。结论 在#25/0.06～#40/0.06根管尺寸范围内，Er:YAG激光联合3% NaOCl、17% EDTA和生理盐水冲洗上颌前牙单直根管时，根管预备尺寸不应小于#30/0.06。

Influence of the root canal instrumentation size on the disinfection of intracanal microbe by Er:YAG laser

PURPOSE To evaluate the influence of different root canal instrumentation size on disinfection of intracanal microbe of dental root canal. METHODS 368 extracted human anterior teeth with single straight root were randomly divided into 8 groups of 46 roots in each. They were instrumented with K3 Ni-Ti files as follows: group A1 and group B1(#25/0.06), group A2 and group B2(#30/0.06), group A3 and group B3(#35/0.06), group A4 and group B4(#40/0.06). After being prepared and sterilized by autoclaving, group A was inoculated with Enterococcus faecalis, and group B was inoculated with Candida albicans. All groups were irrigated with Er:YAG laser combination of 3% NaOCl, 17% EDTA and 0.9% saline, and then the numbers of microbe on the surface of root canal walls were counted after the treatment, the absolute reduction of counting colony forming units(CFUs) and the relative residual rate of CFUs in the individual group was determined. The Date was analyzed with GraphPad Prism 5.02 software package by one-way analysis of variance. RESULTS Levels of disinfection on E.faecalis and C.albicans increased when root canals were enlarged; #40/0.06 showed the best disinfection, #35/0.06 showed a significantly better disinfection than #30/0.06 and #25/0.06. Substantial reduction of microbe was obtained in #35/0.06 and #40/0.06 compared with #25/0.06 and #30/0.06(P＜0.05).CONCLUSIONS Within the root canal size of #25/0.06-#40/0.06, under the conditions of Er:YAG laser combination of 3% NaOCl, 17% EDTA and 0.9% saline, it was concluded that the reduction of E.faecalis and C.albicans of the anterior straight root canals could be predicted by increasing the root canal instrumentation size large than #30/0.06.