目的：以不锈钢K锉作对照,评价机用单根锉WaveOne和机用ProTaper镍钛器械成形及清理重度弯曲根管的能力。方法收集新鲜拔除的离体牙,选取弯曲度为25°~45°的根管30个,随机分成W、P、K 3组,每组10个。 W组：使用WaveOne机用往复式镍钛合金锉冠向下法预备根管；P组：使用ProTaper机用镍钛锉冠向下法预备根管；K组：使用不锈钢K锉逐步后退法预备根管。分别于预备前、后进行锥体束CT ( cone beam computed tomography,CBCT)扫描,比较在距根尖1.5mm、2.5mm、4.5mm、5.5mm处各组根管偏移值差异。将30个根管剖开,通过扫描电子显微镜观察根管预备后根管内壁的碎屑和玷污层。结果在距根尖1.5mm、2.5mm、4.5mm、5.5mm处四层水平上,K组发生的偏移值均较大,与P组和W组相比差异有显著性(P<0.05),而W组和P组间差异无显著性(P>0.05)。扫描电镜下,3组之间在各部分碎屑评分上两两比较差异有显著性(P<0.05)。 W组、P组、K组根尖1/3处玷污层评分差异无显著性(P>0.05),而在根管冠1/3和根中1/3处评分差异有显著性(P<0.05),其中K组与W组、P组有显著差别(P<0.05),W组和P组间无显著差别(P>0.05)。结论 WaveOne和ProTaper预备重度弯曲根管具有良好的成形能力,保持原有根管走向的能力优于不锈钢K锉；配合次氯酸钠冲洗,单根锉WaveOne对根管的清理效果最优。%Objective To evaluate the shaping ability and cleaning efficiency of rotary single-file WaveOne and rotary ProTaper in severely curved root canals by compared with stainless steel K-file. Method 30 root canals with curva-tures ranging from 25° to 45° were selected and randomly assigned to W,K,P three groups with 10 teeth in each. W group:Crown-down technique with single-file WaveOne was used in root canal preparation; P group:Crown-down technique with rotary ProTaper was used in root canal preparation;K group:modified step-back technique with stain-less steel K-file was used in root canal preparation. Cone beam computed tomography scans were performed respec-tively before and after the preparation to evaluate the offset value of root canal at 1. 5mm, 2. 5mm, 4. 5mm and 5. 5mm from the root apex. After preparation,the roots were split into two halves longitudinally and root canal walls were examined the distribution of debris and smear layer under scanning electron microscope. Result At 1. 5mm, 2. 5mm, 4. 5mm and 5. 5mm levels from the root apex, K group showed more root canal transportation than the other two groups, it was also showed significant difference than the others(P<0. 05). But there was no statistical signifi-cant difference between group W and P(P>0. 05). In the case of SEM, there was no significant difference in scores of smear layer at the apical third of root canal in group W, group P and group K(P>0. 05). At the middle third and coronal third sections, the efficiency of cleaning smear layer in W group and P group were significantly better than that of K group(P<0. 05). And statistical significant difference was found in scores of debris at every section among the three groups(P<0. 05). Conclusion WaveOne and ProTaper in preparation of severely curved root canals both show good shaping ability,and are better than stainless steel K-files in keeping the shape of curved root canals. Using the NaOCl as irrigation, single-file WaveOne can do the best cleaning effects.
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