Tsesis I, Amdor B, Tamse A, Kfir A
Department of Endodontology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
Int Endod J. 2008 May;41(5):431-5. doi: 10.1111/j.1365-2591.2008.01387.x. Epub 2008 Feb 25.
To evaluate, ex vivo, the effect of maintaining apical patency on the original canal shape during preparation of curved roots by two different techniques.
Forty extracted human maxillary and mandibular molars were evaluated. Occlusal surfaces were ground and roots sectioned to the level of the cemento-enamel junction to allow only one root to remain for evaluation in each tooth. Specimens were divided into four experimental groups (10 canals each): Group 1--root canals prepared using the balanced force technique with stainless steel K-files, and patency established with size 10 K-files between each instrument; Group 2--same as Group 1 but without the use of a patency file; Group 3--canals instrumented with LightSpeed instruments and patency established with size 10 K-files between each instrument; and Group 4--same as Group 3 but without the use of a patency file. Specimens were mounted and a series of radiographs taken. Initial and post-preparation digital images were superimposed and the distance between two central axes at 1, 2 and 4 mm from the working length (WL) was measured to obtain an indication of the degree of apical transportation. Results were subjected to statistical analysis using two-way analysis of variance (ANOVA).
No significant differences were found in degree of apical transportation at different levels of the root canal (P > 0.05) nor in loss of WL between groups (P > 0.05).
In this laboratory study, maintaining apical patency did not influence canal transportation in the apical 4 mm.
在体外评估两种不同技术预备弯曲根管时保持根尖通畅对原始根管形态的影响。
对40颗拔除的人上颌和下颌磨牙进行评估。磨除咬合面并将牙根在牙骨质-釉质界水平处截断，使每颗牙仅保留一个牙根用于评估。样本分为四个实验组（每组10个根管）：第1组——使用不锈钢K锉采用平衡力技术预备根管，在每个器械之间用10号K锉建立通畅；第2组——与第1组相同，但不使用通畅锉；第3组——用LightSpeed器械预备根管，在每个器械之间用10号K锉建立通畅；第4组——与第3组相同，但不使用通畅锉。将样本固定并拍摄一系列X线片。将初始和预备后的数字图像叠加，测量距工作长度（WL）1、2和4 mm处两个中心轴之间的距离，以获得根尖移位程度的指标。结果采用双向方差分析（ANOVA）进行统计学分析。
根管不同水平处的根尖移位程度（P>0.05）以及各组之间的工作长度丧失情况（P>0.05）均未发现显著差异。
在本实验室研究中，保持根尖通畅对根尖4 mm内的根管移位没有影响。
