Li Hang, Zhang Chenzheng, Li Qing, Wang Changning, Song Yaling
Department of Endodontics, The State Key Laboratory Breeding Base of Basic Science of Stomatology and Key Laboratory for Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Department of Periodontics, The State Key Laboratory Breeding Base of Basic Science of Stomatology and Key Laboratory for Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Eur J Dent. 2014 Apr;8(2):191-196. doi: 10.4103/1305-7456.130598.
The objective of the following study is to compare the cleaning efficiency and deformation characteristics of Twisted File (TF) and ProTaper (PT) nickel-titanium rotary instruments in root canal preparation.
A total of 52 canals from 26 extracted maxillary first molars were randomly assigned into two groups of each including 13 mesiobuccal and 12 distobuccal (DB) canals. Two DB canals were as blank controls. After preparation with TF and PT, we recorded the preparation time and evaluate the amounts of debris and smear layer at apical, middle and coronal canals under scanning electron microscopy (SEM). Three cross-sections of canals at 3 mm, 5 mm and 7 mm from the apex foramens were scanned before and after preparation under micro-computed tomography. Changes of the cross-section area (CSA) at the three levels were calculated with Photoshop CS4. File deformation was also investigated under SEM. Two groups were statistically compared with Mann-Whitney test and independent sample t-test.
Less debris and smear layer were found in coronal regions of canals prepared with TF (P = 0.006, P = 0.001, respectively). TF group displayed more CSA change than PT group (P = 0.045) at cross-sections of 5 mm from the apex foramens and took significantly less preparation time than PT group did (P = 9.06 × 10(-28)). All five TF files without obvious micro-cracks and two out of 25 PT files with many micro-cracks showed visible unwound deformation.
Neither TF nor PT achieves complete cleanliness of canal walls. Their deformation features might indicate different fracture resistance. TF single-file technique would substantially shorten the time of root canal preparation.
以下研究的目的是比较扭转锉（TF）和ProTaper（PT）镍钛旋转器械在根管预备中的清洁效率和变形特征。
从26颗拔除的上颌第一磨牙中选取52个根管，随机分为两组，每组包括13个近中颊根管和12个远中颊（DB）根管。两个DB根管作为空白对照。用TF和PT进行预备后，记录预备时间，并在扫描电子显微镜（SEM）下评估根尖、根管中部和冠部根管内的碎屑和玷污层量。在微计算机断层扫描下，对距根尖孔3mm、5mm和7mm处的根管三个横截面在预备前后进行扫描。用Photoshop CS4计算三个水平处的横截面积（CSA）变化。还在SEM下研究锉的变形情况。两组数据采用Mann-Whitney检验和独立样本t检验进行统计学比较。
用TF预备的根管冠部区域发现的碎屑和玷污层较少（分别为P = 0.006，P = 0.001）。在距根尖孔5mm处的横截面，TF组的CSA变化比PT组大（P = 0.045），且TF组的预备时间明显短于PT组（P = 9.06×10⁻²⁸）。所有5根无明显微裂纹的TF锉和25根PT锉中的2根有许多微裂纹的锉均显示出可见的解绕变形。
TF和PT均未实现根管壁的完全清洁。它们的变形特征可能表明抗折断性不同。TF单锉技术可大幅缩短根管预备时间。
