Oliveira Maria Antonieta Veloso Carvalho de, Alves Letícia Duarte, Pereira Analice Giovani, Raposo Luís Henrique Araújo, Biffi João Carlos Gabrielli
Department of Endodontics, School of Dentistry, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.
Department of Occlusion, School of Dentistry, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.
Braz Oral Res. 2015;29. doi: 10.1590/1807-3107BOR-2015.vol29.0078. Epub 2015 Jun 16.
The aim of this study was to evaluate the influence of the flexion angle of files on the decentralization of root canals during instrumentation. Fifteen lower incisors were instrumented with Protaper Universal files and radiographed in two directions (mesiodistal and buccolingual) before and after instrumentation with a #15 K-file in position for evaluating the flexion angle of files. The specimens were also scanned before and after instrumentation using micro-computed tomography to obtain the canal area and the distance from the center position of the file to the canal walls. Sections located 1.0 mm (end of the canal), 3.0 mm (apical third), 9.0 mm (middle third), and 15.0 mm (cervical third) from the apex were verified. After instrumentation, the flexion angles of files decreased by an average of 0.76º in the buccolingual direction and 1.92º in the mesiodistal direction (p < 0.001); the canal area increased by an average of 0.58, 0.37, 0.23 and 0.13 mm(2) from the cervical to the end of the root canal (p < 0.001). Non-instrumented areas were observed on the buccal and lingual walls, and effective action of files was determined on the mesial and distal walls. The sections from the end of the canal showed canal deviation toward the lingual wall, whereas the other sections showed deviation toward the buccal wall. The flexion angles of files influence the final shape of the root canal, resulting in file decentralization along the pathway of the canal.
本研究的目的是评估锉的弯曲角度对根管预备过程中根管偏移的影响。使用Protaper Universal锉对15颗下颌切牙进行根管预备，并在使用#15 K锉就位以评估锉的弯曲角度前后，从近远中向和颊舌向两个方向进行X线片拍摄。在根管预备前后还使用显微计算机断层扫描对标本进行扫描，以获得根管面积以及锉的中心位置到根管壁的距离。对距根尖1.0 mm（根管末端）、3.0 mm（根尖三分之一）、9.0 mm（根中三分之一）和15.0 mm（根管颈三分之一）处的切片进行验证。根管预备后，锉在颊舌向的弯曲角度平均减小0.76°，在近远中向平均减小1.92°（p < 0.001）；从根管颈到根管末端，根管面积平均增加0.58、0.37、0.23和0.13 mm²（p < 0.001）。在颊侧和舌侧壁观察到未预备的区域，而在近中壁和远中壁确定了锉的有效作用区域。根管末端的切片显示根管向舌侧偏移，而其他切片显示向颊侧偏移。锉的弯曲角度影响根管的最终形态，导致锉沿根管路径偏移。
