Abstract:

Objective    To evaluate the formation of dentinal defects after root canal preparation with reciprocating instruments（Reciproc and WaveOne）and rotary instruments（ProTaper）. Methods    Sixty human mandibular first premolar teeth were randomly divided into 4 groups（15 teeth per group）.The root canals were preparaed by using K-file，ProTaper，Reciproc and WaveOne respectively. All prepared roots were esctioned horizontally at 3，6，and 9mm from the apex and the cracks observed and recorded under a steremicroscope. The presence of cracks was analyzed by using the Chi-square test. Results    There was no crack by using K-file. The group of ProTaper demonstrated siginificantly more cracks than the groups of Reciproc and WaveOne（P < 0.05）. However， there was no siginificant difference between the latter two groups （P > 0.05）. Conclusion    Reciprocating files（Reciproc and WaveOne），when used according to the manufacturer's，instruction，tend to produce fewer cracks than full-sequence rotary system（ProTaper）and have less influence on root fracture resistance.

Key words: Ni-Ti instruments, root canal preparation, dentinal defects, reciprocating

摘要：

目的    评价往复运动和旋转运动的镍钛器械预备根管后牙本质裂纹产生的情况。方法    2015年5月于中国医科大学中心实验室选用人的单根管下颌第一前磨牙60颗，随机分为4组（每组15颗）：A组采用手用不锈钢K锉进行根管预备，B组采用机用Protaper进行根管预备，C组采用Reciproc进行根管预备，D组采用单支锉Wave One进行根管预备。将预备完成的离体牙垂直于牙体长轴分别距离根尖3、6、9 mm水平截断，体视显微镜下观察并记录牙本质裂纹产生情况。结果    使用Protaper预备根管产生的牙本质裂纹明显多于使用Reciproc和Wave One组（P < 0.05），后两组产生裂纹情况差异并无统计学意义（P > 0.05）。结论    旋转运动的镍钛锉比往复运转的镍钛锉产生的牙本质裂纹多，降低牙根的抗折性。

关键词: 镍钛器械, 根管预备, 牙本质裂纹, 往复旋转