Abstract：
OBJECTIVE: To evaluate and compare the formation of dentinal defects using hand Hedstrom files, XP-Shaper, TruNatomy, and Reciproc Blue file systems when used for oval shaped root canals.
METHODS: One hundred and five extracted human mandibular premolars with single root and oval canals were selected for the study. Twenty-one teeth were unprepared (control), and the remaining teeth were divided into the prepared groups (n = 21), that is, Group H-Files, Group XP-Shaper, Group TruNatomy, and Group Reciproc Blue. All selected teeth were de-coronated perpendicular to the long axis of the tooth by using a diamond-coated disk with water cooling, leaving root segments approximately 16 mm in length. Each group was prepared according to the above file system. Then all roots were sectioned perpendicular to their long axes at 3, 6, and 9 mm from the apex using a diamond-coated disk under a continuous water stream. Each specimen was then checked for the presence of dentinal defects/microcracks.
RESULTS: The XP-Endo shaper group had the lowest number of defects (01/21 roots) 4.7%; TN (04/21) 19%, H-Files (04/21) 19%, and RC Blue (05/21) 23.8% had the highest incidence of defects. However, no significant difference was detected among these groups (P > 0.05).
CONCLUSIONS: The motor-driven root canal instrumentation with rotary and reciprocating files and hand files may create microcracks in the radicular dentine, whereas the XP-Shaper file system produces minimal or less cracks compared to other tested rotary file systems and H-file instrumentation.
METHODS: One hundred and five extracted human mandibular premolars with single root and oval canals were selected for the study. Twenty-one teeth were unprepared (control), and the remaining teeth were divided into the prepared groups (n = 21), that is, Group H-Files, Group XP-Shaper, Group TruNatomy, and Group Reciproc Blue. All selected teeth were de-coronated perpendicular to the long axis of the tooth by using a diamond-coated disk with water cooling, leaving root segments approximately 16 mm in length. Each group was prepared according to the above file system. Then all roots were sectioned perpendicular to their long axes at 3, 6, and 9 mm from the apex using a diamond-coated disk under a continuous water stream. Each specimen was then checked for the presence of dentinal defects/microcracks.
RESULTS: The XP-Endo shaper group had the lowest number of defects (01/21 roots) 4.7%; TN (04/21) 19%, H-Files (04/21) 19%, and RC Blue (05/21) 23.8% had the highest incidence of defects. However, no significant difference was detected among these groups (P > 0.05).
CONCLUSIONS: The motor-driven root canal instrumentation with rotary and reciprocating files and hand files may create microcracks in the radicular dentine, whereas the XP-Shaper file system produces minimal or less cracks compared to other tested rotary file systems and H-file instrumentation.
摘要：
目的：使用Hedstrom文件评估和比较牙本质缺损的形成，XP-Shaper,TruNatomy,和ReciprocBlue文件系统用于椭圆形根管时。
方法：选择单根和卵圆管的一百一十五个人下颌前磨牙进行研究。21颗牙齿未经准备（对照），剩下的牙齿被分为准备组（n=21），也就是说,GroupH-Files,组XP-Shaper,TruNatomy集团,和组Reciproc蓝色。通过使用带有水冷的金刚石涂层圆盘，垂直于牙齿的长轴对所有选定的牙齿进行去冠状处理，留下根节约16毫米长。每组均按上述文件系统编制。然后在连续水流下使用金刚石涂层的圆盘在距顶点3、6和9mm处垂直于其长轴剖切所有根。然后检查每个试样是否存在牙本质缺陷/微裂纹。
结果：XP-Endo整形器组的缺陷数量最低（01/21根）4.7％；TN（04/21）19％，H文件（04/21）19%，而RCBlue(05/21)的缺陷发生率最高,为23.8%。然而,各组间差异无统计学意义(P>0.05)。
结论：带有旋转和往复牙套以及手动牙套的电机驱动根管器械可能会在牙根牙本质中产生微裂纹，而与其他经过测试的旋转文件系统和H文件仪器相比，XP-Shaper文件系统产生的裂纹最少或更少。
方法：选择单根和卵圆管的一百一十五个人下颌前磨牙进行研究。21颗牙齿未经准备（对照），剩下的牙齿被分为准备组（n=21），也就是说,GroupH-Files,组XP-Shaper,TruNatomy集团,和组Reciproc蓝色。通过使用带有水冷的金刚石涂层圆盘，垂直于牙齿的长轴对所有选定的牙齿进行去冠状处理，留下根节约16毫米长。每组均按上述文件系统编制。然后在连续水流下使用金刚石涂层的圆盘在距顶点3、6和9mm处垂直于其长轴剖切所有根。然后检查每个试样是否存在牙本质缺陷/微裂纹。
结果：XP-Endo整形器组的缺陷数量最低（01/21根）4.7％；TN（04/21）19％，H文件（04/21）19%，而RCBlue(05/21)的缺陷发生率最高,为23.8%。然而,各组间差异无统计学意义(P>0.05)。
结论：带有旋转和往复牙套以及手动牙套的电机驱动根管器械可能会在牙根牙本质中产生微裂纹，而与其他经过测试的旋转文件系统和H文件仪器相比，XP-Shaper文件系统产生的裂纹最少或更少。
