■要比较使用不锈钢手动K档(HFs)形成的牙本质缺陷,旋转文件,往复文件,和自调整文件(SAF),当用于椭圆形根管。
■本研究选择了一百四十只具有单根和卵圆管的人下颌前磨牙。通过暴露于近端和口腔舌片来确认椭圆形管。排除有开放顶点或解剖不规则的牙齿。所有选定的牙齿都垂直于牙齿的长轴,留下长度约为16毫米的根节段。二十颗牙齿没有准备好(对照),其余120颗牙齿分为6组(n=20),并使用HF(大小40/0.02)进行仪器检测,Revo-S(RS;尺寸40/0.06),ProTaperNEXT(PTN;尺寸40/0.06),WaveOne(WO;尺寸40/0.09),RECIPROC(RC;尺寸40/0.06),和SAF(2毫米)。然后将根从顶点切开3、6和9毫米,在立体显微镜下观察,牙本质缺陷的存在。“无缺陷”定义为无可见微裂纹或断裂的牙根牙本质。“缺陷”由牙根牙本质中的微裂纹或断裂定义。
■控件,HF,SAF没有出现任何牙本质缺损。在RS仪器化的根中,PTN,WO,RC文件显示40%的微裂纹(不完整或完全),30%,55%,50%,分别。
■带有旋转和往复文件的电机驱动的根管器械可能会在牙根牙本质中产生微裂纹,而不锈钢手动文件仪器,和SAF产生最小或更少的裂纹。
UNASSIGNED: To compare the formation of dentinal defects using stainless-steel hand K-files (HFs), rotary files, reciprocating files, and Self-Adjusting File (
SAF), when used for oval root canals.
UNASSIGNED: One hundred and forty extracted human mandibular premolar with single root and oval canal were selected for this
study. Oval canals were confirmed by exposing to mesio-distal and bucco-lingual radiographs. Teeth with open apices or anatomic irregularities were excluded. All selected teeth were de-coronated perpendicular to the long axis of the tooth, leaving roots segments approximately of 16 mm in length. Twenty teeth were left unprepared (control), and the remaining 120 teeth were divided into 6 groups (n = 20) and instrumented using HF (size 40/0.02), Revo-S (RS; size 40/0.06), ProTaper NEXT (PTN; size 40/0.06), WaveOne (WO; size 40/0.09), RECIPROC (RC; size 40/0.06), and the
SAF (2 mm). Roots were then sectioned 3, 6, and 9 mm from the apex, and observed under stereomicroscope, for presence of dentinal defects. \"No defect\" was defined as root dentin that presented with no visible microcracks or fractures. \"Defect\" was defined by microcracks or fractures in the root dentin.
UNASSIGNED: The control, HF, and
SAF did not exhibit any dentinal defects. In roots instrumented by RS, PTN, WO, and RC files exhibited microcracks (incomplete or complete) in 40%, 30%, 55%, and 50%, respectively.
UNASSIGNED: The motor-driven root canal instrumentation with rotary and reciprocating files may create microcracks in radicular dentine, whereas the stainless-steel hand file instrumentation, and the
SAF produce minimal or less cracks.