目的 利用树脂模拟根管比较D-RaCe、ProTaper、Mtwo R去除根管充填物的操作时间及清除率.方法 选取30个透明树脂根管, 随机分为3组, 分别用D-RaCe (A组) 、ProTaper (B组) 、Mtwo R (C组) 去除根充物, 记录操作时间, 并采集根充物去除后的图像, 使用AUTO 2010描记并计算残留物面积, 比较3种锉的整体清除率.再将根尖部分分为距根尖孔0～2 mm、2～4 mm、4～6 mm 3个区段, 分别计算残留面积, 比较3种再治疗锉在哪一区段内清除率最佳.结果 D-RaCe锉操作时间最短, 所有样本根管内均有充填物残留.ProTaper、Mtwo R整体清除率无统计学差异 (P>0.05) , 且均优于D-RaCe组 (P<0.05) .距根尖孔0～2 mm、2～4 mm区段内, D-RaCe组清除率最低, 4～6 mm区段内3组无统计学差异 (P>0.05) .结论 D-RaCe锉操作时间短, 具有更高的抗疲劳及抗折断能力.ProTaper、Mtwo R再治疗锉均能去除大部分根充物, 在距根尖孔0～2 mm、2～4mm区段内清除率均优于D-RaCe组.%Objective To compare the operation time and clearance rate of D-RaCe, ProTaper and Mtwo R in removing root canal filling of simulated resin root canal. Methods 30 transparent resin root canals were selected and randomly divided into 3 groups. DRa Ce ( Group A) , ProTaper ( Group B) , and Mtwo R ( Group C) were used to remove the root fillings. The operation time was recorded, and the images after removal of the root fillings were collected. AUTO 2010 was used to trace and calculate the residual area. The overall clearance rates of the three species were compared. The apical part was divided into three sections from 0-2 mm, 2-4 mm, and4-6 mm from the apical foramen. The residual area was calculated and the clearance rates among the three retreatment groups were compared to find out which regions had the highest rate. Results The operating time was the shortest in group D-RaCe ( P< 0.05). All samples had residual fillings in the root canal, and there was no significant difference in overall clearance rate between ProTaper and Mtwo R ( P>0.05) , and both were superior to those in group D-RaCe ( P<0.05). In the 0-2 mm and 2-4 mm sections of the apical foramen, the clearance rate in the D-RaCe group was the lowest, and there was no statistical difference in the 4-6 mm sections among three groups ( P>0.05). Conclusions D-RaCe has short operating time, higher fatigue resistance and anti-break ability. ProTaper and Mtwo Re-treatments are able to remove most of the root fillings, the clearance rates of which in the 0-2 mm and 2-4 mm sections from the apical foramina are better than those in the D-RaCe group.
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