三种镍钛器械根管预备后牙本质裂纹的研究

Comparison of the dentinal cracks of root canals prepared by using three types of nickel-titanium instruments

目的对三种不同镍钛器械预备后根部牙本质裂纹产生情况的研究。方法选取即刻拔除70颗下颌前磨牙,分为三个试验组(n=20),一个对照组(n=10)。实验组分别为Protaper Universal,Protaper Next,Mtwo根管预备,对照组不使用根管预备。距根尖2、4、6、8 mm处截断,分别放在激光共聚焦显微镜下观察并记录预备后牙根有/无裂纹产生情况。结果阴性对照组没有裂纹产生,其他试验组中Protaper Universal组产生裂纹与MTWO和Protaper Next组有显著差异,而Mtwo和Protaper Next组没有明显差异。结论通过对比三种器械研究发现Protaper Next组和Mtwo组产生的牙本质裂纹较少,能降低牙根纵裂的风险,对今后临床应用有一定指导意义。

Objective To compare the effects of three types of nickel titanium rotary instruments on the incidence of dentinal cracks in root dentin after root canal preparation. Methods A total of 70 mandibular premolars extracted were instantly divided into three groups（ n = 20） and a control group（ n = 10）.The experimental groups were prepared using Protaper Universal,Protaper Next,or Mtwo instruments for root canal preparation. The control group did not use the root canal preparation. After root canal prepara-tion,all of the roots were sectioned perpendicularly to the long axis at 2,4,6,and 8 mm from the apex,and the sections were then observed under a laser scanning confocal microscope. The absence/presence of cracks was recorded and analyzed. Results No cracks were observed in the control group. In the experimental groups,the dentinal cracks of the Protaper Universal group and Mtwo group were significantly different,but no significant difference between the Mtwo and Protaper of Next groups. Conclusions Preparation of root canals with Protaper Next,Mtwo,and Pro Taper Universal instruments may cause damage to root canal dentin. The Pro Taper Next and Mtwo instruments tend to cause fewer dentinal cracks compared with the Pro Taper Universal instrument. Using these instruments may reduce the risk of vertical root cracks,and their clinical application in future is of certain instructive significance.