根管预备中碎屑从根尖推出量的比较研究

目的:比较分析不同横截面形态的机动根管预备器械在根管预备过程中对根尖碎屑推出量的影响。方法:临床收集拔除的90颗单根管下颌前磨牙,共选取6种机动镍钛锉,按照器械横截面形态为等边三角形且三点接触根管壁的器械为参考,共分为三组:第一组为大横截面组,三点接触根管壁,顺时针连续旋转运动器械(ProTaper Universal(PTU));第二组为小横截面组,两点接触根管壁,顺时针连续旋转运动器械(ProTaper Nex t(PTN)、M3-L);第三组为中横截面组,三点接触根管壁,在本组内按照器械的运动方式,又分为A组,顺时针连续旋转运动器械(Hyflex CM(HF)、M3),和B组,智能化往复运动器械(Twisted File Adaptive(TFA));每种器械预备15颗离体牙根管。用预先称量的离心管收集根管预备过程中从根尖溢出的所有物质,烘干,再次称量,计算推出根尖孔碎屑的量。结果:所用6种镍钛锉在根管预备过程中均有碎屑推出根尖孔。PTU根尖碎屑推出量最多(0.000330±0.000162g)(P<0.05);顺时针连续旋转运动的小横截面两点接触器械(PTN、M3-L)(0.000119±0.000016g)与中横截面三点接触器械(H F、M3)(0.000135±0.000018g)根尖碎屑推出量差异无统计学意义(P>0.05);顺时针连续旋转运动器械HF(0.000132±0.000080g)、M3(0.000139±0.000119g)与智能化往复旋转运动器械TFA(0.000158±0.000073g)根尖碎屑推出量差异无统计学意义(P>0.05)。结论:本研究纳入的6种根管预备器械在体外根管预备过程中均有根尖碎屑的推出,中、小横截面、恒定锥度、支数少的器械在减少根尖碎屑推出方面的表现优于大横截面、大锥度、多支数器械。

A comparative study on the amount of debris extruded from the apex during root canal preparation

Objective:To compare and analyze the effect of different cross section shape on the apically extruded debris in mechanical root canal preparation.Methods:Ninety freshly extracted intact mandibular premolars with developed apex were collected.According to the shape of the instrument’s cross-section,an equilateral triangle and three points contacting the root canal wall are were used as a reference.The first group was large cross section group,three points were in contact with root canal wall,the second group was small cross section group,two points were in contact with root canal wall,and the clockwise continuous rotation of sports instrument(ProTaper Next(PTN),M3≤L).The third group was the middle cross section group,which contacted the root canal wall at three points.According to the movement mode of the instrument,it was divided into group A(clockwise continuous rotation of sports instrument(Hyflex CM(HF),M3)and group B(intelligent reciprocating sports instrument(Twisted File Adaptive(TFA))).15 isolated root canals were prepared by each instrument.All the material overflowing from the apex during root canal preparation was collected by a pre-weighed centrifuge tube,dried,weighed again,and the amount of apical debris was calculated.The data were statistically analyzed by one-way ANOVA.Results:A measurable amount of debris was apically extruded in all groups(0.000330±0.000162 g)(P<0.05).The PTU group resulted in the largest amount of debris extrusion among the groups(P<0.05).No statistically significant difference was observed between small-cross-section,two-point contact instruments(PTN、M3-L)(0.000119±0.000016 g)and medium-cross-section,three-point contact instrument(HF、M3)(0.000135±0.000018 g)(P>0.05).There was no statistically significant between the clockwise continuous rotary HF(0.000132±0.000080 g)、M3(0.000139±0.000119 g)system and the TFA system(0.000158±0.000073 g)(P>0.05).Conclusion:In this study,all of the six instruments included in this study had apically extruded debris during in vitro root canal preparation,instruments with small and medium crosssections,constant taper,and low counts are superior to instruments with large cross-sections,large tapers,and multiple counts in reducing the introduction of apical debris.