Analysis of forces developed during mechanical preparation of extracted teeth using Profile NiTi rotary instruments
Analysis of forces developed during mechanical preparation of extracted teeth using Profile NiTi rotary instruments
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DOI：
10.1046/j.1365-2591.1999.00181.x
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发表时间：
1999-01-01
影响因子：
5
通讯作者：
Micallef, JP
中科院分区：
文献类型：
--
作者：
Blum, JY;Cohen, A;Micallef, JP
目的分析Profile NiTi器械机械预备过程中拔牙根管系统中所产生的垂直力和扭矩。方法根管预备过程中反复施加力和扭矩是导致根管系统磨损和断裂的主要原因，但缺乏合适的测量装置阻碍了对其直接关系的研究。使用一种新型的力分析仪EndogRaphe来测量这些力和扭矩，该装置配备了一个夹持器来记录和生成预备过程中施加的垂直力和扭矩的曲线图，结果牙髓医生的垂直作用力和扭矩平均值分别为4~6N和7.105~12.105 Nm，倒退技术为2.9N~4.2N和18.105~20.105 Nm。这表明，冠状向下技术产生了较低的应力(较低的扭矩和较低的垂直力)，尽管这些发现也取决于单个根管的形状，但学生最初在所产生的力方面表现出很大的差异，垂直强度和扭矩值明显较低。到实验结束时，它们的数值与牙髓医生的数值相似，这表明操作效率有所提高。需要用这两种技术来研究力和扭矩数据与器械折断发生率之间的关系，因为这项研究具有相当大的临床意义。然而，必须指出的是，EndogRaphe无法考虑到仪器的切割效率。图形的使用为机械准备的分析提供了一种新的途径。
Aim The aim of this study was to analyse the vertical forces and torque developed in the root canal system of extracted teeth during mechanical preparation using ProFile NiTi instruments.Methodology Instrument wear and fracture is in great part due to the repeated application of forces and torque during the course of root-canal preparation but research into the direct relationship has been hampered by the lack of adequate measuring devices, Measurements of these forces and torque were made with a new force analyser device, the Endographe, that was equipped with a holder to record and generate graphs of the vertical forces and torque exerted during the preparations, These preparations were performed by endodontists or students either with a series of instruments of increasing size or with the crown-down pressureless technique.Results The mean values for the endodontists of the generated vertical forces and torque varied, respectively, from 4 to 6N and from 7.105 to 12.105 Nm for the step-back technique and from 2.9 to 4.2 N and from 18.105 to 20.105 Nm for the crown-down technique. This suggested that the crown-down technique generated lower stresses (lower torque and lower vertical forces), although these findings also depend on the shape of individual canals, The students initially showed wide variations in generated forces, with significantly lower vertical forte and torque values. By the end of the experimental sessions their values were similar to those of the endodontists, which indicated improvement in the efficiency of manipulation.Conclusions Further work. is needed to investigate the relationship between the force and the torque data from this study and the incidence of instrument fracture with the two techniques, as the clinical implications are considerable. It must be noted, however, that the Endographe is unable to take into account the cutting efficiency of the instruments. The use of graphs provides a new approach to the analysis of mechanical preparation.