Comparison Of Dentinal Microcrack Development After Canal Preparation With Three Kinds Of Reciprocating Nickel-titaninm

Objective To evaluate the development of dentinal microcracks after root canal preparation with Reciproc?Wave One?One File and Pro Taper Universal systems using an in situ cadaver model by means of a micro–computed tomography(micro-CT),and to provide the reference for their clinical application.Methods At autopsy,15 mandible bone blocks having at least the anterior teeth(n = 60)with single root were excised,and then randomly distributed into 4 groups(n = 15)according to the preparation protocol: Reciproc ?Wave One ? One File and Pro Taper Universal systems,the Pro Taper Universal systems as a control group.Root canals were prepared up to 25#instruments in the Reciproc ?Wave One?One File and F2 instruments in the Pro Taper Universal groups,respectively.After the preparation procedures,the specimens were scanned again,The number of dentinal microcracks were investigated and analyzed statistically.Datas were analyzed through Chi-squared Test,?at a?significance level of? P<0.05.Results Compared with the Pro Taper Universal groups,root fracture incidence rate of group Reciproc?group Wave One and group One File was significantly reduced.(P<0.05).There were no statistically differences in incidence rate of dentinal microcracks between group Reciproc?group Wave One and group One File(P>0.05).Conclusions Root canal preparation can cause root microcrack,so it is important to choice the types of instruments.Roots canal prepared with Reciproc?Wave One and One File produce less dentinal microcracks,which decrease risk of vertical root fracture.