Comparison Of Effects Of Three Kinds Of Reciprocating Single Nickel-titanium Instruments On Dentinal Microcracks

Objective Comparing the effections of three kinds of reciprocating single nickel-titanium instruments on dentin microcracking after preparation,and providing reference for clinical application.Methods60 mandibular anterior teeth were selected and randomly divided into four groups: Reciproc group,One file group,Wave One group and Pro Taper Universal group.Preparing the root canal according to the root canal preparation standard procedure provided by the manufacturer.Use micro CT and CBCT to scan the samples before and after preparation,and then observe and record.Results No dentinal microcracks was found by CBCT before and after preparation.Micro CT can detect the presence of dentin microcracking.The micro CT results showed that all experimental groups(Waveone,Reciproc,Onefile,PTU)were able to detect the existence of dentin microcracking.There was no significant difference between all of nickel-titanium instruments(P>0.05).Conclusions The result of Micro-CT shows that the generation of dentin microcracks is indeed related to the nickel-titanium instruments.Continuous rotation and reciprocal rotation both cause microcracking.The clinical manifestations associated with dentin microcracking are not yet known.CBCT has no auxiliary effect on the diagnosis of dentin microcracking.Further in vitro studies should focus on the link between dentin microcracking and failure of endodontic treatment.