title: A scanning electron microscopy evaluation of microfractures, deformation and separation in EndoSequence and Profile nickel-titanium rotary files using an extracted molar tooth model.
abstract: The development of microfractures in the EndoSequence nickel-titanium rotary (NTR) file (Brassler USA, Savannah, GA) and Profile NTR file was evaluated by using scanning electron microscopy (SEM). Seventy-three maxillary buccal roots and 53 mandibular mesial roots with an average canal curvature of 37 degrees were randomly assigned to one of three groups and prepared with 21-mm .06 taper NTR files as follows: (1) EndoSequence at 300 rpm, (2) EndoSequence at 600 rpm, and (3) ProFile at 300 rpm. File sizes .45 to .20 were used in a crown-down technique to a master apical file (MAF) size of .35/.06. The MAF instruments were evaluated by SEM before use, after completion of 7 canals, and after completion of 14 canals. All EndoSequence instruments developed microfractures by the seven-canal evaluation. The ProFile instruments showed no microfractures at the 7- or 14-canal evaluations. EndoSequence files separated at a higher rate than ProFile instruments. Under the conditions of this study, unique file design and electropolishing did not inhibit the development of microfractures in EndoSequence NTR.
authors.affiliation: Department of Endodontics, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Keven S
authors.initials: KS
authors.lastname: Herold
authors.forename: Bradford R
authors.initials: BR
authors.lastname: Johnson
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Wenckus
mesh_terms: D003722:Dental Alloys; D003762:Dental Instruments; D003799:Dental Stress Analysis; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium