title: Determination of impedance changes at varying frequencies in relation to root canal file position and irrigant.
abstract: This study was conducted on 10 anterior and premolar teeth that were scheduled for endodontic treatment. After length of tooth determination, a series of test K-file handles were locked at lengths varying from 3 mm short to 0.5 mm long of the foramen. Samples of impedance were taken at each length with a digital signal processor at six different frequencies and for each of seven different irrigants or canal conditions. A total of five different root canal irrigants were used in each tooth (RC Prep, 70% isopropyl alcohol, 14.45% EDTA sodium solution, normal saline, and 5.25% NaOCl), along with two variations of a dry canal. The greatest impedance changes occurred +/- 0.25 mm from the foramen. No significant difference was noted in prediction error at different frequencies (p > 0.05); however, prediction error was significant with respect to different irrigants (p < 0.02). Conductive irrigants demonstrated less change of electrical characteristics with length than nonconductive irrigants, thus allowing a greater prediction of file position in relation to the foramen using electrically nonconductive irrigants.
authors.affiliation: Department of Endodontics, University of Washington, Seattle 98195-7448, USA.
authors.forename: T F
authors.initials: TF
authors.lastname: Pilot
authors.forename: D L
authors.initials: DL
authors.lastname: Pitts
mesh_terms: D001641:Bicuspid; D003481:Cuspid; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging / Q000502:physiology*; D017097:Electric Impedance; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D007180:Incisor; D011379:Prognosis; D011859:Radiography; D012388:Root Canal Irrigants / Q000737:chemistry*; D012390:Root Canal Therapy / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data
chemical_list: D012388:Root Canal Irrigants