title: Stress analysis of human tooth root using various root canal instruments.
abstract: This study compared external root stresses from instrumentation by several motor-driven nickel-titanium instruments to stresses developed by hand files. Twelve curved first molar mesial roots were invested in PLM-9 photoelastic material to disclose net stress transmitted from the canal through the dentin. Minimal fringe patterns were observed during instrumentation with all techniques. Light-speed yielded the least change. In no case was a complete 60 psi fringe change noted.
authors.affiliation: Department of Periodontics, Endodontics, and Dental Hygiene, School of Dentistry, University of Louisville, Louisville, KY 40292, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Mayhew
authors.forename: P D
authors.initials: PD
authors.lastname: Eleazer
authors.forename: W P
authors.initials: WP
authors.lastname: Hnat
mesh_terms: D001718:Birefringence; D003754:Dental High-Speed Equipment; D003762:Dental Instruments; D003799:Dental Stress Analysis; D003804:Dentin / Q000293:injuries; D006801:Humans; D008334:Mandible; D008963:Molar / Q000502:physiology; D009532:Nickel; D018915:Root Canal Preparation / Q000009:adverse effects / Q000295:instrumentation*; D014025:Titanium; D018677:Tooth Injuries / Q000209:etiology; D014092:Tooth Root / Q000502:physiology*
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium