title: Root-end fracture during retropreparation: a comparison between zirconium nitride-coated and stainless steel microsurgical ultrasonic instruments.
abstract: The purpose of this study was to evaluate a stainless steel (CT-5) and zirconium nitride coated (KiS) microsurgical ultrasonic instrument with regard to possible root-end fracture production during retropreparation. Forty extracted human central incisors were prepared in a crown-down fashion. Canals were obturated with gutta-percha by lateral condensation. Root-ends were resected. Teeth were placed in methylene blue for 48 h and evaluated by three independent evaluators under microscope. Teeth with existing fractures were eliminated from the study. The remaining teeth were randomly divided into two equal groups. Group A was prepared with the CT-5 tip and Group B with the KiS tip. Preparation time was recorded for all roots. The teeth were again immersed in methylene blue for 48 h and reevaluated. No root-end fractures were produced by either the KiS or CT-5 microsurgical ultrasonic instruments.
authors.affiliation: Endodontic Department, University of Detroit Mercy School of Dentistry, Michigan, USA.
authors.forename: Stephen William
authors.initials: SW
authors.lastname: Navarre
authors.forename: H Robert
authors.initials: HR
authors.lastname: Steiman
mesh_terms: D001047:Apicoectomy; D020099:Coated Materials, Biocompatible; D004396:Coloring Agents; D004867:Equipment Design; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D007180:Incisor; D008751:Methylene Blue; D008866:Microsurgery / Q000295:instrumentation*; D009584:Nitrogen; D012184:Retrograde Obturation / Q000009:adverse effects / Q000295:instrumentation; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000009:adverse effects / Q000295:instrumentation*; D013193:Stainless Steel; D013997:Time Factors; D019227:Tooth Apex / Q000293:injuries*; D014082:Tooth Fractures / Q000209:etiology*; D014464:Ultrasonic Therapy / Q000295:instrumentation*; D015040:Zirconium
chemical_list: D020099:Coated Materials, Biocompatible; D004396:Coloring Agents; D012387:Root Canal Filling Materials; D013193:Stainless Steel; D006171:Gutta-Percha; D015040:Zirconium; D009584:Nitrogen; D008751:Methylene Blue