title: Preparation of severely curved simulated root canals using engine-driven rotary and conventional hand instruments.
abstract: This in vitro study evaluated the efficacy and safety of six different nickel-titanium engine-driven instruments used with a torque-controlled engine device and nickel-titanium hand and stainless steel hand instruments in preparation of curved canals. A total of 80 curved (36 degrees) simulated root canals were prepared. Images before and after were superimposed, and instrumentation areas were observed. Time of instrumentation, instrument failure, change in working length and weight loss were also recorded. Results show that stainless steel hand instruments cause significantly less transportation towards the inner wall of the canal than do nickel-titanium hand instruments. No instrument fracture occurred with hand instruments, but 30-60% breakage of instruments was recorded during instrumentation with the engine-driven devices. The working length was maintained by all types of instruments. Newly developed nickel-titanium rotary files were not able to prevent straightening of the severely curved canals when a torque-controlled engine-driven device was used.
authors.affiliation: Department of Operative Dentistry (Carolinum), Johann Wolfgang Goethe University of Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Szep
authors.forename: T
authors.initials: T
authors.lastname: Gerhardt
authors.forename: C
authors.initials: C
authors.lastname: Leitzbach
authors.forename: W
authors.initials: W
authors.lastname: Lüder
authors.forename: D
authors.initials: D
authors.lastname: Heidemann
mesh_terms: D003722:Dental Alloys; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004867:Equipment Design; D004868:Equipment Failure; D004869:Equipment Safety; D006801:Humans; D008953:Models, Anatomic; D009532:Nickel; D011670:Pulpectomy / Q000295:instrumentation / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D013193:Stainless Steel; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium; D019415:Torque
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium