title: Evaluation of Time to Fracture and Vertical Forces Applied by a Novel Gentlefile System for Root Canal Preparation in Simulated Root Canals.
abstract: BACKGROUND
  A great number of studies performed in the last 3 decades have shown the superior mechanical features of nickel-titanium files as compared with stainless steel files. A novel file system recently developed, Gentlefile, defies these findings and claims to have superior qualities despite the fact it is made from stainless steel.
  
  
  METHODS
  Three file systems were used in this experiment: ProTaper Next (X1, X2, and X3), RevoS (SC2, SC3, and AS30), and Gentlefile (GF1, GF2, and GF3). Time to fracture, rotations to fracture, and vertical forces applied to a simulated root canal, which was fabricated from a metal block with a Plexiglas cover, were measured.
  
  
  RESULTS
  The GF system required significantly longer time and more rotations to fracture compared with the ProTaper and RevoS systems (P < .001). The GF system applied significantly less vertical force to the canal in comparison with the ProTaper and RevoS systems (P < .01).
  
  
  CONCLUSIONS
  Under the limitations of this study the GF system showed better mechanical properties in comparison with the ProTaper and RevoS systems. Further investigation is needed to assess the clinical meaning of these findings.
authors.affiliation: Department of Endodontics, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel. Electronic address: dmoreinos@gmail.com.
authors.forename: Daniel
authors.initials: D
authors.lastname: Moreinos
authors.affiliation: Department of Endodontics, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel.
authors.forename: Aharon
authors.initials: A
authors.lastname: Dakar
authors.affiliation: Private Practice, Jerusalem, Israel.
authors.forename: Nachum Joseph
authors.initials: NJ
authors.lastname: Stone
authors.affiliation: Department of Endodontics, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel.
authors.forename: Joshua
authors.initials: J
authors.lastname: Moshonov
mesh_terms: D003722:Dental Alloys / Q000737:chemistry; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000473:pathology*; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry*; D018915:Root Canal Preparation / Q000009:adverse effects* / Q000295:instrumentation*; D012390:Root Canal Therapy / Q000295:instrumentation / Q000379:methods; D013193:Stainless Steel; D014025:Titanium / Q000737:chemistry*; D014082:Tooth Fractures
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium
keywords: Cyclic fatigue; Gentlefile; NiTi; ProTaper Next; Revo S; stainless steel; vertical force