title: Comparison of root canal preparation using reciprocating Safesiders stainless steel and Vortex nickel-titanium instruments.
abstract: OBJECTIVE
  The aim of the present study was to assess several parameters related to the clinical usage of 2 root canal preparation instruments: Vortex .06 rotary nickel-titanium instruments, and Safesiders reciprocating stainless steel instruments.
  
  
  METHODS
  Fifty extracted mandibular molars with mesial root canal curvatures between 20° and 50° were divided into 2 groups and embedded in acrylic resin inside a modified Bramante muffle system. All root canals were prepared to ISO size 40 using either Vortex .06 rotary nickel-titanium-instruments in a low-torque motor or Safesiders stainless steel instruments in a proprietary reciprocating handpiece. The following parameters were evaluated: straightening of curved root canals, working safety issues (perforations, instrument breakages, canal blockages, loss of working length), postpreparation root canal cross-section, and working time.
  
  
  RESULTS
  The Vortex .06 instruments maintained canal curvatures well, with the mean degree of straightening recorded as 0.72°. Safesiders instruments demonstrated significantly more canal straightening, with the mean degree of straightening recorded as 15.5°. More than 90% of the root canals prepared with the Vortex .06 instruments resulted in a round or oval cross-section, whereas the Safesiders instruments produced round or oval cross-sections 60% of the time. Neither of the 2 instruments could effectively prepare 100% of the root canal circumference. The area of dentin removed and the remaining dentin thicknesses from each region were similar for the 2 groups. Six procedural incidents were recorded for the Vortex .06 group, compared with 19 for the Safesiders group. There were no instrument fractures recorded in either group. Mean working time was significantly shorter for Vortex .06 (279 s) than for Safesiders (324 s).
  
  
  CONCLUSIONS
  Vortex .06 maintained the original root canal curvatures well, whereas Safesiders instruments demonstrated significant straightening and irregular preparation shapes when used in sizes larger than ISO 20. Preparation of the complete circumference of the root canal was not possible with either system. Fewer procedural errors occurred with the Vortex instruments.
authors.affiliation: Department of Endodontics, University of Alabama School of Dentistry, Birmingham, Alabama, USA. scraigrhodesdmd@gmail.com
authors.forename: S Craig
authors.initials: SC
authors.lastname: Rhodes
authors.forename: Michael
authors.initials: M
authors.lastname: Hülsmann
authors.forename: Sandre F
authors.initials: SF
authors.lastname: McNeal
authors.forename: Preston
authors.initials: P
authors.lastname: Beck
authors.forename: Paul D
authors.initials: PD
authors.lastname: Eleazer
mesh_terms: D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003722:Dental Alloys; D003739:Dental Cementum / Q000033:anatomy & histology; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D003804:Dentin / Q000033:anatomy & histology; D004867:Equipment Design; D006801:Humans; D008963:Molar; D009532:Nickel; D012044:Regression Analysis; D018915:Root Canal Preparation / Q000295:instrumentation*; D013193:Stainless Steel; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium