title: Cutting efficiency of four different rotary nickel: Titanium instruments.
abstract: OBJECTIVE
  The aim of this study was to evaluate the cutting efficiency of rotary nickel-titanium (NiTi) instruments K3, NiTi Tee, Profile, and Quantec with taper size 04/25.
  
  
  METHODS
  The number of samples was 10 for each group (n = 10). The cutting efficiency was measured by the mass loss from each acrylic resin block after instrumentation of a simulated canal using the Crown-down technique.
  
  
  RESULTS
  The analysis of variance (ANOVA) showed that there was a statistically significant difference among the studied groups. The Tukey's test showed that the acrylic resin blocks prepared with instruments K3 (0.00369 ± 0.00022), NiTi Tee (0.00368 ± 0.00023), and Profile (0.00351 ± 0.00026) presented the greatest mass loss, showing no statistically significant difference among them (P < 0.05). The lowest mass loss was found in the blocks prepared with Quantec instruments (0.00311 ± 0.0003) (P < 0.05).
  
  
  CONCLUSIONS
  It could be concluded that the K3, NiTi Tee, and Profile instruments presented a greater cutting efficiency than the Quantec instruments.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Doglas
authors.initials: D
authors.lastname: Cecchin
authors.forename: Manoel Damião
authors.initials: MD
authors.lastname: de Sousa-Neto
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
authors.forename: Ricardo
authors.initials: R
authors.lastname: Gariba-Silva