title: Influence of operator experience on canal preparation time when using the rotary Ni-Ti ProFile system in simulated curved canals.
abstract: OBJECTIVE
  The aim of this study was to determine the influence of operator experience on the time needed for canal preparation when using a rotary nickel-titanium (Ni-Ti) system.
  
  
  METHODS
  A total of 100 simulated curved canals in resin blocks were used. Four operators prepared a total of 25 canals each. The operators included practitioners with prior experience of the preparation technique, and practitioners with no experience. The working length for each instrument was precisely predetermined. All canals were instrumented with rotary Ni-Ti ProFile Variable Taper Series 29 engine-driven instruments using a high-torque handpiece (Maillefer, Ballaigues, Switzerland). The time taken to prepare each canal was recorded. Significant differences between the operators were analysed using the Student's t-test and the Kruskall-Wallis and Dunn nonparametric tests.
  
  
  RESULTS
  Comparison of canal preparation times demonstrated a statistically significant difference between the four operators (P < 0.001). In the inexperienced group, a significant linear regression between canal number and preparation time occurred.
  
  
  CONCLUSIONS
  Time required for canal preparation was inversely related to operator experience.
authors.affiliation: Endodontic Department, School of Dentistry, University Paris 7, Paris, France. catherine.menez@free.fr
authors.forename: C
authors.initials: C
authors.lastname: Mesgouez
authors.forename: F
authors.initials: F
authors.lastname: Rilliard
authors.forename: L
authors.initials: L
authors.lastname: Matossian
authors.forename: K
authors.initials: K
authors.lastname: Nassiri
authors.forename: E
authors.initials: E
authors.lastname: Mandel
mesh_terms: D000704:Analysis of Variance; D002983:Clinical Competence; D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D006801:Humans; D016014:Linear Models; D003765:Models, Dental; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D018709:Statistics, Nonparametric; D013997:Time Factors; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium