title: Apical extrusion of intracanal debris using two engine driven and step-back instrumentation techniques: an in-vitro study.
abstract: OBJECTIVE
  The purpose of this study was to compare in-vitro the amount of debris extruded apically from extracted teeth, using K3, Protaper rotary instruments and manual step-back technique.
  
  
  METHODS
  Forty five human single-rooted mandibular premolar teeth were randomly divided into 3 groups. The teeth in 3 groups were instrumented until reaching the working length with K3, Protaper rotary instruments and K-type stainless steel instruments with manual step-back technique, respectively. Debris extruded from the apical foramen was collected into centrifuge tubes and the amount was determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests, with P=.05 as the level for statistical significance.
  
  
  RESULTS
  Statistically significant difference was observed between K3, Protaper and step-back groups in terms of debris extrusion (P<.05). Step-back group had the highest mean debris weight, which was significantly different from the K3 and Protaper groups (P<.05). The lowest mean debris weight was related to K3 group, which was significantly different from the Protaper group (P<.05).
  
  
  CONCLUSIONS
  Based on the results, all instrumentation techniques produced debris extrusion. The engine-driven Ni-Ti systems extruded significantly less apical debris than step-back technique. However, Protaper rotary instruments extruded significantly more debris than K3 rotary instruments.
authors.affiliation: Cumhuriyet University, Faculty of Dentistry, Department of Endodontics, Sivas, Turkey.
authors.forename: Alper
authors.initials: A
authors.lastname: Kustarci
authors.forename: Neslihan
authors.initials: N
authors.lastname: Akdemir
authors.forename: Seyda Herguner
authors.initials: SH
authors.lastname: Siso
authors.forename: Demet
authors.initials: D
authors.lastname: Altunbas