title: Microtomography-based comparison of reciprocating single-file F2 ProTaper technique versus rotary full sequence.
abstract: BACKGROUND
  A preparation technique with only 1 single instrument was proposed on the basis of the reciprocating movement of the F2 ProTaper instrument. The present study was designed to quantitatively assess canal preparation outcomes achieved by this technique.
  
  
  METHODS
  Twenty-five extracted human mandibular first molars with 2 separate mesial root canals were selected. Canals were randomly assigned to 1 of the 2 experimental groups: group 1, rotary conventional preparation by using ProTaper, and group 2, reciprocate instrumentation with 1 single ProTaper F2 instrument. Specimens were scanned initially and after root canal preparation with an isotropic resolution of 20 μm by using a micro-computed tomography system. The following parameters were assessed: changes in dentin volume, percentage of shaped canal walls, and degree of canal transportation. In addition, the time required to reach working length with the F2 instrument was recorded.
  
  
  RESULTS
  Preoperatively, there were no differences regarding root canal curvature and volume between experimental groups. Overall, instrumentation led to enlarged canal shapes with no evidence of preparation errors. There were no statistical differences between the 2 preparation techniques in the anatomical parameters assessed (P > .01), except for a significantly higher canal transportation caused by the reciprocating file in the coronal canal third. On the other hand, preparation was faster by using the single-file technique (P < .01).
  
  
  CONCLUSIONS
  Shaping outcomes with the single-file F2 ProTaper technique and conventional ProTaper full-sequence rotary approach were similar. However, the single-file F2 ProTaper technique was markedly faster in reaching working length.
authors.affiliation: Division of Preventive Dentistry, University of Zürich Center of Dental Medicine, Zürich, Switzerland. frank.paque@zzm.uzh.ch
authors.forename: Frank
authors.initials: F
authors.lastname: Paqué
authors.forename: Matthias
authors.initials: M
authors.lastname: Zehnder
authors.forename: Gustavo
authors.initials: G
authors.lastname: De-Deus
mesh_terms: D003198:Computer Simulation; D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging; D004867:Equipment Design; D006801:Humans; D008963:Molar; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods*; D014025:Titanium; D055114:X-Ray Microtomography
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium