title: Irrigation of human prepared root canal--ex vivo based computational fluid dynamics analysis.
abstract: OBJECTIVE
  To analyze the influence of the needle type, insertion depth, and irrigant flow rate on irrigant flow pattern, flow velocity, and apical pressure by ex-vivo based endodontic irrigation computational fluid dynamics (CFD) analysis.
  
  
  METHODS
  Human upper canine root canal was prepared using rotary files. Contrast fluid was introduced in the root canal and scanned by computed tomography (CT) providing a three-dimensional object that was exported to the computer-assisted design (CAD) software. Two probe points were established in the apical portion of the root canal model for flow velocity and pressure measurement. Three different CAD models of 27G irrigation needles (closed-end side-vented, notched open-end, and bevel open-end) were created and placed at 25, 50, 75, and 95% of the working length (WL). Flow rates of 0.05, 0.1, 0.2, 0.3, and 0.4 mL/s were simulated. A total of 60 irrigation simulations were performed by CFD fluid flow solver.
  
  
  RESULTS
  Closed-end side-vented needle required insertion depth closer to WL, regarding efficient irrigant replacement, compared to open-end irrigation needle types, which besides increased velocity produced increased irrigant apical pressure. For all irrigation needle types and needle insertion depths, the increase of flow rate was followed by an increased irrigant apical pressure.
  
  
  CONCLUSIONS
  The human root canal shape obtained by CT is applicable in the CFD analysis of endodontic irrigation. All the analyzed values -irrigant flow pattern, velocity, and pressure - were influenced by irrigation needle type, as well as needle insertion depth and irrigant flow rate.
authors.affiliation: Department of Restorative Dentistry and Endodontics, Medical Faculty, School of Dentistry, Kresimirova 40, Rijeka, Croatia.
authors.forename: Damir
authors.initials: D
authors.lastname: Snjaric
authors.forename: Zoran
authors.initials: Z
authors.lastname: Carija
authors.forename: Alen
authors.initials: A
authors.lastname: Braut
authors.forename: Adelaida
authors.initials: A
authors.lastname: Halaji
authors.forename: Maja
authors.initials: M
authors.lastname: Kovacevic
authors.forename: Davor
authors.initials: D
authors.lastname: Kuis
mesh_terms: D000818:Animals; D017076:Computer-Aided Design; D003786:Dental Pulp Cavity; D004285:Dogs; D004867:Equipment Design; D006801:Humans; D057446:Hydrodynamics; D008962:Models, Theoretical; D009339:Needles; D012212:Rheology; D012388:Root Canal Irrigants; D018915:Root Canal Preparation; D012390:Root Canal Therapy; D012984:Software; D007507:Therapeutic Irrigation; D014057:Tomography, X-Ray Computed
chemical_list: D012388:Root Canal Irrigants