title: A comparison between two negative pressure irrigation techniques in simulated immature tooth: an ex vivo study.
abstract: OBJECTIVE
  This ex vivo study evaluated the irrigation efficacy of a new apical negative pressure system (ANP) in canals with simulated immature teeth, by comparing it to EndoVac (EV) system in terms of smear layer (SL) removal and irrigation extrusion.
  
  
  METHODS
  Three millimetres of the root end of 40 single canalled lower incisors were resected and decoronated to standardize root canal length. After instrumentation, the specimens were embedded in warm normal saline agar coloured with 1 % acid red and randomly divided into four groups; one control group and three experimental groups. Except in the control group where distilled water was used as irrigant using positive pressure irrigation needle, the canals were irrigated with 6 % NaOCl and 17 % EDTA using the intracanal negative pressure needle (iNP) system, the EV system or 27G open-ended needle under positive pressure (PP). NaOCl extrusion was determined by observing a discolouration of the agar surrounding the root. The SL was evaluated by observing scanning electron microscope images based on a four-level scoring system.
  
  
  RESULTS
  Two specimens with irrigant extrusion were observed in the iNP group, which was significantly different (logistic regression, p < 0.05) to EV and PP. There were no significant differences (Kruskall-Wallis test, p > 0.05) among the experimental groups in terms of SL removal, but all were significantly different to the control group.
  
  
  CONCLUSIONS
  Irrigation with the iNP could be a viable alternative to EV as an apical negative pressure irrigation technique especially while treating immature teeth.
  
  
  CONCLUSIONS
  ANP in canal cleanliness is recommended to be utilized in treating immature teeth where periapical tissues should be saved and stimulated. The iNP system might have the potential to avoid irrigant extrusion while cleaning the canal till the apical end.
authors.affiliation: Department of Restorative and Prosthetic Scinces, College of Dentistry, King Abdullah International Medical Research Center (KAIMRC)/ King Saud bin Abdulaziz University for Health Sciences, National Guard Health Affairs, Riyadh, Saudi Arabia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Jamleh
authors.affiliation: Private Practice, Tokyo, Japan.
authors.forename: Yasue
authors.initials: Y
authors.lastname: Fukumoto
authors.affiliation: Private Practice, Tokyo, Japan.
authors.forename: Yoshioka
authors.initials: Y
authors.lastname: Takatomo
authors.affiliation: Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Kobayashi
authors.affiliation: Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Suda
authors.affiliation: Endodontics and Research Methods, School of Dentistry, National University of Asuncion, Asuncion, Paraguay. cgadorno@odo.una.py.
authors.forename: Carlos G
authors.identifier: http://orcid.org/0000-0002-7118-2361
authors.initials: CG
authors.lastname: Adorno
mesh_terms: D004492:Edetic Acid / Q000008:administration & dosage; D006801:Humans; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D011312:Pressure; D011897:Random Allocation; D012388:Root Canal Irrigants; D018915:Root Canal Preparation / Q000295:instrumentation*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000008:administration & dosage; D013396:Suction / Q000295:instrumentation; D007507:Therapeutic Irrigation / Q000295:instrumentation*
chemical_list: D012388:Root Canal Irrigants; D004492:Edetic Acid; D012973:Sodium Hypochlorite
keywords: Apical negative pressure; EndoVac; Intracanal negative pressure; Irrigation extrusion; Positive pressure irrigation; Smear layer