title: Histologic Assessment of Debridement of the Root Canal Isthmus of Mandibular Molars by Irrigant Activation Techniques Ex Vivo.
abstract: BACKGROUND
  This study aimed to evaluate the efficacy of a new irrigation system (EndoIrrigator Plus; Innovations Endo, Nasik, India) using a histologic method ex vivo.
  
  
  METHODS
  Mandibular molars with a normal pulp extracted for periodontal reasons (N = 68) were assessed for the presence of an isthmus using cone-beam computed tomographic imaging. Root canals of the included molars (n = 40) were instrumented up to a ProTaper F2 instrument (Dentsply Maillefer, Baillagues, Switzerland) using 3% sodium hypochlorite as irrigant in a closed apical design. Final irrigation delivery/activation was performed as follows (n = 10): group 1, syringe irrigation; group 2, apical negative pressure delivery with continuous warm activated irrigation and evacuation system (CWAIS); group 3, manual dynamic agitation (MDA); and group 4, passive ultrasonic irrigation (PUI). Untreated teeth (n = 5) served as histologic controls. The isthmus regions (1, 3, and 5 mm from the apex) were analyzed by hematoxylin-eosin stain to calculate the percentage of remaining pulp tissue (RPT) relative to the area of the isthmus. Results were analyzed using the Mann-Whitney U test (P = .05).
  
  
  RESULTS
  CWAIS showed significantly less RPT than the other groups at all 3 root levels (P < .05). MDA showed significantly less RPT at 1 and 3 mm from the apex compared with PUI and syringe irrigation (P < .05). There was no significant difference between PUI and MDA at the 5-mm level (P > .05).
  
  
  CONCLUSIONS
  None of the methods could completely clean the isthmus. CWAIS left behind the least amount of RPT.
authors.affiliation: Biofilm Research Cluster, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India. Electronic address: prasanna_neelakantan@yahoo.com.
authors.forename: Prasanna
authors.initials: P
authors.lastname: Neelakantan
authors.affiliation: Biofilm Research Cluster, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India.
authors.forename: Sharmila
authors.initials: S
authors.lastname: Devaraj
authors.affiliation: Biofilm Research Cluster, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India.
authors.forename: Nithya
authors.initials: N
authors.lastname: Jagannathan
mesh_terms: D054893:Cone-Beam Computed Tomography; D003646:Debridement / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D008334:Mandible; D008963:Molar / Q000601:surgery*; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation*; D012973:Sodium Hypochlorite / Q000627:therapeutic use*; D007507:Therapeutic Irrigation / Q000379:methods*; D014465:Ultrasonics / Q000295:instrumentation
chemical_list: D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite
keywords: Apical negative pressure; cleaning efficacy; debridement; histology; manual dynamic agitation; sodium hypochlorite; tissue dissolution; ultrasonic