title: Effectiveness of different irrigant agitation techniques on debris and smear layer removal in curved root canals: a scanning electron microscopy study.
abstract: BACKGROUND
  The aim of this study was to evaluate the cleaning efficacy of different irrigant agitation techniques on debris and smear layer removal in curved root canals.
  
  
  METHODS
  Mesiobuccal root canals of 108 mandibular molars were shaped with nickel-titanium instruments, and a final rinse of NaOCl and ethylenediaminetetraacetic acid was performed. Specimens were assigned to 4 groups (n = 20) and submitted to the following irrigation agitation techniques: no agitation (control), ultrasonic, EndoActivator, and CanalBrush. Root canals were split longitudinally and subjected to scanning electron microscopy. The presence of debris and smear layer at coronal and apical levels was evaluated by using a 5-grade scoring system with 200× and 1000× magnification, respectively.
  
  
  RESULTS
  Concerning debris removal, no significant differences among groups were detected. In the coronal region, agitation of the irrigants resulted in significantly more smear layer removal than the control. EndoActivator was significantly more effective than ultrasonic agitation and CanalBrush.
  
  
  CONCLUSIONS
  In curved root canals, activation of NaOCl and ethylenediaminetetraacetic acid did not enhance debris removal but resulted in significantly more effective smear layer removal at coronal levels.
authors.affiliation: Department of Preventive Dentistry, Periodontology and Cariology, University of Göttingen, Göttingen, Germany. troedig@med.uni-goettingen.de
authors.forename: Tina
authors.initials: T
authors.lastname: Rödig
authors.forename: Stefan
authors.initials: S
authors.lastname: Döllmann
authors.forename: Frank
authors.initials: F
authors.lastname: Konietschke
authors.forename: Steffi
authors.initials: S
authors.lastname: Drebenstedt
authors.forename: Michael
authors.initials: M
authors.lastname: Hülsmann
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D003804:Dentin / Q000648:ultrastructure; D004492:Edetic Acid / Q000008:administration & dosage; D006801:Humans; D008855:Microscopy, Electron, Scanning; D012388:Root Canal Irrigants / Q000008:administration & dosage*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000008:administration & dosage; D013010:Sonication / Q000379:methods; D007507:Therapeutic Irrigation / Q000295:instrumentation / Q000379:methods; D014732:Vibration
chemical_list: D012388:Root Canal Irrigants; D004492:Edetic Acid; D012973:Sodium Hypochlorite