title: Comparison of positive-pressure, passive ultrasonic, and laser-activated irrigations on smear-layer removal from the root canal surface.
abstract: OBJECTIVE
  The purpose of this study was to compare the efficacy of three irrigation techniques for smear-layer removal with 17% EDTA.
  
  
  BACKGROUND
  Cleaning and shaping the root canal system during endodontic treatment produces a smear layer and hard tissue debris. Three irrigation techniques were tested for solution infiltration of this layer: positive-pressure irrigation, passive ultrasonic irrigation, and laser-activated irrigation.
  
  
  METHODS
  Sixty extracted teeth were divided into six equal groups; 17% EDTA was used for 60 sec irrigation of five of the groups. The groups were as follows: Group 1, treated only with ProTaper™ F3 Ni-Ti files; Group 2, positive-pressure irrigation, with a syringe; Group 3, passive ultrasonic irrigation, inserted 1 mm short of the working length; Group 4, passive ultrasonic irrigation, inserted in the upper coronal third of the root; Group 5, Er:YAG laser-activated irrigation, inserted 1 mm short of the working length; and Group 6, Er:YAG laser-activated irrigation, inserted in the upper coronal third of the root.
  
  
  RESULTS
  Scanning electron microscopy showed that the smear layer is removed most efficiently using laser-activated irrigation at low energy with 17% EDTA, inserted either at the working length or only in the coronal upper third of the root. Amounts of Ca, P, and O were not significantly different on all treated dentin surfaces.
  
  
  CONCLUSIONS
  Smear-layer removal was most effective when the root canals were irrigated using Er:YAG laser at low energy with 17% EDTA solution. Interestingly, removal of the smear layer along the entire canal was similar when the laser was inserted in the upper coronal third and at 1 mm short of the working length of the root canal. This effect was not observed with the ultrasonic and positive-pressure techniques.
authors.affiliation: 1 Department of Endodontics, Faculty of Dental Medicine, Hebrew University-Hadassah , Jerusalem, Israel .
authors.forename: Sharonit
authors.initials: S
authors.lastname: Sahar-Helft
authors.forename: Ayşe Sena Kabaş
authors.initials: AS
authors.lastname: Sarp
authors.forename: Adam
authors.initials: A
authors.lastname: Stabholtz
authors.forename: Vitaly
authors.initials: V
authors.lastname: Gutkin
authors.forename: Idan
authors.initials: I
authors.lastname: Redenski
authors.forename: Doron
authors.initials: D
authors.lastname: Steinberg
mesh_terms: D006801:Humans; D007834:Lasers; D011312:Pressure; D018915:Root Canal Preparation / Q000379:methods*; D007507:Therapeutic Irrigation / Q000379:methods*; D014465:Ultrasonics