title: Curved versus straight root canals: the benefit of activated irrigation techniques on dentin debris removal.
abstract: OBJECTIVE
  The aim of this study was to compare the efficacy of hydrodynamic and ultrasonic-activated irrigation to conventional syringe irrigation in removing dentin debris in straight and curved root canals.
  
  
  METHODS
  Twelve human teeth were selected for study. The root canals of 6 single-rooted premolars with straight canals and 6 molar roots with curved canals were prepared to a size of 45 and split longitudinally. To simulate canal irregularities, 3 standardized holes were cut in 1 canal wall. The canals and holes were then covered with debris. After reassembly, 3 irrigation techniques were compared: syringe irrigation, hydrodynamic irrigation, and ultrasonic irrigation. The amount of debris that remained was evaluated microscopically and graded with a 4-score system.
  
  
  RESULTS
  The hydrodynamic and ultrasonic irrigation techniques were significantly (P < .001) more efficient as compared with syringe irrigation in both the straight and curved root canals. Ultrasonic irrigation demonstrated a higher efficiency in the straight root canals (P < .01), whereas hydrodynamic irrigation was more efficient in the curved canals (P < .01).
  
  
  CONCLUSIONS
  In the straight canals, ultrasonic irrigation was the most effective, but in the curved root canals, hydrodynamic irrigation was superior.
authors.affiliation: Department of Periodontology, Endodontology and Cariology, School of Dentistry, University of Basel, Basel, Switzerland. mauro.amato@unibas.ch
authors.forename: Mauro
authors.initials: M
authors.lastname: Amato
authors.forename: Ingrid
authors.initials: I
authors.lastname: Vanoni-Heineken
authors.forename: Hanjo
authors.initials: H
authors.lastname: Hecker
authors.forename: Roland
authors.initials: R
authors.lastname: Weiger
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D006801:Humans; D057446:Hydrodynamics; D016014:Linear Models; D009811:Odontometry; D012388:Root Canal Irrigants / Q000008:administration & dosage*; D018915:Root Canal Preparation / Q000379:methods*; D012973:Sodium Hypochlorite / Q000008:administration & dosage; D013594:Syringes; D007507:Therapeutic Irrigation / Q000379:methods*; D014092:Tooth Root / Q000033:anatomy & histology*; D014465:Ultrasonics
chemical_list: D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite