title: A comparison of residual smear layer and erosion following different endodontic irrigation protocols tested under clinical and laboratory conditions.
abstract: OBJECTIVE
  To compare the smear layer removal efficacy and erosive effects of different irrigation protocols under clinical and laboratory conditions.
  
  
  METHODS
  Mandibular third molars (n = 32) of 30-45 year-old patients were instrumented with rotary files and were randomly assigned to one of the following groups for final irrigation: (1) 5.25% NaOCl; (2) 17% EDTA; and (3) BioPure MTAD. Thereafter, the teeth were immediately extracted and processed for micromorphological investigation. In vitro specimen pairs were prepared by repeating the clinical experiments on freshly-extracted mandibular third molars. To compare open and closed systems, laboratory experiments were repeated on 32 additional teeth with enlarged apical foramen. The cleanliness of the root canals and the extent of erosion were assessed by environmental scanning electron microscopy.
  
  
  RESULTS
  Specimens prepared under clinical and laboratory conditions had similar cleanliness and erosion scores (p > 0.05). Under both conditions, the tested solutions were more effective in removing the smear layer in the coronal and middle regions than in the apical one. Comparison of closed and open systems showed similar levels of cleanliness and erosion in all regions (p > 0.05), with the exception of 17% EDTA showing significantly higher levels of cleanliness and erosion in the apical third of open-end specimens.
  
  
  CONCLUSIONS
  Based on clinical correlates of in vitro root canal cleanliness and erosion, laboratory testing of root canal irrigants on extracted teeth with closed apices can serve as a reliable method to simulate the clinical condition. EDTA was the most effective final irrigation solution in removing the smear layer at the expense of yielding the greatest erosive effect.
authors: Department of Pediatric Dentistry, Faculty of Dentistry, Hacettepe University, Ankara, Turkey. zcehreli@gmail.com
authors: Zafer C
authors: ZC
authors: Cehreli
authors: M Ozgur
authors: MO
authors: Uyanik
authors: Emre
authors: E
authors: Nagas
authors: Behram
authors: B
authors: Tuncel
authors: Nuray
authors: N
authors: Er
authors: Fugen Dagli
authors: FD
authors: Comert
mesh_terms: D000328:Adult; D002985:Clinical Protocols; D004708:Endodontics; D006801:Humans; D007753:Laboratories; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D016369:Smear Layer; D014077:Tooth Erosion