title: Quantitative analysis of the effect of irrigant solution sequences on dentin erosion.
abstract: OBJECTIVE
  The purpose of the study was to examine the level of erosion on root canal wall dentin caused by immersion in different irrigant solutions in alternative sequences.
  
  
  METHODS
  Dentin specimens from teeth with one root canal were instrumented and randomly divided into five groups. Each group was subjected to 17% EDTA, 17% ethyleneglycoltetraacetic acid (EGTA), or 10% citric acid (CA) and 5.25% sodium hypochlorite (NaOCl) varying the time of irrigant exposure and the order of the irrigants. The specimens were examined by scanning electron microscopy (SEM), and randomized digital images of the dentin surface were taken. The area of tubule openings was measured by a semiautomatic method.
  
  
  RESULTS
  No erosion was detected when demineralizing agents were used as a final rinse after NaOCl. However, the erosion of peritubular and intertubular dentin was detected when EDTA, EGTA, or CA were used first followed by 5.25% NaOCl (P < .05), and an increase over 100% in the area of dentin tubule openings was measured (P < .01).
  
  
  CONCLUSIONS
  NaOCl used as a final irrigant solution after demineralization agents causes marked erosion of root canal dentin.
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Qian
authors.forename: Ya
authors.initials: Y
authors.lastname: Shen
authors.forename: Markus
authors.initials: M
authors.lastname: Haapasalo
mesh_terms: D000704:Analysis of Variance; D019343:Citric Acid / Q000008:administration & dosage / Q000009:adverse effects; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D004492:Edetic Acid / Q000008:administration & dosage / Q000009:adverse effects; D004533:Egtazic Acid / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007101:Immersion; D012388:Root Canal Irrigants / Q000008:administration & dosage* / Q000009:adverse effects*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000008:administration & dosage / Q000009:adverse effects; D007507:Therapeutic Irrigation / Q000379:methods
chemical_list: D012388:Root Canal Irrigants; D019343:Citric Acid; D004533:Egtazic Acid; D004492:Edetic Acid; D012973:Sodium Hypochlorite