title: Effects of ethylenediaminetetraacetic, etidronic and peracetic acid irrigation on human root dentine and the smear layer.
abstract: OBJECTIVE
  To evaluate the effects of ethylenediaminetetraacetic (EDTA), etidronic (EA) and peracetic acid (PA) when used in conjunction with sodium hypochlorite (NaOCl) as root canal irrigants on calcium eluted from canals, smear layer, and root dentine demineralization after instrumentation/irrigation.
  
  
  METHODS
  Single-rooted human premolars were irrigated as follows (n = 12 per group): (1) 1% NaOCl during instrumentation, deionized water after instrumentation, (2) 1% NaOCl during, 17% EDTA after instrumentation, (3) a 1 : 1-mixture of 2% NaOCl and 18% EA during and after instrumentation, and (4) 1% NaOCl during, 2.25% PA after instrumentation. Irrigant volumes and contact times were 10 mL/15 min during and 5 mL/3 min after instrumentation. The evaluated outcomes were eluted calcium by atomic absorption spectroscopy, smear-covered areas by scanning electron microscopy in secondary electron mode and apparent canal wall decalcifications on root transsections in backscatter mode. For the smear layer analysis, sclerotic dentine was taken into consideration. Results were compared using appropriate parametric and nonparametric tests, alpha = 0.05.
  
  
  RESULTS
  The statistical comparison of the protocols regarding calcium elution revealed that protocol (1) yielded less calcium than (3), which yielded less than protocols (2) and (4). Most of the instrumented canal walls treated with one of the decalcifying agents were free of smear layer. Protocols (1) and (3) caused no decalcification of root dentine, whilst (2) and (4) showed substance typical demineralization patterns.
  
  
  CONCLUSIONS
  The decalcifying agents under investigation were all able to remove or prevent a smear layer. However, they eroded the dentine wall differently.
authors.affiliation: Department of Preventive Dentistry, Periodontology and Cariology, University of Zürich, Zürich, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Lottanti
authors.forename: H
authors.initials: H
authors.lastname: Gautschi
authors.forename: B
authors.initials: B
authors.lastname: Sener
authors.forename: M
authors.initials: M
authors.lastname: Zehnder
mesh_terms: D002118:Calcium / Q000032:analysis; D003648:Decalcification Technique; D003804:Dentin / Q000187:drug effects*; D004338:Drug Combinations; D004492:Edetic Acid / Q000494:pharmacology; D012968:Etidronic Acid / Q000494:pharmacology; D006801:Humans; D008854:Microscopy, Electron; D010463:Peracetic Acid / Q000494:pharmacology; D012388:Root Canal Irrigants / Q000494:pharmacology*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013054:Spectrophotometry, Atomic
chemical_list: D004338:Drug Combinations; D012388:Root Canal Irrigants; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D010463:Peracetic Acid; D012968:Etidronic Acid; D002118:Calcium