title: Chemical and ultramorphologic effects of ethylenediaminetetraacetic acid and sodium hypochlorite in young and old root canal dentin.
abstract: OBJECTIVE
  The objectives of this study were to evaluate and compare the time-dependent chemical and ultramorphologic effects of ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) in young and old dentin.
  
  
  METHODS
  Sixty-four teeth scheduled for extraction were collected from young (<30 years) and old (>60 years) patients. In 48 teeth, the dentin was reduced to a powder state and treated with EDTA or EDTA + NaOCl for 1 and 10 minutes, respectively. X-ray diffraction analysis was used to determine the changes in the composition of dentin through dissolution of hydroxyapatite (HAp). In the remaining teeth (n = 16), the root canals were prepared, bisected, and subjected to the same time-dependent treatment regimens. The changes in the number and area of dentinal tubules were calculated by image analysis. The data were analyzed statistically by paired t test and one-way analysis of variance, followed by Tukey honestly significant difference test at P = .05.
  
  
  RESULTS
  In both young and old dentin, EDTA significantly decreased the HAp intensity at 1 and 10 minutes, whereas EDTA + NaOCl only decreased that of old dentin at 10 minutes. Pair-wise comparisons revealed that in old dentin, the reduction in HAp intensity after treatment with EDTA and EDTA + NaOCl was significantly greater at 10 minutes than at 1 minute, whereas in young dentin, a significant decrease was only observed in the EDTA/10-minute subgroup. Compared with their 1-minute counterparts, 10-minute treatment with EDTA + NaOCl significantly increased the tubular diameter and tubular area of old dentin. In young dentin, the tubular area and diameter values were not affected by treatment time (P > .05).
  
  
  CONCLUSIONS
  In young root dentin, 10-minute treatment with EDTA + NaOCl does not significantly alter the chemical and ultramorphologic structure and thus appears to be unnecessary. In old dentin, extended treatment time with EDTA + NaOCl should be avoided owing to excessive demineralization and erosion. In both types of dentin, EDTA was not effective in complete removal of the smear layer.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey. dtozguroz@yahoo.com
authors.forename: H Ozgur
authors.initials: HO
authors.lastname: Ozdemir
authors.forename: Hatice Dogan
authors.initials: HD
authors.lastname: Buzoglu
authors.forename: Semra
authors.initials: S
authors.lastname: Calt
authors.forename: Zafer C
authors.initials: ZC
authors.lastname: Cehreli
authors.forename: Elif
authors.initials: E
authors.lastname: Varol
authors.forename: Abidin
authors.initials: A
authors.lastname: Temel
mesh_terms: D000328:Adult; D000367:Age Factors; D002614:Chelating Agents / Q000494:pharmacology*; D003786:Dental Pulp Cavity / Q000187:drug effects* / Q000648:ultrastructure; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D017886:Durapatite / Q000032:analysis; D004492:Edetic Acid / Q000494:pharmacology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D012388:Root Canal Irrigants / Q000494:pharmacology*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D002614:Chelating Agents; D012388:Root Canal Irrigants; D017886:Durapatite; D004492:Edetic Acid; D012973:Sodium Hypochlorite