title: Physical effects of sodium hypochlorite on bone: an ex vivo study.
abstract: BACKGROUND
  Sodium hypochlorite (NaOCl) accidents during endodontic therapy require accurate and prompt action. Understanding the physical properties of bone and evaluating the resultant cell damage from NaOCl exposure could improve management of these accidents. This study assessed the physical and histologic properties of dog femurs exposed to NaOCl for a period of 30 minutes.
  
  
  METHODS
  Four dog femurs were dissected and frozen. Twelve 40-mm-long sections were obtained and cut into 20-mm paired sections. Adjacent surfaces were randomly selected for shallow injection of either NaOCl or saline. Sections were visually assessed for gross physiologic effects. The structural integrity of the cancellous bone was measured by micro-indentation testing, and statistical analysis of needle penetration was conducted. Histologic evaluation of specimens was also conducted.
  
  
  RESULTS
  Grossly, NaOCl caused remarkable changes in cancellous structure, leaving craters of apparent demineralization. There was a significant difference in mean depth of needle penetration and demineralization between the treatments (P = .0397), with NaOCl showing greater mean depth than saline. The NaOCl group showed degradation of the organic matrix collagen.
  
  
  CONCLUSIONS
  These results indicate that NaOCl compromises the integrity of cancellous bone. Calcified elements, especially cortical bone, appeared less affected.
authors.affiliation: Department of Endodontics, University of Alabama School of Dentistry, Birmingham, Alabama, USA.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Kerbl
authors.forename: Patricia
authors.initials: P
authors.lastname: DeVilliers
authors.forename: Mark
authors.initials: M
authors.lastname: Litaker
authors.forename: Paul D
authors.initials: PD
authors.lastname: Eleazer
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects / Q000473:pathology; D000818:Animals; D015519:Bone Density / Q000187:drug effects; D001853:Bone Marrow / Q000187:drug effects / Q000473:pathology; D001857:Bone Matrix / Q000187:drug effects / Q000473:pathology; D001842:Bone and Bones / Q000098:blood supply / Q000187:drug effects* / Q000473:pathology; D003094:Collagen / Q000187:drug effects; D004285:Dogs; D005269:Femur; D006244:Hardness; D055806:Microvessels / Q000187:drug effects / Q000473:pathology; D009339:Needles; D010011:Osteocytes / Q000187:drug effects / Q000473:pathology; D011897:Random Allocation; D012388:Root Canal Irrigants / Q000494:pharmacology*; D012965:Sodium Chloride; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D012388:Root Canal Irrigants; D012965:Sodium Chloride; D003094:Collagen; D012973:Sodium Hypochlorite