title: Chelation in root canal therapy reconsidered.
abstract: The aim of this study was to assess interactions of EDTA and citric acid (CA) with sodium hypochlorite (NaOCl), the indispensable endodontic irrigant. Other chelators were simultaneously evaluated as possible alternatives: sodium triphosphate (STP), amino tris methylenephosphonic acid (ATMA), and 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP). Available chlorine was titrated in chelator-NaOCl solutions. All chelators other than HEBP and STP caused an almost complete, immediate loss of available chlorine in solution. Atomic absorbtion spectrometry and SEM evaluation of root canal walls of instrumented teeth indicated that NaOCl had no negative effect on calcium-complexing ability of chelators. STP was too weak a complexing agent to warrant further studies. Finally, CA-, EDTA-, and HEBP-NaOCl mixtures were evaluated for their antimicrobial capacity. Again, EDTA and CA negatively interfered with NaOCl, while HEBP did not.
authors.affiliation: Department of Preventive Dentistry, Cariology, and Periodontology, Division of Endodontics, University of Zürich Center for Dental Medicine, Zürich, Switzerland. matthias.zehnder@zzmk.unizh.ch
authors.forename: Matthias
authors.initials: M
authors.lastname: Zehnder
authors.forename: Patrick
authors.initials: P
authors.lastname: Schmidlin
authors.forename: Beatrice
authors.initials: B
authors.lastname: Sener
authors.forename: Tuomas
authors.initials: T
authors.lastname: Waltimo
mesh_terms: D000891:Anti-Infective Agents, Local / Q000737:chemistry / Q000627:therapeutic use; D002118:Calcium / Q000737:chemistry; D002614:Chelating Agents / Q000627:therapeutic use*; D002713:Chlorine / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry / Q000627:therapeutic use; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000648:ultrastructure; D004492:Edetic Acid / Q000737:chemistry / Q000627:therapeutic use; D013293:Enterococcus faecalis / Q000187:drug effects; D012968:Etidronic Acid / Q000737:chemistry / Q000627:therapeutic use; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009943:Organophosphorus Compounds / Q000737:chemistry / Q000627:therapeutic use; D011122:Polyphosphates / Q000737:chemistry / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D012390:Root Canal Therapy; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000737:chemistry / Q000627:therapeutic use; D013054:Spectrophotometry, Atomic
chemical_list: D000891:Anti-Infective Agents, Local; D002614:Chelating Agents; D009943:Organophosphorus Compounds; D011122:Polyphosphates; D012388:Root Canal Irrigants; C041182:(nitrilotris(methylene))triphosphonic acid; D019343:Citric Acid; D002713:Chlorine; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D012968:Etidronic Acid; C005692:triphosphoric acid; D002118:Calcium