title: Clinical relevance of standardization of endodontic irrigation needle dimensions according to the ISO 9,626:1991 and 9,626:1991/Amd 1:2001 specification.
abstract: OBJECTIVE
  To examine the current status of standardization of endodontic irrigation needles produced by different manufacturers.
  
  
  METHODS
  Measurements of needle internal and external diameter were conducted under scanning electron microscopy and stereoscopic microscopy to determine the incidence and degree of deviation from ISO 9,626:1991 and ISO 9,626:1991/Amd 1:2001 specification.
  
  
  RESULTS
  None of the needles examined complied with the ISO nominal size. All SS needles were within the ISO tolerance limits. A Ni-Ti needle, which is not included in the specification, was found to exceed ISO external diameter limits.
  
  
  CONCLUSIONS
  Exact knowledge of the tip's external diameter is crucial for the selection of the appropriate size irrigation probe during endodontic treatment. Units of the widely used 'gauge' system cannot be directly extrapolated to clinical practice. Adoption of millimetre as the standard metric unit, already recommended by ISO, should be accelerated. A colour-coding of needles corresponding to endodontic instruments would also be beneficial.
authors.affiliation: Department of Endodontology, Dental School, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: C
authors.initials: C
authors.lastname: Boutsioukis
authors.forename: T
authors.initials: T
authors.lastname: Lambrianidis
authors.forename: L
authors.initials: L
authors.lastname: Vasiliadis
mesh_terms: D004867:Equipment Design / Q000592:standards; D009339:Needles / Q000592:standards*; D012388:Root Canal Irrigants / Q000008:administration & dosage; D018915:Root Canal Preparation / Q000295:instrumentation*; D007507:Therapeutic Irrigation / Q000295:instrumentation*
chemical_list: D012388:Root Canal Irrigants