title: A standard for radiopacity of root-end (retrograde) filling materials is urgently needed.
abstract: OBJECTIVE
  To assess the radiopacity of materials used, or recommended for use, as apical root-end (retrograde) fillings.
  
  
  METHODS
  The radiopacity of 14 materials falling into the category of root-end filling materials was measured in equivalent millimetres of aluminium (mm Al) using a new computerized method. These included temporary or intermediate sealing materials; composite, compomer and GIC filling materials; EBA-derived cements; amalgam, etc. Gutta-percha cone material was added as a control. Samples of 1 mm thickness were radiographed on periapical film alongside an aluminium step wedge calibrated in millimetres, and the opacity of the materials, in greyscale or pseudo-colour, was compared with the equivalent step.
  
  
  RESULTS
  The radiopacity ranged from 1.75 mm Al to >10 mm Al. The lower range appears insufficient for routine clinical detection when it is compared with the minimal requirement for intracanal fillings.
  
  
  CONCLUSIONS
  Because of the proliferation of root-end filling materials with a broad range of radiopacity, an international standard stipulating the required minimal radiopacity, as well as other properties, is needed urgently. It should be based on in vitro results and on large-scale clinical radiographic surveys.
authors.affiliation: Department of Endodontology, The Maurice & Gabriela School of Dental Medicine, Tel Aviv University, Tel Aviv 69978, Israel. taggendo@post.tau.ac.il
authors.forename: M
authors.initials: M
authors.lastname: Tagger
authors.forename: A
authors.initials: A
authors.lastname: Katz
mesh_terms: D003287:Contrast Media / Q000592:standards*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D011857:Radiographic Image Interpretation, Computer-Assisted; D011861:Radiography, Dental / Q000592:standards*; D012184:Retrograde Obturation / Q000592:standards*; D012387:Root Canal Filling Materials / Q000592:standards*
chemical_list: D003287:Contrast Media; D012387:Root Canal Filling Materials