title: Radiopacity of Composite Luting Cements Using a Digital Technique.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate the radiopacity of 20 common dental composite luting materials using a digital technique.
  
  
  METHODS
  A 1-mm-thick specimen of each material with a human tooth slice and aluminium step wedge were tested using digital radiographs under four combinations of exposure and voltage. The radiopacity in pixels was determined using computer software. The equivalent thickness of aluminium for each material was then calculated based on the calibration curve.
  
  
  RESULTS
  All tested materials except one had higher radiopacity than dentin (p > α; α  =  0.01), and 80% of the materials had radiopacity above enamel value (p > α; α  =  0.01). Moreover, 40% of tested materials had radiopacity of three times above the minimal International Organization for Standardization (ISO) values for composite luting cements. At all exposure values, the highest radiopacity was for Solocem and Multilink groups of materials, at three to six times above dentin radiopacity. Only Variolink Veneer showed radiopacity below dentin and enamel.
  
  
  CONCLUSIONS
  Composite luting materials should have radiopacity above ISO values or greater than the dentin or enamel equivalent. The highest radiopacity values were for the Solocem and Multilink family composite luting cements. Clinicians should choose materials with high radiopacity values, and manufacturers should be aware of the radiopacity values when introducing materials on the market.
authors.affiliation: School of Dental Medicine University of Zagreb, Croatia.
authors.forename: Walter
authors.initials: W
authors.lastname: Dukic
mesh_terms: D003738:Dental Cements / Q000737:chemistry*; D003804:Dentin / Q000000981:diagnostic imaging; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D019252:Radiography, Dental, Digital / Q000379:methods*; D012984:Software
chemical_list: D003738:Dental Cements
keywords: Luting cements; X-ray; dental materials; digital radiography; radiopacity; resin cements