title: Radiopacity of dental restorative materials.
abstract: OBJECTIVE
  Radiopacity of dental materials enables clinician to radiographically diagnose secondary caries and marginal defects which are usually located on the proximal gingival margin. The aim of this study was to measure the radiopacity of 33 conventional resin composites, 16 flowable resin composites, and 7 glass ionomer cements and to compare the results with the radiopacity values declared by the manufacturers.
  
  
  METHODS
  From each restorative material, six 2-mm-thick disk-shaped specimens were fabricated and eight 2-mm-thick sections of teeth were made and used as reference. The material samples and tooth sections were digitally radiographed together with the aluminum stepwedge. Gray values were obtained from the radiographic images and radiopacity values were calculated and statistically analyzed. Post hoc Tukey's honestly significant difference test was used to calculate significant differences in radiopacity values between materials and reference dentin and enamel values.
  
  
  RESULTS
  The radiopacity values of all 56 restorative materials were above the dentin reference radiopacity value; however, 4 out of 33 conventional composites and 3 out of 16 flowable resin composites had significantly lower radiopacity than enamel (p < 0.05). There were up to 1.53 mm eq Al differences between the measured and the manufacturers' declared radiopacity values of some materials.
  
  
  CONCLUSIONS
  Majority of the materials exceed enamel radiopacity and would not hamper radiographic diagnosis of secondary caries. However, manufacturers' data are not always reliable.
  
  
  CONCLUSIONS
  Materials with radiopacity lower than enamel might be misinterpreted as secondary enamel caries on radiographic images, especially when applied as initial increment on the proximal gingival margin.
authors: Department of Restorative Dentistry and Endodontics, Dental School, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, SI-1000, Ljubljana, Slovenia. tomazhitij@gmail.com
authors: Tomaž
authors: T
authors: Hitij
authors: Aleš
authors: A
authors: Fidler
mesh_terms: D000535:Aluminum; D000704:Analysis of Variance; D003188:Composite Resins; D003287:Contrast Media; D003731:Dental Caries / Q000000981:diagnostic imaging*; D003743:Dental Enamel / Q000000981:diagnostic imaging; D003793:Dental Restoration, Permanent; D003804:Dentin / Q000000981:diagnostic imaging; D003951:Diagnostic Errors; D005899:Glass Ionomer Cements; D006801:Humans; D008422:Materials Testing; D011861:Radiography, Dental; D012015:Reference Standards; D012016:Reference Values; D018709:Statistics, Nonparametric
chemical_list: D003188:Composite Resins; D003287:Contrast Media; D005899:Glass Ionomer Cements; D000535:Aluminum