title: Radiodensity evaluation of dental impression materials in comparison to tooth structures.
abstract: In the most recent decades, several developments have been made on impression materials' composition, but there are very few radiodensity studies in the literature. It is expected that an acceptable degree of radiodensity would enable the detection of small fragments left inside gingival sulcus or root canals.
  
  
  OBJECTIVE
  The aim of this study was to determine the radiodensity of different impression materials, and to compare them to human and bovine enamel and dentin.
  
  
  METHODS
  Twenty-five impression materials, from 5 classes, were studied: addition and condensation silicones, polyether, polysulfides and alginates. Five 1-mm-thick samples of each material and tooth structure were produced. Each sample was evaluated 3 times (N=15), being exposed to x-ray over a phosphor plate of Digora digital system, and radiodensity was obtained by the software Digora for Windows 2.5 Rev 0. An aluminum stepwedge served as a control. Data were subjected to Kruskal-Wallis and Dunn's method (α=0.05).
  
  
  RESULTS
  Different materials and respective classes had a different behavior with respect to radiodensity. Polysulfides showed high values of radiodensity, comparable to human enamel (p>0.05), but not to bovine enamel (p<0.05). Human dentin was similar only to a heavy-body addition silicon material, but bovine dentin was similar to several materials. Generally, heavy-body materials showed higher radiodensity than light-body ones (p<0.05).
  
  
  CONCLUSIONS
  Impression materials' radiodensity are influenced by composition, and almost all of them would present a difficult detection against enamel or dentin background in radiographic examinations.
authors.affiliation: Restorative Dentistry Area, Dental School, Federal University of Goiás, Goiânia, GO, Brazil. rbfonseca.ufg@gmail.com
authors.forename: Rodrigo Borges
authors.initials: RB
authors.lastname: Fonseca
authors.forename: Carolina Assaf
authors.initials: CA
authors.lastname: Branco
authors.forename: Francisco
authors.initials: F
authors.lastname: Haiter-Neto
authors.forename: Luciano de Souza
authors.initials: Lde S
authors.lastname: Gonçalves
authors.forename: Carlos José
authors.initials: CJ
authors.lastname: Soares
authors.forename: Hugo Lemes
authors.initials: HL
authors.lastname: Carlo
authors.forename: Mário Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Lourenço
authors.initials: L
authors.lastname: Correr-Sobrinho
mesh_terms: D000535:Aluminum / Q000737:chemistry; D000818:Animals; D002417:Cattle; D003743:Dental Enamel / Q000000981:diagnostic imaging* / Q000648:ultrastructure; D003760:Dental Impression Materials; D003804:Dentin / Q000000981:diagnostic imaging* / Q000648:ultrastructure; D006801:Humans; D008855:Microscopy, Electron, Scanning; D011861:Radiography, Dental; D012825:Silicon; D018709:Statistics, Nonparametric
chemical_list: D003760:Dental Impression Materials; D000535:Aluminum; D012825:Silicon