title: Comparative study between the radiopacity levels of high viscosity and of flowable composite resins, using digital imaging.
abstract: BACKGROUND
  The development of countless types and trends of high viscosite and flowable composite resins, with different physical and chemical properties applicable to their broad use in dental clinics calls for further studies regarding their radiopacity level.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the radiopacity levels of high viscosity and the flowable composite resins, using digital imaging.
  
  
  METHODS
  96 composite resin discs 5 mm in diameter and 3 mm thick were radiographed and analyzed. The image acquisition system used was the Digora® Phosphor Storage System and the images were analyzed with the Digora software for Windows. The exposure conditions were: 70 kVp, 8 mA, and 0.2 s. The focal distance was 40 cm. The image densities were obtained with the pixel values of the materials in the digital image.
  
  
  RESULTS
  Most of the high viscosity composite resins presented higher radiopacity levels than the flowable composite resins, with statistically significant differences between the trends and groups analyzed (P < 0.05).
  
  
  CONCLUSIONS
  Among the high viscosity composite resins, Tetric®Ceram presented the highest radiopacity levels and Glacier® presented the lowest. Among the flowable composite resins, Tetric®Flow presented the highest radiopacity levels and Wave® presented the lowest.
authors.affiliation: Department of Oral Radiology, Sao Paulo University, Sao Paulo, Brazil. esarita@usp.br
authors.forename: Emiko S
authors.initials: ES
authors.lastname: Arita
authors.forename: Gilson P
authors.initials: GP
authors.lastname: Silveira
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Cortes
authors.forename: Henrique C
authors.initials: HC
authors.lastname: Brucoli
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003287:Contrast Media / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008422:Materials Testing; D019252:Radiography, Dental, Digital / Q000379:methods*; D014783:Viscosity
chemical_list: C406265:Alert composite resin; D003188:Composite Resins; D003287:Contrast Media; D003764:Dental Materials; C481898:Fill Magic; C467913:Filtek Flow; C438835:Filtek P60 Composite Resin; C477351:Prodigy Condensable; C102735:Revolution (composite resin); C469658:Solitaire 2 composite resin; C403464:SureFil packable composite; C121818:Tetric ceram; C111840:flowable hybrid composite; C471182:glacier hybrid composite; C479082:natural flow composite resin; C452226:tetric flow composite resin; C471181:wave flowable composite; D003723:Dental Amalgam