title: A descriptive study of the radiographic density of implant restorative cements.
abstract: BACKGROUND
  Cementation of implant prostheses is a common practice. Excess cement in the gingival sulcus may harm the periodontal tissues. Identification of the excess cement may be possible with the use of radiographs if the cement has sufficient radiopacity.
  
  
  OBJECTIVE
  The purpose of this study was to compare the radiographic density of different cements used for implant prostheses.
  
  
  METHODS
  Eight different cements were compared: TempBond Original (TBO), TempBond NE (TBN), Fleck's (FL), Dycal (DY), RelyX Unicem (RXU), RelyX Luting (RXL), Improv (IM), and Premier Implant Cement (PIC). Specimen disks, 2 mm in thickness, were radiographed. Images were made using photostimulable phosphor (PSP) plates with standardized exposure values. The average grey level of the central area of each specimen disk was selected and measured in pixels using a software analysis program, ImageTool, providing an average grey level value representative of radiodensity for each of the 8 cements. The radiodensity was determined using the grey level values of the test materials, which were recorded and compared to a standard aluminum step wedge. An equivalent thickness of aluminum in millimeters was calculated using best straight line fit estimates. To assess contrast effects by varying the exposure settings, a second experiment using 1-mm-thick cement specimens radiographed at both 60 kVp and 70 kVp was conducted. The PSP plates with specimens were measured for a grey level value comparison to the standard aluminum step wedge, using the same software program.
  
  
  RESULTS
  The highest grey level values were recorded for the zinc cements (TBO, TBN, and FL), with the 1-mm specimen detectable at both 60- and 70-kVp settings. A lower grey level was recorded for DY, indicative of a lower radiodensity compared to the zinc cements, but higher than RXL and RXU. The implant-specific cements had the lowest grey level values. IM could only be detected in 2-mm-thick sections with a lower aluminum equivalence value than the previously mentioned cements. PIC could not be detected radiographically for either the 1-mm or 2-mm thicknesses at either of the kVp settings.
  
  
  CONCLUSIONS
  Some types of cement commonly used for the cementation of implant-supported prostheses have poor radiodensity and may not be detectable following radiographic examination.
authors.affiliation: Department of Restorative Dentistry; private practice, Bellevue, WA, USA. cpkw@u.washington.edu <cpkw@u.washington.edu>
authors.forename: Chandur
authors.initials: C
authors.lastname: Wadhwani
authors.forename: Timothy
authors.initials: T
authors.lastname: Hess
authors.forename: Thomas
authors.initials: T
authors.lastname: Faber
authors.forename: Alfonso
authors.initials: A
authors.lastname: Piñeyro
authors.forename: Curtis S K
authors.initials: CS
authors.lastname: Chen
mesh_terms: D015502:Absorptiometry, Photon; D002126:Calcium Hydroxide / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry*; D015921:Dental Implants; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008903:Minerals / Q000737:chemistry; D011829:Radiation Dosage; D019252:Radiography, Dental, Digital; D019279:Resin Cements / Q000737:chemistry; D012984:Software; D015034:Zinc Oxide / Q000737:chemistry; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003287:Contrast Media; D003738:Dental Cements; D015921:Dental Implants; C061504:Flecks; D005899:Glass Ionomer Cements; C413303:ImProv; D008903:Minerals; C483701:Rely X Unicem; D019279:Resin Cements; C474196:Tempbond NE; C084550:Vitremer; D015035:Zinc Oxide-Eugenol Cement; C025702:Dycal; D015036:Zinc Phosphate Cement; D002126:Calcium Hydroxide; D015034:Zinc Oxide