Radiopacity of tantalum oxide nanoparticle filled resins

D. C.N. Chan, H. W. Titus, K. H. Chung, H. Dixon, S. T. Wellinghoff, H. R. Rawls

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Objectives: Radiopacity of composite resins allows radiographic distinction of existing restorations and recurrent caries. Current composites must be supplemented with heavy metal-containing glasses or minerals to achieve a desired radiopacity. The purpose of this study was to evaluate the radiopacity of Tantalum oxide (Ta2O5) filled resins at varying percentage loadings. Methods: Methacrylate functionalized Ta2O5 nanoparticles ( < 50 nm) in methanol-dissolved or powder forms were mixed into either glycerol dimethacrylate (GDMA) or a bisGMA, TEGDMA, bisEMA mixture (GTE). Specimens were made in a split brass mold (2 × 2 × 15 mm) and compared with an aluminum stepwedge (99.5% pure Al) and a dentin slice of the same thickness. Kodak Ultraspeed periapical X-ray film on a lead plate at a target distance of 45 cm was exposed at 70 kVp and 10 mA, for 0.5 s and processed automatically. Optical density was measured (n = 3) with an RMI Processor Control Densitometer. Radiopacity was calculated as percent relative linear attenuation coefficient (Alpha). ANOVA and Student-Newman-Keuls comparisons were used to determine significance at the 95% confidence level. Results: Radiopacity increased significantly with Ta2O5 loading (p = 0.001). Ta2O5 nanoparticle filled resins enter the optimal range of diagnostic detectability (α = 150-250) at 50 wt.% and approach equivalence with enamel at approximately 70 wt.%. Significance: The introduction of tantalum oxide nanoparticle filler has potential as a miscible component of a resin composite to provide radiopacity for microfiller-type restorative materials and to circumvent the need for hydrolysis-prone glass reinforcing fillers.

Original languageEnglish (US)
Pages (from-to)219-222
Number of pages4
JournalDental Materials
Issue number3
StatePublished - May 1999


  • Acrylic resins
  • Dental restorations
  • Nanoparticles
  • Radiopacity
  • Reinforcing fillers
  • Resin composites
  • Tantalum oxide

ASJC Scopus subject areas

  • Mechanics of Materials
  • Materials Science(all)
  • Dentistry(all)


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