Nanocomposites with Ca and PO4 release: effects of reinforcement, dicalcium phosphate particle size and silanization

Dent Mater. 2007 Dec;23(12):1482-91. doi: 10.1016/ Epub 2007 Mar 6.


Objectives: Nanoparticles of dicalcium phosphate anhydrous (DCPA) were synthesized in our laboratory for the first time and incorporated into a dental resin. Our goal was to develop a mechanically strong dental composite that has Ca and PO(4) ion release to combat tooth caries, and to investigate the effects of whisker reinforcement, DCPA particle size and silanization.

Methods: DCPA nanoparticles and two larger DCPA particles were used with nano-silica-fused whiskers as fillers in a resin matrix. Composite mechanical properties were measured via three-point flexure, and the release of Ca and PO(4) ions were measured versus time.

Results: Using DCPA nanoparticles with a diameter of 112nm, the composite at a DCPA:whisker mass ratio of 1:1 had a flexural strength (mean+/-S.D.; n=5) of (112+/-17)MPa, not significantly different from (112+/-14)MPa of a commercial non-releasing composite; both were higher than (29+/-7)MPa for the composite at DCPA:whisker of 1:0 (p<0.05). The composite with DCPA particle size of 112nm released Ca to a concentration of 0.85mmol/L and PO(4) of 3.48mmol/L, higher than Ca of 0.67mmol/L and PO(4) of 1.11mmol/L using DCPA with 12microm particle size (p<0.05). Silanization of DCPA increased the composite strength at DCPA:whisker of 1:0 compared to that without silanization, but decreased the Ca and PO(4) release (p<0.05). Increasing the DCPA particle surface area increased the Ca and PO(4) release.

Significance: Decreasing the DCPA particle size increased the Ca and PO(4) release; whisker reinforcement increased the composite strength by two- to three-fold. The nano DCPA-whisker composites, with high strength and Ca and PO(4) release, may provide the needed, unique combination of stress-bearing and caries-inhibiting capabilities.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Calcium
  • Calcium Phosphates / chemistry*
  • Cariostatic Agents / chemistry*
  • Composite Resins / chemistry*
  • Dental Restoration, Permanent*
  • Dental Stress Analysis
  • Drug Delivery Systems
  • Elasticity
  • Materials Testing
  • Nanocomposites / chemistry*
  • Particle Size
  • Phosphates
  • Pliability
  • Silanes


  • Calcium Phosphates
  • Cariostatic Agents
  • Composite Resins
  • Phosphates
  • Silanes
  • calcium phosphate, dibasic, anhydrous
  • Calcium