Effects of incorporating nanosized calcium phosphate particles on properties of whisker-reinforced dental composites†‡

  1. Hockin H. K. Xu1,*,
  2. Limin Sun1,
  3. Mike D. Weir1,
  4. Shozo Takagi1,
  5. Laurence C. Chow1,
  6. Bernard Hockey2

Article first published online: 21 AUG 2006

DOI: 10.1002/jbm.b.30644

Issue

Journal of Biomedical Materials Research Part B: Applied Biomaterials

Journal of Biomedical Materials Research Part B: Applied Biomaterials

Volume 81B, Issue 1, pages 116–125, April 2007

Additional Information

How to Cite

Xu, H. H. K., Sun, L., Weir, M. D., Takagi, S., Chow, L. C. and Hockey, B. (2007), Effects of incorporating nanosized calcium phosphate particles on properties of whisker-reinforced dental composites. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 81B: 116–125. doi: 10.1002/jbm.b.30644

Author Information

  1. 1

    Paffenbarger Research Center, American Dental Association Foundation, Gaithersburg, Maryland, 20899

  2. 2

    National Institute of Standards and Technology, Gaithersburg, Maryland, 20899

*Paffenbarger Research Center, American Dental Association Foundation, Gaithersburg, Maryland, 20899

  1. †

    Certain commercial materials and equipment are identified to specify the experimental procedure. This does not imply recommendation or endorsement by NIST or ADAF or that the material or equipment identified is necessarily the best available for the purpose. One standard deviation was used as the estimated standard uncertainty of the measurements. These values should not be compared with data obtained in other laboratories under different conditions. This is an official contribution of the National Institute of Standards and Technology and is not subjected to copyright in the United States.

  2. ‡

    This article is a US Government work and, as such, is in the public domain in the United States of America.

Publication History

  1. Issue published online: 1 MAR 2007
  2. Article first published online: 21 AUG 2006
  3. Manuscript Accepted: 10 MAY 2006
  4. Manuscript Revised: 1 MAY 2006
  5. Manuscript Received: 23 FEB 2006

Funded by

  • NIH/NIDCR. Grant Number: R01 DE14190
  • NIST
  • ADAF

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Keywords:

  • dental composite;
  • nanoparticles;
  • whisker reinforcement;
  • flexural strength;
  • elastic modulus;
  • Ca and PO4 release;
  • tooth caries

Abstract

Clinical data indicate that secondary caries and restoration fracture are the most common problems facing tooth restorations. Our ultimate goal was to develop mechanically-strong and caries-inhibiting dental composites. The specific goal of this pilot study was to understand the relationships between composite properties and the ratio of reinforcement filler/releasing filler. Nanoparticles of monocalcium phosphate monohydrate (MCPM) were synthesized and incorporated into a dental resin for the first time. Silicon carbide whiskers were fused with silica nanoparticles and mixed with the MCPM particles at MCPM/whisker mass ratios of 1:0, 2:1, 1:1, 1:2, and 0:1. The composites were immersed for 1–56 days to measure Ca and PO4 release. When the MCPM/whisker ratio was changed from 0:1 to 1:2, the composite flexural strength (mean ± SD; n = 5) decreased from 174 ± 26 MPa to 138 ± 9 MPa (p < 0.05). A commercial nonreleasing composite had a strength of 112 ± 14 MPa. When the MCPM/whisker ratio was changed from 1:2 to 1:1, the Ca concentration at 56 days increased from 0.77 ± 0.04 mmol/L to 1.74 ± 0.06 mmol/L (p < 0.05). The corresponding PO4 concentration increased from 3.88 ± 0.21 mmol/L to 9.95 ± 0.69 mmol/L (p < 0.05). Relationships were established between the amount of release and the MCPM volume fraction vMCPM in the resin: [Ca]= 42.9 vmath image, and [PO4] = 48.7 vmath image. In summary, the method of combining nanosized releasing fillers with reinforcing fillers yielded Ca- and PO4-releasing composites with mechanical properties matching or exceeding a commercial stress-bearing, nonreleasing composite. This method may be applicable to the use of other Ca–PO4 fillers in developing composites with high stress-bearing and caries-preventing capabilities, a combination not yet available in any dental materials. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006

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