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Effects of incorporating nanosized calcium phosphate particles on properties of whisker‐reinforced dental composites
Author(s) -
Xu Hockin H. K.,
Sun Limin,
Weir Mike D.,
Takagi Shozo,
Chow Laurence C.,
Hockey Bernard
Publication year - 2007
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.30644
Subject(s) - whisker , monocalcium phosphate , materials science , composite material , composite number , flexural strength , whiskers , nuclear chemistry , nanoparticle , filler (materials) , resin composite , dental composite , chemistry , nanotechnology , fishery , fish <actinopterygii> , fish meal , biology
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 PO 4 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 PO 4 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 v MCPM in the resin: [Ca]= 42.9 v MCPM 2.7 , and [PO 4 ] = 48.7 v MCPM 1.4 . In summary, the method of combining nanosized releasing fillers with reinforcing fillers yielded Ca‐ and PO 4 ‐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–PO 4 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