title: Dental composites based on hybrid and surface-modified amorphous calcium phosphates.
abstract: The objectives of this study were to prepare hybrid and surface-modified amorphous calcium phosphates (ACPs) as fillers for mineral-releasing dental composites, and determine whether the mechanical strength of the composites could be improved without decreasing their remineralization potential. ACP was hybridized with tetraethoxysilane or zirconyl chloride and surface-treated with 3-methacryloxypropoxytrimethoxy silane (MPTMS) or zirconyl dimethacrylate (ZrDMA). Composites fabricated with unmodified ACP (u-ACP), hybrid or surface-modified ACP filler and photo-activated Bis-GMA, TEGDMA and 2-hydroxyethyl methacrylate (HEMA) (BTH resin), Bis-GMA, TEGDMA, HEMA and MPTMS (BTHS resin) or Bis-GMA, TEGDMA, HEMA and ZrDMA (BTHZ resin) were tested for their remineralizing potential and biaxial flexure strength (BFS). Ion releases from all composites were significantly above the minimum necessary for reprecipitation of apatite. The BFS of unfilled polymers was not adversely affected by immersion in saline solutions. The BFS of BTH and BTHS composites deteriorated upon soaking. However, BTHZ composites were practically unaffected by exposure to saline solutions. Filler hybridization resulted in a modest, but significant, improvement in the BFS (up to 24%) of BTHZ composites. Heterogeneous distribution of the ACP on disk surfaces was detected by the FTIR microspectroscopy analyses. This might have been caused by uncontrolled aggregation of ACP particles that appeared to hinder interfacial filler/resin interactions and diminish the mechanical strength of composites.
authors.affiliation: American Dental Association Foundation, Paffenbarger Research Center, National Institute of Standards and Technology, 100 Bureau Drive Stop 8546, Gaithersburg, MD 20899, USA. drago.skrtic@nist.gov
authors.forename: D
authors.initials: D
authors.lastname: Skrtic
authors.forename: J M
authors.initials: JM
authors.lastname: Antonucci
authors.forename: E D
authors.initials: ED
authors.lastname: Eanes
authors.forename: N
authors.initials: N
authors.lastname: Eidelman
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry*; D003764:Dental Materials / Q000138:chemical synthesis / Q000737:chemistry*; D019554:Dental Restoration Wear; D003793:Dental Restoration, Permanent / Q000295:instrumentation / Q000379:methods; D005240:Feasibility Studies; D006801:Humans; D008420:Manufactured Materials / Q000032:analysis; D008422:Materials Testing / Q000379:methods; D008968:Molecular Conformation; D012117:Resins, Synthetic / Q000737:chemistry*; D013499:Surface Properties; D013718:Tensile Strength; D014089:Tooth Remineralization / Q000379:methods
chemical_list: D002130:Calcium Phosphates; D003764:Dental Materials; D012117:Resins, Synthetic