title: Novel CaF(2) nanocomposite with high strength and fluoride ion release.
abstract: Secondary caries and restoration fracture remain common problems in dentistry. This study tested the hypothesis that combining nano-CaF(2) and glass fillers would yield nanocomposites with high mechanical properties and F release. Novel CaF(2) nanoparticles (56-nm) were synthesized via spray-drying and incorporated into resin. F release increased with increasing the nano-CaF(2) content, or with decreasing pH (p < 0.05). F-release rates at 70-84 days were 1.13 microg/(cm(2) x day) and 0.50 microg/(cm(2) x day) for nanocomposites containing 30% and 20% nano-CaF(2), respectively. They matched the 0.65 microg/(cm(2) x day) of resin-modified glass ionomer (p > 0.1). The nanocomposites had flexural strengths of 70-120 MPa, after 84-day immersion at pH 4, pH 5.5, and pH 7. These strengths were nearly three-fold that of resin-modified glass ionomer, and matched/exceeded a composite with little F release. In summary, novel CaF(2) nanoparticles produced high F release at low filler levels, thereby making room in resin for reinforcement glass. This yielded nanocomposites with high F-release and stress-bearing properties, which may help reduce secondary caries and restoration fracture.
authors.affiliation: Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201, USA. hxu@umaryland.edu
authors.forename: H H K
authors.initials: HH
authors.lastname: Xu
authors.forename: J L
authors.initials: JL
authors.lastname: Moreau
authors.forename: L
authors.initials: L
authors.lastname: Sun
authors.forename: L C
authors.initials: LC
authors.lastname: Chow
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002124:Calcium Fluoride / Q000737:chemistry*; D002327:Cariostatic Agents / Q000737:chemistry*; D055598:Chemical Phenomena; D003188:Composite Resins / Q000138:chemical synthesis / Q000737:chemistry*; D003764:Dental Materials / Q000138:chemical synthesis / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D004058:Diffusion; D055119:Elastic Modulus; D005459:Fluorides / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry*; D018583:Pliability; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D002327:Cariostatic Agents; D003188:Composite Resins; D003764:Dental Materials; D005899:Glass Ionomer Cements; C513708:Heliomolar; D011140:Polyurethanes; D019279:Resin Cements; C084550:Vitremer; D002124:Calcium Fluoride; D005459:Fluorides