title: Synthesis and characterization of hybrid silica/PMMA nanoparticles and their use as filler in dental composites.
abstract: The effect of hybrid silica/poly(methylmethacrylate) (PMMA) nanoparticles on the properties of composites for dental restoration was evaluated. Hybrid nanoparticles with silica as core and PMMA as shell were obtained by a seeded emulsion polymerization process. Fourier transform infrared spectrum of the hybrid nanoparticles shows an intense peak at 1,730 cm(-1), corresponding to carbonyl groups (CO) of the ester. The thermal stability of the hybrid particles decreases with increasing amounts of PMMA and the residual mass at 700°C corresponds to the silica content in the hybrid particles. Composites were obtained by dispersing nanoparticles (silica or hybrid), as fillers, in a resin-bis glycidyl dimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (40%/60% (w/w)). The paste was then placed in a mold and polymerized under light irradiation. During the preparation of the composites, with the hybrid nanoparticles, the monomers swell the PMMA shell and after photo-curing, a semi-interpenetrating network (semi-IPN) is obtained around the silica core. The properties of the composites, obtained using the hybrid nanoparticles, depend on the filler content and the amount of PMMA in the semi-IPN matrix. For composites with similar inorganic filler contents, the composites with low amounts of PMMA shell had higher modulus than those in which silica was used as the filler.
authors: Unidad de Materiales, Centro de Investigación Científica de Yucatán A.C. Calle 43 No. 130 Col. Chuburná de Hidalgo, Mérida, Yucatán 97200, Mexico. Electronic address: gcanche@cicy.mx.
authors: G
authors: G
authors: Canché-Escamilla
authors: Unidad de Materiales, Centro de Investigación Científica de Yucatán A.C. Calle 43 No. 130 Col. Chuburná de Hidalgo, Mérida, Yucatán 97200, Mexico.
authors: S
authors: S
authors: Duarte-Aranda
authors: Facultad de Odontología, Universidad de Granada, Campus Universitario de Cartuja s/n, Granada 18071, Spain.
authors: M
authors: M
authors: Toledano
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D055119:Elastic Modulus; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature
chemical_list: D001672:Biocompatible Materials; D003188:Composite Resins; D012822:Silicon Dioxide; D019904:Polymethyl Methacrylate
keywords: Dental composites; Hybrid composite; Mechanical properties; Nanoparticles; Semi-interpenetrating network