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Monomers used in resin composites: degree of conversion, mechanical properties and water sorption/solubility.
Gajewski, Vinícius E S; Pfeifer, Carmem S; Fróes-Salgado, Nívea R G; Boaro, Letícia C C; Braga, Roberto R.
Afiliação
  • Gajewski VE; Department of Biomaterials and Oral Biology, Dental School, University of São Paulo, Brazil.
Braz Dent J ; 23(5): 508-14, 2012.
Article em En | MEDLINE | ID: mdl-23306226
The organic phase of resin composites is constituted by dimethacrylate resins, the most common monomers being the bisphenol A diglycidildimethacrylate (BisGMA), its ethoxylated version (BisEMA), triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA). This study compared the homopolymers formed from the monomers used in restorative dental composites in terms of their degree of conversion (DC) and reaction kinetics (by near infra-red spectroscopy, n=3), mechanical properties (flexural modulus and strength in three point-bending, FM and FS, respectively, n=15), water sorption and solubility (WS and SL, respectively - ISO 4049, n=5). Materials were made photopolymerizable by the addition of camphoroquinone/dimethylamine ethyl methacrylate. TEGDMA showed the highest DC, followed by BisEMA, UDMA and BisGMA, both at 10 min and at 24h (p<0.001). UDMA showed the highest rate of polymerization, followed by TEGDMA, BisEMA and BisGMA (H(0)=13.254, p<0.001). UDMA and TEGDMA presented similar FM, significantly higher (p<0.001) than BisEMA and BisGMA, which in turn present statistically similar values (p>0.001). For FS, UDMA presented the highest value (p<0.001), followed by TEGDMA, then by BisEMA and BisGMA, which were statistically similar (p>0.001). BisGMA showed the highest WS, and TEGDMA and BisEMA the lowest. UDMA was statistically similar to all (H(0)=16.074, p<0.001). TEGDMA presented the highest SL, followed by UDMA, BisGMA and BisEMA (p<0.001). The tested homopolymers presented different behaviors in terms of polymerization kinetics, flexural properties, water sorption and solubility. Therefore, the use of copolymers is justified in order to obtain high DC and mechanical properties, as well as good resistance to water degradation.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Resinas Compostas / Fotoiniciadores Dentários / Metacrilatos Idioma: En Revista: Braz Dent J Assunto da revista: ODONTOLOGIA Ano de publicação: 2012 Tipo de documento: Article País de afiliação: Brasil País de publicação: Brasil

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Resinas Compostas / Fotoiniciadores Dentários / Metacrilatos Idioma: En Revista: Braz Dent J Assunto da revista: ODONTOLOGIA Ano de publicação: 2012 Tipo de documento: Article País de afiliação: Brasil País de publicação: Brasil