A biocompatibility study of a reinforced acrylic-based hybrid denture composite resin with polyhedraloligosilsesquioxane.
ABSTRACT Acrylic-based denture materials have several common weak points, such as shrinkage after curing, lack of strength and toxicity. In order to solve these problems, we adapted a hybrid system using acrylic polymer and polyhedraloligosilsesquioxane (POSS). The aim of the study was to investigate the biocompatibility of a reinforced acrylic-based hybrid denture composite resin with POSS. Specimens of a novel polymeric denture base resin, in which POSS was used to partially replace the commonly used base monomer, were fabricated. In order to examine changes in biocompatibility with time, fresh specimens, along with specimens soaked in distilled water for 24 and 72 h were fabricated. Three other types of acrylic denture base resins were used to prepare the resin specimens. Biocompatibility (as measured by a metabolic assay, an agar overlay test, and a mutagenesis assay) of the composites was tested. The metabolic and mutagenesis assays were conducted with pure culture medium as a control. In this study, the reinforced acrylic-based hybrid denture composite resin with POSS showed improved biocompatibility and lower mutagenicity than the control. Statistical examinations showed the cell metabolic activity of the novel polymeric denture base resin in the 72-h immersion case as having almost the same inclination as the control. We hope that these results might aid in the development of a reinforced acrylic-based denture resin.
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ABSTRACT: We studied the influence of salivary acidity on leachability of denture-base acrylic resins with etiological interest in denture stomatitis because denture surfaces are frequently exposed to acidic conditions in the oral cavities. Auto-, heat-, and microwave-polymerized resins were immersed in artificial saliva with pH ranging from 4.0 to 6.8 at 37 degrees C, and leachables were pursued quantitatively with time. Methyl methacrylate, methacrylic acid, and benzoic acid leached from all resins. Their concentrations in the saliva were markedly high for auto-polymerized resins, while leachability of heat- and microwave-polymerized resins was so low that quantitative analysis of leachables was impossible. Lower pH showed higher concentrations of methyl methacrylate, although no apparent association was confirmed between salivary acidity and its own leachability. The concentrations of methacrylic acid increased remarkably with an increase in pH, which was probably due to hydrolysis of methyl methacrylate. These results suggest that chemotoxic actions of auto-polymerized resins are potentially ascribable to methyl methacrylate under more acidic conditions and to methacrylic acid under less acidic conditions.Dental Materials 02/1990; 6(1):13-6. · 3.77 Impact Factor
- British dental journal 06/1976; 140(10):347-50. · 0.81 Impact Factor
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ABSTRACT: The aim of this study was to determine the in vitro cytotoxicity of fibre-polymethyl methacrylate (PMMA) composite used in denture bases. Both heat-cured and autopolymerized PMMA were tested as the matrix of the fibre composite or as a plain denture polymer. The fibres tested included unsized E-glass and silica fibres, silica fibres which were sized with a silane coupling agent only, as well as commercially epoxy-silane or methacrylate-chrome complex sized E-glass fibres. The indirect contact cytotoxicity test by agar diffusion was carried out according to the international standard ISO 10993-5 after storing the test specimens in water for 24 h. PVC plastic was used as a positive control and polyethylene plastic was used as a negative control. Within the limitations of the agar diffusion test, it can be concluded that neither the unreinforced PMMA nor the fibre composite made from PMMA and fibres was cytotoxic.Journal of Oral Rehabilitation 09/1999; 26(8):666-71. · 2.34 Impact Factor