RESUMEN
OBJECTIVES: The aim of this investigation was to determine the effect of storage in disinfectants and artificial saliva on a series of commercial soft lining materials for dentures. Changes in mechanical properties and the nature of chemicals released into these solutions were studied. METHODS: Four soft lining materials were studied (Vertex Soft® and Villacryl Soft®, both of which are plasticized acrylics; Molloplast B® and Mollosil®, both of which are silicone elastomers). All were cured according to manufacturers' instructions, and then cylindrical specimens (6 mm height × 10 mm diameter) prepared. These were stored under various conditions then loaded in uniaxial compression and the stress measured at a strain corresponding to a 10% deformation to determine Young's modulus. Storage involved exposure either to the following disinfectants: 2% aqueous chlorhexidine gluconate, 2% aqueous sodium hypochlorite, Corega Tabs® cleansing tablets or 3% aqueous hydrogen peroxide; or to artificial saliva. For the latter, storage involved either immersion in artificial saliva at 37°C for the whole study, or immersion for 16h a day and dry at room temperature for the next 8h each day. GC/MS was used to determine species leached into these solutions. RESULTS: The acrylic materials Villacryl Soft and Vertex Soft became less elastic on storage for up to 28 days whereas the silicone materials Molloplast B and Mollosil, showed no change in elastic properties. Various compounds were found to be released from these materials, including EGDMA, methyl methacrylate and dibutyl phthalate. Generally, the silicones were more stable than acrylics, releasing smaller amounts of the various eluants. In all cases, amounts eluted were well below permitted exposure limits. SIGNIFICANCE: Practical denture cleansing agents affect the properties of soft lining materials, reducing their elastomeric character, acrylics being more adversely affected than the silicones. These changes are associated with the loss of various chemicals, including plasticizers and monomers, from the soft lining materials.
Asunto(s)
Limpiadores de Dentadura , Alineadores Dentales , Resinas Acrílicas/química , Clorhexidina , Fuerza Compresiva , Desinfectantes Dentales , Análisis del Estrés Dental , Dibutil Ftalato/análisis , Almacenaje de Medicamentos , Módulo de Elasticidad , Peróxido de Hidrógeno , Ensayo de Materiales , Metacrilatos/análisis , Metilmetacrilato/análisis , Saliva Artificial , Elastómeros de Silicona/química , Hipoclorito de SodioRESUMEN
Biocompatibility constitutes the most fundamental requirement with respect to all dental materials to be applied within the oral cavity. In its environment, various toxic compounds may be released by dental materials which pose potential threats to the patient's health. Due to the fact that dentures remain in the oral cavity for a very long time, a detailed examination and verification of prosthetic materials with a view to their toxicity seems to be essential. By using very sensitive measurement techniques such as gas chromatography, one may determine which compounds are released by these materials. The aim of this paper was to determine the influence of various denture cleansers on the release of organic compounds from four soft dental materials used in prosthetics for lining dentures. These materials when placed in commonly used disinfectants (Corega Tabs, sodium hypochlorite, chlorhexidine, hydrogen peroxide), as well as in artificial saliva, produced 13 chemical compounds such as monomers (methyl methacrylate, ethyl methacrylate, dodecyl methacrylate), plasticizers (dibutyl phthalate, diethyl phthalate, tributyl acetylcitrate) and others (e.g. benzophenone). A comparison of chemical compounds released from acrylic-based materials and those released from silica-based materials demonstrated that acrylic-based materials are less resistant to disinfectants.
Asunto(s)
Desinfectantes Dentales/toxicidad , Limpiadores de Dentadura/toxicidad , Alineadores Dentales , Compuestos Orgánicos , Plastificantes/toxicidad , Saliva Artificial/toxicidad , Acrilatos/análisis , Acrilatos/toxicidad , Desinfectantes Dentales/química , Limpiadores de Dentadura/química , Humanos , Compuestos Orgánicos/análisis , Compuestos Orgánicos/toxicidad , Plastificantes/química , Medición de Riesgo , Saliva Artificial/químicaRESUMEN
Elution of organic compounds from resin-based dental fillings during their application in the human mouth environment may have a potential impact on the human health. Ethanol, water and other solvents very often present in the human mouth have the ability to penetrate dental fillings placed in the human tooth. Penetration of liquids into the tooth may lead to the liberation of unreacted dental filling ingredients or their degradation products. Determination of these compounds is necessary for better knowledge from possible harmful effects caused by dental fillings. The aim of this study was the isolation and identification of compounds released from resin-modified glass-ionomer cements (RMGICs), resin-based dental materials applied in dentistry. Compounds were extracted from fillings by using four solvents (40% ethanol, water, 1% acetic acid and artificial saliva). Liquid samples containing eluted compounds were then extracted, evaporated and analyzed by using of HPLC-MS (high-performance liquid chromatography-mass spectrometry) and HPLC-DAD (high-performance liquid chromatography-diode array detection) techniques. Almost thirty components (monomers and additives) of RMGICs were identified. The main identified extractables were: Bis-GMA (bisphenol A glycidyl dimethacrylate), Bis-EMA (ethoxylated bisphenol A dimethacrylate), UDMA (urethane dimethacrylate), TEGDMA (triethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate) as monomers and diphenyliodonium chloride, camphorquinone (initiators), BHA (inhibitor), 4-(dimethylamino) ethyl benzoate (co-initiator) as additives.
Asunto(s)
Resinas Compuestas/química , Cementos de Ionómero Vítreo/química , Cromatografía Líquida de Alta Presión , Restauración Dental Permanente , Etanol/química , Ensayo de Materiales , Saliva/química , Agua/químicaRESUMEN
Leaching of volatile substances from resin-based dental materials may have a potential impact on the biocompatibility as well as safety of these materials. Information from manufacturers on ingredients in the materials is very often incomplete. Patients and dentists may be in contact with components emitted from cured dental fillings or from substrates applied in their preparation. Therefore, determination of the components of these materials is necessary for better prevention from possible harmful effects caused by dental fillings. The aim of this work was the isolation and identification of organic compounds evolved from four commercial resin-modified glass-ionomer cements (resin-based dental materials applied in dentistry) by using an alternative method of volatile compounds analysis-HS-SPME (headspace-solid phase microextraction). Dental materials were heated in closed vial at various temperatures and volatile substances released into the headspace phase above the sample were isolated on a thin polymeric fibre placed in SPME syringe. Identification was performed by using the GC-MS (gas chromatography-mass spectrometry) technique. Almost 50 RMGIC (resin-modified glass-ionomer cement) components (monomers and additives) were identified. The main identified leachables were: iodobenzene (DPICls-diphenyliodonium chloride degradation product), camphorquinone (photo-initiator), tert-butyl-p-hydroxyanisole (inhibitor), 4-(dimethylamino)ethyl benzoate (co-initiator), ethylene glycol dimethacrylate (monomer).