title: [Water uptake and solubility of 3 filling plastic materials in relation to hardness tests and time].
abstract: 10 samples each of 0.25 mm, 0.5 mm, and 1 mm thickness of a conventional PMMA, a PMMA composite, and a Bowen composite were tested according to FDI specification no. 3 for 60 days. Sample thickness influences the rate of water uptake, and especially solubility. The sample size of 50 plus or minus 1 mm diameter and 0.5 plus or minus 0.1 mm thickness is suitable for obtaining reproducible, comparable, and clinically characteristic results. Water saturation is normally obtained after 3 to 5 days. Because of the varying sample thickness during production and due to different density of the materials, water uptake should only be expressed in per cent by volume. Solubility should not be disregarded when determining water uptake. It may simulate saturation or equilibrium. Solubility amounts to up to 2 per cent by weight after 60 days. Clinical findings regarding loss in substance may be explainable by this.
mesh_terms: D000180:Acrylic Resins; D003764:Dental Materials; D006245:Hardness Tests; D006801:Humans; D012995:Solubility; D013997:Time Factors; D014867:Water
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D014867:Water
vernacular_title: Wasseraufnahme und Löslichkeit von 3 Füllungskunststoffen in Abhängigkeitvon der Probenstärke und der Zeit