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The influence of the technological glass-melting parameters of the selected composition in the SrO–Al2O3–P2O3–SiO2–F system on the value of the refractive index and the amount of fluorine remaining in the glass structure post-melting was investigated. The lowering of the melting temperature combined with tableting of the charge [batch] increases fluorine absorption in the glass up to 17 wt.% at the same time, and the value of the refractive index reduction to nD = 1.49. It was experimentally established that in the multicomponent glass selected for glass-ionomer cements with two glass-forming oxides (SiO2 and P2O2) and a high Al2O3 content, each wt.% of fluorine reduces the refractive index by about 3.5 × 10 –4 units. [ABSTRACT FROM AUTHOR]

A new glass-filler for dental composites has been developed based on glass in the system SrO–Al2O3–B2O3–SiO2. This filler meets contemporary requirements for filling materials and is characterized by high chemical resistant to water, acids and alkalis (Class I), high visible-range transparency (> 80%), and CLTE-compatibility with the polymer matrix. The melting temperature is acceptable, and crystallization is not a proclivity. It is shown [demonstrated that the new glass filler effects high-level medical-biological, operational, and functional properties of the dental composite based on it, and competitiveness with respect to the popular foreign-made analog materials. [ABSTRACT FROM AUTHOR]

Functional fillers with 13 wt.% F were obtained, based on SrO–Al2O3–P2O5–SiO2–F glass, for glass-ionomer cements. A high level of radiopacity of the filling material was achieved by jointly introducing strontium oxide together with strontium fluoride into the glass filler. The use of readily fusible fluorine-containing raw materials in quantities that secure transparent glass made it possible to lower the glass transition temperature to 1500°C and lower, thereby affording industrial development of the developed compositions. The values of the refractive index of glasses with a high fluorine content nD is at about 1.50 and correspond to that of a polymer matrix of glass-ionomer cement, thereby securing dental material with high aesthetic characteristics. Samples of transparent, filling, glass-ionomer cement with high compressive strength > 100 MPa and 5 min hardening were obtained. [ABSTRACT FROM AUTHOR]