STUDY OF THE INFLUENCE OF THE PARTIAL REPLACING OF FELDSPARS WITH BIOGENIC HYDROXYAPATITE IN DENTAL TRANSPARENT GLAZE

Four glass compositions for dental glaze on zirconium ceramics were melted at temperature at 1200 oC in corundum crucible with hold for 2 h at maximum temperature and rapidly cooled in water. The following raw materials for melting of the glasses were used: sodium feldspar, potassium feldspar, sodium nitrate, barium carbonate, lithium carbonate, boric acid and biogenic hydroxyapatite (BHA). The glass composition 1 does not contain hydroxyapatite. The other compositions (2, 3 and 4) contain 10, 20 and 30 wt. % BHA, respectively, which partially replaces sodium and potassium feldspars. The biogenic hydroxyapatite powder (BHA) was synthesized by us from Black Sea Rapana venosa shells and monocalcium phosphate monohydrate Ca(H2PO4 )2.H2O by solid-state synthesis at 1180 oC. With the present study by methods of XRD, FT-IR-ATR and Fluorescence analysis, we prove that 10 mass % BHA can participate in the composition of glass for dental glaze on zirconium ceramics in the place of feldspars, which would increase its bioactive properties and optical properties.