An innovative all-ceramic dental restorative material, based on fluorcanasite(K2Na4Ca5Si12O30F4) glass-ceramic, has been developed as an alternative to typicalcommercial dental ceramics, zirconia (ZrO2) and lithium disilicate (Li2Si2O5). Someglasses with compositions based on SiO2-CaO-Na2O-K2O-CaF2-Al2O3-ZrO2-P2O5system have been produced by melting at controlled temperature between 1250-1350ºC to avoid fluorine loss, and by casting in adequate molds (Fig.1). Theseglasses were characterized by DTA to determine characteristic temperatures, andbased on DTA data, glass-ceramics were produced by nucleation and crystallizationat 550ºC and 900ºC, respectively. XRD analysis was used to assess the evolution ofcrystallinity with the temperature. Canasite-A (K3(Na3Ca5)Si12O30F4) was formed at750C, it increased until 850C and then remained constant. Quartz formation wasalso identified, but it decreased with temperature. SEM micrographs of the producedglass-ceramics show the needle-like interlocking microstructures (Fig.2), typical ofchain silicates, which are adequate to achieve glass-ceramics with high strength andfracture toughness. Vickers microhardness values for the produced glass-ceramicwere about 5.0 MPa. Characterization of flexural strength and chemical durabilitywill be performed during the next steps of the work. It is expected that results of thisstudy confirm the possibility of obtaining a glass-ceramic with satisfactory propertiesfor use in dental restorations.
|Publication status||Published - 1 Jan 2014|