Influence of titanium oxide additions with co2 laser treatment on the microstructural properties of glazes layer-dental zirconia ceramics

Abstract

This paper presents the effect of CO2 laser on the glazes layer-dental zirconia ceramics after adding TiO2 nanoparticles to the glazes and study the its improvement. The specimens has been prepared by using CAD/CAM dental machine and sintered at 1530°C. Then the surface was glazed by VITA Glaze with (5% and 10%) of nano-TiO2 additions. The glaze layer were irradiated by continuous CO2 laser of 15Watt as indicated power. It was found that the main phases of the ceramic substrate are tetragonal zirconia with a percentage of alumina in the corundum phase. The glazing of the ceramic substrate led to a change in the X-ray diffraction pattern by the emergence of new phases, thus changing the crystallite size and percentage of lattice strain. The change in grain size measured by AFM technique, ranging from 88.46 nm to nm 62.18 in addition to changing surface roughness due to the emergence of centers of nuclei and grain growth. Moreover, the addition of TiO2 and laser irradiation changed the residual stresses on the surface, and this was reflected in the increasing hardness values from 575 kg/mm2 to 1215 kg/mm2 after added 5% TiO2 with laser treatment. Generally, addition of 5% TiO2 is better than 10% in terms the structure of the glaze layer surface and hardness, as the additions of 10% need a higher glazing temperature.