Abstract:

BACKGROUND: Some studies have proposed adding rare earth oxides into zirconia, to change the color of zirconia oxide in order to meet the clinical requirements of the mouth for beautility.
OBJECTIVE: To evaluate the chromatic value and mechanical properties of zirconia added with rare earth oxides.
METHODS: ShadeEye computer colorimetric meter was used to test the L * a * b * values of the specimens. X-ray diffraction (D/Max-RB) was used to analyze the crystalline structure of materials. Using EZ-100 universal experiment machine, three-point bending strength was measured. The bending fracture microscopic form was observed under scanning electron microscope.
RESULTS AND CONCLUSION: ①The main crystalline structure of sintered ziconia specimens was tetragonal zirconia, and there was no another crystalline structure. ②The mixture of cerium oxide and ziconia presented with pale yellow; the mixture of erbium oxide and ziconia presented with pale pink, and the color deepened with the dose increase. Two hybrid specimens made ziconia presenting orange, and with the color deepened with the dose increase. ③The flexural strength of the materials added with cerium dioxide or erbium oxide alone was in downtrend. The flexural strength of the specimens added with the mixture of cerium dioxide and erbium oxide was decreased with the increase of cerium dioxide and erbium oxide. However, the single cerium dioxide only led to a small decrease in the flexural strength, and erbium oxide significantly increased the decrease of flexural strength. The color of zironia mixed with rare earth oxides can be changed, and a certain flexural resistance appears.