Shrinkage-free, alumina-glass dental composites via aluminum oxidation

Alumina-glass composites that contain oxidized aluminum were investigated to make shrinkage-free, all-ceramic dental porcelain. This was achieved by control of the volume expansion and shrinkage that occur during the aluminum oxidation and densification processes. The dimensional change and strength of the alumina-glass composites were dependent on the aluminum content and particle size. A shrinkage-free sample with a strength of 330 MPa and transmittance of 1.21 was fabricated by using 4-5 vol% of aluminum powder with an average particle size of 6 μm in the alumina-glass composite made by the In-Ceram method.