• Surface finish: the surface should be smooth, lustrous and non-porous, and it can be polished to restore the original finish;
• Bonding to denture base polymer: well bonded to heat-polymerizable denture-base materials;
• Colour stability: no perceptible colour change after ultraviolet radiation test;
• Resistance to blanching, distortion and crazing: no blanching, distortion or crazing after boiling;
• Dimensional stability: the dimensional change of a tooth is within ± 2 % of its original mesio-distal dimension after heat curing treatment with denture base polymer.