Abstract: The ceramic builder based investment is coloured to simulate naturally prepared tooth dentin. Upon final set, the solid refractory dies are fired to enable them to receive porcelain. The expansion and contraction of the refractory die upon temperature fluctuations, is correlated with the corresponding porcelains' expansion. This correlation of the materials enables the restoration to maintain proper form and shape through multiple firings. The primary basis of this invention is the ability to colour (chromatize) individual refractory dies to simulate natural prepared teeth from the dentist.