Abstract: Refractory investment material for forming a positive replication of a tooth structure on which a high-alumina based porcelain tooth restoration is to be formed, the material being formed from a refractory powder which includes alumina mixed with a liquid carrier comprising an aqueous dispersion of silicon dioxide.

Abstract: Refractory investment material and method for forming a positive replication of a tooth structure on which a high-alumina based porcelain tooth restoration is to be formed, the material being formed from a refractory powder which includes calcined alumina mixed with a liquid carrier comprising an aqueous colloidal dispersion of silicon dioxide. The method comprises the steps of: preparing a negative impression of the tooth structure on which a tooth restoration is to be placed; forming a positive replication of the tooth structure by pouring the mixture of refractory powder and aqueous dispersion into the negative impression; allowing the positive replication to harden; removing the positive replication from the negative impression for degassing and cooling; and coating the positive replication with a mixture of high-alumina porcelain in an aqueous carrier to form a core layer of porcelain on which subsequent layers of high-alumina porcelain may be applied.

Abstract: A method of forming a porcelain tooth restoration from a positive replication of the tooth structure on which the tooth restoration is to be placed. Areas of the replication are coated with a liquid preparation which substantially inhibits moisture absorption by the replication. A slurry of powdered porcelain is applied over the coated area of the replication to form at least a portion of the tooth restoration which is cured and eventually separated from the tooth replication for bonding to the tooth structure.