Abstract: A novel process for the polymerization of aziridine compounds is disclosed. The polymerization process includes mixing an aziridine compound with a polymerization initiator having the formula: ##STR1## where R.sup.1 is an alkyl radical of 1 to 18 C atoms,R.sup.2 is an alkyl radical of 1 to 18 C atoms or a phenyl alkyl radical of 7 to 18 C atoms, wherein said alkyl radicals may contain an ester group and/or ether group, R.sup.3 and R.sup.4 are hydrogen, an alkyl radical of 1 to 18 C atoms, and/or an aryl radical which can be substituted with a chloro, nitro or alkoxy group, whereby the alkyl radicals of R.sup.3 and R.sup.4 together or in combination with B can form a cycloaliphatic or heterocyclic ring, B is an electron attracting radical, and A.sup..crclbar. is a non-nucleophilic anion.Polyimines are quickly formed at ambient temperature.

Abstract: Compositions, which may be mixed with water to prepare a dental silicate cement, consist essentially of a silicate glass powder and a solid polymeric material selected of polymers of unsaturated .alpha.,.beta.-dicarboxylic acids.

Abstract: Superior artificial teeth, dentures, other dental replacement parts and dental prosthetic articles and devices, which exhibit high abrasion resistance, stability to moisture and which do not undergo volume changes, are obtained by polymerization of a compound of the formula ##STR1## in which R is H or -CH.sub.3, X is an alkylidene or the -SO.sub.2 -group, Y is an oxyalkylene group having between 2 and 5 carbon atoms, or an alkylidene group having between 1 and 5 carbon atoms. In some instances, the polymerization is carried out in the presence of a filler.

Abstract: Dental cements are prepared by mixing a silicate powder with an aqueous solution of polymers of unsaturated alpha, beta-dicarboxylic acids.