Two-part dental impression material curable by a metathesis reaction
comprising a base paste with first and second resin components each
containing at least two cycloolefin groups per molecule curable by a
metathesis reaction with a metathesis catalyst. The first resin includes
a urethane polyether or polyester carboxylate backbone terminated with
the cycloolefin groups and the second resin includes an alkoxy-siloxane
polyether or polyester carboxylate backbone terminated with the
cycloolefin groups. The metathesis catalyst can be a ruthenium carbene
complex catalyst.