A dental impression or doubling composition comprising A) alkoxysilyl-functional polyethers with linear or branched main chains with an average molecular weight (Mn) of 800 to 20,000, containing 20 to 95 weight percent of polyether groups and 0.2 to 25 weight percent of SIR1R2R3 alkoxysilyl groups, in which R1, R2 and R3, independently of one another, are hydrogen, alkyl or alkoxy, and 0 to 10 weight percent of urethane groups or 0 to 10 weight percent of urea groups, and B) a mixture, containing water and organic and/or inorganic acids in a ratio by weight of 1:0.01 to 1:40.