A composition for use in the treatment of a root canal in a tooth, said composition being a hydrate gel that can harden, which is formed by mixing together a particulate and a liquid carrier, wherein the composition comprises: (A) 1 to 80% by weight of particulate material selected from the group consisting of calcium silicate, calcium aluminate, tetracalcium aluminoferrite, calcium phosphate, calcium sulfate, silica, alumina, calcium oxide, calcium hydroxide, and mixtures thereof； and (B) 1 to 50% by weight liquid carrier comprising (i) water-sodble polymer selected from the group consisting of polyvinyl alcohols, polyvinyl-pyrrolidone (PVP), partially hydrolyzed polyvinyl acetates (PVAc), polyacrylic acid (PAA), and polymethacrylic acid (PMA), and copolymers and mixtures thereof, (ii) 1 to 40 % by weight based on the weight of the composition, of a surfactant selected from the group consisting of alkyl sulfates, alkyl ether sulfates, and sarcosinates, and mixtures thereof, and (iii) water, the ratio of the surfactant to water-soluble polymer being no greater than 6 to 1.
