One subject of the invention is a composition comprising from 5 to 65%, by weight relative to the total weight of the composition, of calcium silicate crystals; from 1 to 20%, by weight relative to the total weight of the composition, of calcium carbonate crystals; in addition from 0 to 50%, preferably from 1 to 40%, by weight relative to the total weight of the composition, of a compound of general formula mCaO.nSiO2.pH2O in which m and n, each independently, vary from 1 to 3 and p varies from 3 to 6; the ratio between the particle size d50 of the calcium silicate crystals and the particle size d50 of the calcium carbonate crystals being less than 10; another subject of the invention is a process for preparing said composition, and also the use of said composition in the dental field.