Stabilized amorphous calcium magnesium phosphate particle compositions

Composition comprising a paste forming compound and XRD amorphous calcium magnesium phosphate spherical particles having a hollow core and a shell wherein the particles are XRD amorphous and wherein the shell of the particles comprises 15-30 weight % of calcium, 50-70 weight % of phosphate, 5-11 weight % magnesium, and 1 to 20 weight % bound water, and wherein the Ca/P molar ratio is in the range of 0.70 to 1.20, and wherein the (Ca+Mg)/P molar ratio is in the range of 1.00 to 1.70, and wherein the particles have a mean particle size in the range of 100 to 500 nm, and wherein the amount of particles in the composition is 25-50 weight %.