Abstract: Described are abrasive silica particles suitable for use in a dentifrice composition, the particles comprising particles of a first abrasive silica in an amount of at least 90 wt % relative to the total weight of the abrasive silica particles; and particles of a second abrasive silica in an amount of up to 10 wt % relative to the total weight of the abrasive silica particles, wherein the weight median particle diameter (d50) of the particles of the second abrasive silica is less than the weight median particle diameter (d50) of the particles of the first abrasive silica and from 15% to 70% of the d50 value of the particles of the first abrasive silica. Dentifrice compositions comprising such particles and methods of preparing such particles are also described.

Abstract: An aqueous slurry comprises (a) a crystalline aluminosilicate represented by the empirical formula M2/nO.Al2O3.xSiO2.yH2O wherein M represents a first metal moiety, said first metal having a valency of n, x is the molar ratio of silica to alumina and y indicates the molar ratio of water to alumina, (b) a mineral or organic acid, and (c) particulate silica. The silica may have a BET surface area greater than 500 m2/g and a pore volume, as measured by nitrogen manometry of less than 2.1 cm3/g. The slurry is stable on storage but has a low viscosity at low shear rate.

Abstract: An aqueous slurry according to the invention comprises (a) a crystalline aluminosilicate represented by the empirical formula M2/nO Al2O3.xSiO2.yH2O wherein M represents a first metal moiety, said first metal having a valency of n, x indicates the ratio of atoms of silicon to atoms of aluminium and y indicates the ratio of molecules of water to atoms of aluminium, (b) a salt of a second metal selected from the group consisting of Group III metals, metallic elements of Group IV, magnesium, titanium, chromium, iron, nickel, copper, zinc, zirconium and silver, said salt of a second metal being present in an amount which is sufficient to replace from about 2.0 to about 40 per cent by weight of the first metal moiety, and (c) particulate silica having a BET surface area greater than 500 m2/g and a pore volume, as measured by nitrogen manometry of less than 2.1 cm3/g. The slurry is stable on storage but has a low viscosity at low shear rate.

Abstract: An amorphous silica suitable for use in a dental composition has a weight mean particle size in the range 3 to 15 ?m with at least 90 per cent by weight of particles having a size below 20 ?m, a Radioactive Dentine Abrasion (RDA) determined on an aqueous slurry of the silica powder of 100 to 220, a Pellicle Cleaning Ratio (PCR), when incorporated in a dental composition at 10 per cent by weight, greater than 85, the ratio of PCR to RDA being in the range 0.4:1 to less than 1:1 and having a Plastics Abrasion Value (PAV) in the range 11 to 19. A silica having the above properties is prepared by a precipitation route. The silica made available by the invention is also useful as an anti-blocking agent in plastics.

Abstract: An oral composition comprises a particulate amorphous silica and a cationic antibacterial agent characterised in that the particles of said amorphous silica have a polyether glycol deposited thereon. The silica used in the composition of the invention has a good compatibility with the cationic antibacterial agent.