When they are released in the oral cavity some forms of phosphate bind with the calcium ions in saliva, limiting the mineralisation of dental plaque.This slows down the formation of dental tartar.The tartar deposits in dogs and cats fed daily with kibbles coated in sodium phosphates are significantly lower than animals fed with the same diet without sodium phosphates.
Sodium phosphate salts are used in many human toothpastes to improve oral hygiene. In animals, phosphates must be incorporated in the coating of kibbles or in a chewing bar, to facilitate their release during mastication and promote their contact with the calcium in the saliva.
The calcium ions in saliva are liable to form calcium hydroxyapatite crystals, the mineral form of calcium used for the formation of tartar. Sodium phosphates have the capacity to chelate the calcium, significantly reducing tartar deposits on the teeth. The calcium phosphate complexes disassociate during digestion and the calcium and the phosphorus are released into the digestive tract where they are absorbed in accordance with the needs of the animal.
Sodium phosphates are a family of mineral salts comprising more than 150 different substances (orthophosphate, pyrophosphate, polyphosphate, metaphosphate).