SANGI first encountered hydroxyapatite when it acquired a patent from the US National Aeronautics and Space Administration ( NASA ) in the 1970s. NASA was looking for ways to compensate for the loss of minerals in astronauts ’ teeth and bones during weightlessness. It was proposed to use a precursor material – brushite – to create a new hydroxyapatite (tooth mineral). SANGI went a step further and proposed to deliver hydroxyapatite itself directly in toothpaste to restore tooth mineral with daily use.