Our teeth enamel is in chemical interaction with our saliva. Lower pH favour the dissolution of the apatite (attacking the teeth), and higher pH favour its prec

Our teeth enamel is in chemical interaction with our saliva. Lower pH favour the dissolution of the apatite (attacking the teeth), and higher pH favour its precipitation (growing enamel). So it’s true that the components are in our saliva as well, in itself it is not enough to make it grow. These toothpastes change this by providing lots of the building blocks of apatite, saturating the saliva and promoting growth, but also by increasing the pH. It tends to decrease after a meal (or particularly after drinking sugary drinks, which tend to be awfully acidic), which is why it’s useful to have the toothpaste stabilising it.