The sequestering agent tetrasodium pyrophosphate (TSPP) removes calcium and magnesium from the saliva, so they can't deposit on teeth as insoluble deposits called tartar, (calcified plaque). In this respect it acts as a water-softening agent. It won't remove tartar that already exists.
TSPP is slightly alkaline, and has a bitter taste, requiring additional flavorings to mask it. Also, additional detergents must be added to keep it in solution. All of these factors can irritate oral membranes and cause sensitivity.
Sodium bicarbonate: Na2(HCO3) is the predominate base.
it is weaker than the strong base NaOH