2) Buffer capacity Saliva contains specific buffer mechanisms such as bicarbonates, phosphate and some protein systems The carbonic acid-bicarbonate buffer acts above all when the stimulated salivary flow rate rises The phosphate buffer plays an essential role when salivary flow is low Certain proteins such as histatins or sialin are important for controlling the pH of saliva Buffer mechanisms occur faster on the surfaces of teeth which are covered by thin layer of plaque, than on the interproximal surfaces