Characterization of saliva proteins from 'stainers' and 'non-stainers' adsorbed to hydroxyapatite.

Stainers and non-stainers were selected on the basis of their individual tendency to develop extrinsic tooth discolorations from a chlorhexidine mouth rinse. Saliva proteins adsorbed to hydroxyapatite in vitro and in vivo pellicle from the participants were analyzed by gel filtration and ion-exchange chromatography. Two distinct anionic components were isolated. The elution patterns from stainers and non-stainers were identical. Amino acid analyses of the main peaks demonstrated a prevalence of serine, glycine, and glutamic acid.