Synopsis
Interest in esthetics has increased in recent years, and demand for tooth coloration treatments is increasing. Since proteolytic enzymes, such as papain (papaya proteinase I), have been used in toothpastes to prevent tooth discoloration, this study investigated the mechanism by which papain prevents tooth discoloration. Various concentrations of papain (0.005, 0.05, and 0.5 mg/mL) were added to saliva, salivary proteins were subjected to electrophoresis, and changes in protein properties were examined by Coomassie Brilliant Blue staining. In addition, saliva specimens containing hydroxyapatite (HA) powder were mixed with papain (0.5 mg/mL) to examine changes in the proteins adsorbed onto HA. As a result, papain was found to degrade salivary proteins in a concentration-dependent manner. Papain also degraded salivary proteins that had adsorbed onto HA. Treatment with papain suppressed discoloration by decomposing the pellicles on tooth surfaces.
Key words: papain, saliva protein, hydroxyapatite
