Saliva and Dental Pellicle-A Review

The acquired enamel pellicle is an organic film covering the surfaces of teeth. When this film was first discovered, it was thought to be of embryologic origin. Only in the middle of this century did it become clear that it was acquired after tooth eruption. Initially, the small amounts of material that could be obtained have virtually limited the investigation of pellicle proteins to amino acid analysis. Nevertheless, this technique revealed that the pellicle is mainly proteinaceous and is formed by selective adsorption of salivary proteins on tooth enamel. Later, immunologic techniques allowed for the identification of many salivary and fewer non-salivary proteins as constituents of pellicle. However, to this date, isolation and direct biochemical characterization of in vivo pellicle protein have not been possible, because only a few micrograms can be obtained from a single donor. Therefore, the composition and structure of the acquired enamel pellicle are still essentially unknown. Information on the functions of pellicle has been obtained mainly from in vitro experiments carried out with saliva-coated hydroxyapatite and enamel discs. It was found that pellicle protects enamel by reducing demineralization upon acid challenge. Improved pellicle harvesting procedures and analysis by state-of-the-art proteomics with mass spectroscopy approaches promise to make major inroads into the characterization of enamel pellicle.