The protective nature of the salivary pellicle

All solid substrata exposed to the oral environment are rapidly covered by a layer of adsorbed salivary proteins, the acquired pellicle. The physiological role of the pellicle is lubrication and protection of the underlying surface. This review focuses on the protective properties of the salivary pellicle. Several in vitro as well as in vivo investigations indicate that the adsorbed protein layer on the one hand has the potential to reduce the extent of enamel demineralisation upon acid challenge. On the other hand pellicle could be dissolved and removed from the enamel surface due to the acid exposure. However, pellicle reformation starts rapidly. Conflicting data have been published concerning the importance of pellicle formation time ('maturation') with regard to its protective function. Recently published studies indicate that pellicle formation time is probably of less importance for the pellicle's protective properties under in vivo conditions than supposed from the in vitro experiments. Since pellicle formation is useful for the protection of the enamel surface, it should be also considered in daily oral hygiene. Tooth brushing with and without toothpaste causes reduction of the pellicle's thickness. However, the pellicle layer is not completely removed from the enamel surface after brushing procedures. Therefore the presence of a pellicle will be an important modifying factor when considering tooth wear models. In situ tooth wear models offer the opportunity to measure toothpaste abrasion effects in the presence of a pellicle film.