The Salivary Pellicle

Besides saliva, another key biological factor that can influence the progression of dental erosion is the pellicle. The salivary, or acquired, pellicle is a protein-based layer that covers all orally exposed surfaces of the teeth. Although this pellicle film can be modified somewhat through brushing, the pellicle film is essentially never removed from the teeth, with the exception of during a dental prophylaxis (prophy). During a prophy, the abrasiveness of prophy pastes is sufficiently high to enable the complete removal of this film from the tooth surface, exposing the natural enamel surface. The reason for removing the pellicle during the prophy is to allow for the complete removal of extrinsic stains from the tooth surface. While chemical cleaning agents like peroxide are able to bleach stains from an intact pellicle, prophy pastes actually remove the pellicle. In order to restore its natural level of protection, the saliva generates a new, fresh pellicle within just a few short hours. Though thin in absolute terms, the pellicle provides protection to the tooth surface against extrinsic acid damage.8,36,39

When acidic foods and beverages are taken in excess, the pellicle layer can be overwhelmed by either the sheer volume of dietary or gastric acids, the high titratable acidity of a particular beverage, or a complex combination of factors such as the mineral content of saliva.38 When this occurs, the surface enamel softens quickly, and even the fluoride rich outer enamel, which provides a measurable level of ‘second defense’ against cariogenic acids, cannot defend itself against a strong erosive acid challenge. The outer enamel becomes softened and susceptible to damage; due primarily to a multitude of potential “tooth wear” factors present in the mouth.14