AVS 50th International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI-TuP

Paper BI-TuP5
The Topography and Viscoelastic Properties of Salivary Pellicle and Their Interaction with Tannins

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: M.E. Dickinson, Rutgers University
Authors: M.E. Dickinson, Rutgers University
A.B. Mann, Rutgers University
Correspondent: Click to Email
The acquired pellicle is an organic film formed by the adsorption of proteins and carbohydrates on dental enamel exposed to the oral environment. The pellicle is now understood to have several roles including lubrication and reduction of friction between teeth during mastication, as well as protection against acidic solutions. Using in vitro AFM, growth, structure and topology of pellicle grown in vivo on a clean enamel surface has been studied. Complete coverage of the enamel surface was found to occur within the first few minutes of exposure, with the layer increasing in thickness until a maximum is reached at around 2 hours. The thickness of the pellicle varies with position, but fully developed pellicle can range in thickness from 200-500nm. Tannins found in food can interact with pellicle to change its viscoelastic properties and alter the color which is a cause of extrinsic staining in teeth. Tannins are phenolic compounds capable of precipitating alkaloids, gelatin and other proteins, they are naturally found in many food stuffs especially leafy products such as tea. The topology of the pellicle surface, as studied using AFM and SEM, consists of a dense arrangement of adsorbed globular shaped proteins with no break in the structure, even when tannins are added. The viscoelastic properties of the pellicle have been studied using nanoscale dynamic mechanical analysis, this shows that substantial variations in the storage and loss modulus occur with increasing exposure to tannin containing solutions. These changes in viscoelasticity will impinge directly on the pellicle's performance as a lubricant and also its ability to act as a chemical barrier to acid attack.