A conditioning film, the pellicle, of which many salivary proteins areimportant constituents, covers the surfaces present in the mouth. The pellicleforms in a selective adsorption process, and it has protective and lubricatingfunctions as well as an influence on the adherence of oral microbes thatultimately leads to the development of dental plaque. Understanding theinteractions responsible for the selective pellicle formation would make itpossible to strive at creating a pellicle that serves its protective and lubricatingfunctions and also promotes a healthy biofilm for the benefit of the individual.The aim of this research was to characterize the adsorption of salivaryproteins to different types of substrates, to evaluate the influence of differentprotein-surface interactions on the adsorption process, and also to assesssubstrate dependent differences in film composition. Furthermore, as it is wellknown that complexes form between different salivary proteins and mucins(large glycoproteins) in bulk saliva, the aim was also to study interactionsbetween mucins and other pellicle constituents at the solid/liquid interface.Additionally, the effects of a surfactant, sodium dodecyl sulphate (SDS), onthe protein films were investigated, to evaluate the stability of the films andalso the possibilities to completely remove the in vivo formed pellicle.The adsorption experiments were performed in vitro using nullellipsometry, by which parameters such as adsorbed amount per unit area andaverage layer thickness can be obtained. Hydrophilic and hydrophobized silicawere used as model substrates. The adsorption behaviour of the cationic,antimicrobial proteins lactoferrin, lactoperoxidase, lysozyme, and histatin 5indicated that the adsorption on hydrophilic substrates was mainly driven byelectrostatics, while on hydrophobized substrates hydrophobic interactionsalso influenced the adsorption process. Furthermore, it was shown that12sequential alternating adsorption of the anionic salivary mucin MUC5B andlactoperoxidase resulted in the build-up of multilayered structures on thesurface. The rate of build-up was influenced by the surface characteristics.Sequential adsorption studies showed that neither MUC5B nor human wholesaliva (HWS) was able to exchange substantial amounts of the pre-adsorbedanionic pellicle proteins acidic proline-rich protein 1 (PRP-1) or statherin,respectively. The resistance of the adsorbed mixed protein films to SDS elutiondepended on surface properties as well as on the number of layers adsorbedand adsorbed components. Pre-adsorbed PRP-1 was to some extent protectedfrom SDS elution by the sequential adsorption of MUC5B to the PRP-1 film.Pellicles formed on natural tooth enamel were collected in vivo andinvestigated using two-dimensional gel electrophoresis (2-DE). MechanicallyassistedSDS elution was used to collect the in vivo formed pellicle. Theeffectiveness of the collection procedure was validated in vitro by means ofmechanical removal in combination with HCl treatment. The results indicatedthat rubbing the tooth surfaces with fibre pellets soaked in 0.5 % (w/v) SDSwas sufficient to completely remove the pellicle from human enamel. Inaddition, 2-DE analysis of pellicles formed in vitro on human enamel and thedental materials titanium and poly (methyl methacrylate) (PMMA) showeddifferences in composition when compared to each other, revealing that thepellicle is influenced by the substrate properties.