This study is aimed towards the appreciation of the structure-activity relationships of polymeric materials with regard to their capability to form coatings that inhibit common oral diseases, and addresses the need for new actives and technologies for improved dental care. Potential tooth-coating materials, including a series of poly(alkyl methacrylate)s, have been selected and evaluated for their capacity to resist acid demineralisation, to inhibit staining and to prevent the pain associated with dentine hypersensitivity. Systematic variation of the length of the pendent alkyl chain (from ethyl to octadecyl) has shown that a poly(butyl methacrylate) forms films of good quality on dentally relevant substrates. The data have indicated that the glass transition temperature of the material is the single most important factor determining film quality. To facilitate formulation in dental care products, miniemulsion methods have been used to suspend this polymer into an aqueous medium as highly stable nanoparticles with an average diameter of less than 100 nm. The integrity of the coatings prepared from these nanoparticles has been assessed using microscopic imaging techniques and has been tested in challenges designed to mimic those imposed by the oral environment. Poly(butyl methacrylate) films have been shown to provide a substantive coating that inhibits acid demineralisation and staining, and prevents dentine hypersensitivity.