Abstract: The present invention is based on the discovery that when a tooth primordium is inserted into a mammalian jaw and tooth formation follows, new alveolar bone around the new tooth forms. The present invention is based on the idea of stimulating new tooth formation via the implantation of tooth primordia at selected places in the jaw (e.g. at four points in the molar regions) to result in the formation of bony protuberances which could facilitate denture retention. The teeth may then be removed from the jaw of the patient to leave the new alveolar bone.

Abstract: New materials having improved biocompatibility have novel zwitterionic groups at the surface. The zwitterion is characterized by having at least one monovalent substituent at the atom carrying the cationic charge which is an aryl group. Preferably the atom carries at least two, and preferably three such aryl, usually phenyl, groups. The cationic group is preferably a triphenylphosphonium. Treatment of surfaces to provide pendant zwitterionic groups of the specified type have reduced platelet activation, whilst they do not appear to reduce platelet adhesion. The invention has utility in the field of blood contacting device, especially devices for implantation, such as vascular grafts.