ORMOCER's, inorganic-organic polymer materials for applications in micro systems technology

Due to the unesthetic appearance, the toxicologigal problems of mercury and the galvanic corrision there is a need for a posterior dental filling material which is able to substitute the amalgam fillings. To provide such materials mulifunktional urethane- and thioether oligo (meth)acrylate alkoxysilanes as sol-gel precursors have been used for preparation of a special family of inorganic/organic copolymer composites (ORMOCER s) on a molecular scale.The alkoysilyl groups of the silane allow the formation of inorganic Si-O-Si-network by hydrolysis and polycondensation reactions. In order to achieve X-ray-opacity higher than that of dental enamel silicon can partly be replaced by heavier elements,e.g. zirconium. After incorporation of special dental glass fillers the resulting paste-like composite can be applied by the dentist. Beside the UV- and thermally induced polymersation a light- and redox-induced curing is also possible to build up the additional organic polymer structure. Toxicol ogical problems are not exspected because of the usage of silane-connected acrylates and methacrylates and therefore the linkage to the inorganic polymer structure.