Development of ceramic dental crowns and bridges using electrophoretic deposition

In the dental branch much effort is undertaken for production of metal- free ceramic restoration. Because of esthetical aspects and their biocompatibility ceramics are the material of choice. Allergic reactions or toxic tissue damages can be prevented largely by application of ceramic dental products. Zirconia in its tetragonal yttria stabilized polycrystal form (TZP) and alumina toughened zirconia (ATZ) offer highest strength combined with highest toughness. Unfortunately this favourable, outstanding combination of mechanical properties leads to difficulties in conventional hard machining in the sintered state, which is too time- and cost-consuming. For this reason, electrophoretic deposition of alumina toughened zirconia powder and TZP powder was used for preparation of metal-free dental crowns and bridges. The electrophoretic deposition process was carried out directly onto the plaster moulds for single crowns, three-unit and four-unit bridges. The electrophoretic deposition process was investigated concerning the deposition rate and the output of dental crowns per volume of ethanolic ceramic suspension. Furthermore, the influence of the amount of dispersing agent on the rheological properties of the ceramic suspensions was investigated.