Clinical study of zirconium oxide bridges in lateral tooth region made with the DCM system

B. Sturzenegger, A. Fehrer, H. Lüthy, M. Schumacher, O. Loeffel, F. Filser, P. Kocher, L. Gauckler, P. Schärer

Dental therapies call for reconstructions of the highest aesthetic quality and biocompatibility. All-ceramic reconstructions make it possible to broadly meet these demands, from the inlay to the single crown and small anterior tooth bridge. With multi-unit bridges, the interdental connectors were the weak points. Based on independent lab tests, the high-performance ceramic ZrO2-TZP could also be suitable for multi-unit bridges in the lateral tooth region. 22 lateral tooth bridges with zirconium oxide framework (on 19 molars and 25 premolars) were made with the DCM process (direct ceramic machining; ETH Zurich) and clinically applied. All the bridges were loaded by antagonists. After an average observation period of 385 days (307 to 488 days), all 22 bridges were still intact. Neither cracks nor splitting could be observed. The patients were satisfied with the zirconium oxide reconstructions. In particular, they liked the low heat conductivity. A single endodontic problem that did occur could not be connected with the all-ceramic bridge frameworks. The promising results of this clinical study only apply to the dental restoration made with the DCM process. No clinical evidence can be inferred for zirconium oxide bridges made with other CAD/CAM systems.