Sintered bodies containing zirconia-based ceramic materials and partially sintered bodies that are intermediates in the preparation of the sintered bodies are described. The zirconia-based ceramic material is doped with lanthanum and yttrium. The grain size of the zirconia-based ceramic material can be controlled by the addition of lanthanum. The crystalline phase of the zirconia-based ceramic material can be influenced by the addition of yttrium.