The invention relates to lithium silicate glass ceramics and lithium silicate glasses which have a content in special oxides of hexavalent elements, which crystallize at low temperatures and which are particularly suitable as dental materials.Se describen cerámicas de vidrio de silicato de litio y vidrios que contienen óxidos específicos de elementos hexavalentes que se cristalizan a temperaturas bajas y son adecuados en particular como materiales dentales.