The aim of the modern dental medicine is not only to preserve oral health: it is also to keep the oral cavity free from metals and metal alloys which may for instance cause allergies. The solution is an all-ceramic dental prosthesis. Due to today's ceramic mixture and materials it is not only "biologically neutral", but it also has the same physical properties as the natural dental enamel. Because of that, thermal stimuli as for instance in case of amalgam fillings or gold crowns can be ruled out as well. Another advantage offers the aesthetic which is no less important and guaranteed by all-ceramic (see also Aesthetic dentistry).