[Trends in orthodontic biomaterials: metals and ceramics].

While the beginning of orthodontics was marked by an acute scarcity in materials, the modern clinician has to face a large array of devices made of metals, plastics, ceramics and combinations thereof. Each of these materials have been developed for other purposes than orthodontics, and then transplanted "as is" in a field which has its own demands. During the years, theses devices, as well as the materials these are made of, have been modified most of time to the benefit of both the patient and the clinician, and some time to that of the manufacturer who has tried to save, or bypass limiting patients. Among the latter are the harder, but less corrosion resistant steels, the efficient but corrosion prone brazing, the inexpensive but weaker molded attachments, the aesthetic but fragile ceramics. Understanding the trends and basics of materials science should help the clinician to avoid being sued iatrogenic inflicted affections.