Chapter 4: Metals

Metals are used in various branches of surgery, mainly orthopaedics. Most metals are not degradable, although the recently developed magnesium alloys are, and these are mentioned. The most important alloys used surgically are cobalt–chrome, stainless steel and titanium alloys (mainly Ti6Al4V) used in orthopaedics for components of artificial hips and knees. Titanium, which is the most biocompatible of the metals in bone contact, is also used in alloys for dental implants, where its ability to osseointegrate is crucial. Gold alloys are also used in dentistry and these are described. Also, for around 150 years silver amalgam has been the material of choice for dental fillings, but environmental problems with the mining and disposal of mercury have led to international agreement to discontinue this use. These topics are covered in full detail, together with information on surgical procedures, biological effects and treatment outcomes.