Pioneering dental research started in Sweden in the 1960s is now helping to rehabilitate patients who have lost limbs or part of their face.
Per-Ingvar Branemark, head of the institute of applied biotechnology and professor of anatomy at Gothenburg University, developed a system of dental implants after discovering that titanium, a remarkably corrosion-resistant metal, was accepted by the body, and that through careful surgical technique, bone tissue could grow together with the titanium surface.
Traditional dental bridges attached to neighbouring healthy teeth can damage these teeth, but Professor Branemark devised the osseointegration method, putting a titanium fixture in jawbone tissue. The metal and bone heal together over several months, and then a small titanium screw is added, allowing the new teeth to be attached.
Speaking yesterday at Imperial College, London, Professor Branemark, who has been appointed Glaxo European visiting professor by the Royal Society of Medicine, described how osseointegration is now allowing reconstructive surgery which was previously impossible.
Over the past 15 years, Gothenburg has pioneered a range of head and facial reconstructions for people disfigured by accidents, birth defects, cancer and other illnesses.
As well as using titanium implants for replacement spare parts, such as eyes, noses and ears, Professor Branemark has used them to attach bone conduction hearing aids, which provide a path to the inner ear, past damaged middle ear bones.
Until now, hearing aids have had to be pressed into the skin behind the ear, which can lead to pressure sores and headaches.
Titanium is not as strong as materials such as stainless steel, but it is still ten times stronger than bone, and has been used to replace amputated arms and legs in several pilot projects.
Some three years on, there have not been any problems with the osseointegrated implants bearing the patients' entire body weight.
Professor Branemark believes that even if there is a slight loss of titanium oxide molecules, the implants will probably retain their strength indefinitely.
So far, there have been no cases of the implants causing allergies or tumour growth.