Complete dental prostheses that are lighter, better fitting and more comfortable than traditional prostheses have been developed by a research team at King's College in London, UK, using an industrial process called superplastic forming. These new prostheses will allow patients much greater comfort but could also mean an end to problems associated with prosthesis fracture and wear.
Superplastic forming, traditionally used by industry as an effective way of making complex and highly structured parts, is allowing the team at King's College to make dental structures that are tailor made to fit a patient's mouth while providing better performance and improved comfort. The die used to produce a dental prosthesis in the superplastic forming process is based on a mould of the patient's mouth taken by the dentist. A stone model based on this mould is then duplicated in an "investment" material to produce a completed die which is inserted into the superplastic forming press and heated to 900 degrees Celsius over a period of 90 minutes. A disk of titanium is then inserted into the press, clamped above the die and 'blown' onto the die by Argon gas at pressures of up to 600 psi forming a completed superstructure in up to 3 hours.
Feedback from patients in Japan fitted with these new prostheses suggests that the new denture prostheses are much more comfortable, much lighter and better fitting than traditional prostheses. The new prostheses also allow better taste sensation from food substances and provide more extensive tongue space to allow a more distinctive pronunciation. Dentists are becoming aware of the other potential uses for titanium and the superplastic forming process because of the tremendous weight savings and improved functionality. The research team is looking to develop superplastic forming for even more biomedical devices. "As far as we[the research team] are aware, we are the only group looking at applications other than complete upper denture bases," says Richard Curtis, head of the research team. "Some of our plates are extremely complex and include forming over gold crowns and copings, over natural teeth and into areas where tumours have been removed or are the result of clefting."
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Notes For Editors
1. This item is due to appear as an article in the October 1999 issue of
Materials World. The article "Superplastic forming to get your teeth into" is
written by Richard Curtis. Ref: Materials World, Volume 7, Issue 10, page 607.
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