Dental scanner could cut X-ray threat

The new scanner gives detailed images of teeth

Researchers have developed a method of scanning teeth without using potentially harmful X-rays.

The Cambridge team's "tera-hertz" scanner can check on the condition and thickness of tooth enamel, but does not use traditional X-ray radiation, which can disrupt the structure of the body's cells.

But it could be five years before the experimental technique is ready for use in the dentist's surgery.

Dr Don Arnone, one of the research team, told the BBC: "Looking at things such as teeth, we can actually examine the enamel in detail.

Dr Don Arnone says the technique can give detailed images of teeth

"We can tell what the state of the enamel is, what the condition of the enamel is and can actually measure the thickness of the enamel on the tooth. We can look into the cavity of a person's tooth."

Dentist Jacinta Yeo said: "It seems fascinating, although it's early days yet.

"Because it seems to will do everything that an X-ray does and perhaps more, and the exposure will be less."

There has been widespread concern in dentistry about the amount of X-rays given to children from an early age.

The British Dental Association has issued guidance to dentists on the correct use of X-rays.

With very high levels of tooth decay in the under-fives, particularly in poorer areas, there is a real need for accurate images of teeth - but this is measured against the need to keep X-raying at a minimum.

Long term users at risk

X-rays work by passing through ordinary body tissues, but not through bones. An x-ray sensitive plate held on the other side of the body picks up the resulting pattern, allowing doctors or dentists to look at the structure of bone or tooth.

But x-rays can are thought to occasionally cause changes to the cells they pass through, although humans are only thought to be at risk when subjected to repeated higher doses of radiation over a long period.

The British Dental Association says that doses from well-conducted dental x-rays are very low, even in comparison with those used in medicine.

But their guidelines say that X-raying should only be used if likely to lead to a change in the treatment or outlook for the patient.

"There is no justification for routine panoramic (all round) screening of new patients," says the guidance.