Radiography

Radiography is the use of X-rays to obtain informaton about the patient's teeth and bones.

In dentistry, it is common to take 'bitewing' radiographs which show the upper and lower teeth on the same film and so reduce the number of X-rays the person has. These are used to check for dental decay and the loss of bone support caused by gum disease. Depending on the previous dental history, they may be taken at intervals as short as six-monthly or only every 2-3 years.

Another type of X-ray called a 'periapical' is used to look at the full length of a tooth when it it needs root filling or extraction.

The dentist will place a film in a holder and ask the patient to bite on it while aligning the X-ray tube and exposing the film. The dentist and nurse will stand outside the room while the exposure is taken. Some patients worry that the radiation involved is harmful to them but each exposure delivers a very low dose. It is permitted these days to take dental X-rays for pregnant women as the X-ray beam does not pass through the woman's womb and the dose to a baby inside is so low that it cannot be measured.

For example, 140 dental X-rays give the same radiation dose as flight to New York and 4 films are equivalent to a day in Cornwall (where background radiation is 3 times higher than the UK average).