Updated: Jan 22
Many procedures carried out routinely in dental diagnosis involve exposure to radiation. The total dose received depends on the number and type of procedures. The Radiological Protection Institute of Ireland (RPII) has created comparisons for common types of x-rays. Some well-known procedures include: dental X-ray (10 μSv); chest X-ray (20 μSv); mammography to identify breast cancer (500 μSv); CT scan (5400 μSv); angiocardiogram to determine heart function (6000 μSv).
All medical and dental exposures to radiation must be clinically justified and should only be carried out if recommended by a doctor or dentist. Dental x-rays should only be taken following a thorough clinical examination by your dentist.
Dental x-rays are an important tool for helping to see parts of the mouth which are not visible to the eye. They can help diagnose a number of different conditions such as decay between teeth and missing teeth in growing children. Dental x-rays are often necessary if you are having an extraction or a filling. They may be necessary to help diagnose and monitor injuries to the teeth. Dental x-rays are particularly important in children, because when decay starts in a baby tooth, it only takes a very short time for that decay to reach the nerve of the tooth. Once this happens pain and infection often follow. By picking up problems early on x-ray it may be possible to prevent unnecessary pain and suffering. But are there risks associated with radiation exposure?
Radiation is energy that is transmitted in the form of waves or particles. We encounter radiation constantly in our every day environment. It occurs naturally in the rocks and soil, in the food and water we eat and drink, and bombards the earth’s atmosphere from outer space. It is produced artificially, and widely used in medicine, dentistry industry and research. It is used in X-rays, in radiotherapy to treat cancers, in smoke detectors, and in many industrial processes. The production of electricity from nuclear power generates ionising radiation as a by-product.
The effects of ionising radiation on the human body depend on the quantities of ionising radiation received. In general, when ionising radiation enters the body it deposits some of its energy in human tissue typically by ionising atoms or possibly breaking the bonds of a molecule. These chemical changes may damage the tissue which may not be repaired properly. In time, the damaged tissue may become a cancer. The important thing to remember is how small the dose of radiation is and to balance that against the benefits of its use. The advent of digital x-rays has also significantly reduced the exposure to radiation from x-rays.
Parents sometimes worry about the risk from radiation associated with dental x-rays for children. The radiation dosage associated with a dental x-ray is the equivalent of 4-5 days of environmental radiation exposure. The risk from the radiation is very remote. In any case the use of dental x-rays must always be carefully justified to balance the risks and the benefits. For instance, for children who have a lot of risk factors for tooth decay such as not flossing, infrequent brushing or a history of decay in the past, dental x-rays would be indicated on a more frequent basis than for children with optimal oral health.
In preschool children whose back teeth are close together, taking x-rays can increase the chance of finding decay by up to 900%. I frequently see children where after drying the teeth and checking them I do not find decay. When the x-rays are taken, there can be as many as 8 decayed molars. It is important that parents are aware of the importance of dental x-rays for the detection of tooth decay in young children’s teeth.