Most medical or dental procedures have risks as well as benefits associated with them, and dental CT scanning is no exception. The very real benefit is that the implant procedure can be planned in detail on the computer before any surgery takes place. This helps both the surgeon and the patient by shortening the operating time and avoiding complications such as damage to sensitive structures such as nerves.

The Effective Dose from a well-conducted dental CT scan should be no more than 0.5 mSv per jaw and in fact is less than 0.3 mSv per jaw on the most modern CT equipment. This is a small fraction of the dose that everyone receives annually from natural sources (background radiation in the U.K. is about 2.2 mSv per year). In other words, the dose from a single-jaw dental CT scan is about the same as the dose the patient would receive anyway, from background radiation, over the next few months.

Harmful effects from doses as low as 0.3 mSv have never been observed in humans. There is however a very small hypothetical risk - approximately 1 in 65,000 - that the patient might develop a fatal cancer later in life as a consequence of the dental CT scan. This has never been observed in practice and is based entirely on theoretical calculations. However, to be on the safe side, radiation doses should always be kept "As Low As Reasonably Achievable" (ALARA).

To put this in perspective, the risk from smoking 20 cigarettes is also approximately 1 in 65,000 - that's 20 cigarettes in total, not 20 cigarettes a day!

For further information on radiation safety please visit the Health Protection Agency (Radiation Protection Division).