One only has to view a skull to realise how much of the teeth and jaws is hidden from view. What shows inside the mouth is only the tip of the iceberg. The magic of X-rays is able to unlock the hidden area and show clearly what lies out of normal sight. It is little wonder that dentistry was one of the earliest users of X-rays and still finds them indispensable for accurate diagnosis of dental conditions.
Specially designed dental X-ray machines are much smaller and less powerful than medical X-ray machines, as they deal with a smaller and more confined portion of the body. The modern machines with their heavy shielding and highly accurate exposure control mechanisms, coupled with the new fast photographic films used, ensure the lowest possible dose of radiation. Generally speaking, the dangers of radiation from dental X-rays are quite negligible. This view needs to be modified if, for example, other sources of radiation have been absorbed as well, or during pregnancy when exposure to radiation is inappropriate.
Most dental X-rays are taken with a small film inside the mouth, and show either views of individual teeth (periapical X-rays), or views of the crowns of all the back teeth both upper and lower (bite-wing X-rays). Larger X-ray films can be placed outside the mouth. One such picture is a side view of the whole of the head used at times by orthodontists to predict bone growth in the face. Another external type of X-ray uses a machine which rotates around the head and has the effect of stretching out the jaws and teeth in a straight line on a long oblong film.
X-rays are superb for searching out hidden decay leading to tooth loss, discovering buried teeth and old roots, finding bone fractures, looking for bone cancers and other conditions such as cysts of the jaws, and checking on bone loss around otherwise healthy teeth.
There is no facet of dentistry that does not use X-rays at some stage to assist in diagnosis and treatment. Modern preventive and constructive dentistry is dependent on the skilful interpretation of X-ray pictures. A further use is in the identification of dead bodies when other methods fail.