( 5 ) COMPUTED TOMOGRAPHY or CT scanning, usually is performed in a hospital, not the dentist’s office, although a dentist may refer a patient for this test. With this process, the patient lies still in the CT machine while the X-ray beam rotates around. From the X-ray information, a computer creates a three-dimensional image of the interior structures. It is used to identify problems in the bones of the face, such as tumors or fractures.
SIALOGRAPHY is a way of visualizing the salivary glands on a radiograph. Soft tissues, like gums and salivary glands, can’t usually be seen on an X-ray because they are not dense enough to absorb enough X-rays to appear clearly on film. With sialography, the dentist injects a radiopaque contrast material directly into the salivary glands. This material shows up easily on film, allowing dentists to diagnose salivary gland problems, such as blockages or Sjögren’s disease.
The benefits of X-rays are well known: They help dentists diagnose relatively common disorders such as cavities, periodontal disease and infections. Without this ability to see inside a tooth and beneath the gums, more disease would go unchecked, patients would experience more pain and discomfort and more teeth would be lost because proper treatment couldn’t be started in time.
The X-rays used in dental and medical offices emit extremely small doses of radiation. However, cells can be damaged by many small doses that add up over time. That’s why experts recommend that X-rays be used with precautions and only when necessary.
Several changes made by dentists or required by regulatory agencies have reduced radiation exposure in dental X-rays through the years:
Lower X-ray dose — The single most important way dentists keep their patients safe from radiation is by limiting the X-ray beam to a small area and by reducing the amount of radiation that strays from that path. Although an X-ray machine looks quite large, the X-rays come out of a small cone that limits them to an area less than three inches in diameter. X-ray machines are well shielded and there is very little radiation exposure beyond the diameter of the beam.
Better film — The speed of films used for dental X-rays has been improved so less exposure is needed to get the same results.
Digital radiography — The use of digital X-rays reduces radiation by as much as 80%.
Film holders — Dental patients used to hold X-ray film in their mouths with their fingers. Those days are long gone. Now, holders keep the film in place.
Lead shields — Today, they offer more peace of mind than actual protection because stray radiation from modern dental X-ray machines is almost nonexistent.
Limited use of X-rays — Dentists take radiographs only when they believe they are necessary for an accurate dental assessment or diagnosis.
Current guidelines recommend that X-rays be given only when needed to diagnose a suspected problem..
EXPOSURE TO RADIATION
All health care providers are sensitive to patients’ concerns about exposure to radiation. Your dentist has been trained to prescribe radiographs when they are appropriate and to tailor radiographic schedules to each patient’s individual needs. By using state-of-the-art technology and by staying knowledgeable about recent advances, your dentist knows which techniques, procedures and X-ray films can minimize your exposure to radiation.
The ionizing radiation that you receive from one dental x-ray is substantially less that the radiation you receive every day from the sun and stars. Advances in technology have made dental x-rays safer. Doses of radiation are kept at the lowest practical value to minimize patient exposure. This is done with the use of a long cone position-indicating device, appropriate settings on the machine and using newer, high-speed film. Many times a radiograph is necessary to diagnose certain conditions; and therefore, the benefit outweighs the risk . It has been proven that x-rays have a minimal risk on a pregnant woman and her unborn baby. However, radiographs for pregnant women are only taken in an emergency situation.
DIGITAL x-rays are one of the newest X-ray techniques around. With digital radiographs, film is replaced with a flat electronic pad or sensor. The X-rays hit the pad the same way they hit the film. But instead of developing the film in a dark room, the image is electronically sent directly to a computer where the image appears on the screen. The image can then be stored on the computer or printed out. One of the great advantages of this process is that radiographs can be digitally compared to previous radiographs in a process called subtraction radiography. The computer can digitally compare the two images, subtract out everything that is the same and give a clear image of anything that is different. This means that tiny changes that may not be noticeable with the naked eye can be caught earlier and more clearly with digital-subtraction radiography. Subtraction radiography requires a specialized projection technique and additional software. At Dr. Khosla’s Dental Centre we have been using digital x-rays (SUNI RVG) for several years.