The benefits of X-rays are well known: They help dentists diagnose common problems such as cavities, gum disease and some types of infections. X-rays allow dentists to see inside a tooth and beneath the gums. Without them, more disease would go unchecked. Treatment would begin later. As a result, people would have more pain and lose more teeth.

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 say that X-rays should be used with caution and only when necessary.

Several changes 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 dose. An X-ray machine is quite large, but the X-rays come out of a small cone. This limits the rays to an area less than three inches in diameter. X-ray machines also are well shielded. Very little radiation exposure occurs beyond the diameter of the beam.
• Better film — The speed of films used for dental X-rays has been improved. This means that 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.
• Regular inspections and licensing — State local health departments regularly check X-ray machines to make sure they are accurate and safe.
• Lead shields — Before you get X-rays, you will be covered from the neck to the knees with a lead-lined full-body apron. Sometimes you'll also have a separate neck protector. These shields have been used for decades, and many states require them. Today, however, they offer more peace of mind than actual protection. That's because modern dental X-ray machines emit almost no stray radiation.
• Limited use of X-rays — Dentists take X-rays only when they believe they are necessary for an accurate dental assessment or diagnosis.

Current guidelines say X-rays should be given only when needed to diagnose a suspected problem. As a patient, you can help increase X-ray safety. Talk to your dentist about how often you or your children need X-rays and why.