X-rays are a form of energy that can travel through or be absorbed by solid objects. This energy is absorbed by dense objects, such as teeth and bones, and show up in X-rays as light-colored areas. X-rays pass through less dense objects, such as gums and cheeks, and appear as dark areas on X-ray film.

X-rays help us see the condition of your teeth, roots, jaw placement and facial bone composition. They also help us find and treat dental problems early in their development.

X-rays can help find problems that cannot be seen with an oral exam. Finding and treating problems early in their development may save you money, avoid discomfort (if these problems are treated at a later time) and possibly even save your life.

X-rays help us diagnose problems in your teeth and jaws.

In adults, X-rays show:

• Decay, especially small areas of decay between teeth.
• Decay beneath existing fillings.
• Bone loss in the jaw.
• Changes in the bone or root canal due to infection.
• Condition and position of teeth to help prepare for tooth implants, braces, dentures or other dental procedures.
• Abscesses (an infection at the root of a tooth or between the gum and a tooth).
• Cysts and some types of tumors.

In children, X-rays determine:

• If decay is developing.
• If there is enough space in the mouth to fit all incoming teeth.
• If wisdom teeth are developing.
• If teeth are impacted (unable to emerge through the gums).

How often X-rays need to be taken depends on your medical and dental history and current condition. Some people may need X-rays as often as every six months. Others who don’t have recent dental or gum disease and who have ongoing scheduled visits with their dentist may only need X-rays every couple of years. New patients may have X-rays taken at their first exam. First-visit X-rays are also used to compare with X-rays taken over time to look for problems and unexpected changes. X-rays may need to be taken more often in people at high risk for dental problems. These people include:

• Children: Children generally need more X-rays than adults because their teeth and jaws are still developing and because their teeth are more likely to be affected by tooth decay than adults.
• Adults with a lot of restorative work, such as fillings: To look for decay beneath existing fillings or in new locations.
• People who drink a lot of sugary beverages: To look for tooth decay.
• People with periodontal (gum) disease: To monitor bone loss.
• People who have dry mouth: Whether due to medications (such as antidepressants, antianxiety drugs, antihistamines and others) or health conditions (such as Sjogren’s syndrome, damaged salivary glands, radiation treatment to head and neck). Dry mouth conditions cause decay.
• Smokers: To monitor bone loss that results from gum disease (smokers are at increased risk of gum disease).

The amount of radiation emitted from X-rays is extremely small. Advances in dentistry — such as X-ray machines that limit the radiation beam to a small area; high-speed X-rays; use of lead-lined, full-body aprons; and federal laws that require accuracy and safety checks for X-ray machines — are a few of the improvements that limit the amount of radiation patients receive. Despite the safety of X-rays, some questions to ask your dentist include:

• Was there something you found in your clinical exam that you feel needs to be further examined with an X-ray?
• How will these X-rays help guide the treatment plan you have in mind for me?