Dental X-rays Explained: Types, Frequency and Safety

X-rays let your dentist see what is hidden inside and between your teeth, under the gums and in the jawbone. Much of what matters for your long-term dental health, such as early decay between back teeth, infection at the tip of a root or bone loss from gum disease, simply cannot be spotted by looking. This guide explains the main types of dental X-rays, how dentists decide when to take them, and what to know about safety.

What X-rays can show that eyes cannot

X-rays pass through soft tissue more easily than through dense structures like enamel, dentin and bone. On the image, dense areas look light and less dense areas look dark. That contrast lets a dentist see:

• Cavities between teeth and under existing fillings.
• Bone loss around teeth, a key sign of gum disease.
• Infections or cysts at the ends of roots.
• Teeth that have not come in, including wisdom teeth, and their position.
• The fit of crowns, fillings and root canal treatments.
• Developing adult teeth in children.

The main types of dental X-ray

Most offices now use digital sensors rather than film. The sensor is a flat plate placed in your mouth, connected to a computer. Images appear on screen within seconds, which makes it easy for the dentist to show you what they see. Ask them to; seeing your own X-rays is one of the best ways to understand a diagnosis.

How often are X-rays taken?

There is no fixed schedule for everyone. Professional guidance in the United States, developed by the American Dental Association together with the FDA, recommends that dentists decide on X-rays for each patient based on their age, history, symptoms and risk. In practice:

• A new patient often has a set of X-rays to create a baseline, unless recent images can be transferred from a previous dentist.
• People at higher risk of cavities, such as those with frequent new decay, dry mouth or lots of existing fillings, may have bitewings more often.
• People with healthy mouths and a low risk history may go longer between bitewings.
• Symptoms such as pain or swelling usually call for a targeted image of the problem area.

If you are unsure why an X-ray is being taken, ask. A good answer will connect the image to a specific question the dentist is trying to answer.

What about radiation?

Dental X-rays use a small amount of radiation, and digital sensors generally need less than traditional film. Still, the guiding principle in health care is to keep radiation exposure "as low as reasonably achievable": take the images that will change decisions, and avoid those that will not. That is why dentists tailor frequency to risk.

Many offices use a lead or lead-equivalent apron and a thyroid collar. Recommendations on shielding have been evolving because modern equipment focuses the beam tightly, and some professional bodies have concluded that routine patient shielding is not necessary. Practices differ, so if you would feel more comfortable with a thyroid collar or apron, simply ask.

X-rays during pregnancy

Tell your dentist if you are pregnant or might be. Routine X-rays are often postponed until after pregnancy. However, when a dental problem needs diagnosing and treating, such as a painful infection, dental X-rays of the mouth are generally considered acceptable during pregnancy, because the dose is small and directed away from the abdomen. Untreated dental infections carry their own risks. Your dentist can talk through the benefits and precautions with you, and can coordinate with your obstetric provider if needed.

What having an X-ray feels like

Your X-rays belong in your care, wherever you go

If you change dentists, ask your previous office to send your most recent X-rays to the new practice. This helps avoid repeat images and gives the new dentist a baseline for comparison, which is valuable when tracking slowly changing conditions like bone loss or a small cavity that is being monitored. Offices can usually send digital images electronically.