Dental X-Rays: Why They're Taken, How Often, and Questions to Ask

Much of what matters in dental health happens where no one can see it: between teeth that touch, beneath existing fillings and crowns, inside the root, and in the bone that holds teeth in place. Dental X-rays, also called radiographs, let a clinician look at these areas. They are a routine part of dental care, yet many people are unsure why they are taken, how often they are needed, or whether they can say no. This guide explains the basics so you can ask informed questions.

It is general educational information, not individualized advice. The decision to take any image belongs to a licensed dentist who has examined you and knows your history.

Common types and what each shows

• Bitewings show the crowns of upper and lower back teeth together. They are especially useful for finding decay between teeth and checking bone levels.
• Periapicals show one or a few teeth from crown to root tip and the surrounding bone. They help evaluate a painful tooth, infection, or a root.
• Panoramic images show both jaws, all teeth, and surrounding structures in one wide picture. They are useful for wisdom teeth, jaw development, and broad overviews, but show less fine detail than bitewings.
• Cone-beam CT (CBCT) produces three-dimensional images. It may be used for implant planning, complex root anatomy, or specific surgical questions. The FDA notes that CBCT generally involves more radiation than conventional dental X-rays and should be used when its added information is needed.

What X-rays can find that an exam cannot

Early decay between teeth, decay under restorations, bone loss from gum disease, infections at root tips, impacted or missing teeth, cysts, and some other abnormalities may be invisible or only suspected during a visual examination. Finding problems earlier can mean simpler options. At the same time, an X-ray is one piece of information. It is interpreted alongside symptoms, the visual exam, and history, and some findings call for monitoring rather than immediate treatment.

Why frequency should be individualized

The American Dental Association supports taking radiographs based on a person's individual needs rather than on a fixed schedule for everyone. Someone with frequent new cavities, active gum disease, or many restorations may reasonably need images more often than someone with a long history of stable, healthy teeth. Children's needs change as teeth erupt. A new patient may need a baseline set, but previous images from another office can sometimes be requested to avoid repeating them.

A practical example: an adult with no new cavities in many years and stable gums may be advised that bitewings are due less often, while a teenager with several recent cavities may be advised to have them sooner. Both recommendations can be appropriate because the risks differ.

What is known about radiation dose

Dental X-rays use low doses of radiation, and modern digital sensors and fast film reduce exposure further. A set of bitewings is generally a small fraction of the radiation people receive from natural background sources over a year. Still, the guiding principle in dentistry and medicine is to keep exposure as low as reasonably achievable: take images when they will affect care, use the type that answers the question, and avoid unnecessary repeats. Lead or lead-equivalent aprons and thyroid collars have been standard; current ADA guidance has reassessed routine use of some shielding as modern equipment improves, so practices may differ. It is reasonable to ask what your office does and why.

Pregnancy and other special situations

Tell the dental team if you are or may be pregnant. Routine images are often postponed, while images needed to diagnose a problem such as an infection may still be appropriate, because untreated dental disease also carries risk. The decision should be made with the clinician, and with your obstetric provider if you prefer. Mention any previous head and neck radiation therapy and any recent imaging done elsewhere.

Can you decline?

You can ask questions and decline any procedure. It helps to understand the trade-off: without images, some problems may not be detected until they are larger, and a dentist may be limited in what they can responsibly diagnose or treat. A useful conversation focuses on what the image is expected to show and what would happen if it were delayed.

Questions to ask

• What type of image is this, and what are you looking for?
• How would the result change my care?
• Given my history, how often do I actually need this?
• Can you use images from my previous dentist instead?
• If a CBCT is suggested, what will it show that a standard X-ray cannot?
• Can I see the image and have the findings explained?

Related reading

See What Actually Happens at a Cleaning, When a Dental Crown Needs Replacement, and Questions to Ask Before Starting a Dental Treatment Plan, or browse the Preventive Dentistry learning center.

Source notes

ADA: X-Rays/Radiographs discusses types of dental images, individualized frequency, and dose principles. FDA: Dental Cone-Beam Computed Tomography explains CBCT uses and radiation considerations. This article paraphrases general guidance in original wording.

This article provides general educational information, not individualized advice, a diagnosis, or clinical services. Please consult a currently licensed dentist about your imaging needs.