Dental X-Rays: How Often You Need Them and What the Radiation Means

Why dentists take X-rays at all

Much of what matters in dentistry is hidden. Decay often begins between teeth where it cannot be seen, bone loss from gum disease happens below the gumline, and infections at the tips of roots may cause no symptoms for a long time. Dental radiographs make those areas visible so problems can be found while they are smaller and simpler to treat.

X-rays are a diagnostic tool, not a routine to be performed automatically. Current professional guidance emphasizes taking images when they are likely to change a decision, rather than on a fixed calendar for everyone.

The common types

Bitewings show the crowns of upper and lower back teeth together and are mainly used to find decay between teeth and check bone levels. Periapical films show a whole tooth from crown to root tip and help evaluate pain, infection, or a specific tooth.

A panoramic image wraps around the whole jaw in one picture, showing wisdom teeth, the jaw joints, and the sinuses in broad strokes; it is less detailed for small cavities. Cone-beam computed tomography (CBCT) produces a three-dimensional image and is typically reserved for specific needs such as implant planning, complex root canal anatomy, or evaluating impacted teeth.

How often is appropriate

Joint guidance from the American Dental Association and the U.S. Food and Drug Administration recommends tailoring imaging to each person. Factors include age, cavity history, gum health, existing restorations, symptoms, and whether you are a new patient whose history is unknown.

As a general pattern, adults with low cavity risk may need bitewings only every couple of years or longer, while people with frequent new decay may need them more often. Children often need them more frequently than adults because their teeth and risk change quickly. If you are unsure why an image is being recommended, it is reasonable to ask what the dentist expects to learn from it.

Putting the radiation in perspective

Dental X-rays use low doses. A set of digital bitewings is commonly estimated at a few microsieverts, which is roughly comparable to a day or less of the natural background radiation everyone receives from the environment. Panoramic images are somewhat higher, and CBCT scans vary widely depending on the machine and the field of view, from modest to considerably higher than standard dental films.

Low is not zero, which is why the guiding principle in radiology is ALARA: as low as reasonably achievable. That means taking images only when useful, using digital sensors and the smallest practical field, and using appropriate shielding techniques such as rectangular collimation.

Pregnancy, thyroid collars, and other common questions

Dental X-rays are aimed at the mouth, far from the abdomen, and guidance from major dental and obstetric organizations indicates that necessary dental imaging can be performed during pregnancy. Elective imaging is often postponed. Always tell the dental team if you are or might be pregnant.

Practices around lead aprons and thyroid collars have evolved. Some recent professional recommendations conclude that routine lead aprons are no longer necessary with modern equipment, while thyroid collars may still be used in certain situations, especially for children. If you prefer shielding, it is fine to ask.

Keeping copies and avoiding repeats

If you change dentists, you can usually request copies of recent X-rays to be sent to your new office. That may reduce the need to retake images, although a new dentist may still request additional views for a specific question.

Happy Smiles Dental is closed and no longer provides care; this article is general educational information. A licensed dentist who knows your history is best placed to decide which images, if any, you need.

Further reading

• U.S. FDA — Dental Radiographs: Benefits and Safety
• American Dental Association — Dental Radiographs: Benefits and Safety

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