Why Dental X-Rays Are Necessary

You are probably familiar with dental X-rays from your trips to the dentist over the years. But what is the purpose of these X-rays, and why do we need them? Dentists use dental X-rays (radiographs) to diagnose dental disease or damage that is not visible on a clinical oral examination. These X-rays indicate recommendations for treatment that your dentist may or may not make.

Learn more about dental X-rays, how they work, what they detect, and the risks associated with them.

How X-Rays Work

During your dental X-ray, a small amount of electromagnetic radiation is used to create an X-ray image of your teeth, roots, gums, jaw, and facial bones.

Like other forms of X-rays, dental radiographs work by sending a type of energy that is absorbed by solid objects but passes through less dense tissues, like your skin. The solid objects (teeth and bones) absorb the energy and appear lighter on the X-ray image. This gives your dentist an internal view of your oral health.

What They Detect

Dental X-rays can detect various abnormalities in your oral health, including early detection of dental issues that weren't found on a visual oral exam. This is useful, as your dentist can recommend certain treatments (for example, braces, implants, or wisdom teeth removal) based on your results.

Some of the things your dentist will examine in your dental X-rays include:

• Position, size, and number of teeth
• Changes in the root canal
• Bone loss in the jaw or facial bones
• Bone fractures
• Tooth decay, including between teeth or under fillings
• Abscesses and cysts
• Impaction of teeth
• How the upper and lower teeth fit together

In children and young adults, dentists also look for the presence (including number and size) of the teeth that have not yet grown in. This includes the adult teeth, wisdom teeth, or molars. They also look at the spacing within the jaw to determine how and if the adult teeth will fit when they grow in.

Types

Dentists use different types of dental X-rays to examine different aspects of your oral health. Some types are better suited than others for what your dentist is assessing.

The main types of dental X-rays include:

• Bitewing: Bitewing X-rays are used to look for cavities between teeth. You will bite down on a biting tab during this X-ray. The image displays the crown of your top and bottom teeth. These are typically taken every six to 12 months for children and six to 18 months for adults, although the American Dental Association has stated that they can be administered less frequently for some people.
• Periapical: The image displays the whole tooth, from the crown to the root. These are typically taken as a way for your dentist to examine specific teeth that are symptomatic (with root canal infection, for example) and can reveal abnormalities in the bone.
• Occlusal: This type of X-ray displays all the upper or lower teeth in one image. They are used less frequently than other types of dental X-rays, but can show issues in an arch of teeth, such as impactions or extra teeth.
• Panoramic: For this type of X-ray, you will likely stand or sit in a specialized machine that rotates around your head. The X-ray shows your jaw, upper set, and lower set of teeth all in one image. These are used most often in braces or surgery planning, and otherwise completed every three to five years.
• Cephalometric: This image shows the profile view of the face, and can identify issues with the airway or how the upper and lower jaw fit together. Orthodontists use cephalometric X-rays to better understand the jaw structure and relationships.
  

Risks

Radiation

Like other forms of X-rays, dental radiographs carry risk associated with radiation. When possible, digital imaging is now recommended by the American Dental Association (ADA) because it allows for lower radiation exposure than film-based imaging does.

The 2024 ADA guideline updates on radiation safety note that radiation exposure associated with dental X-rays is minimal, but it can be cumulative across a lifetime. The importance of these images in dental care is balanced with acceptable risk and protection measures.

During your dental X-ray, the technician may place a lead apron, and often a thyroid collar, on you. This protects your organs from minimal radiation they do not need to be exposed to. However, the ADA no longer recommends this intervention as necessary, especially because digital imaging options are available.

Dental professionals adhere to the "as low as reasonably achievable (ALARA)" principle when using X-rays and imaging in dentistry, including higher-dose cone beam computed tomography (CBCT). The ALARA principle has been in place since 1977.

Pregnancy

The current official position of both the American Dental Association and the American College of Obstetricians and Gynecologists (ACOG) is that dental X-rays during pregnancy are safe and, like all other dental X-rays, frequency should be determined on a case-by-case basis.

However, ACOG continues to recommend shielding of the abdomen and thyroid in pregnant people even though it may not be necessary in all populations. And the ADA recommends that dental professionals who are pregnant continue to wear protective gear when taking X-ray images in patients.

If you are pregnant, talk to your dentist about whether you should undergo dental X-rays. You will likely make a decision together based on the risks and benefits of your unique situation.

Meningioma and Thyroid Cancer

There is a large body of research examining the relationship between dental X-rays and meningioma (brain or spinal cord tumor) or thyroid cancer.

A 2019 systematic review and meta-analysis of previous studies found that exposure to multiple dental X-rays across the lifetime is associated with an increase in the risk of thyroid cancer and meningioma.

However, the study notes that the recent widespread adoption of thyroid collars during dental X-rays, study biases, and lack of evidence may influence the applicability of results. Still, the authors recommended reducing diagnostic radiation exposure as much as possible.

Summary

Dentists use different types of dental radiographs (X-rays) to identify oral damage or disease that they cannot view during a clinical examination. Using these X-rays, they can provide early diagnosis and recommend the most appropriate treatment. There are some risks associated with X-rays because of the radiation, but the benefits of identifying oral disease early outweigh the risk.

A Word From Verywell

Dental X-rays are an important part of keeping healthy. They are fast and painless, but if you do experience discomfort, you can ask your technician to make adjustments. If you have any concerns about the risks of dental X-rays, discuss it with your dentist. They can explain the reasons for and frequency of X-rays, as well as the steps they take to keep you safe and limit radiation exposure.