Why Dental X-Rays Are Necessary

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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.

Dentist examining x-ray on patient in dental clinic

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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.

Frequency of Dental X-rays

The U.S. Food and Drug Administration (FDA) and American Dental Association recommend that the frequency of dental X-rays should be decided on a case-by-case basis, based on the caries (tooth decay or cavity) risk assessment. Some people are more prone to tooth decay, and this will affect the dental X-ray frequency that a dentist recommends. Your caries risk also changes over time.

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: 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, and can reveal abnormalities in the bone or root.
  • 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.

Risks

Radiation

Like other forms of X-rays, dental radiographs carry risk associated with radiation.

However, according to the American Dental Association, radiation exposure associated with dental X-rays is minimal, compared with the average person's total exposure from natural and human-made sources in their daily life. It is actually riskier not to have recommended dental X-rays and potentially miss out on early diagnosis of dental disease or damage.

During your dental X-ray, the technician will 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.

Dentists also adhere to the "as low as reasonably achievable (ALARA)" principle, as set forth in the 1973 International Commission on Radiologic Protection. This ensures that X-ray exposure is justifiable and as low as reasonably achievable.

Pregnancy

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.

The evidence on dental X-ray safety for pregnant people is mixed. Some studies show an association between maternal dental X-rays and low birth weight, and other studies show no effect.

The current official position of both the American Dental Association and the American College of Obstetricians and Gynecologists 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.

The FDA recommends that pregnant operators of dental X-rays wear a personal dosimeter to monitor radiation exposure levels, in addition to their normal protection gear and barrier.

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 recent systematic review and meta-analysis, the highest form of research, found that exposure to multiple dental X-rays across the lifetime is associated with a small increase in the risk of thyroid cancer and meningioma.

However, the study notes that 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.

Frequently Asked Questions

  • How many dental X-rays are safe to go through in a day?

    There isn't an exact number of dental X-rays that are safe to have done in one day. Your dentist will follow the ALARA (as low as reasonably achievable) principles of justifying the need for X-rays, and reducing exposure to X-ray radiation.

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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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