Sarah Bence, OTR/L, is an occupational therapist and freelance writer.

Edmund Khoo, DDS, is board-certified in orthodontics and is a Diplomate of the American Board of Orthodontics.

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.

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.

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.

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:

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.

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:

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.

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.

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.

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.

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.

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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American Dental Association. X-rays/radiographs.

U.S. Food and Drug Administration. The selection of patients for dental radiographic examinations.

Mark AM. Dental care during pregnancy. JADA. 2018;149(11). doi:10.1016/j.adaj.2018.09.006

Chauhan V, Wilkins RC. A comprehensive review of the literature on the biological effects from dental X-ray exposures. International Journal of Radiation Biology. 2019;95(2):107-119. doi:10.1080/09553002.2019.1547436

Memon A, Rogers I, Paudyal P, Sundin J. Dental x-rays and the risk of thyroid cancer and meningioma: a systematic review and meta-analysis of current epidemiological evidence. Thyroid. 2019;29(11):1572-1593. doi:10.1089/thy.2019.0105

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