Oral Health Topics
X-Rays
Overview
Dental X-ray examinations provide valuable information that helps your dentist evaluate your oral health. With the help of radiographs (the term for pictures taken with X-rays), your dentist can look at what is happening beneath the surface of your teeth and gums. If you have questions about your dental X-ray exam, talk with your dentist.
Frequently Asked Questions (FAQ)
- How do dental X-rays work?
- How often should radiographs be taken?
- What are the benefits of a dental radiograph examination?
- How do dental X-rays compare to other sources of radiation?
- What if I'm pregnant and need a dental radiograph examination?
How do dental X-rays work?
As X-rays pass through your mouth they are mostly absorbed by teeth and bone because these tissues, which are called hard tissues, are denser than cheeks and gums, which are called soft tissues. When X-rays strike the film or a digital sensor, an image called a radiograph is created. Radiographs allow your dentist to see hidden abnormalities, like tooth decay, infections and signs of gum disease, including changes in the bone and ligaments holding teeth in place
How often should radiographs be taken?
How often X-rays (radiographs) should be taken depends on your present oral health, your age, your risk for disease, and any signs and symptoms of oral disease you may be experiencing. For example, children may require X-rays more often than adults. This is because their teeth and jaws are still developing. Also their teeth are more likely to be affected by tooth decay than those of adults. Your dentist will review your history, examine your mouth and then decide whether or not you need radiographs.
If you are a new patient, the dentist may recommend radiographs to determine the present status of your oral health and to help identify changes that may occur later. A new set of X-rays may be needed to help your dentist detect any new cavities, determine the status of your gum health or evaluate the growth and development of your teeth. If a previous dentist has any radiographs of you, your new dentist may ask you for copies of them. Ask both dentists to help you with forwarding your X-rays.
What are the benefits of a dental radiograph examination?
Because many diseases of the teeth and surrounding tissues cannot be seen when your dentist examines your mouth, an X-ray examination can help reveal:
- small areas of decay between the teeth or below existing restorations (fillings);
- infections in the bone;
- periodontal (gum) disease;
- abscesses or cysts;
- developmental abnormalities;
- some types of tumors.
Finding and treating dental problems at an early stage can save time, money and unnecessary discomfort. Radiographs can help your dentist detect problems in your mouth that otherwise would not be seen.
How do dental X-rays compare to other sources of radiation?
The amount of radiation that we are exposed to from dental X-rays is very small compared to our daily exposure from things like, cosmic radiation and naturally-occurring radioactive elements (for example, those producing radon).
The table below compares our estimated exposure to radiation from dental X-ray with other various sources. As indicated below, a millisievert (mSv) is a unit of measure that allows for some comparison between radiation sources that expose the entire body (such as natural background radiation) and those that only expose a portion of the body (such as X-rays).
|
Source |
Estimated Exposure (mSv) |
|
Man Made Dental X-rays Bitewing radiographs |
0.038 |
|
Medical X-rays Lower gastrointestinal tract radiography |
4.060 |
|
Natural Cosmic (Outer Space) Radiation Average radiation from outer space In Denver, CO (per year) |
0.510 |
|
Earth and Atmospheric Radiation Average radiation in the U.S. from Natural sources (per year) |
3.000 |
Source: Adapted from Frederiksen NL. X-Rays: What is the Risk? Texas Dental Journal. 1995;112(2):68-72.
What if I'm pregnant and need a dental radiograph examination?
A radiograph may be needed for dental treatment that can’t wait until after the baby is born. Because untreated dental infections can pose a risk to the fetus, dental treatment may be necessary to maintain the health of the mother and child. Radiation exposure resulting from dental X-rays is low. However, every precaution is taken to ensure that radiation exposure is As Low As Reasonable Achievable (the ALARA principle). A leaded apron minimizes exposure to the abdomen and should be used when any dental radiograph is taken. Also, a leaded thyroid collar can protect the thyroid from radiation, and should also be used whenever possible. The use of a leaded thyroid collar is recommended for women of childbearing age, pregnant women and children. Dental X-ray exams do not need to be delayed if you are trying to become pregnant or are breast feeding.
Additional Resources
For more scientific information about radiation see:
- Radiation Answers sponsored by the Health Physics Society
- The EPA Ionizing Radiation Fact Book
- Radiation and Pregnancy: A Fact Sheet for the Public (Centers for Disease Control and Prevention)
- Radiation Exposure
- Radiation Safety Requirements
- Guide to Patient Selection for Dental Radiographs
- Additional Resources
Radiation Exposure
Radiation exposure associated with dentistry represents a minor contribution to the total exposure from all sources (about 0.2 percent). The National Council on Radiation Protection and Measurements (NCRP)[1] has estimated that the mean effective radiation dose equivalent from all sources in the United States is 3.6 millisieverts (mSv) per year, with about 3 mSv of this dose from natural sources and about 0.6 mSv from manmade sources. The majority of manmade radiation exposure is medical-related. It is estimated that dental X-rays contribute approximately one percent of the total dose of exposure in health care settings.[2]
Occupational exposure in dental settings is far lower than that in hospitals and medical offices. According to the NCRP, the total limit for occupational exposure is 50 mSv in one year. In addition, the lifetime occupational effective dose is limited to 10 mSv times the number of an individual’s age. The NCRP concludes that occupational exposure for dental personnel will not exceed these limits, excepting for problems associated with facility design, diagnostic equipment performance, or operating procedures. For pregnant dental personnel, the radiation exposure limit is 0.5 mSv per month.
Radiation Safety Requirements
State laws and regulations set specific requirements for the use of ionizing radiation (which includes X-rays). Contact the state radiation protection program to determine specific requirements for:
- Inspection and testing for the facility, X-ray machine, radiation monitoring equipment and radiograph processing equipment
- Permits or licensing
- Supervision of personnel
- Use of dosimetry badges
- Training or certification
- Dental office design and radiation shielding
- Record keeping
- Equipment
Radiographic training requirements for dental office personnel frequently differ from and are less rigorous than those of medical personnel who take X-ray. Training requirements for dental office personnel typically are found in state dental practice acts or dental board regulations.
Guide to Patient Selection for Dental Radiographs
The ADA, in collaboration with the FDA, developed guidelines for the prescription of dental radiographic examinations to serve as an adjunct to the dentist's professional judgment of how to best use diagnostic imaging. Radiographs can help the dental practitioner evaluate and definitively diagnose many oral diseases and conditions. However, the dentist must weigh the benefits of taking dental radiographs against the risk of exposing a patient to X-rays, the effects of which accumulate from multiple sources over time. The dentist, knowing the patient's health history and vulnerability to oral disease, is in the best position to make this judgment. For this reason, the guidelines are intended to serve as a resource for the practitioner and are not intended to be standards of care, nor requirements or regulations.
- The Selection of Patients for Dental Radiographic Examinations (PDF)
- Guidelines for Prescribing Dental Radiographs Chart (PDF)
Additional Resources
- The Use of Dental Radiographs: Update and Recommendations (PDF)
- Managing Silver and Lead Waste in a Dental Office (PDF)
- Directory of Dental Waste Recyclers (PDF)
- The Health Physics Society (Occupational and Environmental Radiation Safety)
- FDA - Dental Radiography: Doses and Film Speed
- Radiation and Pregnancy: A Fact Sheet for the Public ( Centers for Disease Control and Prevention)
