X-Rays/Radiographs

Dentists use X-rays to help diagnose damage and disease that is not visible during a clinical dental examination. How often X-rays, or radiographs, should be taken depends on specific factors such as an individual’s current oral health, age, risk for disease and any signs or symptoms of oral disease. This means that there is no “one size fits all” when it comes to the interval between dental X-rays. The “ALARA” principle, a phrase coined 1973 by the International Commission on Radiologic Protection that stands for “As Low as Reasonably Achievable,” means taking precautions¹ to help ensure that:

• all X-ray exposures are justified in relation to their benefits;
• necessary exposures are kept as low as reasonably achievable (i.e., ALARA); and
• the doses received by patients and personnel are kept well below the allowable limits.

The ADA encourages dentists and patients to discuss dental treatment recommendations, including the need for X-rays, in order to make informed decisions together.

The ADA, in collaboration with the U.S. Food and Drug Administration (FDA), developed recommendations for dental radiographic examinations to serve as an adjunct to the dentist’s professional judgment of how to best use diagnostic imaging.² Radiographs can help the dentist 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 recommendations are intended to serve as a resource for the practitioner and are not intended to be standards of care, nor requirements or regulations.

Radiation dosage is expressed as effective dose, a term applied to the weighted sum of doses to tissues that are sensitive to radiation. This number is derived by calculation. Effective dose as a unit of measurement was devised by the International Commission on Radiological Protection in 1990, and the method of calculation was updated in 2007.³ Effective radiation doses for dental radiographic examinations are listed in Table 1.

Table 1. Effective Dose Exposures from Medical Examinations and Procedures^{3, 4}

Abbreviations: CBCT: cone-beam computed tomography; PSP: photo-stimulable phosphor

Radiation exposure associated with dentistry represents a minor contribution to the total exposure from all sources. The National Council on Radiation Protection and Measurements (NCRP) has estimated that the mean effective radiation dose from all sources in the U.S. is 6.2 millisieverts (mSv) per year, with about half of this dose (i.e., 3.1 mSv) from natural sources (e.g., soil, radon) and about 3.1 mSv from man-made sources.⁵ About half of the man-made radiation exposure is related to computed tomographic (CT) scanning. Dental radiographs account for approximately 2.1 to 2.5 percent of the effective dose received from medical radiographs and fluoroscopies (see Table 2).^{6, 7}

Table 2. Effective Dose Exposures from Medical Examinations and Procedures^7-9

The ADA has joined with more than 80 other health care organizations to promote Image Gently, an initiative to “child size” radiographic examination of children in medicine and dentistry.¹⁰ Providers are urged to:

• select X-rays for individual needs, not as a routine;
• use the fastest image receptor available;
• use cone-beam CT (CBCT) only when necessary;
• collimate the beam to the area of interest;
• always use a thyroid collar/shield;
• “child-size” the exposure time.¹¹

Similar to Image Gently, Image Wisely, is a program to limit X-ray exposure in adults to only that which is needed.

State laws and regulations set specific requirements for the use of ionizing radiation, including X-rays. The radiation protection program in your state may provide 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 for medical personnel who take medical X-rays. Training requirements for dental office personnel typically are found in state dental practice acts or dental board regulations. The risk of occupational exposure in dental settings is far lower than that in hospitals and medical offices. According to the NCRP,⁵ the occupational exposure limit is 50 mSv in one year, although, 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 shall 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 (see following section).⁶

The ADA recommends the use of dosimeters and work practice controls for pregnant dental staff who work with X-rays.²  Studies of pregnant patients receiving dental care have affirmed the safety of dental treatment.^{12, 13} The American College of Obstetricians and Gynecologists Committee on Health Care for Underserved Women reaffirmed its committee opinion in 2017: “Patients often need reassurance that prevention, diagnosis, and treatment of oral conditions, including dental X-rays (with shielding of the abdomen and thyroid) … [is] safe during pregnancy.”¹⁴

The digital era of dental radiography began in 1988 with RVG – radio/visio/graphy.¹⁵ The first film-like sensor was introduced in 1994. In addition to a reduction in exposure, digital radiography enables efficient communication of electronic information, provides portability,¹⁶ and eliminates the environmental burden of silver and chemicals used to develop X-rays.  One of the concerns associated with digital radiography is that in an effort to diminish the appearance of image “noise,” the individual taking the radiograph may increase the dose of X-ray exposure.  Sometimes termed “exposure creep,” manufacturers are building tools into equipment to provide methods other than increasing dose to improve detector sensitivity.¹⁷

Cone-beam computed tomography (CBCT), introduced in the U.S. in 2001, produces a three-dimensional image of maxillofacial structures, with uses in oral surgery, orthodontics, and endodontics. The scanner rotates around the patient’s head producing up to 600 images, which are assembled or reconstructed by scanning software.  Analogous to a 2-D image comprised of pixels, CBCT creates a 3-D image comprised of voxels. A drawback of CBCT imaging is the radiation exposure it requires.  CBCT in dentistry is the major single contributor of diagnostic radiation, and recent publications have expressed concerns regarding the safety of this imaging procedure in children.¹¹  A 2012 advisory statement from the ADA Council on Scientific Affairs states: “As with other radiographic modalities, CBCT imaging should be used only after a review of the patient’s health and imaging history and the completion of a thorough clinical examination,” and “Dental practitioners should prescribe CBCT imaging only when they expect that the diagnostic yield will benefit patient care, enhance patient safety or improve clinical outcomes significantly.”⁴ Recommendations from regulatory agencies such as the FDA¹⁸ provide guidance regarding strategies to maximize safety and efficacy.

Hand-held units, which facilitate imaging when patients are sedated or anesthetized, were approved by the FDA in July 2005. The FDA advises dentists¹⁹ to use devices legally marketed for this purpose, and to check to see that they are properly labeled to indicate that this is the case.  Studies of legally marketed devices found that radiation exposure was within safety limits^{19, 20} and, in fact, were significantly less than for wall-mounted systems (0.28 mSv vs. 7.86 mSv).  The studies concluded that there was, therefore, no need for additional shielding.²⁰

Radiographs in Diagnosis (Trans.1974:653)

Resolved, that the House of Delegates reconfirms that a diagnosis and treatment plan cannot be made from radiographs alone. Benefits shall not be determined solely on the basis of radiographic evidence.

American Dental Association
Adopted 1974

Delegation of Radiographic Film Exposure (Trans.1982:534)

Resolved, that the American Dental Association, in the public interest, supports the principle that dentists who choose to delegate the taking of radiographic films should delegate the function to personnel who have had a structured course in such procedures, and be it further

Resolved, that a structured course in radiography is defined as a planned sequence of instruction of specified content, designed to meet stated educational objectives and to include evaluation of attainment of those objectives.

American Dental Association
Adopted 1982; Reviewed 2018

Inclusion of Radiographic Examinations in Dental Benefits (Trans.1991:634)

Resolved, that in working with plan purchasers, health benefits consultants and third-party payers, the American Dental Association stress the importance of including, as part of a comprehensive dental benefits program, radiographic examinations in patient diagnosis and treatment when indicated, as determined by the treating dentist.

American Dental Association
Adopted 1991; Reviewed 2016

Dental Radiographs for Victim Identification (Trans.2003:364; 2012:442)

Resolved, that the ADA promote to practicing dentists the importance of providing, as permitted by law, radiographs, images and records on patients of record that are requested by a legally authorized entity for victim identification and which will be returned to the dentist when no longer needed, and be it further

Resolved, that copies of these records should be retained by dentists as required by law.

American Dental Association
Adopted 2003; Amended 2012; Reviewed 2017

Guidelines on Capture and Use of Diagnostic Images by Dentists, and by Third-Party Payers or Administrators of Dental Benefit Programs (Trans.1995:617; 2007:419; 2016:284)

Resolved, that the following guidelines pertain to dentists:
1. Dentists should refer to the joint ADA/FDA publication titled DENTAL RADIOGRAPHIC EXAMINATIONS: RECOMMENDATIONS FOR PATIENT SELECTION AND LIMITING RADIATION EXPOSURE, or its successors, for assistance in determining clinical necessity for such diagnostic imaging.
2. If a third party requests an image which was not generated as part of the dentist’s clinical treatment, dentists should consider the clinical necessity of the image in connection with the request.
3. When a dentist determines that it is appropriate to comply with a third-party payer’s request for images, submit a duplicate set and retain the originals.
4. Postoperative images should be required only as part of dental treatment.
5. Images must be correctly identified and be of diagnostic quality.
6. Images are an integral part of the dentist’s clinical records and are considered the dentist’s property, consistent with state law.
7. The confidentiality of images and all other patient record content must be maintained in accordance with applicable HIPAA and state privacy and security regulations.
8. Additional costs incurred by the dentist in copying images and clinical records for claims determination that are not reimbursed by the third-party payer may be billed to the patient. And be it further

Resolved, that the following guidelines pertain to third-party payers and dental benefit plan administrators:
1. Payers and administrators should refer to the joint ADA/FDA publication titled DENTAL RADIOGRAPHIC EXAMINATIONS: RECOMMENDATIONS FOR PATIENT SELECTION AND LIMITING RADIATION EXPOSURE, or its successors, for assistance in determining their necessity for such diagnostic imaging. Third-party payers should not request that images be generated solely for administrative purposes.
2. All images, including duplicates, except those submitted in digital or other electronic form, and whether or not it has been requested, should be returned to the dentist.
3. It is improper for third-party payers to deny authorization for payment or make determinations about treatment based solely on images.
4. Third-party payers should not use images to infringe upon the professional judgment of the treating dentist or to interfere in any way with the dentist/patient relationship. All questions of interpretation of images must be reviewed by a dentist consultant.
5. Clinical images should only be requested when they will be reviewed by a dentist to make a determination regarding the patient’s entitlement to benefits. Dentists reviewing images for this purpose should be licensed in the U.S., preferably within the jurisdiction of the dentist providing the images in accordance with applicable state law.
6. Patients should be exposed to radiation only when clinically necessary, as determined by the treating dentist. Postoperative images should be required only as part of dental treatment.
7. Third-party payers must protect all images submitted by dental offices in accordance with applicable HIPAA and state privacy and security regulations.
8. All images submitted to third-party payers should be returned to the treating dentist within fifteen (15) working days. Images received in an electronic form should be permanently deleted within 30 days of the completion of claims adjudication.
9. Where a claim or predetermination request indicates that images are provided, the third-party payer should immediately notify the submitting dentist’s office if the images are missing.
10. A patient’s predetermination request or claim should not be prejudiced by the third-party payer’s loss or misplacement of images.
11. As it is necessary for a dentist to maintain accurate and complete records, third-party payers should accept copies of images in lieu of originals.
12. Any additional costs incurred by the dentist in copying images and clinical records for claims determination should be reimbursed by the third-party payer.

American Dental Association
Adopted 1995; Amended 2007, 2016

1. U.S. Environmental Protection Agency. Federal Guidance Report No. 14: Radiation Protection Guidance for Diagnostic and Interventional X-Ray Procedures; 2014.
2. American Dental Association Council on Scientific Affairs., U.S. Food and Drug Administration. Dental radiographic examinations: recommendations for patient selection and limiting radiation exposure.  2012.
3. Ludlow JB, Davies-Ludlow LE, White SC. Patient risk related to common dental radiographic examinations: the impact of 2007 International Commission on Radiological Protection recommendations regarding dose calculation. J Am Dent Assoc 2008;139(9):1237-43.
4. American Dental Association Council on Scientific Affairs. The use of cone-beam computed tomography in dentistry: an advisory statement from the American Dental Association Council on Scientific Affairs. J Am Dent Assoc 2012;143(8):899-902.
5. U.S. Nuclear Regulatory Commission. Sources of Radiation.  2009. "https://www.nrc.gov/about-nrc/radiation/around-us/sources.html". Accessed December 21, 2021.
6. National Council on Radiation Protection Measurements. Ionizing radiation exposure of the population of the United States: Recommendations of the National Council on Radiation Protection and Measurements (NRCP Report No. 160). Bethesda, MD: National Council on Radiation Protection and Measurements; 2009.
7. Mettler Jr FA, Mahesh M, Bhargavan-Chatfield M, et al. Patient exposure from radiologic and nuclear medicine procedures in the United States: procedure volume and effective dose for the period 2006–2016. Radiology 2020;295(2):418-27.
8. Mettler FA, Jr., Huda W, Yoshizumi TT, Mahesh M. Effective doses in radiology and diagnostic nuclear medicine: a catalog. Radiology 2008;248(1):254-63.
9. Radiological Society of North America. Radiation Dose in X-Ray and CT Exams. "https://www.radiologyinfo.org/en/info/safety-xray". Accessed December 21, 2021.
10. Williams J ADA News:  Child safety is goal of Image Gently campaign. American Dental Association September 1, 2014. "http://www.ada.org/en/publications/ada-news/2014-archive/september/child-safety-is-goal-of-image-gently-campaign". Accessed February 18, 2019.
11. White SC, Scarfe WC, Schulze RK, et al. The Image Gently in Dentistry campaign: promotion of responsible use of maxillofacial radiology in dentistry for children. Oral Surg Oral Med Oral Pathol Oral Radiol 2014;118(3):257-61.
12. Giglio JA, Lanni SM, Laskin DM, Giglio NW. Oral health care for the pregnant patient. J Can Dent Assoc 2009;75(1):43-8.
13. Michalowicz BS, DiAngelis AJ, Novak MJ, et al. Examining the safety of dental treatment in pregnant women. J Am Dent Assoc 2008;139(6):685-95.
14. American College of Obstetricians and Gynecologists Committee on Health Care for Underserved Women. Committee Opinion: Oral health care during pregnancy and through the lifespan. American College of Obstetricians and Gynecologists August 2013 (Reaffirmed 2017). "https://www.acog.org/-/media/Committee-Opinions/Committee-on-Health-Care-for-Underserved-Women/co569.pdf". Accessed February 18, 2019.
15. Dental technology: knocking at high tech's door. J Am Dent Assoc 1989;118(3):285-8, 91-4.
    
16. van der Stelt PF. Filmless imaging: the uses of digital radiography in dental practice. J Am Dent Assoc 2005;136(10):1379-87.
17. Strauss J, Pitura K, Spahn G, Schwind R, MacCutcheon D Strategies for reducing 'dose creep' in digital x-ray.  2007. "https://www.auntminnie.com/index.aspx?sec=ser&sub=def&pag=dis&ItemID=75242". Accessed December 21, 2021.
18. U.S. Food and Drug Administration. Dental Cone-beam Computed Tomography. "https://www.fda.gov/radiation-emitting-products/medical-x-ray-imaging/dental-cone-beam-computed-tomography". Accessed December 21, 2021.
19. Mahdian M, Pakchoian AJ, Dagdeviren D, et al. Using hand-held dental x-ray devices: ensuring safety for patients and operators. J Am Dent Assoc 2014;145(11):1130-2.
20. Gray JE, Bailey ED, Ludlow JB. Dental staff doses with handheld dental intraoral x-ray units. Health Phys 2012;102(2):137-42.

Professional Resources

• Recommendations for Patient Selection and Limiting Radiation Exposure
• The Use of Cone-Beam Computed Tomography in Dentistry
• Managing Silver and Lead Waste in a Dental Office

Patient Resources

• Dental Radiographs: Benefits and Safety (September 2011)
• Dental Care During Pregnancy (November 2018)

• X-rays
• Is It Safe to Go to the Dentist During Pregnancy?
• 5 Questions to Ask at Your Child’s Back-to-School Dental Visit
• Oral and Maxillofacial Radiology

• The Health Physics Society (Occupational and Environmental Radiation Safety)
• U.S. Food and Drug Administration:
  • Dental Radiography: Doses and Film Speed
  • Dental Cone-beam Computed Tomography
• U.S. Centers for Disease Control and Prevention: Radiation and Pregnancy: A Fact Sheet for the Public