By Spring Hatfield, RDH, BSPH – September 18, 2023
The Role of Radiographs in Patient Care
Dental radiographs are vital tools in diagnosing conditions like periodontal disease, dental caries, abscesses, and jaw lesions. While patients often hesitate, radiographs are essential for delivering comprehensive care.
Today’s dentistry offers various imaging types—such as intraoral, panoramic, cephalometric, and cone-beam computed tomography (CBCT)—each serving specific diagnostic purposes. However, choosing the right imaging method should be based on clinical need and radiation safety.
Ask These Questions Before Ordering Radiographs
According to the Journal of the American Dental Association, before capturing any image, consider the following:
- What image is needed to answer diagnostic questions?
- Which technique uses the least radiation while meeting diagnostic needs?
- What are the benefits of obtaining the image?
- What are the risks of obtaining the image?
By asking these questions, dental professionals can significantly limit unnecessary radiation exposure.
ALARA: A Guiding Principle
ALARA stands for “As Low As Reasonably Achievable,” and it’s a key standard in minimizing radiation exposure while ensuring accurate diagnostics.
Methods to Reduce Radiation Exposure:
- Digital Radiography: Reduces radiation exposure by 90% compared to E-speed film. Initially introduced in the 1980s, digital systems have since evolved and are now widely adopted.
- Rectangular Collimation: Cuts radiation by 60%, although it may slightly increase the chance of retakes.
- Lead Shielding: Traditionally used, but now found to offer minimal benefit.
In fact, the American Association of Physicists in Medicine (2019) recommended discontinuing lead shielding, highlighting its ineffectiveness in reducing internal scatter radiation.
Reconsidering Gonadal Shielding
While still mandated in some states, routine gonadal shielding is no longer supported by scientific evidence. There’s no proof that dental imaging radiation causes heritable genetic effects in humans. Consequently, the American Academy of Oral and Maxillofacial Radiology recommends eliminating this practice.
Thyroid Protection: Rethinking the Norm
The thyroid is only minimally exposed during dental imaging. For clarity, here’s a quick look at thyroid-absorbed radiation doses:
| Procedure | Unshielded Dose (mGy) | Shielded Dose (mGy) |
|---|---|---|
| Intraoral (FMX, digital) | 0.2 | 0.1 |
| Bitewing radiographs | 0 | NA |
| Panoramic | < 0.1 | < 0.1 |
| Cephalometric | < 0.1 | < 0.1 |
| CBCT | 0.3 | 0.1 |
Source: Benavides et al.
Moreover, applying thyroid shielding can result in image artifacts that require retakes—ultimately increasing patient exposure.
Breast Shielding: Low Risk, Low Reward
Although breast tissue is sensitive—particularly in patients under 30—radiation from dental procedures is negligible:
| Procedure | Unshielded Dose (mGy) | Shielded Dose (mGy) |
|---|---|---|
| Intraoral | < 0.1 | < 0.1 |
| Panoramic | < 0.1 | < 0.1 |
| Cephalometric | < 0.1 | < 0.1 |
| CBCT | < 0.1 | < 0.1 |
| Mammography | 1.4 – 3.1 | NA |
Source: Benavides et al.
Therefore, current data do not support the routine use of breast shielding in dental radiography.
Imaging During Pregnancy: Safe and Supported
In dental radiography, the fetus is far outside the imaging field. The radiation dose is under 0.1 mGy—well below the 100 mGy safety threshold:
| Effect | Threshold (mGy) | Sensitive Period | Risk in Dental Imaging |
|---|---|---|---|
| Prenatal death | 100 | < 10 days | None |
| Microcephaly | 100 | 2–15 weeks | None |
| Intellectual disabilities | 300 | 8–15 weeks | None |
| Radiation-induced cancer | None | Entire pregnancy | Negligible (1 in 1.7 million) |
Source: Benavides et al.
To reassure expectant patients, confidently communicate the lack of risk and the absence of benefits from shielding.
Pediatric Imaging: A Smarter Approach
Though well-intentioned, shielding children may cause more harm than good. Lead aprons can lead to movement and poor-quality images. Instead, rely on patient selection, digital imaging, and proper collimation to lower exposure.
Radiographic Guidelines by Age and Risk Level
Use the following simplified guide for patient selection:
| Encounter Type | Recommendation |
|---|---|
| New Patient | Custom exam; may include bitewings, panoramic, or full-mouth images |
| Recall – Caries Risk | Bitewings every 6–12 months |
| Recall – Low Risk | Bitewings every 12–36 months (age-dependent) |
| Periodontal Disease | Clinician’s judgment—bitewings or periapicals |
| Growth/Development | Evaluate based on age; often panoramic or periapicals |
| Special Cases | Judge based on implants, pathoses, endo, etc. |
Final Thoughts: Let Science Guide the Standard
Introduced in the 1950s, lead shielding was meant to prevent genetic effects. However, modern research—and advanced imaging technology—tells a different story.
Radiation exposure from dental radiographs is exceptionally low, and current evidence supports removing routine shielding altogether. The American Academy of Oral and Maxillofacial Radiology recommends updating federal and state regulations to reflect these findings.
While some practitioners may wish to “play it safe” and continue shielding, this outdated approach reinforces unnecessary fears. Instead, by embracing evidence-based practices, we ensure both patient safety and trust.
If your state still requires shielding, comply accordingly—but stay informed. Changes to dental regulations are likely on the horizon.
Let’s move forward with clarity, confidence, and science.
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References
- Benavides, E., Bhula, A., Gohel, A., et al. Patient Shielding during Dentomaxillofacial Radiography: Recommendations from the American Academy of Oral and Maxillofacial Radiology.Journal of the American Dental Association. 2023; 154(9): 826-835.e2. https://doi.org/10.1016/j.adaj.2023.06.015
- Jayachandran, S. Digital Imaging in Dentistry: A Review.Contemporary Clinical Dentistry. 2017; 8(2): 193-194. https://doi.org/10.4103/ccd.ccd_535_17
- van der Stelt, P.F. Filmless Imaging: The Uses of Digital Radiography in Dental Practice.Journal of the American Dental Association. 2005; 136(10): 1379-1387. https://doi.org/10.14219/jada.archive.2005.0051
- AAPM Position Statement on the Use of Patient Gonadal and Fetal Shielding [PP 32-A]. (2019, April 2). American Association of Physicists in Medicine. https://www.aapm.org/org/policies/details.asp?id=468&type=PP
- Hiles, P., Gilligan, P., Damilakis, J., et al. European Consensus on Patient Contact Shielding.Insights into Imaging. 2021; 12(1). https://doi.org/10.1186/s13244-021-01085-4
- Rottke, D., Grossekettler, L., Sawada, K., et al. Influence of Lead Apron Shielding on Absorbed Doses from Panoramic Radiography.Dentomaxillofacial Radiology. 2013; 42(10): 20130302. https://doi.org/10.1259/dmfr.20130302
- Rottke, D., Andersson, J., Ejima, K.I., et al. Influence of Lead Apron Shielding on Absorbed Doses from Cone-beam Computed Tomography.Radiation Protection Dosimetry. 2017; 175(1): 110-117. https://doi.org/10.1093/rpd/ncw275
- Hruska, C.B., O’Connor, M.K. Curies, and Grays, and Sieverts, Oh My: A Guide for Discussing Radiation Dose and Risk of Molecular Breast Imaging.Journal of the American College of Radiology. 2015; 12(10): 1103-1105. https://doi.org/10.1016/j.jacr.2015.07.001
- The Selection of Patients for Dental Radiographic Examinations. (2019, June 20). U.S. Food and Drug Administration. https://www.fda.gov/radiation-emitting-products/medical-x-ray-imaging/selection-patients-dental-radiographic-examinations
Article by Spring Hatfield, RDH, BSPH – September 18, 2023