Do dental x-rays cause brain tumors? A study published in April 2012 reported an association between dental radiographs and an increased risk of meningioma, a benign form of brain tumor (Rundell, 2021). However, the results of this study are highly controversial as radiation from dental exams and x-rays have never been scientifically proven to increase the risk of the incidence of cancer (Evearitt, 2016; Hwang, et. al., 2018; (Rundell, 2021). A meta-analysis study which reviewed the relationship between dental diagnostic-rays and the development of brain tumors, specifically meningiomas, revealed that there was no significant association between these two entities (Hwang, et. al., 2018). One major weakness was the requirement that subjects recall their dental x-ray history over the course of their lifetimes, including when they were children. Recall data , as collected in this study, are known to be highly unreliable. In addition, bitewing x-rays, which include 2 to 4 views, were reported to put patients at a greater risk than full mouth x-rays, which involve up to 20 views, including 2 to 4 bitewings. This result appeared to defy logic. Also, because absorbed doses of radiation from dental x-rays have declined over the years, and because the average patient had no idea of his or her absorbed doses and how they had changed over the years, there was no way that the study could establish a dose-response relationship. The limitations of studies that seek to correlate dental x-rays etiologic agent in the development of cancer include poorly designed experiments, recall bias and a paucity of information about the confounding factors of the patient (Chauhan and Wilkins, 2019). These weaknesses in the study’s design and inconsistencies in its conclusions put its finding of a relationship between dental x-rays and meningioma into serious doubt. Points to consider 1. While respecting a patient’s refusal for radiographic examination, how could Sara educate her patients on the safety of dental radiography? She could inform her concerned patients that digital radiography as used in their office exposes patients to far less radiation than most traditional films. In fact, a set of four bitewing radiographs taken with either digital radiography or F-speed film with rectangular collimation is equivalent to approximately 0.6 days of U.S. background radiation. Regardless, concerned patients should be assured that risk is minimal, and all precautions are being taken to reduce unnecessary patient exposure. 2. How might Sara reply if Marilyn has an extensive history of carious activity and/or periodontal disease instead of excellent oral health? First, Marilyn’s concerns should be understood and acknowledged. Sara should then inform her that the risk of undiagnosed dental disease (and subsequent nontreatment) outweighs the minimal risk to her health posed by dental x-rays. The role of the provider is to educate, while it is ultimately up to patients to decide whether they will submit to radiographic procedures. 3. If Marilyn changes her mind and consents to radiographs being taken, how can Sara still take steps to reduce radiation exposure? As always, the lead apron should be used. Based on Marilyn’s low risk of disease, Sara may be able to obtain only two bitewings that are adequately diagnostic, rather than four. Using a positioning device will further aid Sara in obtaining diagnostic radiographs and reduce the need for additional exposure.
patients. For example, a set of four bitewing radiographs taken with rectangular collimation and either digital radiography or F- speed film is equal to approximately 0.6 days of background radiation in the United States. This puts the radiation risk in more concrete terms that the average dental patient can understand. Table 8: Common Dental Radiographic Examinations with Equivalent Days of Background Radiation Dental Radiographic Examination Days of U.S. Background Radiation
Four bitewings, PSP/F-speed film, rectangular collimation
0.6
Panoramic
1.2
Full mouth survey, PSP/F- speed film, rectangular collimation Full mouth survey, PSP/F- speed film, round collimation Dentoalveolar CBCT, small and medium field view Maxillofacial CBCT, large field view
4.6
21.2
1.3 to 82
3.6 to 130.5
PSP = photostimulable phosphor plate; CBCT = cone beam computed tomography. Note : From American Dental Association X-Rays and Radiographs, 2019)
Case scenario Sara is a dental hygienist who just finished hygiene school within the past year. She now works in a private dental office, replacing a hygienist who has retired after 30 years in the practice. Sara is responsible for taking her own radiographs, which are obtained digitally via CCDs (sensors). As a new hygienist in the office, Sara is concerned about quickly earning the confidence and trust of her patients, many of whom have loyally seen her predecessor for years. Marilyn, a 68-year-old long-time patient in the practice, arrives for an adult prophylaxis with Sara on a particular afternoon. It is the first time they have met, and Sara briefly introduces herself. She then explains to Marilyn that she will begin by taking bitewing radiographs since it has been just over three years since the last set was taken. Marilyn politely objects, stating, “I would be more comfortable not having x-rays taken today. I rarely have any dental problems and I take good care of my teeth. I’m getting older, and I’m quite concerned about being exposed to too much radiation. My sister was just diagnosed with breast cancer, and I would rather not take any risks. Could we perhaps do X-rays every few years instead of every year?” Initially, Sara is not sure how to respond. However, looking over Marilyn’s chart she can see that her most recent filling was just 15 months ago, and she has a history of moderate periodontal disease. Sara believes that patients should have control over the care they receive and agrees to Marilyn’s request. However, she asks Marilyn to sign an informed refusal document, stating that she understands that by not completing a radiographic examination, diagnosis of any existing dental conditions will be significantly curtailed.
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Book Code: DHFL2624
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