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| Fig. 1: Dental Clinic Panorex. (Source: Wikimedia Commons) |
Dental practice has its own way of radiation exposure. During radiation in dental examination, there is a risk of induction of cancer or other diseases from x-ray devices. Not only that, after the radiation there is a increased risk of oral complication that is related to dental work. The practicing dentist differs from medical colleagues as he exposes, processes and interprets the radiograph (Fig. 1). Though the exposure is minimal, it is very important to reduce the radiation to avoid the accumulated dose to the dentist in their lifetime. Furthermore, it is crucial to minimize the risk for the patients who are getting dental examination. Another point that the practicing dentist has to understand is the risk of radiation for head and neck cancer patients so that they can prevent the further side effect after their radiation. This article will review what dentists should know about radiation for the sake of themselves as well as patients.
For radiation exposure in dentistry, 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. [1] Effective doses in microsieverts were 34.9 μSv for full-mouth radiographs, 24.3 μSv for panoramic image and 5.1 μSv for posteroanterior cephalogram. [1] Interestingly, the risk-estimates depend on the shape and length of the collimator, or position-indicating device, as reported by Cederberg et al. [2] They showed that long and short rectangular cones have the lowest probability of stochastic effects, followed by long round cones, short round cones and pointed cones. All of these cones were open-ended except the short pointed cone. [2]
Based on these results, in dental practice more importance should be given to optimizing radiologic procedures, as it is the best way to minimize patient and operator exposure. All dentists have a professional responsibility to their patients, staff and themselves to minimize any risks which might be associated with radiation. Exposure modification can be achieved by taking action at 3 levels of radiologic process at source, at the exposure pathway and modifying characteristics or location of exposed individuals. Furthermore, dentists must be aware of, and use, safe practices for radiation procedures at all times. The International Commission on Radiological Protection (ICRP) has published guidelines for radiation protection since 1928. [3] These guidelines have been updated from time to time and they concern protection for patients as well as protection for operators of radiation generating equipment.
Dentists should also recognize that when they are treating head and neck cancer patients, they should have special treatment plan before and after the radiation because of the risk of radiation related damage to dentition. Because of typical tissue reactions to ionizing radiation, radiotherapy in the head and neck region usually results in complex oral complications affecting the salivary glands, oral mucosa, bone, masticatory musculature, and dentition. [4] When the oral cavity and salivary glands are exposed to high doses of radiation, clinical consequences including hyposalivation, mucositis, taste loss, trismus, and osteoradionecrosis should be regarded as the most common side-effects. While mucositis and taste loss are reversible consequences, usually subsiding early post-irradiation, hyposalivation is commonly irreversible. [4] Additionally, the risk of rampant tooth decay with its sudden onset and osteonecrosis is a lifelong threat. [4] Thus, cancer patients who are planned to get radiation commonly have dental checkup to prevent further side effects. Thus, early, active participation of the dental profession in the development of preventive and therapeutic strategies, and in the education and rehabilitation of patients is paramount in consideration of quality-of-life issues during and after radiotherapy.
Without due care, due to their increased exposure to radiation at work, both dentists and their staff are at risk of developing radiation-induced diseases.This is in addition to any radiation they receive from natural background and man-made sources during their leisure time. Any exposure at work has no therapeutic benefit and needs to be kept to an absolute minimum at all times. Furthermore, the dentists should understand how to treat cancer patients who have gone through the radiation.
© Dahee Chung. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] J. B. Ludlow, L. E. Davies-Ludlow, and S. C. White, "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. 139, 1237 (2008).
[2] R. A. Cederberg et al., "Effect of the Geometry of the Intraoral Position-Indicating Device on Effective Dose," Or. Surg. Or. Med. O. 84, 101 (1997).
[3] B. Praveen et al., "Radiation in Dental Practice: Awareness, Protection and Recommendations," J. Contemp. Dental Practice 14, 143 (2013)
[4] A. M. Kielbassa et al., "Radiation-Related Damage to Dentition," Lancet Oncol. 7, 326 (2006).
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