Answer to Question #11088 Submitted to "Ask the Experts"

Category: Medical and Dental Patient Issues — Pediatric Issues

The following question was answered by an expert in the appropriate field:


My six-year-old daughter had her first set of bitewing x rays recently. I asked that they cover her thyroid. I did not think to ask about lower settings for children. I looked at the pulse settings and what brand of machine. I looked up this manufacturer for this particular machine and their recommended settings for children were half the pulses that the machine was on the day she had x rays. I believe she got a double dose of radiation. I am so concerned. Any information about how this could increase her risk for any cancer would be appreciated.


The amount of radiation required to produce a diagnostic radiograph (x ray) will vary with body part imaged, size of the patient, and the type of image receptor (film, digital sensor) used, along with specific characteristics of the x-ray machine itself. The recommended exposure settings that you found on the company’s website may not have been for the type of imaging receptor used in the office. Without more information from the dental office itself as to exactly what they use, we do not have the answer as to whether they used more radiation than they had to.

Bitewing radiographs are a very important part of a thorough dental examination for all patients, children and adults alike. With children, not only are they used to find dental caries (cavities) while they are still small enough to be treated early or even reversed with remineralization techniques, they also can show how the permanent teeth are developing so that the dentist can address any issues before they become a problem and help guide the child to a full and healthy adult dentition.

The risk of developing cancer from a set of dental x rays is extremely small. The radiation dose that your daughter may have been exposed to during her bitewing examination, while seeming to be "double the recommended level," was probably what would have been considered ideal just a few years ago when film types were not as sensitive as they are today.

When it is time for your daughter to have another set of bitewings or other dental x rays, it is perfectly appropriate to ask the dentist why the x rays are needed, what they are doing to keep the dose as small as possible (you can mention what you read on the x-ray company's website), and to request use of the thyroid collar if it is not offered automatically. The American Dental Association recommends bitewing x rays for children every six months to two years, depending on the child's oral health, diet, exposure to fluoride in the drinking water, and other factors that affect the child's risk for dental decay.

The Health Physics Society, the American Dental Association, and the American Academy of Oral and Maxillofacial Radiology are three of the many organizations that have endorsed the Image Gently campaign of the Alliance for Radiation Safety in Pediatric Imaging to keep the radiation dose to children as low as possible while still receiving the diagnostic benefits that x rays can bring. Many individual dentists have already made the pledge to "kid-size" the radiation dose. The Image Gently website has information for parents as well as for professionals and you may want to take a look at it. They discuss the benefits and risks of many types of dental x rays and classify the risk to children from dental x rays of any kind as "minimal."

Sharon L. Brooks, DDS, MS
Professor Emerita
Dip, American Board of Oral and Maxillofacial Radiology

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 7 January 2015. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.