What I’m about to share with you isn’t new news for dental professionals, but it may surprise the average patient or parent of a patient: the age-old tradition of being draped in a lead apron when taking routine dental X-rays has been deemed unnecessary.
Scientists at Tokyo’s Nihon University and the University of Freiburg in Germany went in search of consensus on this controversial subject and found sparse research about the radiation protection provided by lead apron shielding, according to their findings published in the December 2013 issue of Dentomaxillofacial Radiology.
The researchers evaluated possible differences in the amount of radiation a patient absorbs while wearing a lead apron, as well as without one.
“No statistically significant difference was found between the two protocols in the two different panoramic radiography devices tested,” according to the American Dental Association.
The American Academy of Oral and Maxillofacial Radiology also states that the gonadal dose from dental radiography is so minimal using a lead apron when capturing X-ray images should be considered optional unless required by law.
It turns out that technological advancements in dental radiology – not lead aprons – have been more instrumental in reducing patient radiation exposure. One such advancement is mentioned in the updated American Dental Association and U.S. Food and Drug Administration guidelines. Their guidelines support what is known as “rectangular collimation,” which is a shift from circular collimation. A collimator is a metallic barrier with a hole in the middle that reduces the size and shape of the X-ray beam. A rectangular collimator reduces the volume of irradiated tissue in the patient by up to five times that of its circular counterpart when taking bitewing X-rays and images of the tooth roots.
Other ADA and FDA recommendations include:
- The position-indicating device should be open ended and have a metallic lining to restrict the primary beam and reduce the amount of tissue that gets exposed to radiation.
- Use of long source-to-skin distances of 40 centimeters, rather than short distances of 20 centimeters, decreases exposure by 10 to 25 percent. Distances between 20 cm and 40 cm are appropriate, but the longer distances are optimal.
- Use of abdominal shielding such as lead aprons may not be necessary if all the recommendations for limiting radiation exposure are put into practice, as it doesn’t significantly affect radiation exposure.
- Continued use of a thyroid collar when taking X-rays.
The reason for the thyroid collar particularly when X-raying children is due to the thyroid gland being among the most sensitive organs to benign and malignant radiation-induced tumors. Even when optimum techniques are in use, the primary dental X-ray beam may still pass near and occasionally through the gland, according to the Health Physics Society, specialists in radiation safety.
Another technological advancement that has reduced patient radiation exposure has been the switch from film to digital radiography. Digital X-rays reduce radiation by as much as 90 percent.
Origin of Lead Apron Recommendations
Radiology pioneer Antoine Beclere introduced safety equipment, lead aprons and lead rubber gloves in the late 1890s – the early days of X-ray technology – because of their usefulness in absorbing radiation. Lead aprons can absorb up to about 95 percent of any scatter X-rays that may hit the wearer, according to Columbia University.
Medical professionals first recommended these precautions for dental X-rays because the X-ray equipment was far less sophisticated than today’s equipment, and films were slower than today’s standards. They offered a solution to the poorly collimated and unfiltered dental X-ray beams of that era, according to the Health Physics Society.
Changing Public Perception
The biggest challenge in adopting this new guideline that tosses aside the apron is educating patients on these new findings.
Our patients and their parents have grown up donning that heavy lead apron each time they’ve had X-rays taken at their dentist’s or orthodontist’s office. Seeing that step skipped sometimes causes concern, so we are sure to educate patients and parents on the research when questions arise.
We also use this as an opportunity to provide education on the numerous technological advancements in place that provide additional reductions in radiation exposure. Cone beam 3D technology, which is what we use in our office, emits less radiation than a medical CT scan. At the same time, it provides images that are vastly superior in detail, which paves the way to a clearer oral health picture as we devise treatment plans for our patients.
The Purpose of X-rays
As an orthodontist in Miami, I get lots of questions about the number and purpose of X-rays that we take during an initial consultation and periodic follow-up appointments. We take the following types of X-rays at your first consultation:
- Cephalometric- a complete radiographic image of your profile
- Panoramic- a radiographic image of your entire mouth, including teeth, upper and lower jaws, surrounding structures and tissues, in one image
- Periapical- an image that shows all of a tooth, along with its surrounding bone
- i-CAT cone beam computer assembled tomography- this provides 3-D images of teeth, jaws, bones and facial structures
These images help me evaluate the condition of your teeth, gums and bone. They also assist in assessing your specific bite issues as they relate to your facial skeletal structure. Thanks to X-rays images I can assess the following:
- The state of eruption of teeth in children
- Pathologies associated with teeth and jaws
- Whether root resorption exists, and the extent of it
- The presence of supernumerary (extra) teeth
- Size and shape of teeth that haven’t yet erupted
As you can see, X-rays are powerful diagnostic tools that provide a window into your dental health. These images make it possible for me to map out your treatment plan with specificity. That ensures an outcome everyone will be happy with once treatment is complete.
I hope you’ve found this information enlightening and educational. If you have questions about the topic of lead aprons in taking X-rays, or you have other general questions about the types of X-rays we take in our office, please don’t hesitate to call.