Dental x-rays are an important tool to help you keep your teeth. X-rays help dentists reduce pain and suffering by detecting cavities early, before they get to the stage of painful toothaches and are an economical way of keeping your dental costs low.
Dental x-rays deliver a small amount of radiation to our tissues compared to annual dose of radiation we are exposed to from all other natural sources.
A common unit of measurement of radiation exposure is the millirem (mRem).
The amount of cosmic and solar radiation, as well as the natural radiation we are exposed to from our air, water and soil (including radon gas) amounts to 360 mRem/yr or about 1 mRem of radiation per day.
Regarding dental x-rays, four x-rays contain 0.3 mRem of radiation. Compare the number 0.3 to the 360 mRem’s of radiation you are exposed to simply by living on planet earth. This is less than one tenth of one percent of your annual radiation exposure. A full set of dental x-rays is 1.5 mRem which we may take once every 5 years in selected patients.
Introduction
It would be impossible to deliver high quality dental care that our patients deserve and expect without dental x-rays. While some procedures can be done without the aid of x-rays, the more complex and comprehensive treatments that dentists provide would be simply impossible without first taking x-rays of a patient’s teeth or jaws.
Let us for a moment imagine what dental treatment would be like if dental x-rays were not available to us:
Children and adults would be far more likely to need root canal treatment or extraction of teeth that are too far gone for simple fillings.
Tooth removal would not be able to be safely performed without dental x-rays. X-rays help us safely remove teeth without harming nearby teeth and nerves. As well, some teeth have curved, twisted roots or multiple roots that would make their removal much more difficult if we attempted to treat them sight unseen.
Root canal treatment would not enjoy the high success rate that it enjoys today without dental x-rays, as dentists would not have a clue of how many canals are in a tooth to be treated nor their length or shape. Proper root canal treatment would be quite impossible without at least an initial x-ray to help us plan the treatment.
The success rate of dental implants would plummet as x-rays are invaluable in the planning and placement implants. For example, they tell us if we have enough room to place an implant in a given site.
Gum disease would often go undiagnosed and would be difficult to treat if we did not have x-rays to give us a sense of the health status of the bone that holds our teeth in.
I could on for pages about all the benefits of dental x-rays but I won’t. Suffice it to say that our dental health would deteriorate if we could not offer dental x-rays to our patients. Images of Tibetan street dentistry come to mind. That is an eye opening interesting internet search if you haven’t seen how dentistry is sometimes unfortunately practiced literally on the side walk in places like India and Tibet.
So the next question is how often are x-rays needed and how many are needed?
Dentists are supposed to take the fewest x-rays as necessary for the diagnosis and treatment of our patients.
Here a some brief guidelines that we use in our office.
Young children:
Sometimes the baby molars in the back of the mouth have a little bit of spacing between them, allowing for visual cavity inspection without the need for x-rays. There are times, however, that for children as starting at about three years of age we do try to take two x-rays once per year to check for cavities starting in between the back teeth, if these teeth are positioned close together.
As well, if a child is having a problem with a particular tooth further x-rays to see the root area of the tooth will usually be required.
Older Children and youths up until age 18:
Some children and teenagers are more cavity prone than others. This can be due to not flossing or brushing regularly, eating too many sweets or drinking too much pop or sports drinks. Patients who are more prone to cavities should have x-rays taken once a year (one x-ray one each side of the mouth) to check for decay in between the teeth.
Teenagers who keep their teeth clean and maintain a good diet and who rarely get a cavity could have x-rays taken less often i.e. once every two years.
Adults
Adults who seem to get cavities often or who have a lot of existing dental restorations in their mouth (fillings, crowns,bridges, etc.) would benefit from having two x-rays taken on each side in the back of the mouth once per year.
These x-rays, known as bitewings, also allow us to monitor bone levels between the teeth as well and help detect defects in the bone that occur when gum disease is present.
Additional x-rays may be required if there are any teeth bothering the patient.
Adult patients who never or rarely seem to get a cavity, who maintain good oral hygiene and have a a healthy diet will not require x-rays to check for cavities as often i.e. every two years: 2-4 x-rays may be all that are needed to help detect cavities.
In patients in their mid to late teens we will often take a Panorex x-ray, which is a large x-ray film that shows us the upper and lower jaws and all of the teeth. This is often done to allow us to see to check the position of the wisdom teeth.
Sometimes it will be necessary to take a set of x-rays of all the teeth in the mouth. This should be reserved only for patients with extensive dental problems, such as widespread decay, evidence of gum disease, for patients wanting certain dental appliances or for patients who need extensive dental treatment. Full sets of x-rays are normally not necessary for a patient with a healthy set of teeth and gums who just requires a routine check-up and cleaning.
So now we have some of background knowledge regarding why x-rays are important and how often they are necessary. The next question is they safe?
The thing about dental x-rays that concerns most patients is the fact that they are a source of radiation. But is the amount of radiation produced by dental x-rays a cause for concern?
To address this question I used information from the following sources: Articles from the Health Physics Society of the University of Michigan, A fact book on radiation put out by The United States Environmental Protection Agency Articles from the Mayo Clinic and the American Dental Association
Links to these articles are in my show notes for this episode of my podcast. You can find the links by clicking dentalhealthpodcast.com
Here are some facts about x-rays and radiation:
Our world is a radioactive place to live and it always has been. We are exposed to many sources of natural radiation on a daily basis. This is because the ground we walk on, the air we breathe, the water we drink and the soil in which we grow our food contain radioactive particles that give off radiation.
Examples of these natural radioactive particles are: certain forms of uranium, thorium, radium and even some forms of potassium.
According to physicists these radioactive particles were created during the formation of our universe and as well during the formation of our planet.
In addition, we are exposed to cosmic radiation from both the sun’s rays as well as from high speed radioactive particles that originate from outside of our solar system.
Because radioactive particles, also known as radionucleotides are naturally occurring in our water and food, we digest these particles and they become part of the tissues of our body, so to a small extent our bodies are literally radioactive.
The largest single source of radiation that we are exposed to comes from radon, which is a colorless, odorless gas that is produced by the natural breakdown or decay of the element radium. Radium is found in trace amounts in almost all rocks and soil. Radon gas passes from the ground up into houses and buildings through small openings small in floors or walls. Some geographic areas have higher amounts of radon gas production and this gas can become a health hazard if it reaches high levels in homes or buildings.
Many building materials such as granite, cement, and drywall also contain measurable amounts of radioactive particles of uranium, thorium and potassium and thus are a source of radiation.
X-rays are a man made source of radiation and are used for diagnosis and therapies in medicine, for instance in radiation treatment and in nuclear medicine.
In high amounts, radiation can have significant effects on our bodies.
High doses of radiation can cause cell damage or cell death. Damaged cells can be affected temporarily or permanently.
The amount of cell damage depends on the how much energy is absorbed by our tissues, over what period of time and which organ is exposed.
Large doses of radiation can damage the genetic material in our cells and can cause cancer and as well can cause birth defects to occur in newborns.
However as we will see in a moment, the dose or amount of radiation in dental x-rays is extremely small and is barely noticeable compared to your daily or yearly dose of radiation from all the sources we mentioned above. Let’s have a closer look at this.
A common unit of measurement of radiation exposure is the millirem (mRem).
The amount of cosmic and solar radiation, as well as the natural radiation we are exposed to from our air, water and soil (including radon gas) amounts to 360 mRem/yr or about 1 mRem of radiation per day.
Regarding dental x-rays, four x-rays contain 0.3 mRem of radiation. Compare the number 0.3 to the 360mRem’s of radiation you are exposed to simply by living on planet earth. This is less than one tenth of one percent of your annual radiation exposure.
This is equal to the amount of natural radiation exposure you receive in half of a day, from the sun, cosmic radiation and the bricks of your house.
A full set of dental x-rays is 1.5 mRem which we may take once every 5 years in selected patients.
A typical chest x-ray is 4 mRem.
Your yearly dose of radiation from your dentist, although already low, can be reduced if your dentist uses fast exposure x-ray film, takes quick x-rays settings and uses a lead apron with a thyroid collars. In Canada dental offices must have their x-ray equipment tested regularly to ensure it is performing properly.
In conclusion, dental x-rays deliver a small amount of radiation to our tissues compared to annual dose of radiation we are exposed to from all other natural sources.
Dental x-rays are an important tool to help you keep your teeth. X-rays help dentists reduce pain and suffering by detecting cavities early, before they get to the stage of painful toothaches and are an economical way of keeping your dental costs low. A small filling is less expensive to place than a large filling or a root canal that will be more likely to be needed if you don’t catch cavities before they become big.
X-rays will also allow the earlier detection of gum disease and help prevent tooth loss.
Dental x-rays play an important role in helping to maintain healthy teeth and gums which is important in maintaining your overall health. For example, an adequate number of teeth to chew with are important in helping you maintain a healthy diet. Patients who lose teeth unnecessarily may have a more difficult time chewing coarser foods such as whole grain breads and raw vegetables and opt for a softer diet, which can lead to a diet lower in fibre. This in turn can lead to higher incidence of colon cancer and other health issues.
References Used and Further Reading:
The following are good sources of additional information on this topic.
Radioactivity in Nature. The Health Physics Society, University Of Michigan, 2005
The use of dental radiographs, Update and recommendations. American Dental Association Council on Scientific Affairs, JADA, Vol. 137, September 2006.
Radiation: Risks and Realities, United States Environmental Protection Agency, May 2007
Oral Health Topics: X-Rays (Radiography), American Dental Association, 2011.
Ionizing Radiation: Fact Book, United States Environmental Protection Agency, May 2007
Radiation Exposure During Imaging Exams, Mayo Clinic , Patient Education Article, 2009 Scottsdale Arizona, USA.,