Compared to dental appointments of the past, “x-rays” or “radiographs” seem to happen a lot more frequently. Some people have heard that dentists just take them because they can charge the patient for them, or claim them for money from the health funds. This could not be further from the truth. Dentists are very aware of the risks of radiation (which is why you see them exit the room every time they take an x-ray!) and operate under a strict protocol of exposing a patient to the least amount of radiation required to make a diagnosis.
If this is all getting confusing, let’s start with some basics.
What Is An X-ray?
When dentists and patients refer to an x-ray, they are actually referring to a radiograph. A radiograph is the image produced by the x-rays which pass through anatomical structures. X-rays are a form of electromagnetic radiation.
Where Does Radiation Come From?
In our environment, we are exposed to background radiation from many different sources without even knowing it! The sun exposes us to radiation, as does flying on an aeroplane. Building materials, such as clay bricks and granite, expose us to radiation too. If you’ve got a granite benchtop at home, you’ve got background radiation in your kitchen!
Radiation is measured in millisieverts. A small dental radiograph, such as the kind that the dentist puts in your mouth, is 0.005 millisieverts. Taking two of these is the equivalent to eating 100g of Brazil nuts. Taking a transatlantic airplane flight is the equivalent to eight of these radiographs.
The average Australian receives 1.5-2 millisieverts of radiation every year and exposure to this low-grade radiation is not harmful.
Ok, But Why Does the Dentist Need to Take Radiographs So Often?
The information that can be gained from a radiograph far outweighs what your dentist can see with their eyes, even when they’re wearing their magnifying glasses! Sometimes very large cavities that form between the teeth can only be detected with radiographs, which is why your dentist takes a set approximately every two years to ensure such cavities aren’t being missed.
The beauty of radiographs is that they also allow your dentist to monitor very small or early cavities which may not need to be filled if they remain static over time. Previously any shadow or dark spot on a tooth may have looked like decay and dentists filled them for fear of them getting worse. Now that we have radiographs, we can monitor these areas and only drill the tooth if we see the decay has reached a certain depth.
There are different kinds of radiographs for different needs as well. Sometimes your dentist may want to look at your jaw joint or other anatomical structures around the teeth. For this purpose, they would need to take a panoramic radiograph, or OPG. Sometimes they may need to look at the root of a specific tooth to determine if there is an abscess developing. For this, they need a different type of radiograph. Your dentist will take the minimum number of radiographs required to make a diagnosis, but they understand that a couple of low dose radiographs may be of huge benefit to you if it means, for instance, detecting an abscess before it gets bigger and causes you pain. Every dental decision requires your dentist to weigh up the risk versus the benefit of a procedure to you - a very small amount of radiation can often be very beneficial to your oral and overall health.