You may be unaware of a radical new tool that has come into dentistry in the last 10 years. Its called Cone Beam CT, or CBCT for short. Well, the CT bit might sound familiar. Some of you might know that CT means computerized tomography, and a few of you may have had a CT x-ray scan in hospitals. So you will know that a CT machine generates a three dimensional image of part of your body. This is fantastic for viewing your internal anatomy and any disease which might be present. Older machines use an array of small sensors to pick up the x-rays, and consequently the x-ray dose is really quite high and were still quite blurry. The revolutionary new breakthrough in the last decade has been to use a single big sensor to pick up the x-rays all at once. Big sensors like that were not possible previously, and even now are still expensive. But with a large sensor, the scans can be much quicker, and can also use far less radiation; perhaps only 2% of a traditional multi-sensor medical CT scanner. Also the image clarity is far better too, with details as small as 0.1 mm in size now visible. This is a game changer in dentistry because not only can we now see details like fine root canals, but the radiation dose is now low enough to be justifiable for use in dentistry. Previously high doses of radiation were just not justifiable for something as relatively trivial as treating a tooth. New dental CBCT scanners only give about 30 uSv; that’s about the same as one week of the background radiation we are all exposed to anyway. Or to put it another way, its equivalent to the extra radiation we get in about a 4 hour flight at high altitude. Yes, while you sit back at 40,000 feet jetting off on holiday, you are getting blasted with significant amounts of nasty cosmic rays. Most people will not decline to fly because of this level of radiation risk. And so it is with dental CBCT scans. So it’s probably acceptable as a one off event to have a dental CBCT to help save a tooth.
I can tell you as a dentist that CBCT has revolutionized my practice. I researched three dimensional radiography as part of my masters research project in 2000. I realized then that CBCT was technically possible, and was very excited about it. I even coded a proof of concept software which made 3D slices from normal dental x-rays. Commercial technology only became available in about 2005 and only affordable in 2013, when we bought our first CBCT machine. The ability to take CBCT scans for my patients has been a radical game changer. The images materially change either the diagnosis, treatment plan or treatment method in about seven out of ten cases. The benefit to patients is very great. It’s because we can see properly. It’s as simple as that. We can see a detail and a clarity that was unimaginable with normal dental x-rays. For endodontics we need to appreciate the fine anatomy of root canals, of the bone structures around the roots, and of where dental materials have been placed. Without the CBCT we are half guessing and can not do such a good job. With it, we are masters of our game – we can see what’s there, what’s wrong, and whether we have a good chance of fixing it. So please appreciate that we have invested in the technology and can help you far better with a CBCT scan, where appropriate. CBCT delivers a much higher standard of care to you.