Information for Patients

 

What is a Cone Beam CT (CBCT) scan?

CBCT is a new type of X-ray examination for dental patients which produces 3-dimensional images of your teeth and jaws. It is also sometimes called “Digital Volumetric Tomography” (DVT) or other alternative names.  

Why have I been asked to have a CBCT scan?

The scans are useful in many different types of dentistry, especially for dental implant planning, managing impacted teeth and root canal treatments.

If you aren’t sure why you have been asked to have a scan, you should ask your dentist.   

A CBCT scan of the upper and lower jaws

What does the scan look like when it is done?

The CBCT examination produces 3-dimensional pictures of a “volume” of your face. The size of the volume depends on the scanner and your particular clinical needs. The information can be viewed on a computer screen by the dentist to help plan treatment.  

Why aren’t ordinary X-ray pictures enough for my dentist?

Only your dentist can answer that for your particular situation!  Ordinary X-ray images (radiographs) are 2-dimensional, flat, pictures. Your teeth and jaws are 3-dimensional, so 2-dimensional images may not give the best information.  

Where do I go for a scan?

Your dentist might have their own CBCT machine, but if not you may be referred to a specialist practice or a Hospital X-ray Department. There are even some mobile CBCT scanner services.  

What will happen when I attend for the scan?

Depending on the machine, you will be positioned carefully in a seated, standing position. For one machine you have to lie down. After you are positioned properly the operator will use various methods, depending on the equipment, to stop you accidentally moving during the scan (usually a head band and chin rest). You will then be ready for the scan itself.   Sometimes the operator will take “scout” pictures at the start so that accurate scanning can be planned. The scan itself will then happen. The machine will move around your head in a circular motion, but will not touch you. Once the scan is finished, you will be asked to stay in the chair until the images are checked.  

A CBCT scan taken for assessment of impacted wisdom teeth

How long does the scan take?

The scan itself takes only a minute or so but, in most cases, the preparation and positioning will mean that the complete scan will take about 20 minutes.  

Is there anything I need to do before I come for my appointment?

If you have earrings or other facial jewellery or piercings, these may need to be removed before the scan, so doing this in advance of your visit will save time. If you wear dentures, you will probably be asked to remove these before the scan.  

Should the amount of X-rays I will receive worry me?

No. All CBCT referrals should be justified and only carried out when it is judged that the scan is appropriate. Although the X-ray exposure with CBCT is greater than with a traditional dental X-ray examination, it is almost always much less than you would get with a “medical” CT scan that might be the only alternative.  

How can I get further information?

In the first instance, you should discuss things with your dentist. He/she is in the best position to explain your particular situation. If you are going to another practice or hospital for the scan, do not be afraid to ask questions when you go for your appointment. Just like any medical procedure, you have to give your “informed consent”, so you have the right to know what is being done and why. This website contains educational material about CBCT that you may find interesting.

 

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FAQs for patients733 KB