Information for the Patient

What is a Dental CT or CBCT Scan?

Computed Tomography (CT) or Cone Beam Computed Tomography (CBCT) uses computer software to create images of the body from a series of x-ray measurements. In the case of a medical CT scanner, the patient lies on a flat surface called a “table” and the x-ray equipment rotates around the patient’s body. (The x-ray tube and detectors are housed in a large doughnut-shaped apparatus called a “gantry”, so they are not usually visible). During the CT scan, the patient table moves through the gantry while the x-ray tube and detectors rotate rapidly around it. In this way, very accurate x-ray measurements are taken from a large number of different directions. The computer software then has the task of putting these measurements together to make a series of images of the human body. Sometimes these can be displayed as 3-dimensional (3D) views, to make a very realistic presentation.

While medical CT scanners are highly accurate, they are expensive machines and are usually located in hospitals or large imaging centres. Many dental scans are carried out on special equipment called cone beam computed tomography (CBCT) scanners, which are smaller machines that can conveniently be located in a dental practice. The patient sits or stands in the CBCT scanner, while the x-ray tube and detectors rotate around the patient’s head. A typical dental CBCT scan takes 20 seconds or less to complete.

How is CT or CBCT different from conventional x-rays?

Conventional x-rays are two-dimensional - they can show the location of your teeth and the height of the bone, but they cannot depict the thickness of your jawbone. Two-dimensional x-rays can be subject to distortion, depending on the magnification used.

A CT or CBCT scan, on the other hand, is distortion free. The scan provides valuable information about the interior of the bone, and the results can be displayed as a 3D presentation, or as cross-sectional views of your jaws. These distortion-free images allow your dentist to accurately measure the amount of bone that is available for dental implants. Dental CT or CBCT scans enable your dentist to select the best location for your implants, and plan the details of your treatment with pinpoint accuracy, so there will be no surprises at the time of surgery.

Dental CT or CBCT scans can help your dentist determine whether you are a good candidate for implant surgery. They can also be very useful in diagnosing conditions such as fractured roots, impacted or supernumerary teeth, temporomandibular joint (TMJ) or airways disorders.

What are dental implants?

Dental implants are titanium roots placed directly into the bone of the jaw to support replacement teeth. The dentist or surgeon needs to know whether there is enough bone of adequate consistency to support the implants. The images generated from reformatted CT or CBCT scans provide exactly that information.

In cases where the quantity or quality of the patient’s natural bone is not sufficient, bone grafts can be used to build up the implant site. Once the implant has been placed and allowed to heal, it becomes firmly embedded in the bone (a process known as osseointegration).

Dental implants hold out the promise of restoring your mouth permanently without the use of removable dentures. It is the next best thing to “getting your own teeth back”. Biting and chewing with successful implants is the same as with normal teeth. However, this precise and sophisticated technology requires careful planning, based on highly accurate imaging, to be effective.

Why do I need a dental CT or CBCT scan?

Because a CT or CBCT study tells your dentist a lot more than conventional x-rays, it helps him or her prepare for your surgery in more detail. By studying the CT or CBCT scan, your dentist will know the exact location of anatomical structures, the contours of your jaw bone, and the best sites for your implants, before the surgery takes place. That means less operating time, and fewer complications. By sending you for this type of study your dentist is providing you with the very best possible care.

What is IDT’s role in this process?

Image Diagnostic Technology Ltd (trading as IDT Scans) has over 25 years’ experience with dental CT and CBCT scans, and we can assist your dentist at each step of the way.

First, your dentist can choose from one of the hospitals or imaging centres we have trained to meet our Quality Assurance criteria. Second, we carry out any reformatting of the data that is needed after the scan (for example, generating 3D views). Third, we send the resulting images to your dentist in a format that is compatible with the software he or she will be using to plan your treatment. Last but not least, we are available to provide help and technical assistance at each step of the way, making sure that everything goes smoothly and your dentist has all the information needed to provide you with the best possible treatment.

What will happen during the scan?

You do not need to prepare for the dental CT or CBCT scan. You may be asked to remove any jewellry from your head and neck, so that it does not interfere with the study. On a medical CT scanner, you will be lying face up on a comfortable CT scanner table. On a CBCT scanner, you will be imaged sitting or standing up.

Your dentist may provide you with a special denture (also called a “scanning appliance” or “stent”) to wear during the scan. If your dentist didn’t provide you with a stent, the radiographer may provide something for you to bite on. This will separate your jaws and help you to keep them entirely still.

Keeping still and not moving for those few seconds or minutes that the scan takes is very important, otherwise clear pictures will not be obtained, and the scan may have to be repeated.

The radiographer will explain each stage before it happens. You will not feel anything and the only part of your body inside the scanner will be your head. In 5 to 10 minutes you will be finished.

After the scan the radiographer will send the data to IDT Scans for processing and analysis on our computers. IDT Scans will send the final results to your dentist. And that’s all there is to it!

Where do I go?

Some dentists have CBCT scanners in their dental practice, other dentists will ask IDT Scans to arrange an appointment at a Hospital or Imaging Centre convenient for you.

If your dentist gives you a “scanning appliance” or “stent”, please be sure to take it with you and wear it during the scan, as the radiographer may be unable to perform the study without it.

How do I pay?

Some Private Hospitals and Imaging Centre will accept payment on the day of the scan. Please check with your dentist or with IDT Scans to see if this is the case.

For most Public (NHS or HSE) Hospitals, you need to pay IDT Scans in advance. You can pay by Bank Transfer, or we can send you a link to pay online by Credit Card or PayPal. Unfortunately we cannot accept payment by cheque or over the phone.

Please do not delay in making payment, otherwise your treatment may be delayed.

Can I claim the cost on my health insurance?

Many insurance companies do not pay for dental treatment or the associated imaging. Some insurance companies do cover this element of your dental treatment with ‘add-ons’ which are issued at an additional premium.

Please consult your insurance company prior to your CT or CBCT scan, to find out whether the scan is covered by your insurance. IDT Scans can provide any general information that is requested, however, we cannot discuss your specific treatment with the insurance company.

What about the radiation aspects?

There has been considerable publicity recently regarding the radiation doses received from a number of medical procedures. At IDT Scans we are constantly working with our scanning site partners to ensure that radiation doses are kept “as low as reasonably achievable” (ALARA). The radiation dose varies from patient to patient, but is typically in the range of 100 to 500 microSievert for a dental CT scan performed on a medical CT scanner. For a dental CBCT scan the dose is usually lower, around 25 to 150 microSievert.

To put this in perspective, everyone in the UK receives about 2000 microSievert annually from natural background radiation, so the dose from a dental CT or CBCT scan is the same as the dose you would have received anyway, in the next few days or weeks, through natural background radiation.

A dental CT or CBCT scan (or any type of x-ray) can only be taken if the expected benefits to the patient vastly outweigh the risks. One of the main benefits of a dental CT or CBCT scan is avoiding complications during surgery. On the other hand, the risks are very low (so low that we cannot measure them or calculate them accurately). Nevertheless, there is no point in receiving radiation that you do not need. For this reason, your dentist will choose an imaging procedure (CT, CBCT or conventional x-ray) that provides the best possible balance between high quality images and low radiation dose.

Where can I find out more?

For further information on dental CT and CBCT scans please contact IDT Scans.

For further information on ‘Dental Implants’ please speak with your dentist, or contact a professional body such as the Association of Dental Implantology.

For government regulations concerning radiation dose please refer to IR(ME)R 2017 in the UK and SI 256 of 2018 in Ireland.