▶ CBCT - Cone beam computed tomography

A CBCT (cone beam computed tomography) is an X-ray that produces thee-dimensional radiological images. These high-quality images are used for diagnostics of detailed anatomical structures. Cone beam CTs are mainly used in dentistry and primarily for the planning of dental implants and oral surgical operations. With the help of a CBCT, complex dental resorations can be planned and carried out optimally.

DVT – High precision three-dimensional X-ray

Digital volume tomography is capable of imaging skull bones, teeth and soft tissue with high precision. This enables the dentist and oral surgeon to plan the therapy accurately and avoid errors. With the help of a CBCT/DVT, delicate anatomical structures, such as nerves, vessels and maxillary sinuses, are detected and can be protected during dental operations. In addition, 3D X-rays are able shows various pathological processes, such as periodontitis, bone inflammation or scattered foreign bodies, so that suboptimal surgery planning is kept to a minimum.

In our dental practice we use DVTs for ceramic implants, removal of implacted wisdom teeth and to search for inflammation. We use the Planmeca ProMax Mid, which has excellent image quality with low radiation exposure.

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Pathologies that are detected in a CBCT/DVT

Bone inflammation

There are different types of bone inflammation. These always show softening and degradation/resorption of the jawbone. Inflammation of the bone can be seen as dark areas in the X-ray. The image shows bone inflammation in the area of the root tip of a broken premolar. Often, pronounced periodontitis can also severely degrade the jawbone and lead to jaw inflammation. This can be seen in the section below.

Periodontitis

Periodontitis (inflammation of the periodontium) can easily be detected in a 3D X-ray. The three-dimensional imaging below shows degradation of the periodontium, resulting in less anchorage of the tooth in the tooth socket. Since the jawbone forms part of the periodontium, periodontitis is often accompanied by inflammation of the jaw. The image below shows various longitudinal-sections of an upper molar. There is severe periodontal bone loss and the maxillary sinus is affected as well.

The maxillary sinus

An inflammation-free maxillary sinus is filled only with air. If the 3D X-ray shows that the cavities of the maxillary sinus are filled, there is a pathological process. This is often caused by a diseased or infected tooth. In the image below, a thickened maxillary sinus mucosa is seen protruding into the lumen. It shows a maxillary sinusitis that is caused by a tooth.

Cavities

3D X-rays produced with high-quality equipment of the latest generation can be used to detect cavities. The dentist can also distinguish between enamel and dental caries The image below shows sectional views through an upper molar. The cavity can be seen as a dark area in the crown of the tooth. The distance between the cavity and the tooth nerve can be measured according to the dimensions.

Foreign Bodies

Impacted foreign bodies can often be found in the jaw bone and/or soft tissue. Some examples of foreign particles are scattered amalgam splinters, overpressed root filling material or broken root tips. With the help of a CBCT/DVT, the exact location of the foreign body can be determined. The removal of the foreign body can be planned accordingly, which ensures a safe and atraumatic removal. In the images below, the exact location of the foreign body can be seen in various sections.

Anatomical structures that can be seen in a CBCT/DVT

Maxillary sinus

Changes in the maxillary sinuses can be diagnosed using a cone beam ct/digital volume tomography. It is very helpful during surgeries and when placing dental implants, to avoid injuring the maxillary sinus. For a better anatomical representation, the image on the right shows a maxillary sinus. The proximity of the root tips to the maxillary sinus is clearly visible.

Mandibular nerve (lower jaw nerve)

The mandibular nerve is one of the structures that is frequently damaged during operations and implantations in the lower jaw. The nerve runs bilaterally through the lower jaws. The damage of these nerves can lead to numbness of teeth, lower lips and chin of the corresponding side. Arteries and veins also run parallel along the mandibular nerve. In the images below, the origin and course of the mandibular nerve are shown in red.

Nerve supply of the upper incisors

This nerve can be injured during implantations in the area of the central upper incisors and lead to a numbness of the anterior palate. Here, too, blood vessels run alongside the nerves through the palate. The image shows the anatomical structures and location of the nerve. The origin of the nerve on the palate is shown in red.

Procedure of a three-dimenstional dental X-ray

The process of a CBCT/DVT is very simple and straightforward. After dental prosthesis and metals such as earrings or necklaces have been removed, a dental X-ray apron in put on, and the 3D X-ray is taken. The patient is seated and positioned with forehead and chin rest, which allows the head to be held still for a few seconds. In this short time, the X-ray tube and X-ray sensor move around the head and create a three-dimensional image of the anatomical structures. After a few seconds, the DVT can be openened on the computer and the dentist can diagnose and discuss with the patient.

Radiation exposure during a CBCT/DVT

For dental tomographies, the radiation exposure depends on the chosen parameters (settings), the image size of the 3D X-ray and the X-ray device used. Therefore, it is important that the parameters are set correctly and the ideal image size is chosen according to the individual situation. The 3D X-ray device should be high-quality and of the latest generation. This is important because advances in technology and high-quality devices can minimise radiation exposure. In general, the radiation exposure of a CBCT/DVT is about ten times lower than that of a computer tomography of the head (head CT). In our practices, we use the Planmeca ProMax Mid. The device has the Planmeca Ultra Low Dose Protocol, which enables the creation of 3D images in high quality with minimal radiation exposure. If the lose dose setting is chosen, the radiation is approximately 0.021 millisievert (mSv), which is lower than a 2D panoramic X-ray. For comparison: On average, the annual radiation exposure of a person in Switzerland is about 5.6 mSv.

FAQ about three-dimensional dental X-rays

Are contrast agents needed for a dental CBCT/DVT?

No contrast agents are used for dental X-rays.

Can the 3D X-ray be sent to the patient?

Yes, the 3D images can be sent to the patient or transfered onto a USB. With a viewer software, patients can open the three-dimensional X-ray at home.

Does every dental practice have a CBCT/DVT system?

No. Three-dimensional X-ray systems are useful for dental practices that specialise in oral surgery.

Can all teeth be seen on a 3D X-ray?

Yes. All teeth (including wisdom teeth) of the upper and lower jaw can be seen with a CBCT/DVT.

Is this procedure painful?

No. A CBCT/DVT is a completely pain-free examination.

CBCT – Cone Beam Computed Tomography / DVT (Digital Volume Tomography)