Cone beam computed tomography of the maxillofacial area in dentistry: principle, cost

Remember the recent past. This is the time when the mere thought of the upcoming dental treatment was associated with the drilling of an ultra-deep well on the Kola Peninsula.

And the tool for removing teeth has been compared to an instrument of torture for the executioners of the Holy Inquisition.

Yes, dear dentists forgive - it is not their fault. They did not have other instruments for diagnosing diseases and treating them.

Everything, to the joy of the sufferers, has sunk into oblivion.

Whether it is now. A revolutionary toolkit has appeared in dentistry - the method of cone-beam computed tomography. This is the most objective, safe and informative way of examination. But quite recently it was difficult to pronounce, not to mention its practical application.

What it is?

By creating this technique, scientists from medicine have based it on the X-ray principle of research. At the same time, they were faced with the task of ensuring maximum protection of the patient from hard radiation and at the same time obtaining maximum objective information about the state of the maxillofacial region.

To their credit and to the delight of the patients, the task was accomplished brilliantly.

For clinical use, the technique was first adapted in 1982 at the Biodynamics Research Laboratory at the Mayo Clinic (USA). Initially, it found applied application in angiography - a contrast study of blood vessels.

Having shown its remarkable characteristics, since 2001 this technique has been successfully used in Italy for the diagnosis of the maxillofacial region.

This research principle allows you to obtain a three-dimensional image of a problem location, and in ideal digital quality.

The device implements a unique synchronization of the X-ray device with an exclusive software product. It is thanks to this that the volumetric image is "built" at the output.

Functionally, the device is equipped with:

1. A rotating frame on which the X-ray generator is fixed.
2. Receiving plane sensor (sensor). It is he who collects (receives) the waves of an X-ray emitter that have passed through tissues of different densities.
3. Computer with software. The program, making a proportional comparison of the attenuation (attenuation) of the beam power with the density of cells, "draws" in a 3D-format an informative picture of the examined area.

The resulting image allows you to identify pathology in the sagittal (imaginary vertical), frontal and horizontal planes and conduct a study of the condition channels and the very root of the tooth.

In addition, the resulting three-dimensional image makes it possible to differentially evaluate periodontium - the tissues surrounding the teeth and ensuring their vital activity, as well as periodontium - connective tissue between the root and the alveolar (cellular) plate.

It is worth clarifying that CBCT is a relatively "young" invention, with a definitive name still not fixed.

Due to the fact that in practice, multiple technical and methodological additions (updates) are introduced that do not change the basic principle of the methodology, in the scientific and educational literature there may be different names for the same process:

1. Dental tomography.
2. Computed tomography of teeth.
3. 3D CT.
4. X-ray tomosynthesis of the maxillofacial area.
5. Volumetric CT of the maxillofacial area.
6. 3D view of the jaws.
7. Dental cone-beam CT.
8. Three-dimensional radiography of teeth.

Don't be confused by this - we are talking about CBCT.

Perhaps, it will be appropriate here to say about the cost of cone-beam computed tomography of the maxillofacial region.

The price list for this type of service differs in each clinic. The regional location of the medical institution (the capital, the regional center or the periphery), as well as the novelty of the equipment, can also affect here. The survey area also affects the price.

The average price tag looks like this:

1. CT scan of both jaws - 2 thousand rubles.
2. Tomography of one jaw - up to 1.6 thousand rubles.
3. Sighting dental CT - from 800 to 1,000 rubles.

Benefits of using technology

After the discovery in 1895 by Wilhelm Konrad Roentgen of the well-known radiation, named after him, its all-pervading properties began to be successfully used in medicine.

And already from the beginning of the 30s of the last century, the resulting two-dimensional image was a serious help for doctors in the diagnosis of pathology in the maxillofacial areas.

But the 2D format had significant drawbacks. This is primarily a linear and geometric distortion of the resulting image. And also the visual overlapping of the studied areas, which significantly reduced the objectivity and quality of the final diagnosis.

They were replaced by 3D visualization implemented in multislice computed tomography (MSCT).

But even she, in comparison with CBCT of the maxillofacial region, objectively had significant drawbacks.

Multispiral CT

Cone Beam CT

High radiation load - at least 400 microsieverts. The scanning step is 0.5 mm. The examination requires several turns of the X-ray scanner. A horizontal position of the patient is required. The image is formed in layers, in the form of slices. Comparatively low resolution of the resulting image.

High speed survey of the problem area. One turn of the frame significantly reduces the radiation dose (up to 15 times). Radiation load - no more than 50 microsieverts. The scanning step is 0.125 mm. The position of the patient does not require a prerequisite. Openness and mobility of the design. Possibility of obtaining layered and three-dimensional images. The use of one in-plane sensor, in contrast to thousands of point detectors in spiral CT, significantly increases the resolution of the resulting image. In comparison with MSCT, the image quality has been improved 5 times. In the future, the 3D image can be used to obtain a sample - an ideal copy for further implantation. It is produced on a 3D printer. Special complex software products allow the doctor to conduct research based on the solution of the tasks at hand, i.e. selection of the required angle and scan mode.

Types and results of the study of CBCT

Computed tomography seems to be an indispensable tool for identifying various pathologies in different segments of dental research:

1. In therapeutic dentistry, it provides diagnostics of soft tissues in contact with teeth. In addition, it is used to examine the canals, to determine the nature and extent of damage to the root of the tooth, as well as the results and effectiveness of the adopted tactics of further therapy.
2. In surgical dentistry, this method is able to reveal not only the focus of inflammation, but also its size, as well as the site for the collection of bone for further implantation. In addition, it will allow the doctor to identify tooth residues after extraction or another unsuccessful surgical procedure.
3. In dental orthopedics, CT will help to objectively assess the support structure and condition auxiliary teeth, timely localize possible complications and compose the optimal treatment algorithm.
4. In orthodontics - constructions bite, its role is simply impossible to overestimate, because it will indicate the interfering circumstances for the high-quality installation of the structure.

Cone Beam CT is recommended in the following cases:

1. Various injuries and mechanical damage to the jaws and teeth.
2. To identify cavitieshidden when using traditional survey methods.
3. Pathologies in the development and placement of teeth in the oral cavity.
4. When organizing implantation and other surgical procedures.
5. To find out the causes of complications after the implementation of intracanal (endodontic) treatment.
6. Pathology of the maxillary sinuses.
7. To determine the tactics of orthodontic, orthopedic and therapeutic treatment.
8. To confirm the quality of the treatment performed.

However, there are some limitations that prevent CT:

1. The patient's pregnancy and the period of milk production (lactation).
2. Pathologies associated with the mental state of the patient.
3. The inability of the patient to independently ensure an immobile state during the examination.
4. Renal failure
5. For children under five years of age in the absence of vital necessity.

During the study, the patient's head should be stationary on its own, without auxiliary fixators. For at this time an X-ray generator and a ruler with receiving detectors simultaneously revolve around the head.

The undoubted leader in the consumption of three-dimensional diagnostics services is therapeutic dentistry. There is even an Association for 3D Radiology in Endodontics in the USA.

Various types of research, which include panoramic and sighting dental 3D computer tomograms, allow early detection of pathologies and take exclusive measures to stop them and treatment.

Detection of pathology of tissues surrounding teeth

In the event of pathological processes in the periapical tissues, LCT, creating a three-dimensional image, is able to accurately fix the focus of inflammation or the presence of a foreign body.

Also, CT is able to ascertain an anomaly of the cortical plate. In addition, it makes it possible to obtain visual information from the lingual side - the inner part, i.e. from the side of the tongue and the labial side, which is adjacent to the lips.

Traumatic tooth decay

The CT method provides a three-dimensional image when diagnosing various mechanical damages:

1. Destruction or local damage to the root.
2. Luxation - tooth mobility resulting from trauma.
3. Dental alveolar damage - chipping (shortening) of the tooth.
4. Fracture of the alveolar process of the upper jaw, which carries the teeth.

It is worth noting that CT does not have the ability to fix root faults that have arisen in the horizontal or vertical planes.

Detailed study of tooth root damage

With differentiation of destruction, internal and external damage to the root is highlighted. If the latter can be diagnosed visually, then deep internal destruction can only be traced when using computer tomograph, since this method allows you to build a 3D image with a changed density (transparency) of the bone material.

Computed tomography algorithm

Scientists have developed a method (algorithm) for step-by-step study (description) of an aiming and panoramic dental 3D computed tomogram obtained during the examination. Its detailed study and "running-in" in practice made it possible for dentists to deeply and consistently study the resulting three-dimensional image, without losing detail to the detriment of quality.

Stages of CT examination:

1. Study of the obtained three-dimensional image (X-ray): sharpness, contrast, the presence of distorted projections, the latitude of capture of the surveyed location.
2. Study of the state of bone tissue:
   • The quality of the interdental septa. Their shape, height, state of the cortical layer, end compact plate, spongy substance and level of mineralization.
   • The presence and level of changes in the intraosseous structure: localization, shape, size, geometry of the contour and its intensity.
   • Identification of impacted teeth that are unable to erupt on their own. Their location, number, stage of development, group membership.
   • Temporomandibular joint.
   • Assessment of the maxillary and paranasal sinuses: symmetrical arrangement, the presence of darkened areas, clear severity of bone contours, no pathology of the nasal septum.
   • Mandibular canal.
3. Identifying the need for additional research information. Practice convinces that for a deep diagnosis of complex pathology, an orthopantomogram - a panoramic picture, as a rule, is not enough. This requires a sighting or extraoral radiograph.
4. Teeth examination:
   • Identification of a carious cavity, the presence of fillings and their integrity.
   • Assessment of the quality of the roots of teeth: shape, size, contours, pathology.
   • Study of root canals: dimensions (depth, width), quality and reliability of filling.
   • Analysis of the periodontal gap: width, uniformity, quality of the compact socket plate.
   • Study of non-removable orthopedic and orthodontic structures.
5. Study and diagnosis of pathological changes. At the initial stage of studying pathology, the doctor is able to assess the affected areas, their size, location and nature of the change. We can talk about both disorders in metabolic and endocrine processes, benign formations (cyst), oncology, and other diseases.

CT tomography on video:

The physical examination method implemented in Cone Beam CT has taken dentistry to a new level, making it safer, more productive and aesthetic.