CT (computed tomography) teeth — 3D
Dental scan with 3D reconstruction images of exotic and expensive survey technique is gradually becoming a routine diagnostic procedure. If initially it recommended that in preparation for implantation or complex operations in the maxillofacial region, but now the indications for the use of CT has increased significantly.
To conduct the dental imaging uses cone-beam tomography, which compared with the spiral have significant advantages:
Cone-beam tomography with 3D reconstruction allows the doctor to find the cause and solution to the problem in the most difficult diagnostic situations:
- In dentistry used CT segment jaws with a length of 3-4 teeth. The technique is indispensable for the study of unusual anatomy of root canals, diagnose changes in the periodontium in early stages, assessment of quality of sealing of the channel and determining the ratio of the roots of the teeth of the upper jaw and maxillary sinus. To do this using other methods: radiography, orthopantomography, and even spiral CT was impossible.
- Dental implant according to modern standards may not be conducted without prior computed tomography of the jaws with 3D reconstruction. This study is necessary for planning surgical intervention. With this program, image processing physician can not only determine the amount of bone available, but also to determine its density. This will help to pre-select the implant and method of surgery: staged implants or immediate loading. The distance to anatomically important structures (maxillary sinus, mandibular canal) can be determined with millimeter precision.
- Surgeons dentists and oral surgeons were among the first to use computed tomography for the diagnosis of diseases of the teeth and jaws. Some benefit could be obtained from spiral CT images, but with the advent of cone beam technology diagnosis was as accurate as possible. Using CT to reveal:
- bone injury of the facial skeleton;
- benign and malignant tumors of the jaws;
- atypically located (close to critical anatomical structures);
- impacted and supernumerary teeth;
- periodontal pockets of chronic infection (granulomas, cysts, cystogranulomas);
- conduct a differential diagnosis of odontogenic and rhinogenous sinusitis.
Dental CT scanners allow for a scan of the jaw fragment or even a single tooth, the cost of research in this case will be lower.
The technologist teeth?
Specialized dental imaging differs from conventional, spiral, and in appearance more reminiscent of an apparatus for carrying out the orthopantomography. The study was conducted in the standing or sitting position the head is fixed by means of supports for the forehead and chin. From the back of the head is flat, the receiving sensor. During the study frame of the machine performs a circular motion in front of the patient’s face, when it heard a slight noise and clicks. The whole scanning process takes several minutes.
The resulting image is processed and saved on the hard disk of the computer. According to the analysis of tomograms and 3D reconstructions, the radiologist makes a description. In addition, the patient is given a disc of image files and a program for viewing and printing of image on film or paper.
Radiation exposure from the conduct of cone-beam dental imaging in 10 times less than in the survey on the spiral CT scanner and the accuracy of the result – much higher.
Each manufacturer supplies their scanners original software. The images made on the scanner of one company cannot be viewed and processed using software developed by another. For this reason, dentists often send their patients for dental 3D imaging in a certain place. The level of ownership and knowledge of software depends on the amount of information that will be able to extract the doctor from the received image.
Dental imaging in implant dentistry
Conduct dental tomography in the planning phase of implant surgery is considered mandatory. Only under the condition of obtaining accurate and complete information about individual peculiarities of the structure of the jaws of the patient the doctor will be able to make the optimal plan for surgical intervention and make the risk minimal.
- When carrying out the implantation in the side portions of the upper jaw, it is important to determine the level of the location of the bottom of the maxillary sinus and in accordance with this calculate the required length of the implant. If it is longer than necessary, there will be a perforation of the maxillary sinus and the implant will not be successful and the implant can «get away» in the bosom or to provoke inflammation;
- At the planning stage of implant surgery in the mandible it is important to determine the location of the mandibular canal. It contains nerves and blood vessels that feed the lower jaw. If the implant perforeret canal wall and damage the neurovascular bundle during the surgery there may be massive bleeding, postoperative – severe pain.
Sighting radiography and orthopantomography do not provide exhaustive information about the position of these structures, so they are insufficient for examination in preparation for implantation.
Contraindications and limitations in the use of dental imaging
Dental imaging lasts a matter of minutes, does not require prolonged immobility and of being in a confined space. Radiation exposure during CT of the teeth with 3D reconstructions is 40 – 60 mSv, which is approximately 10 times smaller than in spiral tomography and is less than 1% of the allowable annual radiation exposure. The list of contraindications for this diagnostic procedure is limited.
Dental imaging is not carried out during pregnancy and early childhood, as well as the presence of mental illness, when the patient’s behavior may be inadequate. Claustrophobia is not considered a contraindication to CT with 3D reconstruction, since the study does not involve being in a closed loop.