Basic methods of X-ray diagnostics in dentistry.
Saint Petersburg
2006.
The role of X-ray examination in modern dentistry and maxillofacial surgery is steadily growing. To the traditional task of identifying and clarifying the nature of diseases of the dental system, indications for the use of radiological techniques are increasingly being added to determine the results of conservative and surgical treatment, assessing the dynamics of the course of pathological processes and the completeness of convalescence.
The basis of X-ray examination for most dental and periodontal diseases is still intraoral radiography. Currently, there are four of its techniques used in photographing teeth, para- and periodontal tissues: radiography of periapical tissues according to the rule isometric projection, interproximal(bite-wings-radiography), Shooting in a bite(occlusal) and radiography from an increased focal length with a parallel beam of rays.
For 60 years, in the X-ray diagnosis of dental diseases, the shooting technique was mainly used according to the bisector rule or isometric projection, developed by Cies&inski (1907). The main objective of research using this technique is to obtain a clear image of the periapical tissues, therefore the beam is centered on the projection onto the facial skin of the apexes of the roots of various teeth of the upper and lower jaws. On the upper jaw they are projected along a line connecting the wing of the nose and the tragus of the ear, and on the lower jaw - along a line running parallel to the edge of the lower jaw 1 cm above it.
A common method of intraoral photography is bitewing radiography(occlusal radiography), with which you can obtain an image of a large area of the alveolar process - over 4 teeth or more. This type of radiography is usually used as an additional one, making it possible to clarify the spatial features of the pathological focus - an impacted tooth, a large cystic cavity, etc. Bitewing photography is carried out when examining children and adolescents, patients with impaired mouth opening, as well as people with sensitive oral mucosa , in whom the touch of the film causes a gag reflex. Bitewing radiography is also used to obtain an image of the floor of the mouth in case of suspected stones of the submandibular and sublingual salivary glands, to obtain an image of the jaws in an axial projection . It allows you to clarify the course of the fracture line within the dentition, the location of bone fragments, the state of the outer and inner cortical plates in cysts and neoplasms, and identify the reaction of the periosteum.
You can avoid the disadvantages of isometric photography, while maintaining many of its positive features (covering a significant part of the alveolar process vertically, a complete image of the tooth, good reproduction of the structure of bone tissue), using intraoral radiography from a long distance almost parallel beam of rays. To eliminate image parallax, the film in these cases is positioned in the mouth parallel to the long axis of the tooth. This method of radiography, which is called differently (shooting with parallel rays, long-focus radiography), was proposed by E. Hilscher (1960). Since then, it or a modification of it has been increasingly used in many countries instead of isometric radiography.
Over the past 7-10 years, so-called radiovisiographs have been used in the study of teeth and periapical tissues, which are increasingly used by dental therapists. Radiovisiography
produces an image recorded not on X-ray film, but on a special electronic matrix that is highly sensitive to X-rays. The image from the matrix is transmitted via a fiber optic system to a computer, processed there and displayed on the monitor screen. During the processing of a digitized image, its size can be increased, contrast enhanced, polarity changed, if necessary, from negative to positive, and color correction. The computer makes it possible to study certain zones in more detail, measure the necessary parameters, in particular the length of the root canals, and densitometry. The image from the monitor screen can be transferred to paper using the printer included in the equipment package. Of all the advantages of digital X-ray image processing, we especially note the following: the speed of obtaining information, the possibility of eliminating the photo process and reducing the dose of ionizing radiation to the patient by 2-3 times. The use of radiovisiography provides the greatest practical effect in cases where the equipment is placed in close proximity to the dental unit, which makes it easy to monitor treatment measures without moving the patient from the chair.
More than 3 decades ago, X-ray diagnostics of diseases of the dental system included panoramic radiography. Observations have shown that direct panoramic radiographs have an advantage over intraoral photographs in the richness of detail in the image of bone tissue and hard dental tissues. With minimal radiation exposure, they allow one to obtain a wide view of the alveolar process and dentition, facilitate the work of the x-ray technician and sharply reduce the examination time. These photographs clearly show tooth cavities, root canals, periodontal fissures, interalveolar ridges and the bone structure of not only the alveolar processes, but also the bodies of the jaws. Panoramic radiographs reveal the alveolar bay and the lower wall of the maxillary sinus, the mandibular canal and the base of the mandibular bone. Based on panoramic images, caries and its complications, cysts of various types, neoplasms, damage to the jaw bones and teeth, inflammatory and systemic lesions are diagnosed. In children, the condition and position of the tooth buds are well determined. It is much more difficult to assess the significance of panoramic radiography in periodontal diseases. The breadth of visibility and good visibility of details of the condition of bone tissue make it easy to navigate the nature of bone changes and early identify their presence. Initial bone changes are found in all areas of both jaws, with the exception of the molar areas, where the alveolar processes are often poorly displayed or practically not detected. However, due to the peculiarities of image acquisition during panoramic radiography, the relationships between the interalveolar ridges and the enamel-cementum boundary are distorted, so the degree of bone tissue destruction cannot be objectively determined. The disadvantage of all types of panoramic radiography is the inability to control the position of the X-ray tube applicator in the mouth, since it is not determined by any anatomical landmarks. This predetermines individual distortions in the relationships of individual anatomical details, which are relatively easily assessed by radiologists, but are not always clear to clinicians. It is very difficult to achieve identical images. It is necessary to constantly take into account the individual characteristics of the structure of the skull and dentition and make adjustments when styling.
ABOUT 
about 30
For years, panoramic zonography has been widely used in dentistry, or, as it is more often called, orthopantomography. This technique has no equal in a number of indicators (view of a large part of the facial skull under identical conditions, minimal radiation exposure, short time spent on research). Panoramic zonography allows you to obtain a flat image of curved surfaces of volumetric areas, for which rotation of either the patient and the cassette, or the X-ray tube and cassette is used. Devices of the second type were mainly developed. The X-ray film, bent around a special cassette holder, giving it the shape of a half-cylinder, is enclosed in a plastic cassette, placed away from the patient's head and secured with a console on one side of the moving axis. On the other side of the same axis is the X-ray tube. During the x-ray, the tube and film describe an eccentric, partial circle around the subject's head. At the same time, the film on the cassette holder rotates concentrically around a vertical axis. X-rays, passing through different parts of the distal half of the skull, hit different parts of the film. A layer is clearly visible, which moves at the same speed as the film during the photograph. All objects that have a movement speed different from that characteristic of the selected layer are “smeared”.
The complexity of the anatomical structure of the facial skull makes it necessary to widely use not only orthopantomography, but also longitudinal tomography and zonography. Indications for their use are pathological changes in small bone fragments around the nasal cavity and orbit, the base of the skull, and cells of the ethmoid labyrinth. This need often arises with complex fractures of the midface, post-traumatic deformities, neoplasms, and systemic lesions. In these cases, until recently, linear tomograms with a tube rotation angle of 30, 45 and 60° were traditionally used. They make it possible to detect the growth of tumors of the facial bones and sinuses into the deep parts of the skull, fractures and structural changes in thin bones. Tomography in direct and lateral projections has become the main method of x-ray examination of the soft palate, as well as the temporomandibular joint, and has made it possible to solve many issues in the diagnosis of its diseases, including dysfunctions. When tomography, it is necessary to use the main easily reproducible projections - frontal, lateral, posterior or anterior axial. The patient's head must be fixed during shooting so as not to increase the blurriness of the images. Simultaneous tomography, which uses special cassettes that make it possible to obtain several tomograms with a specified interval between layers during one exposure, would provide many advantages for reducing the patient’s radiation dose. However, the unsatisfactory quality of simultaneous tomograms limited the use of this technique.
Among the numerous methods of contrast radiological examinations for maxillofacial pathology, the most commonly used are arthrography of the temporomandibular joints, angiography, sialography, dacryocystography.
The task arthrography is to detail the diagnosis of lesions of the temporomandibular joint by clarifying the condition of the intra-articular meniscus. The technique was introduced into radiology practice in 1947 by T. Norgaard. In practice, it has been used since the late 60s, since the widespread introduction into practice of layer-by-layer studies, which facilitated the interpretation of arthrograms. As a rule, it is enough to contrast the lower floor of the articulation. The manipulation is carried out after skin anesthesia under X-ray television control. The joint is punctured in the posterior sections with a needle, through which 0.8 to 1.5 ml of a viscous water-soluble contrast agent is injected. Tomograms or zonograms of the joint are produced during various movements of the lower jaw. The procedure requires caution and experience. Some authors have performed air arthrography of the joint, but its results are more difficult to decipher.
Angiography- a complex procedure that should be performed in a specially equipped X-ray operating room under aseptic and antiseptic conditions, under local anesthesia. Its implementation requires special equipment that provides automated recording of a series of angiograms at high speed and in accordance with a given program. Most modern angiographic units are equipped with an automatic syringe, including a tube and a serial cassette according to a given program, two X-ray tubes and a two-projection cassette, which records the state of the vessels in the frontal and lateral projections simultaneously with a single injection of a contrast agent. The passage of catheters and the correctness of their location in the vessels are controlled using the X-ray television channel of the X-ray image intensifier. The range of water-soluble contrast agents for angiography is very wide. Their choice depends on many indicators: viscosity, concentration of iodine-containing substances, allergenic effect.
Sialography- the oldest and most frequently used method of contrast examination in dentistry. Its methodology has changed relatively little since its introduction into practice. Contrast agents are injected into the ducts of the salivary glands using a conventional syringe through a blunt and slightly curved needle in the shape of the duct, a cannula or a catheter. Using a needle has a number of disadvantages: it is not always possible to insert it into the duct, it is not fixed in the duct and can come out of it at the time of administration of the contrast agent, installation of the needle is often a labor-intensive procedure for the doctor and a painful procedure for the patient. Orthopantomography significantly simplifies the sialography technique and allows you to simultaneously obtain images of various glands without layering the bone tissue of the lower jaw. Panoramic radiography can also be used: when examining the parotid salivary gland in a lateral projection, and the submandibular gland in a direct projection. If salivary stone disease is suspected, the study should always begin with overview (direct, lateral, occlusal or panoramic) photographs.
Significant progress in the X-ray examination of various organs and systems is associated with the introduction into practice computed tomography. ABOUT 
It allows you to obtain a cross-sectional layer-by-layer image of any area of the human body, including the skull. By analyzing the density characteristics of an X-ray image, using a computer or computed tomograph, subtle tissue changes can be identified. Modern computed tomographs have high resolution, can distinguish very small differences in density, quickly scan the part of the body being examined (one slice per second) and can reconstruct an overview image based on a study performed in one projection. Currently, this is the only way to simultaneously obtain images of not only bone parts, but also soft tissues, including the brain. Computed tomography is widely used in recognizing diseases of the facial skull and dental system: pathologies of the temporomandibular joints, especially menisci, congenital and acquired deformities, fractures, tumors, cysts, systemic diseases, pathologies of the salivary glands, diseases of the nasopharynx and oropharynx. It allows you to accurately determine the location of lesions, carry out differential diagnosis of diseases, plan surgical interventions and radiation therapy. The high resolution capabilities of computed tomographs are combined with a low level of radiation exposure to patients and ample opportunities for documenting and storing images using magnetic recording, radiography and photography.
ABOUT 
occupies a special place among radiological methods used in dentistry telex-ray examination. It is used as a method of quantitative study of the proportions and relationships of various parts of the facial and cerebral skull in patients with disorders of the relationships of the dentition and deformations of congenital and acquired origin, using images taken from a distance of at least 1.5 m. Teleradiography helps to assess the nature of the deformation, the direction of growth bone sections and determine the timing and order of surgical and orthodontic measures.
Thus, diagnostic methods of X-ray examination can provide a variety of information about the morphology and function of various parts of the maxillofacial region and are necessary for recognizing pathological processes and their dynamic assessment. At the same time, rational research designs are usually used to an extremely limited extent, mainly in large research centers. In the bulk of outpatient dental institutions, intraoral isometric radiography is used exclusively, and unsystematically and often in a much smaller volume than necessary. This deprives the clinician of valuable information and negatively affects the quality of treatment.
Survey radiography;
SURVEY RADIOGRAMS
EXTRAORAL (extraoral)
INTRAORAL radiography
DIGITAL RADIOGRAPHY
PANORAMIC RADIOGRAPHY
PANORAMIC ZONOGRAPHY method
TELERENTGRAPHY
CT SCAN
SIALOGRAPHY.
DOUBLE CONTRAST
FISTULOGRAPHY
ARTHROGRAPHY
ANGIOGRAPHY
HIMOROGRAPHY
ULTRASONOGRAPHY.
Source: I.I. Sergeeva, T.F. Tikhomirov, V.V. Rozhkovskaya, N.A. Savrasova
Belarusian State Medical University
based on materials from zhuravlev.info
Information is presented on the basic and special methods of radiation examination used in the diagnosis of diseases of the maxillofacial region. The diagnostic capabilities of the methods are reviewed and indications for their use are determined. The capabilities of modern methods - computed tomography, ultrasound - are also covered.
X-ray research methods are leading in the diagnosis of diseases of the maxillofacial region, due to their reliability and information content. X-ray diagnostic methods have found wide application in the practice of therapeutic dentistry (for identifying peri- and periodontal diseases); in orthopedic dentistry (to assess the condition of remaining teeth, periapical tissues, periodontal tissue, which determines the choice of orthopedic measures). X-ray methods are also in demand in maxillofacial surgery in the diagnosis of traumatic injuries, inflammatory diseases, cysts, tumors and other pathological conditions. The method and technique of x-ray examination of teeth and jaws has its own characteristics.
The most commonly used in dental practice are:
Survey radiography;
Extraoral radiography of teeth and jaws;
Intraoral radiography.
SURVEY RADIOGRAMS can be performed in three projections - direct, lateral and anterior semi-axial - and allow you to obtain an image of the entire facial and cerebral skull. The direct projection can be performed with naso-frontal or naso-mental adherence to the cassette. Indications for images in the nasofrontal projection are: injuries and diseases of the brain and facial skull. This installation is also used for sialography and fistulography. Images in the nasomental projection are used: to study the bones of the middle and upper floors of the facial skull, paranasal sinuses. The condition of teeth on radiographs in direct projection is not analyzed.
Lateral photographs of the skull are taken as a mandatory addition to direct ones. However, it is quite difficult to study the condition of the bones of the facial skeleton from these photographs due to the summative effect of the right and left halves of the skull. Usually only gross, extensive bone changes are visible. Lateral photographs are often performed to examine the condition of the skull, its base, sella turcica, sphenoid and frontal sinuses, as well as to determine the location of foreign bodies.
Axial and anterior semi-axial photographs are performed if it is necessary to examine all structures of the base of the skull, bones of the midface, including the orbits, maxillary sinuses, and zygomatic bones.
EXTRAORAL (extraoral) X-rays of the jaws are taken using both dental and other X-ray machines. X-ray film measuring 13x18 or 18x24 cm and corresponding cassettes with intensifying screens are used. Extraoral radiographs are performed to study the lower jaw, zygomatic bones, temporomandibular joint (TMJ), as well as for sialography and fistulography. Indications for such images may be inflammatory, tumor, traumatic injuries of the jaws, extensive cysts, periodontal lesions of the lower jaw when it is impossible to perform intraoral radiographs. To study the condition of the TMJ, special installations according to Schüller and Parma can be used. Pictures must be taken on both sides to compare the joints.
INTRAORAL radiography still serves as the basis for radiographic examination in most dental and periodontal diseases. Currently, there are four methods of intraoral radiography used to study the condition of teeth, para- and periodontal tissue:
1. Contact radiography according to the isometric rule.
2. Interproximal radiography.
3. Bitewing radiography (occlusal).
4. Radiography with increasing focal length by a parallel beam of rays (long-focus radiography).
For many years, in the X-ray diagnosis of dental and periodontal diseases, the technique of contact radiography according to the bisector rule or isometric projection, developed by Cieszinski (1907), was mainly used. The main objective of research using this technique is to obtain a clear image of the periapical tissues, therefore the beam is centered on the facial skin at a point corresponding to the projection of the apex of the root of the tooth being studied.
One of the objectives of this technique is to obtain an image of teeth identical to their true size. To reduce projection distortions in practical work, the isometric rule is used - the central beam is directed to the apex of the root of the tooth under study perpendicular to the bisector of the angle formed by the tooth axis and the plane of the film. Any other direction of the central ray leads to lengthening or shortening of the tooth image. It must be remembered that the permissible shortening of the tooth image should not exceed 0.2, and the elongation should not exceed 0.1 of its true dimensions.
However, exact adherence to the isometric rule, unfortunately, is impossible, because It is difficult for each patient to accurately determine the bisector of the angle formed by the axis of the tooth and the plane of the film. Therefore, they use angles of inclination of the tube, calculated empirically for certain groups of teeth. So, for images of molars, the angle of inclination of the X-ray tube to the horizontal plane is 25-30°, for premolars - 35°, canines - 45°, incisors - 55°. When photographing the same groups of teeth using the bite technique, the angle increases by 20°.
Equally important is compliance with the orthoradial rule, when using which the central beam at the time of the image is directed perpendicular to the tangent drawn to the dental arch of the upper or lower jaw in the area of the tooth being examined. If this rule is observed, the image of the tooth being examined does not overlap the image of neighboring teeth.
For contact photographs, the film size is 2x3 cm, 3x4 cm (the latter format is available in the form of standard packages), for bite-size photographs the film size is slightly larger - 5x6 cm, 6x8 cm. In the absence of factory packaging, use a special film for radiography of teeth RM. The corners of the film are cut off so that they do not injure the oral mucosa, and placed in a small envelope made of opaque paper, and then in wax paper. A bag of film is inserted into the oral cavity, and the patient presses it firmly against the hard palate and alveolar process of the area under study with the first finger of the opposite hand. Dental X-rays are usually performed with the patient sitting. The head is fixed on the headrest in the desired position.
When examining the teeth of the upper jaw, the patient's head is placed in a position in which the wings of the nose and the external auditory canal are in a plane parallel to the plane of the floor. The film is inserted into the oral cavity so that its edge is parallel to the occlusal plane and protrudes 0.5 cm from the edge of the teeth, while the tooth to be removed should be in the center of the film. In this position, the film is pressed with the second or first fingers of the patient’s hand to the mucous membrane of the hard palate. The apexes of the roots of the teeth of the upper jaw are usually projected onto the skin of the face along a line connecting the wing of the nose and the tragus of the ear: when examining the central incisors, the beam is directed to the tip of the nose, the lateral incisors to the wing of the nose, and the canines to the upper part of the nasolabial fold.
When radiography of the lower jaw, the patient's head is fixed on the headrest so that the line connecting the angle of the open mouth and the tragus of the ear is in a plane parallel to the floor. To do this, the patient tilts his head back a little. The projection of the apexes of the roots of the teeth of the lower jaw onto the skin of the face corresponds to a line running 1 cm above the lower edge of the jaw. The central beam is directed from bottom to top and medially to the apex of the tooth being examined, while maintaining the angles for the corresponding groups of teeth. When taking photographs using the bite-to-bite technique, the angle increases by 20°.
In some cases, it is necessary to deliberately change the projection of the beam to obtain a separate image of the roots of multi-rooted teeth or to clarify the relationship of the roots with pathological formations. In such cases, oblique intraoral projections are used: mesodistal (the central ray is directed obliquely from the front to the medial and back) and distomedial (the ray is directed from the back to the medial and forward).
Thus, contact radiography according to the isometric rule can be used to obtain images of teeth identical to their true sizes, to obtain a clear image of periapical tissues and to determine the spatial relationships of objects localized in the zone of roots and periapical tissues.
At the same time, the isometric imaging technique has a significant drawback; it does not allow assessing the condition of the marginal sections of the interalveolar ridges, since the latter are filmed with an oblique beam, which leads to a shortening of their image.
That is why it should be abandoned when diagnosing periodontal diseases.
Interproximal radiography is used to obtain a clear, undistorted image of the marginal parts of the alveolar processes of the jaws. The method allows you to objectively assess the degree of bone tissue resorption over time and is the best way to identify proximal and cervical caries.
X-ray film, using special film holders, is placed in the oral cavity parallel to the crowns of the teeth at some distance from them, which makes it possible to obtain an image of symmetrical areas of both jaws. To secure the film, you can use a piece of thick paper attached to the film wrapper and pressed between closed teeth. The central beam is directed perpendicular to the crowns and film. Radiographs simultaneously display the crowns of the teeth and the marginal sections of the alveolar processes of the upper and lower jaws. To study the entire bite, 3-4 photographs are taken.
Bitewing (occlusal) radiography technique. A simple and common technique for intraoral imaging. Bitewing photographs are performed when it is necessary to study large areas of the alveolar process - 4 or more teeth, when looking for impacted and dystopic teeth. Bitewing radiography is used when examining children, as well as in cases where intraoral contact photographs are not possible (in case of jaw damage, TMJ stiffness, increased gag reflex). The technique is indicated for obtaining an image of the floor of the mouth in case of suspected stones of the submandibular and sublingual salivary glands, as well as for studying the condition of the hard palate. Bite X-ray allows you to assess the condition of the outer and inner cortical plates of the jaws in case of cysts and neoplasms, and to identify the reaction of the periosteum.
When conducting occlusal radiography, the rules of bisector and tangent are observed. A film measuring 5x6 or 6x8 cm is inserted between the rows of teeth and is held in place by their closure.
When x-raying the upper jaw, the film is inserted as deep into the oral cavity as possible and clamped between the teeth. The patient sits in a dental chair, the midsagittal plane of the skull is perpendicular to the floor, and the line connecting the tragus of the ear and the wing of the nose should be parallel to the floor of the office. The central beam at an angle of +80° is directed to the root of the nose. The image shows a significant part of the alveolar process of the upper jaw and the floor of the nasal cavity.
When taking pictures of the lower jaw, the patient's head is tilted back so that the line from the corner of the mouth to the tragus of the ear is parallel to the floor of the office. The central beam is directed perpendicular to the film 3-4 cm posterior to the chin. The radiograph clearly shows the area of the floor of the mouth, the buccal and lingual cortical plates of the lower jaw, and the entire dentition in the axial projection.
Long focal radiography (parallel beam imaging) was introduced by Hilscher in 1960 and is increasingly used in many countries instead of contact intraoral radiography. Long-focus radiography allows you to avoid the disadvantages of contact photography and preserve its positive aspects: coverage of a significant part of the alveolar process vertically, a complete image of the tooth, a clear structure of the bone tissue. One of the important advantages of shooting with parallel beams is that the image of the marginal parts of the alveolar processes is not distorted, and therefore the technique can be recommended for wide use in periodontology.
The X-ray film is placed in the mouth parallel to the long axis of the tooth, for which special film holders or hemostatic clamps are used (cotton or gauze rolls can also be used).
For long-focus radiography, devices with a more powerful X-ray tube and a long localizer tube (36-40 cm minimum) are used. The object-film distance ranges from 1.5 to 3 cm, and the central beam hits the film perpendicularly or at an angle of no more than 15°. The image and the object are almost equal in size to each other.
When performing any methods of radiography of the dentofacial apparatus, in order to eliminate dynamic blurriness of the image obtained in the image, an indispensable and most important condition is complete immobility of the patient. For this purpose, it is necessary to ensure the stabilization of the patient using a comfortable chair with a fixing headrest and armrests. Usually the picture is taken 3-4 seconds after the command: “do not breathe.”
In recent years, a new branch of radiation diagnostics has emerged - DIGITAL RADIOGRAPHY, which is not so much an independent method of x-ray diagnostics as a progressive modification of the transformation of the energy of the x-ray beam. If in classical radiography the radiation receiver was x-ray film, then in digital radiography these are highly sensitive sensors that directly form a digital image (direct digital radiography), or electro-optical converters that create an analog video signal, which is later converted into a digital signal using an analog-to-digital converter signal. The digital code is then processed by a computer and transformed again into a visible (analog) image on the monitor screen. Computer information processing allows you to improve image quality by manipulating contrast, brightness, clarity, size, eliminating technical errors, and highlighting areas of interest. The advantages of digital radiography are also a significant reduction in radiation exposure (tens of times), economic costs (since expensive X-ray film is not used), and the possibility of archiving information. The principle of digital information processing is also used in computer, magnetic resonance imaging and in some modes of ultrasound diagnostics. Currently, digital radiography has become the leading method of radiological diagnostics.
Similar systems are widely used in dental practice: these are X-ray machines from Siemens, Finnish-made Digora devices, etc. With their help, you can obtain intraoral radiographs and panoramic tomograms.
X-RAY PROTECTION
The widespread use of X-ray examinations in dentistry requires careful monitoring of doses, given that a significant number of patients are children and young people. The biological effect of small doses of ionizing radiation associated with X-ray examinations does not cause immediate radiation reactions, but can cause so-called stochastic long-term consequences in the form of induced malignant diseases, genetic consequences, shortened life span, etc.
Radiation exposure to patients is assessed using an effective equivalent dose (EDD), which is measured in microsieverts (µSv) and is determined by measuring the exposure of vital organs that are most sensitive to the effects of ionizing radiation (lens of the eye, brain, thyroid gland, etc.).
As can be seen from the table above, the dose loads are especially high when examining the entire dentition, performed on a device of type 5D-1 and 5D-2m without additional protection. Examination using an orthopantomograph sharply reduces the radiation dose to the patient. Additional shielding, including the thyroid gland, makes the study even safer.
Thus. Radiation safety of patients can be ensured in the following ways:
The dentist’s knowledge of optimal algorithms for examining patients with various types of pathology,
The dentist’s knowledge of radiation load values for various methods of x-ray examination,
Shielding the patient’s vital and highly sensitive organs,
By diaphragming the irradiation field,
Reducing research time to a minimum, which is ensured by the quality of the film and intensifying screens.
Special research methods
PANORAMIC RADIOGRAPHY(Fig. 1) is a technique that allows you to obtain a detailed (slightly enlarged) image of one of the jaws on one film.
An X-ray machine with a special high-focus X-ray tube is used to obtain the image. The anode of the X-ray tube is inserted into the patient's mouth during imaging. When photographing the upper dentition, the focus of the tube is placed above the tongue at the level of the fifth teeth; for photographing the lower row, in the area of the frenulum under the tongue.
X-ray film with a format of 18x24 cm is placed in a flexible polyethylene cassette with high-resolution intensifying screens. During filming, the patient presses the cassette with his hands to the skin around the area of the face being examined. If the cassette is not firmly fixed, the image of the bone structure will be unclear.
Since the focus of the X-ray tube is as close as possible to the object of study, and the film is located at a certain distance from the teeth, due to the thickness of the soft tissues, the image is almost doubled in size. Thanks to this circumstance, small details that are poorly visible on conventional x-rays are visible in panoramic images.
Panoramic photographs of the upper jaw also provide images of the maxillary sinuses, nasal cavity, cusps of the upper jaw and zygomatic bones. The inferior panoramic radiograph clearly shows the mandibular canal and the base of the mandibular bone. The lateral panoramic image simultaneously displays the teeth of the upper and lower rows of each half of the jaw.
Based on panoramic images, caries and its complications, inflammatory processes, cysts, neoplasms and traumatic injuries of the jaws are diagnosed. However, this method is not suitable for assessing the degree of resorption of interalveolar ridges.
Another disadvantage of panoramic radiography is the inability to control the position of the X-ray tube applicator in the mouth.
This research method exposes the oral mucosa to significant radiation, so panoramic radiography is recommended to be used only when indicated and no more than 1-2 times a year for each patient. Additional protection with this type of radiography is ineffective, because Oral organs located outside the protective zone are exposed to irradiation.
It should be borne in mind that this technique, due to the emergence in recent years of more modern research methods, is rarely used.
LINEAR TOMOGRAPHY or layer-by-layer radiography– a method that allows you to eliminate the summative nature of the image and most clearly highlight a certain flat layer of the organ or area being studied. The essence of the method is the synchronous movement of the tube and film relative to the patient. A clear image of the layer located at the level of the geometric axis of rotation of the lever is obtained. The remaining elements of the object are blurred as a result of the dynamic blur effect. The swing angle of the X-ray tube during tomography is 30-60 є, the slice thickness is 0.2-0.5 cm. Typically, tomography is performed after survey X-rays have been taken, which make it possible to determine the required slice depth.
In dentistry, tomography is used to study the TMJ, for complex fractures of the midface, post-traumatic deformities, neoplasms, inflammatory processes and can be performed in direct and lateral projections. In the last 10-15 years, LINEAR ZONOGRAPHY has been widely used in practice - layer-by-layer research with a small swing angle of the X-ray tube (usually 8º). The advantage of zonography is that it produces thicker slices, which reduces the number of images, makes the procedure more economical and safe in terms of radiation exposure, and obtains the same information as a series of tomograms.
ORTHOPANTOMOGRAPHY (panoramic tomography)– a method that allows you to obtain an image of a curved layer on a flat X-ray film. During shooting, the tube and film cassette describe an incomplete circle around the patient’s head (270º). At the same time, the cassette rotates around its own vertical axis, as if “rolling” the patient’s jaws from the front. The X-ray beam passes through a 2 mm wide slit-shaped diaphragm, then through the anatomical structures of the head and facial part of the skull and enters new unexposed areas of the film. As with linear tomography, anatomical structures distant from the film are projectedly enlarged and their image is blurred. Modern orthopantomographs provide programs for studying the dentition, the bone structure of the upper, middle and lower zones of the facial skull, the TMJ, as well as the craniovertebral junction, the inner and middle ear, and the optic nerve canal. It is possible to change the thickness and depth of the layer being studied.
The simplicity of the method, high information content and relatively low radiation exposure allow the technique to be widely used for diagnosing almost the entire range of diseases of the maxillofacial area.
The disadvantages of the method include the unequal degree of magnification of the resulting image, as well as the deformation of anatomical structures in some types of devices.
PANORAMIC ZONOGRAPHY method is a type of orthopantomography that allows you to obtain an image of a thicker layer of the object (up to 3 cm), which increases the information content of the method.
TELERENTGRAPHY– a technique that allows you to obtain images of anatomical structures with minimal projection magnification. During teleradiography, the object of study and the film cassette are moved away from the X-ray tube to a distance of 2-2.5 m or more. The image magnification is 2-4% and can practically be neglected. Teleradiograms of the skull are performed on films measuring 24x30 cm. The photographs should show not only bone structures, but also soft tissues of the maxillofacial area, soft palate, tongue, and posterior wall of the pharynx. If necessary, soft tissues are marked with a viscous contrast agent (iodolipol, bariodol, etc.), and radiopaque marks are also applied to the soft palate. Subsequently, craniometric calculations are performed according to a certain scheme. Despite the errors that arise when analyzing teleroentgenograms, the technique is widely used in orthodontics for diagnosing and planning the treatment of malocclusions, as well as for planning surgical treatment for congenital and acquired deformities of the maxillofacial region.
CT SCAN allows you to obtain a cross-sectional layer-by-layer image of any area of the human body, including the skull. It is based on recording the energy of a beam of X-ray radiation passing through the human body at different angles when the tube is rotated by highly sensitive sensors that convert the received information into electrical signals. The latter are “digitized” and sent for analysis to a computer, where the program allows you to calculate the density of each voxel (volume unit of the layer) and present it on the display screen in the form of a pixel of the corresponding brightness. Contrast enhancement techniques are used to enhance tissue contrast. A series of cross sections can be transformed into a planar or volumetric image in any longitudinal plane.
The examination is not burdensome for the patient; when examining the maxillofacial area, it does not require special preparation.
CT is used in the diagnosis of diseases of the facial skull and dental system: fractures, tumors, cysts, systemic diseases, pathology of the salivary glands and TMJ. CT examination is especially indicated for processes in hard-to-reach locations (ethmoidal labyrinth, sphenoid bone, pterygopalatine fossa, etc.). Spiral CT scanners have a new “dental” program for studying the dentition.
However, the use of this method is associated with significant radiation exposure to the patient. Thus, with CT of the facial skull, the surface dose is 2-10, and the dose to the lens of the eye is 100 times higher than that with radiography and linear tomography.
MAGNETIC RESONANCE TOMOGRAPHY (MRI)- a method of radiation diagnostics based on recording the energy emitted by protons of hydrogen nuclei in the internal environments of the human body when they return from an excited state to their original state (so-called relaxation). Resonant excitation of nuclei and the spin effect occur under the influence of radio frequency pulses generated by the interaction of a magnet creating a static magnetic field and an additional high-frequency coil. The latter also serves to record the relaxation signal. A powerful computer analyzes the information received.
MRI allows you to obtain images of the layers of the human body in any plane - frontal, sagittal, axial, etc., which can then be reconstructed into three-dimensional images. To enhance the contrast of the tissues being studied, chemical substances containing nuclei with an odd number of protons and neutrons (fluorine compounds, paramagnetic substances) are used, which change the relaxation time of water. This method has advantages in visualizing soft tissues, such as muscle, fat, cartilage, etc., which makes its use especially necessary when studying the TMJ, mucous membranes of the paranasal sinuses and oral cavity, salivary glands and other soft tissue structures of the head and neck . The method is not burdensome for the patient and does not have any harmful effects on his body. A contraindication for MRI examination is the presence of metal foreign bodies in the patient (including some types of crowns).
Artificial contrast techniques
Artificial contrast is widely used in practical work in the study of: ducts of the salivary glands (sialography), fistulous tracts (fistulography), maxillary sinuses (maxillary sinusography), etc.
SIALOGRAPHY. On plain radiographs, the salivary glands are usually not visible; only shadows of radiopaque salivary stones can be detected. To examine the ducts of the salivary glands, 1.5-3 ml of contrast agent is injected at the mouth of the duct using a blunt-tipped needle or through a thin catheter until a feeling of tension appears in the gland area. As contrast agents, water-soluble contrast agents of high viscosity or sharply diluted and emulsified oil preparations (dianosyl, ultra-liquid lipiodol, ethiodol, mayodil, etc.) are used. Pictures are taken in frontal and lateral projections. To obtain a contrast image of all major salivary glands simultaneously, orthopantomography is also indicated. Sialography is used to diagnose salivary stone disease, inflammatory and tumor processes.
DOUBLE CONTRAST– the technique consists of simultaneous injection of lipoiodol into the ducts of the salivary glands, and oxygen into the tissues surrounding the gland. This technique is the most informative in the diagnosis of tumor processes of the salivary glands.
FISTULOGRAPHY– filling the fistula tracts with a contrast agent in order to study their extent, direction, and connection with the pathological process in the image. Warmed iodolipol is used as a contrast agent. Immediately after the administration of the contrast agent, photographs are taken in two mutually perpendicular projections.
ARTHROGRAPHY used to study the condition of the TMJ and, first of all, to clarify the condition of the intra-articular meniscus. Under the control of a television screen, 0.8-1.5 ml of a viscous water-soluble contrast agent is injected into the joint cavity and tomograms or zonograms of the joint are performed with the mouth open and closed.
ANGIOGRAPHY– a technique for studying the vessels of the maxillofacial area using water-soluble and non-ionic contrast agents (cardiotrast, verografin, hypaque, omnipaque, ultravist, etc.). The technique is performed in a cath lab environment.
Angiography is used to diagnose diseases and anomalies of the vascular system (hemangiomas, juvenile angiofibromas of the skull base). In the practice of maxillofacial surgery, this technique is used quite rarely.
HIMOROGRAPHY– X-ray examination of the maxillary sinuses after introducing a contrast agent into them by puncturing its wall, through the socket of an extracted tooth (if there is communication with the sinus) or through a fistulous tract. After aspiration of the sinus contents, 3-7 ml of slightly warmed contrast (iodolipol, iodipine, lipiodol, etc.) is injected. Pictures are taken in the nasomental and lateral projections. The technique is indicated for the diagnosis of cysts, sinus polyps, productive forms of sinusitis, and tumor diseases.
ULTRASONOGRAPHY. The method is based on the effect of registering reflected ultrasonic radiation within the range of 1.0-2.0 MHz and forming a linear (static) or multidimensional (dynamic) image. The method is harmless and informative when studying soft tissues. It is quite widely used in the diagnosis of diseases of the salivary glands, pathology of the soft tissues of the neck, and lymph nodes.
22.09.2014
X-ray research methods are leading in the diagnosis of diseases of the maxillofacial region, due to their reliability and information content. X-ray diagnostic methods have found wide application in the practice of therapeutic dentistry (for identifying peri- and periodontal diseases); in orthopedic dentistry (to assess the condition of remaining teeth, periapical tissues, periodontal tissue), which determines the choice of orthopedic measures. X-ray methods are also in demand in maxillofacial surgery in the diagnosis of traumatic injuries, inflammatory diseases, cysts, tumors and other pathological conditions.
The method and technique of x-ray examination of teeth and jaws has its own characteristics.
The following methods of radiation diagnostics are used in dental practice:
. Intraoral contact radiograph
. Intraoral bite radiography
. Extraoral radiographs
. Panoramic radiography
. Orthopantomography
. Radiovisiography
Additional research methods:
. CT scan
. Magnetic resonance imaging
. Methods with the introduction of contrast agents
1. Intraoral contact radiography
The basis of radiological examination for most dental and periodontal diseases is still intraoral radiography.
It is performed on a special dental X-ray machine (although it can also be performed on a regular one).
For intraoral radiography, bagged or specially cut (3x4 cm) film is used, packaged in light-proof standard bags.
One image can show no more than 2-3 teeth
2. Intraoral bitewing radiography.
Bitewing radiographs are performed in cases where it is impossible to take intraoral contact photographs (increased gag reflex, trismus, in children), if it is necessary to study large sections of the alveolar process (for 4 teeth or more) and the hard palate, to assess the condition of the buccal and lingual cortical plates of the lower jaw and floor of the mouth.
A standard envelope with film is inserted into the oral cavity and held with closed teeth. Bitewing radiographs are used to examine all upper and lower anterior teeth.
Also, occlusal radiography is used to obtain an image of the floor of the mouth in case of suspected stones of the submandibular and sublingual salivary glands, to obtain an image of the jaws in an axial projection. It allows you to clarify the course of the fracture line within the dentition, the location of bone fragments, the state of the outer and inner cortical plates in cysts and neoplasms, and identify the reaction of the periosteum
3. Extraoral (extraoral) radiographs.
Extraoral radiographs make it possible to assess the condition of the upper and lower jaws, temporomandibular joints, and facial bones that are not imaged or are only partially visible on intraoral photographs.
Due to the fact that the image of the teeth and surrounding formations is less structural, extraoral photographs are used to evaluate them only in cases where it is impossible to perform intraoral radiographs (increased gag reflex, trismus, etc.). 
The chin-nasal projection is used to examine the upper jaw, maxillary sinuses, nasal cavity, frontal bone, orbit, zygomatic bones and zygomatic arches. 
On radiographs of the facial skull in the frontonasal projection, the upper and lower jaws are visible, the bones of the base of the skull and cervical vertebrae are projected onto them.
X-rays of the body and ramus of the lower jaw in the lateral projection are carried out using a dental X-ray diagnostic apparatus. 
An x-ray of the skull in the anterior axial projection is performed to evaluate the walls of the maxillary sinus, including the posterior one, the nasal cavity, the zygomatic bones and arches; it shows the lower jaw in an axial projection.
4. Panoramic tomography
More than three decades ago, panoramic radiography was included in the arsenal of X-ray diagnostics of diseases of the dental system, ENT organs and other parts of the skull. In this test, an X-ray tube applicator is inserted into the patient's mouth and a cassette is placed around the upper or lower arch of the jaw. In both cases, the patient holds the cassette from the outside with his palms, pressing it tightly against the soft tissues of the face.
A lateral panoramic tomography is also performed; the lateral panoramic image simultaneously displays the teeth of the upper and lower rows of each half of the jaw.
Direct panoramic radiographs have an advantage over intraoral photographs in the richness of detail in the image of bone tissue and hard dental tissues. With minimal radiation exposure, they allow one to obtain a wide view of the alveolar process and dentition, facilitate the work of the x-ray technician and sharply reduce the examination time. These photographs clearly show tooth cavities, root canals, periodontal fissures, interalveolar ridges and the bone structure of not only the alveolar processes, but also the bodies of the jaws. Panoramic radiographs reveal the alveolar bay and the lower wall of the maxillary sinus, the mandibular canal and the base of the mandibular bone.
Based on panoramic images, caries and its complications, cysts of various types, neoplasms, damage to the jaw bones and teeth, inflammatory and systemic lesions are diagnosed. In children, the condition and position of the tooth buds are well determined. 
5. Orthopantomography
Panoramic zonography, or, as it is more often called, orthopantomography, was a kind of revolution in the radiology of the maxillofacial region and has no equal in a number of indicators (review of a large part of the facial skull under identical conditions, minimal radiation exposure, short time spent on research) .
Panoramic zonography allows you to obtain a flat image of curved surfaces of volumetric areas, for which rotation of the X-ray tube and cassette is used.
The advantage of orthopantomography is the ability to demonstrate intermaxillary contacts, evaluate the results of the impact of intermaxillary load on the condition of the end plates of the sockets and determine the width of the periodontal tracts.
Orthopantomograms demonstrate the relationship of the teeth of the upper row with the bottom of the maxillary sinuses and make it possible to identify pathological changes of odontogenic origin in the lower parts of the sinuses.
It is especially important to use orthopantomography in pediatric dentistry, where it has no competitors due to low radiation doses and the large amount of information obtained. In pediatric practice, orthopantomography helps diagnose fractures, tumors, osteomyelitis, caries, periodontitis, cysts, determine the characteristics of teething and the position of the rudiments. 
6. Radiovisiography
Radiovisiography produces an image recorded not on x-ray film, but on a special electronic matrix that is highly sensitive to x-rays. The image from the matrix is transmitted via a fiber optic system to a computer, processed there and displayed on the monitor screen. During the processing of a digitized image, its size can be increased, contrast enhanced, polarity changed, if necessary, from negative to positive, and color correction.
The computer makes it possible to study certain zones in more detail, measure the necessary parameters, in particular the length of the root canals, and densitometry. The image from the monitor screen can be transferred to paper using the printer included in the equipment package. Of all the advantages of digital X-ray image processing, we especially note the following: the speed of obtaining information, the possibility of eliminating the photo process and reducing the dose of ionizing radiation to the patient by 2-3 times.
7. Computed tomography (CT).
The method allows you to image not only the bone structures of the maxillofacial area, but also soft tissues, including skin, subcutaneous fat, muscles, large nerves, blood vessels and lymph nodes.
Computed tomography is widely used in recognizing diseases of the facial skull and dental system: pathologies of the temporomandibular joints, congenital and acquired deformities, fractures, tumors, cysts, systemic diseases, pathologies of the salivary glands, diseases of the nasopharynx and oropharynx.
The method allows one to resolve diagnostic difficulties, especially when the process spreads to the pterygopalatine and infratemporal fossa, orbit, and cells of the ethmoidal labyrinth.
With the help of CT, intracranial complications of acute sinusitis (epidural and subdural abscesses), involvement of orbital tissue in the inflammatory process, and intracranial hematomas in injuries of the maxillofacial area are well recognized.
Computed tomography allows you to accurately determine the location of lesions, carry out differential diagnosis of diseases, and plan surgical interventions and radiation therapy. 
8. Contrasting methods.
Among the numerous methods of contrast radiological examinations for maxillofacial pathology, the most commonly used are arthrography of the temporomandibular joints, angiography, sialography, and dacryocystography.
Sialography consists of examining the ducts of the large salivary glands by filling them with iodine-containing preparations. For this purpose, water-soluble contrast or emulsified oil preparations (dianosyl, ultra-liquid lipoidinol, ethidol, mayodil, etc.) are used. Before administration, the drugs are heated to a temperature of 37-40 ° C to prevent cold vascular spasm.
The study is carried out to diagnose mainly inflammatory diseases of the salivary glands and salivary stones.
A special cannula, a thin polyethylene or non-Laton catheter with a diameter of 0.6-0.9 mm or a blunt and slightly bent injection needle is inserted into the opening of the excretory duct of the salivary gland under study. After bougienage of the duct, a catheter with a mandrel, inserted into it to a depth of 2-3 cm, is tightly covered by the walls of the duct. To study the parotid gland, 2-2.5 ml are injected, and the submandibular gland - 1-1.5 ml of a contrast agent.
Radiography is carried out in standard lateral and direct projections, sometimes axial and tangential images are taken.
The introduction of contrast agents into cystic formations is carried out by puncturing the cyst wall. After suctioning out the contents, a heated contrast agent is injected into the cavity. Radiographs are performed in two mutually perpendicular projections. 
Contrasting fistula tracts (fistulography) is performed to determine their connection with a pathological process or foreign body. After introducing a contrast agent under pressure into the fistula tract, radiographs are taken in two mutually perpendicular projections.
To contrast arterial and venous vessels of the maxillofacial area (for formations, hemangiomas), a contrast agent can be administered in three ways. The simplest of them is puncture of the hemangioma with the introduction of a contrast agent into the thickness of the tumor and registration of the image on separate images. To get an idea of the extent of the tumor in direct and lateral projections, the puncture is performed 2 times. The technique allows us to identify the nature of venous changes, but does not always allow us to see the details of the blood flow, the vessels approaching the hemangioma, and is not suitable for contrasting the arterial vascular network.
For cavernous hemangiomas and arteriovenous shunts, it is practiced to inject contrast agents into the afferent vessel, which is isolated surgically.
For pulsating arterial and arteriovenous formations, serial angiography is performed after the introduction of contrast agents into the afferent vessel.
Purposeful integrated use of clinical and radiological data in a single scheme for examining patients with pathology of the dentoalveolar region allows not only to make the primary and differential diagnosis more accurate, but also to objectively assess the effectiveness of the treatment. Using a digital image, it is possible to correct distortions, thanks to the improvement of visual characteristics, to identify subtle differential diagnostic pathological conditions, and to transfer the image by e-mail for subsequent consultations with specialists.
Prospects for the further use of an X-ray computer network in dental practice are associated with increasing the technical capabilities of modern X-ray equipment, optimizing computer programs for image analysis, as well as the development of rational diagnostic algorithms for a comprehensive clinical and radiological examination of patients, depending on the nosological form of the disease and the objectives of the upcoming treatment.
Caries constitutes the most common group of dental diseases and is characterized by local destruction of enamel, dentin and cement, which determines the x-ray picture of the disease. Teeth are affected in people of any age, but more often in children. Defects in teeth can range from barely noticeable to pronounced cavities of various shapes and sizes. The X-ray picture of caries is characterized by a defect in the tooth tissue and depends on the shape and depth of the carious cavity.
X-ray examination is of great importance for the diagnosis of carious defects localized on the contact surfaces of the tooth, in the neck or root area, under fillings, crowns, etc. If the carious defects of the teeth are not edge-forming, then it is very difficult to diagnose them radiographically.
Periodontitis(pericementitis) is an inflammatory process of the periodontium as a result of infection. It begins at the root apex and then spreads to the entire periodontal space.
Acute periodontitis is not recognized radiologically.
Chronic periodontitis is characterized by an increase in the size and deformation of the periodontal fissure, disruption of the integrity of the interalveolar septa and changes in the structure of the tissues around the alveoli.
Based on clinical and anatomical changes, granulating, granulomatous and fibrous forms of chronic periodontitis are distinguished (I. G. Lukomsky).
Granulating form of periodontitis characterized by the proliferation of granulations and purulent melting of tissue around the periodontium. The X-ray picture fully reflects the pathological changes and is manifested by an increase in the periodontal fissure, often in the area of the root apex, and destruction of the interalveolar septa.
Granulomatous periodontitis is characterized by the formation of a localized granuloma located at the apex of the root and presented on the radiograph as a focus of irritation or destruction of bone tissue of an irregular round shape with clear, even contours. With the so-called cystic granuloma, the defect has a spherical shape with more sharply and clearly defined boundaries, and often with the presence of a surrounding sclerotic shaft.
Fibrous periodontitis is the final phase of acute periodontitis or a favorable outcome of granulating and sometimes granulomatous periodontitis and represents the most benign form of chronic periodontitis. Accompanied by the development of coarse fibrous connective tissue in the presence of separate foci of inflammatory infiltration, fibrous periodontitis is characterized by the following X-ray picture: the periodontal fissure is deformed and unevenly widened, the closing compact plate is not only preserved, but often appears compacted and sclerotic. A long course of the process may be accompanied by hypercementosis, as a result of which the tooth root appears thickened.
Osteomyelitis of the upper and lower jaw can be traumatic, odontogenic and hematogenous. Traumatic osteomyelitis often occurs as a complication of fractures of the lower jaw and within the dental arch, and can also be caused by odontogenic infection.
Despite the significant achievements of modern surgical dentistry and the presence of a large arsenal of antibiotics, the frequency of inflammatory complications in fractures, especially of the lower jaw, continues to remain quite high.
Many authors point out the connection between the developing osteomyelitic process and infection of bone tissue from oral cavity- II chronic inflammatory foci in the periodontium.
The relatively rare occurrence of traumatic osteomyelitis in the upper jaw is due not only to the rarer damage to this bone, but also to the peculiarities of its blood supply.
In most cases, there are no clinical manifestations at the first stages of the development of osteomyelitis, since they are masked by post-traumatic swelling of the soft tissues. The first radiological symptoms of traumatic osteomyelitis are detected after 8-10 days. By this time, the contours of the bone fragments become uneven and unclear, foci of bone tissue destruction appear on the edges of the fragments, which initially look like spotty osteoporosis, and then merge and turn into foci of destruction.
Sequesters in traumatic osteomyelitis can be formed from necrotizing small fragments or necrotizing zones of bone fragments. X-ray sequestration appears as a significantly greater shadow intensity compared to the density of healthy tissue. The unique structure of the lower jaw contributes to the formation of very small spongy sequestra, the diagnosis of which is significantly difficult.
Odontogenic osteomyelitis- an inflammatory process in bone tissue caused by dental and periodontal disease. It occurs more often in children of younger age groups.
The clinical manifestation of the disease and its radiological symptoms do not coincide in time. Only on the 8-10th day are areas of osteoporosis revealed, which quickly turn into zones of bone tissue destruction, covering large areas of the jaw. Sequesters are formed in the spongy and cortical substance. With timely active treatment after rejection of sequestra in the area of the osteomyelitic process, children experience rapid restoration of bone tissue.
The most rare is the hematogenous form of osteomyelitis of the jaws; Young people, more often men, get sick. The disease is spreading! with high body temperature, symptoms of intoxication.
First X-ray symptoms appear on the 8-10th day. Hematogenous osteomyelitis is characterized by extensive pathological changes, often involving almost completely the bone. Areas of osteoporosis merge and form multiple sites of destruction BONE tissue, with the presence of sequesters of various sizes and shapes. Periostitis is detected when
transition to the chronic phase.
Chronic osteomyelitis is characterized by the presence of both necrotic and destructive changes, and regenerative processes.
X-rays reveal extensive areas of destruction of the lower jaw with the presence of sequesters, prolonged course of the disease and well-defined regenerative processes; the bone tissue is unevenly compacted and sclerosed.
Complications of osteomyelitis in the jaw bones are rare. With osteomyelitis of the lower jaw, a pathological fracture and the formation of a pseudarthrosis can be observed. Osteomyelitis of the maxilla can spread to the maxillary sinus, palate and nasal cavity. Fistulas are a common complication of osteomyelitis of the jaws.
Periodontal disease. The disease is based on a degenerative-dystrophic process in the tissues surrounding the tooth, which is progressive in nature and simultaneously affects the alveolar processes of both jaws. The disease is accompanied by loosening of the teeth, and then serous and purulent discharge appears from the gum pockets.
The etiology and pathogenesis of the disease are not clear. Most domestic scientists consider periodontal disease as a disorder of neurotrophic function. Disturbance of periodontal trophism during sclerosis of arterioles of the alveolar process is of great importance, and an important role in this is played by neurogenic factors.
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