05.09.2022

X-ray diagnostics in dentistry. Radiography (radiation diagnostics) in modern dentistry: what does a picture of a healthy tooth and caries look like? X-ray research methods in dentistry

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 temperature body, intoxication phenomena.

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. Great importance has a violation of periodontal trophism due to sclerosis of arterioles of the alveolar process, and an important role in this is played by neurogenic factors.

X-RAY EXAMINATION

In modern dentistry, various X-ray diagnostic methods are widely used. The main method of X-ray examination in surgical dentistry is radiography. IN Lately New methods of X-ray examination of teeth and jaws have been developed and put into practice - panoramic tomography, teleradiography, X-ray cinematography, which make it possible to give a more complete X-ray characterization of most dental diseases.

There are two methods of dental radiography - intraoral (intraoral) and extraoral (extraoral). Intraoral photographs, in turn, are divided into contact and bite-based.

When taking contact photographs, a film wrapped in black or wax paper is pressed against the mucous membrane of the inner surface of the alveolar process of the jaw. Bite photographs - the film is clamped between the teeth of the upper and lower jaws. Extraoral x-rays are often used to view the mandible, facial bones, temporomandibular joint, paranasal sinuses, zygomatic and cranial bones, and salivary glands.

On survey radiographs of the facial bones in direct, lateral and axial projections, both (upper and lower) jaws and palatine bones, forming the bony walls of the oral cavity, are identified. For a detailed analysis of a number of anatomical formations, special targeted images are used. Sight radiography is performed intra- and extraorally. Intraoral photographs taken in the bite are used to study the bony palate, alveolar processes of the upper and lower jaws, and the floor of the mouth. Contact intraoral photographs with a film pressed against the alveolar process make it possible to study the structure of the corresponding limited areas of the upper and lower jaws, periodontium and teeth. Extraoral x-rays are taken to study the structure of the bones of the maxillofacial area.

The upper jaw in a direct anterior projection can be traced from the infraorbital margin to the alveolar process. It is projectively shortened. In the lateral sections, the body of the upper jaw is limited by a clear concave contour, smoothly passing outward and upward into the zygomatic bone. The nasal cavity is located medially above the bony palate, and the sinuses of the same name are located laterally in the bodies of the maxillary bones. In the nasomental projection, the distortion of the body of the upper jaw is less than in the anterior view. In the lateral projection, the right and left upper jaws are projectively summed up. The bony palate is represented by an intense linear shadow extending to the anterior part of the alveolar process of the upper jaw. At this level it bifurcates. One of the lines, continuing horizontally anteriorly, is the bottom of the nasal cavity, and the second, arcuately deviating downwards, is formed by the vault of the oral cavity. The alveoli and teeth are not clearly differentiated due to summation.

Intraoral radiography of the bony palate is performed in the axial chin position. The central x-ray beam is directed from top to bottom at the tip of the nose in relation to the film at an angle of 75°, open anteriorly. The bony palate on intraoral radiographs is defined as irregular rectangles with an anterior rounded contour. The posterior contour cannot be reproduced, since it is impossible to introduce the film into the oral cavity to the required depth. The anterior and lateral contours of the bony palate are bordered by the alveolar arch with teeth located on it. The structure of the bony palate is finely looped, oval or round in shape with alveolar lacunae measuring 3-5 mm, located near the incisors in the thickness of the spongy substance.

The median palatine suture can be traced in the sagittal plane. The incisive foramen has the appearance of an oval lucency, turning into a narrow slit-like incisive canal, located parallel or at an angle to the median palatal suture. When the projection coincidence of the incisive foramen with the apex of the incisor root, it resembles a granuloma. Unlike granuloma, the incisive opening, projected onto the root of the tooth, and on repeated radiographs taken with a change in the centering of the beam of rays, projectionally moves relative to its root. In this case, the tooth and periodontal gap are not changed.

The lower jaw is also examined on survey and targeted radiographs. On survey x-rays of the facial bones in the anterior and nasomental projections, the body of the jaw is projected in the form of an irregular quadrangle with a convex lower contour, passing into the area of the angle in its branches. The base of the lower jaw is represented by a clear wide (up to 2-4 mm) strip of the cortical layer. The formation of the upper contour is due to the alveolar arch of the lower jaw and the alveoli with the teeth located in them. On a radiograph in the nasomental projection, the sockets and heads of the temporomandibular joints with the articular spaces located between them, as well as the neck of the lower jaw, are clearly visible, which makes it possible to evaluate them in comparison. The coronoid and condylar processes coincide in projection.

On a radiograph taken in an axial projection, the lower jaw is projected onto the middle cranial fossa and gives a convex horseshoe-shaped shadow caused by the body and projectionally shortened branches of the lower jaw. The condylar processes end in transversely oriented ovals of the head of the mandible. The coronoid processes are revealed in the form of triangular pointed formations located medially from the condylar ones. On a targeted lateral radiograph of the lower jaw, the same details are determined as on a survey one, but without significant projection layering. The examined half of the body of the lower jaw and its branch with the coronoid and condylar processes and the notch located between them are clearly visible. The anterior section of the jaw body, oriented orthogradely along the central ray, forms an oval-shaped clearing with clear, intense contours. The cortical layer of the base of the lower jaw reaches 3-4 mm in an adult.

The alveolar arch of the lower jaw does not have projection layers to the level of the premolars; it is covered medially by the opposite side of its body. The structure of the spongy substance is wide-lobed. In the body and lower part of the jaw branch, the mandibular canal can be traced - a linear clearing with dense walls. At the point of transition of the body into the branch there is an arched or obtuse angle of the lower jaw. The coronoid process is clearly contoured, its apex can projectively coincide with the angle of the opposite side of the lower jaw, less often with the tubercle of the upper jaw. The condylar process coincides with the image of the cervical vertebrae.

On a targeted radiograph of the temporomandibular joint, taken in a lateral projection, the bottom of the glenoid cavity is clearly defined. Anterior to it is the articular tubercle of the temporal bone, which continues at the base of the zygomatic arch. The head of the lower jaw has the shape of a compacted semi-oval and smoothly passes into the condylar process of the jaw. The head is covered with a thin cortical layer, which thickens significantly in the neck area. The joint space is widened in the central section, corresponding to the deepening of the bottom of the articular cavity.

Application of the X-ray method of examination in the diagnosis of odontogenic inflammatory diseases. Periodontitis is inflammation of periodontal tissue. Granulating periodontitis is an active form of inflammation, characterized by frequent exacerbations. With granulating periodontitis, on radiographs performed using the intraoral method of examination (regardless of the degree of exacerbation), in the bone at the apex of the tooth root one can discern an area of bone tissue resorption with uneven and unclear contours. Bone destruction can spread to the alveoli of adjacent teeth. Sometimes partial resorption of the root of the causative tooth is detected. Periodontitis of multi-rooted teeth leads to resorption of the interradicular bone septum. At the same time, on radiographs, the roots of the teeth are visible against the background of an area of osteolysis of bone tissue that does not have clear boundaries. Chronic periodontitis of the central incisors of the lower jaw, especially traumatic, is accompanied by bone loss around their roots and resembles a perihilar cyst in size and shape. The final diagnosis is established after pathohistological examination of the removed tissues.

Granulomatous periodontitis (granuloma) is asymptomatic for a long time. On x-rays taken using the intraoral method of examination, a center of destruction of a round shape with clear contours is detected at the apex of the tooth root. The apices of the roots of the teeth included in the granuloma are often resorbed. In children, during the formation of the apex of the roots of the teeth, on radiographs these places resemble a granuloma, especially if a carious cavity is found in the coronal part of the tooth. It should be remembered that with granulomas the end plate of the alveoli is partially destroyed, but in growing teeth at the stage of an unclosed apex it is preserved. At the stage of the Unformed apex, the root is thin, with a wide canal, expanding in the form of a center of clearing, clearly surrounded by a closing plate.

Fibrous periodontitis is essentially the outcome of an acute inflammatory process. On the radiograph, the periodontal fissure of the affected tooth is widened over a large area and narrows in places. If the periodontium has undergone ossification as a result of inflammation, the periodontal fissure is absent on the radiograph.

Periostitis. Exacerbation of chronic periodontitis leads to acute periostitis of the jaws. According to radiological signs, acute periostitis is indistinguishable from periodontitis, while chronic periostitis is characterized by radiological changes. A muff-like compaction with smooth and indistinct boundaries appears on the lower jaw. Bite radiographs reveal a soft tissue shadow of infiltrated periosteum. Chronic ossifying periostitis is detected on the outer surface of the lower jaw in the form of a linear shadow or hemispherical bone formation, inferior in intensity to the structure of the cortical substance of the jaw. Referential periostitis most often has a post-traumatic origin and is localized in the lower jaw in the area of the anterior teeth. X-ray shows a focus of osteoporosis of bone tissue with fairly clear boundaries, which resembles a radicular cyst, but unlike it, the periodontal gap of the teeth located in the affected area is not changed.

Odontogenic osteomyelitis. It is impossible to differentiate acute odontogenic osteomyelitis of the jaw from periostitis radiographically, since the phenomena of destruction are not yet clearly expressed. Bone necrosis occurs on the 3rd-4th day, but the first signs of bone tissue damage on radiographs can be detected only by the end of the 2-3rd week from the onset of the disease. Changes in the jaw are manifested by the unclearness of their structure, and subsequently foci of osteolysis or necrosis appear. In the subacute phase, a zone of sclerotic demarcation gradually appears around them, more clearly expressed in the lower jaw. In the upper jaw after 5-6 weeks, and in the lower jaw after 6-7 weeks, cavities containing bone sequestra, denser than the surrounding bone tissue, are clearly visible on X-ray. The edges of the sequestra are uneven, jagged. Between them and the viable bone tissue, a clearing zone is visible; its appearance is due to the formation of pus and granulations. In the chronic phase, as sclerosis develops, sequestral cavities form. Around them in the lower jaw, as a result of subperiosteal bone formation, a sequestral capsule is formed, clearly visible on the radiograph. A sequestral capsule does not form on the upper jaw. Bone regeneration in the upper jaw is much less pronounced than in the lower jaw. Chronic odontogenic osteomyelitis after removal of rejected bone sequestra is completed by reparative processes. After sequestrectomy, X-ray control is performed. Its implementation is necessary to determine the effectiveness of surgical treatment and detect bone regeneration.

Pericoronitis. An X-ray of the lower jaw taken in a lateral view shows the wisdom tooth in an incorrect position in relation to the lower jaw and other teeth. It can be tilted (at different angles) with the crown forward or backward. In the first case, it rests on the tooth in front, in the second - on the anterior edge of the lower jaw branch. In a strictly vertical position, the tooth is in inclusion. With repeated exacerbations, an x-ray taken in a lateral projection can reveal bone resorption between the second and third molars or behind the crown of the wisdom tooth, in the anterior edge of the mandibular ramus. The presence of these changes and corresponding clinical symptoms allows us to establish a diagnosis with maximum confidence. The tactics of medical manipulations depend on the nature of the changes detected radiographically in the hard tissues of the tooth in front and in the bone tissue surrounding the crown of the wisdom tooth on the distal side. According to Harniseh, expansion of up to 2 mm of the pericoronal space on the distal side of the wisdom tooth crown is a physiological norm.

Odontogenic sinusitis. To study diseases of the maxillary sinus and identify their causal relationship with the teeth of the upper jaw, both intraoral and extraoral x-rays are used. In our opinion, of all the positions used for radiography of the maxillary sinuses, the most appropriate is the anterior nasofrontal one. Inflammatory processes in the maxillary sinus create an x-ray picture ranging from slight veiling to complete disappearance of radiation permeability. If during a tooth extraction operation the root is pushed into the maxillary sinus, it is not always possible to detect it on extraoral x-rays. To locate the tooth, an intraoral contact photograph is taken.

Contrast radiography of the salivary glands - sialography - is a reliable diagnostic method and is included in the examination plan for patients with inflammatory diseases of the corresponding anatomical areas.

For sialography, we use aqueous solutions of triiodinated organic compounds: Visotrast 76%, Urotrast 75%, Verotrast 76%, Urografin 76%, etc. They are low-toxic, quite radiopaque, have a high resorption capacity, due to which they do not remain in the gland even with significant impairment its functions. However, it is difficult to administer water-soluble radiopaque contrast agents with a conventional syringe. A. M. Solntsev and co-authors developed a special technique for sialography using water-soluble X-ray contrast agents.

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.

I.I. Sergeeva, T.F. Tikhomirov, V.V. Rozhkovskaya, N.A. Savrasova, Belarusian State Medical University

Presented are the data on the basic and special methods of beam research used in diagnostics of diseases of maxillofacial area. Diagnostic opportunities of methods are considered and indications to their application are determined. Opportunities of modern methods - a computer tomography, ultrasonic research are covered also.

Key words: roentgenography, intraoral roentgenography, a linear, panoramic and computer tomography, ultrasonic diagnostics.

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:

· plain 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) photographs of the jaws are performed 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 continues to be the basis of radiographic examination for 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).

One of the objectives of this technique is to obtain an image of teeth identical to their true size. To reduce projection distortion 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).

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.

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.

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 radiography of the upper jaw, the film is inserted deeply into the oral cavity and clenches it with his 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 last years A new branch of X-ray diagnostics has appeared - 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 an 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 the radiation load values during various methods x-ray examination,

shielding the patient’s vital and highly sensitive organs,

· diaphragm of 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.

Fig.1. Panoramic radiograph of the upper jaw

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 kept in mind that this technique, due to the emergence in recent years of more modern methods research, rarely used.

LINEAR TOMOGRAPHY or layer-by-layer radiography is 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) (Fig. 2) is 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.

Fig.2. Panoramic tomogram of the lower face area

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.

The PANORAMIC ZONOGRAPHY method (Fig. 3) 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.

Fig.3. Panoramic zonogram of the midface

TELERENTGRAPHY is 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.

COMPUTED TOMOGRAPHY allows you to obtain a transverse layer-by-layer image of any area human body, including skulls. 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 IMAGRAPHY (MRI) is a radiation diagnostic method 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, use chemical substances, containing nuclei with an odd number of protons and neutrons (fluorine compounds, paramagnets), 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 is 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 is 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.

MAXILLARY - X-ray examination of the maxillary sinuses after the introduction of 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.

Bibliography

1. Arzhantsev A.P. Diagnostic capabilities of panoramic zonography of the maxillofacial region: Author's abstract. dis. ...Dr. med. Sciences: 14.00.21, 14.0019 / TsNIIS Ministry of Health of the Russian Federation. - M., 1998. – 29 p.

2. Computed tomography in the diagnosis of head and neck diseases / A.G. Prikhodko, Yu.P. Efimtsev, V.V. Bazhenov and others // Vestn. radiology and radiology. – 1991. - No. 4. - P.38-43.

3. Lindenbraten L.D. Medical radiology and radiology./ Lindenbraten L.D., Korolyuk I.P - M. Medicine, 1993. - P. 438-504.

4. Orthopantomography in dentistry: Method. recommendations / Ministry of Health of the USSR; Developed Central Research Institute of Dentistry; Comp.: N.A. Rabukhina, E.I. Zhibitskaya, A.P. Arzhantsev, E.G. Chikirdin. – M., 1989. - 17 p.

5. Rabukhina N.A. Zonografiya of the maxillofacial region on a panoramic tomograph “Zonark” / N.A. Rabukhina, E.I. Zhibitskaya // Vestn. radiology and radiology. – 1986. - No. 3. – P. 27-31.

6. Rabukhina N.A. X-ray diagnostics in dentistry / N.A. Rabukhina, A.P. Arzhantsev. – M.: LLC “Med. information agency”, 1999. – 452 p.

7. Radiation safety in maxillofacial radiology / N.A. Rabukhina, R.V. Stavitsky, E.V. Sakharova and others // Vestn. radiology and radiology. - 1993. - No. 3. - P. 55-57.

8. Rabukhina N.A. Current state of maxillofacial radiology // New in dentistry. - 1993. - No. 1. - P. 2-18.

9. Bergstedt H. Zonarc: a new unit for X-raytomography of the skull and cervical spine / H. Bergstedt, M. Heverling // Electromedica. - 1985. – Vol. 53, No. 4. - P. 168-173.

10. Radiation doses during panoramic zonography, linear tomography and plain film radiography of maxillofacial skeleton / P. Paukku, J. Gothlin, S. Totterman e.a. //Eur. J. Radiol. – 1983. - Vol. 3, No. 3. – P. 239-241.

X-ray examinations in dentistry should be carried out both in relation to the lesion and for systemic studies of the gastrointestinal tract, lungs, kidneys, and joints. Although radiological research methods in dentistry are set out in special manuals, we took the liberty of dwelling on a number of features of the examination of the maxillofacial area that will be useful to both dentists and radiologists. Currently, the vast majority of dental patients undergo X-ray examination.

When performing an X-ray examination, it is necessary to take into account the physiological and anatomical specifics of the maxillofacial area: the presence of airiness in the sinuses, bones with different densities, layering of bones and cavities on the opposite side, involuntary displacement of the lower jaw during imaging. Without taking these features into account, you can make a mistake in an x-ray examination and thereby incorrectly diagnose the disease or fail to detect the lesion. A slight deviation of the beam due to incorrect installation of the device, insufficient exposure will give a fuzzy and incorrect image on the film. The teeth can be depicted as very elongated or shortened. The roots of multi-rooted teeth overlap each other on the radiograph. The contours of the bones are sometimes mistaken for the fracture line of the roots.

The radiologist must clearly know the basics of the direction of rays for various projections of the teeth of the lower and upper jaws. This avoids the above mistakes.

One of the features of radiography in dentistry is that X-rays of the maxillofacial area must be developed quickly in order to immediately give an opinion. It is necessary to take into account and be aware of some differences in the visibility of tissues in wet and dry photographs.

With the help of X-ray images of the maxillofacial area, intraoral, targeted and overview images, external overview images, orthopantomographic images, panoramic images are produced, X-ray cinematographic and tomographic studies, electro-radiographic studies are carried out.

To avoid mistakes and taking into account the complexity of the maxillofacial area, when performing radiography, cavities are filled with a contrast mass - iodolipol. This method is especially useful when it is necessary to distinguish the edge of the maxillary sinus from the border of a cyst or an area of bone loss. Inexperienced doctors often mistake a sinus bulge for a cystic formation or granuloma. Using a contrast agent, it is necessary to examine the condition of the ducts of the salivary glands and perform sialography.

Sialography is used to study the salivary glands. Damage to the ducts and parenchyma of the gland can be determined by injecting a contrast agent - iodolipol. Warmed iodolipol is injected into the salivary ducts through a blunt needle from a syringe under pressure. Pouring should be done in the X-ray room.

In order to determine pathological changes located deep in tissues, a tomography method is used, which allows one to obtain an X-ray image of a certain layer of bone or tissue located at a particular depth.

As auxiliary methods for diagnostic purposes in dentistry, the use of fluoroscopy and fluorography is not excluded, especially when identifying foreign bodies, fractures and the presence of conglomerates in the salivary glands.

The dentist must be able to analyze radiographs, since not all dental institutions have radiologists, and the conclusion must be given during the treatment process. The patient should not be released from the facility until the doctor gives an opinion on the x-ray.

Radiographs reveal the shape and size of the roots, the shape and width of the canals, theriodont, the structure of the bone tissue, and determine the patency and quality of canal filling. When giving a conclusion based on x-rays, it is necessary to take into account the patient’s age (senile changes in bones, juvenile bones), concomitant diseases in which specific changes in teeth and bones may occur (endocrine diseases, syphilis, etc.), abnormal development of teeth and jaws.

When conducting x-ray examinations, measures must be taken to protect patients and personnel from x-ray exposure. To do this, aluminum filters are used, short exposures are used, the operating rules of the devices are followed, and unreasonable repetitions of X-ray studies are avoided.

Medical personnel who work in X-ray rooms must systematically undergo medical examination (blood tests, examinations, etc.).

X-ray research methods have recently become more advanced and improved diagnostics in dentistry, but X-ray data should never be interpreted without taking into account the clinical ones, which remain the main ones in diagnosis. The clinic and the doctor’s thinking are the basis of diagnosis.

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INTRODUCTION

1. BASIC METHODS FOR X-RAY STUDY OF TEETH AND JAWS

1.1 Survey radiographs

1.2 Extraoral radiography

1.3 Intraoral radiography

2. MODERN RESEARCH METHODS: DIGITAL RADIOGRAPHY

2.1 Radiovisiograph

2.2 Orthopantomograph

CONCLUSION

LIST OF SOURCES USED

INTRODUCTION

Relevance of the topic. Modern dental treatment in dentistry is impossible without X-ray examinations. X-ray research methods are leading in the diagnosis of diseases of the maxillofacial region, due to their reliability and information content.

X-ray diagnostics is used to confirm and sometimes make a medical diagnosis necessary for proper treatment teeth. X-ray studies help monitor the process of dental treatment and the accuracy of dental treatment.

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:

plain radiography;

intraoral radiography.

In the practice of a dentist, a panoramic image allows both to control the quality of canal filling and to recognize the initial stage of dental caries. A panoramic photograph is needed to diagnose changes in the supporting apparatus of the teeth; a panoramic photograph records changes in bone tissue. At the same time, dental treatment should not harm other organs of the human body, and, as we all know from school, X-ray radiation is dangerous.

Fortunately, modern X-ray equipment (orthopantomograph, radiovisiograph) uses only low doses of radiation that are harmless to the human body when obtaining images of any complexity, including panoramic images.

The purpose of this work is to study radiological research methods in dental practice.

Based on the goal, the following tasks are solved in the work:

Learn the basic methods of x-ray examination of teeth and jaws.

Explore modern methods X-ray examination of teeth and jaws.

1. BASIC METHODS FOR X-RAY STUDY OF TEETH AND JAWS

1.1 Survey radiographs

Survey radiographs can be performed in three projections - direct, lateral and anterior semi-axial - and provide 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.

1.2 Vnon-oralradiography

Extraoral (extraoral) photographs of the jaws are performed 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.

1.3 Intraoral radiography

Intraoral radiography continues to be the mainstay of radiographic evaluation for most dental and periodontal diseases. Currently, there are four methods of intraoral radiography used to study the condition of teeth, para- and periodontal tissue:

Contact radiography according to the isometric rule.

Interproximal radiography.

Bitewing radiography (occlusal).

Radiography with an increase in 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 - 0.1 of its true dimensions.

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 technique, the angle increases by 20°. In some cases, it is necessary to deliberately change the beam projection 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.

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.

2. MODERN RESEARCH METHODS: DIGITAL RADIOGRAPHY

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.

2.1 Radiovisiograph

Figure 1 - Radiovisiograph

It should be noted that there are many options for the names of the radiovisiograph:

Radiovisiograph

Radio videographer

X-ray complex

Teleradiograph

Visiograph

The official name of this class of devices is “Radiovisiograph”. In everyday practice, for brevity, the name “visiograph” is adopted.

The radiovisiograph produces an image (including a panoramic image) recorded on a special matrix that is highly sensitive to X-rays. The resulting image (panoramic image) is transferred to the computer screen and can then be printed on paper.

With wired visiographs, the sensor is applied to the diseased tooth and an image is taken using an X-ray machine, which is displayed on the computer screen.

In wireless visiographs, the sensor is additionally placed in a special scanner, which reads the image and also displays it on the computer screen.

The visiograph has two significant advantages, which ensured its widespread use.

Firstly, the radiation exposure to the patient is significantly reduced, since the sensitivity of the sensor is higher than that of X-ray film.

Secondly, a large and contrasting image of a tooth on a computer screen is much better perceived by a dentist than a small and blurry image on x-ray film.

When using a standard X-ray, the radiation dose is reduced tenfold by reducing the exposure time from an average of 0.8 s. up to 0.08 s.

When using a specialized X-ray, the radiation dose is further reduced by reducing the size of the focal spot and the level of scattering radiation.

So, what makes using a vision machine more attractive?

High speed of image acquisition;

Possibility of computer enhancement of image quality;

Possibility of measuring the lengths of root canals;

Ability to save pictures in computer memory;

Quickly search for previous patient images;

Possibility of storing images along with the patient’s card;

Transferring images over a computer network.

2.2 Orthopantomograph

radiovisiograph orthopantomograph radiography jaw

Figure 2 - Orthopantomograph

Using an orthopantomograph, you can make operational and highly accurate:

basic panoramic photograph of the dentition in adults;

panoramic photograph of the dentition in children;

targeted panoramic shot - the middle part of the dentition;

targeted panoramic shot - the left part of the dentition;

targeted panoramic shot - the right side of the dentition;

a photograph of the temporomandibular joint with the mouth open;

photograph of the temporomandibular joint with the mouth closed;

picture of the sinuses.

An orthopantomogram is especially relevant if you need to simultaneously and quickly take a panoramic image of the upper and lower jaw.

A panoramic photograph of teeth (orthopantomogram) allows, unlike conventional x-rays, to observe full picture condition of the oral cavity.

Panoramic photographs of teeth are needed for correct prompt diagnosis and treatment of most dental diseases.

An orthopantomogram is prescribed after a detailed examination of the oral cavity by a dentist.

A panoramic photograph of the teeth (orthopantomogram) makes it possible to determine and find out:

presence and size of tooth buds (degree of root formation);

the need to begin correcting malocclusion;

dental anomalies;

spread of infections, cysts;

condition of periodontal tissues;

caries at the initial stage;

control the process of dental canal filling;

the presence of periodontal pockets and hidden carious cavities;

risks when installing a dental implant;

the condition of the bone at the site of the proposed tooth implantation, and the relationship of the implant with the most important anatomical formations (vessels, nerves);

diagnosis of maxillofacial fractures;

simulate the location of implants in the jaw using a special computer program;

treatment strategy, identify diseases at the earliest stage and much more.

Panoramic photographs of teeth using an orthomantomograph are usually taken in a standing position.

For children and disabled people, panoramic dental photography can be performed while sitting in a chair. There is an automatic height adjustment for panoramic photography of teeth in a standing or sitting position - adults, children and disabled people in wheelchairs.

Before starting the procedure, you must remove all metal objects, including metal prostheses, earrings, glasses, hair clips, and facial jewelry. All of these objects obstruct the X-ray beam and make the image inaccurate. A special X-ray protective lead apron (nikidka) must be worn on the chest. An orthopantogram is done inside a special miniature X-ray machine. The patient stands in the place indicated by the doctor, biting a plastic tag covered in a disposable cover with his front teeth, presses his chest against the platform, and waits for further instructions from the doctor. It is very important that the mark is strictly in the center. If any teeth are missing in the mouth, then cotton swabs are placed in their place. Next, the patient is asked to grasp the handrails in the ortapontamograph in order to take a stable position at the time of shooting. It is very important to keep your back as straight as possible and not move during panoramic dental photography. During an orthopantomogram, the module and the irradiator will move around the head without touching it. The process lasts about 15-20 seconds.

After taking a panoramic photograph of your teeth, the doctor asks you to wait a little while the process of processing and initial study of the image is completed.

It is important to make sure that the panoramic photo is taken clearly, correctly, and that a repeat procedure is not required. The finished panoramic image can be transferred to the patient in in electronic format. The entire panoramic photograph of teeth using an orthopantomograph takes no more than 2-3 minutes.

Orthopantomographs can be film or digital. The latter are more modern and easy to use. The radiation dose from digital orthopantomographs is several times less than from film devices.

CONCLUSION

Based on all of the above, the following conclusions can be drawn.

The most commonly used in dental practice are:

plain radiography;

extraoral radiography of teeth and jaws;

intraoral radiography.

Currently, the method of digital x-ray diagnostics using the so-called radiovisiograph has become widespread.

An orthopantomograph is a type of modern x-ray equipment (x-ray machine) with a low dose of radiation.

Unlike a conventional X-ray machine, an orthopantomograph has a circular rotating element.

It can be used to take a panoramic image of all teeth, maxillofacial joints, sinuses and cranial bones.

LIST OF SOURCES USED

2. Computed tomography in the diagnosis of head and neck diseases / A.G. Prikhodko, Yu.P. Efimtsev, V.V. Bazhenov and others // Vestn. radiology and radiology. - 1991. - No. 4. - P.38-43.

3. Lindenbraten L.D. Medical radiology and radiology./ Lindenbraten L.D., Korolyuk I.P. - M. Medicine, 1993.

5. Rabukhina N.A. Current state of maxillofacial radiology // New in dentistry. - 2008. - No. 7. - P. 7-12.

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X-ray diagnostics in dentistry. Radiography (radiation diagnostics) in modern dentistry: what does a picture of a healthy tooth and caries look like? X-ray research methods in dentistry

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