X-ray signs of caries, pulpitis, periodontitis, periodontal diseases

X-ray diagnostics of caries, pulpitis, periodontitis, periodontal diseases

X-ray diagnostics of caries

Caries is a pathological process manifested by demineralization and progressive destruction of hard dental tissues with the formation of a defect. This is the most common dental disease: the incidence of caries in the population reaches 100%. Depending on the location, fissure caries, cervical caries, contact (approximal), vestibular and lingual surfaces are distinguished on erupting teeth. In molars, caries most often develops on the chewing surface, in incisors, canines and premolars - on the contact surfaces.

Depending on the depth of the lesion, a distinction is made between the stage of the spot (carious spot), superficial, medium and deep caries. With simple or uncomplicated caries, there are no changes in the pulp. Complicated caries is accompanied by the development of inflammation in the pulp (pulpitis) and periodontium (periodontitis).

Caries can affect individual teeth, several teeth (multiple caries) or almost all teeth (systemic lesion). Multiple caries can manifest itself as so-called circular and superficial, spreading mainly along the surface. Clinical examination fails to diagnose small carious cavities and carious lesions that are inaccessible for direct examination. Only a combination of clinical and radiographic examination ensures the detection of all carious cavities.

The objectives of radiographic examination for caries:

1. identification of a carious cavity and determination of its size, including depth;
2. establishing its relationship with the dental cavity;
3. assessment of the periodontal condition;
4. diagnostics of secondary caries under fillings and crowns;
5. control of the correct formation of the cavity;
6. assessment of the application of the medical pad and its adhesion to the walls;
7. detection of overhanging or merging fillings.

Radiologically, only carious lesions are recognized in which the hard tissues of the tooth lose at least 1/3 of their mineral composition. The radiological picture of a carious cavity depends on its size and location.

The shape and contours of carious cavities are variable, which is due to the peculiarities of the spread of the carious process. When projecting a carious defect onto unchanged tooth tissue (caries on the vestibular, lingual and chewing surfaces), it is presented as a clearing area of a round, oval, irregular or linear shape. Marginal carious cavities (located in the approximal, cervical areas and along the cutting edge of incisors and canines), extending onto the contour, change the shape of the crown.

The clarity or blurriness of the cavity contours is determined by the characteristics of the course of the carious process. On contact surfaces, carious cavities are especially clearly visible and at certain stages of development, their shape resembles the letter V, the apex of which is directed toward the enamel-dentine border.

Difficulties arise in distinguishing small cervical carious cavities from the variant of the anatomical structure, when depressions are observed due to the absence of enamel in these areas. Probing the gingival pocket allows to overcome the difficulties that have arisen.

Small carious cavities on the chewing, vestibular or lingual surface of the tooth are covered by unchanged hard tissues of the tooth and are not reflected in the radiograph.

Carious cavities are easily recognized clinically, and X-ray examination is used in most cases to diagnose hidden carious cavities that are inaccessible to visual inspection and instrumental examination. These include carious cavities on the root, under fillings (secondary caries), crowns and on contact surfaces.

In most cases, an X-ray examination makes it possible to assess the depth of the carious process. The stage of the spot is not determined by X-ray. In superficial caries, especially in cases where the cavity is marginal, a defect is visible within the enamel. In moderate and deep caries, dentin is involved in the process to a varying degree. Due to the slower spread of the process in the enamel, a discrepancy between the dimensions of the cavity in the enamel and dentin is sometimes determined on the X-ray.

Difficulties in determining the relationship between a carious cavity and a tooth cavity are due to the location, depth of the carious lesion, and projection features. On radiographs taken in compliance with the "bisector rule," the tooth cavity is reduced in height projectionally. In moderate caries, deformation and reduction of the tooth cavity also occur due to the deposition of secondary dentin. A carious lesion on the vestibular and lingual surfaces of a tooth is sometimes projected onto the tooth cavity. When a carious cavity is located on the chewing and contact surfaces, an X-ray examination makes it possible to fairly clearly assess the thickness of the dentin layer separating the carious lesion from the tooth cavity.

Secondary caries under a filling is presented as a defect of various sizes, a strip of light appears between the filling and dentin. A similar picture occurs when filling with pads that do not absorb X-rays. Uneven, unclear, undermined contours of the cavity indicate secondary caries. A comparison with an X-ray taken before filling can help in diagnostics.

An X-ray examination allows us to assess how the cavity is formed, the quality of the filling, the adhesion of the filling material to the walls, the overhang of the filling between the teeth and in the gingival pocket.

Fillings made of amalgam and phosphate-containing filling materials are determined as a high-intensity shadow against the background of tooth tissue. Fillings made of silicate cement, epoxy material and plastics are radiolucent, so the prepared cavity and the linear shadow of the liner adjacent to the walls are visible on the image.

In children, caries occurs even at the stage of teething. The highest frequency of its development is noted at the age of 7-8 years and after 13 years. In baby teeth, caries mainly affects the contact surfaces, is characterized by rapid progression of the process and complications in the form of pulpitis and periodontitis.

Multiple caries of primary teeth, caused by metabolic disorders, is sometimes localized symmetrically on the same teeth. Changes in hard dental tissues also occur with non-carious lesions: hypoplasia, fluorosis, wedge-shaped defects, pathological abrasion.

The wedge-shaped defect is located on the vestibular surface of the crowns in the neck area. On the radiograph it is determined as stripes of enlightenment in the cervical area, running parallel to the cutting edge.

Pathological abrasion may be caused by bad habits (holding foreign objects in the mouth - nails, mouthpiece of a pipe). When abraded, replacement dentin may form, causing a decrease in the height of the tooth cavity. In the area of the apex of the teeth, secondary cement is layered (hypercementosis picture).

Spotty defects in fluorosis are usually not reflected in radiographs.

The widespread dental X-ray examination technique with beam centering on the tooth apex is the least effective in caries diagnostics due to the resulting projection distortions. The interproximal technique, which excludes projection overlap of adjacent teeth contact surfaces, is more effective. The future in this regard belongs to X-ray imaging with a parallel beam from a large focal length, which does not distort the size and shape of the crown. On direct panoramic X-rays, the crowns of premolars and molars overlap, this does not happen on orthopantomograms, but difficulties arise in assessing the condition of the front teeth.

Radiation damage to teeth

According to G.M. Barer, 4 months after remote gamma therapy of malignant tumors of the maxillofacial region, destruction of hard tissues of teeth included in the irradiation volume was noted in 58.4% of cases. Cervical and multiple foci of crown destruction appear, and intensive abrasion of the cutting and chewing surfaces occurs. A higher frequency of damage to the lower incisors and canines is noted. The features of the clinical manifestation and the nature of the course allow us to distinguish radiation damage to teeth as an independent nosological unit.

Among the etiological factors, the influence of hyposalivation, changes in the crystal lattice, denaturation and demineralization of enamel, dentin and cement are noted.

X-ray diagnostics of pulp diseases

The inflammatory process in the pulp usually does not cause changes in the hard tissues that limit the cavity of the tooth and root canals, and does not have direct radiological signs.

An indirect sign of pulpitis is a deep carious cavity, which is visible on an X-ray and communicates with the tooth cavity. However, the final diagnosis of pulpitis is established only on the basis of a set of clinical data, probing results, and determination of the electrical excitability of the pulp.

Dystrophic processes in the pulp can lead to the formation of denticles located at the walls of the tooth cavity and root canal (parietal denticles) or freely in the pulp (free denticles). On the radiograph, denticles are determined as rounded single or multiple dense shadows against the background of the tooth cavity or root canal.

Sometimes pains of a neuralgic nature occur due to the pinching of the nerve fibers of the pulp by denticles. In these cases, the diagnosis is established only after performing an X-ray examination.

Chronic granulomatous pulpitis may develop an "internal granuloma", causing destruction of the tooth adjacent to the dentin cavity. This lesion is more common on the front teeth. The radiograph shows a clearly contoured rounded enlightenment projected onto the tooth cavity. Difficulties arise in distinguishing it from caries on the lingual or buccal surface of the tooth. Internal granuloma may be complicated by a pathological fracture of the tooth.

X-ray diagnosis of periodontitis

Intraoral contact radiographs performed according to the rules of isometric projection are widely used for the purpose of diagnosing periodontitis. To assess the relationship of the roots with the bottom of the maxillary sinus, panoramic lateral radiographs and orthopantomograms are produced, and in the absence of special equipment, extraoral contact radiographs in oblique projection, which we have developed, are used.

Acute apical periodontitis. Despite the pronounced clinical picture, a slight widening of the periodontal gap at the root apex, caused by periodontal inflammation, is usually not detected radiographically. The diagnosis of acute periodontitis is established practically on the basis of clinical data. The acute process, lasting from 2-3 days to 2 weeks, can become chronic.

Chronic granulating periodontitis. The morphological process is characterized by the proliferation of granulation tissue, causing intensive resorption of hard dental tissues (cement, dentin), the cortical plate of the dental alveolus wall and spongy bone tissue. On the radiograph, the normal image of the periodontal gap at the apex of the affected root is absent, the compact plate of the dental alveolus is destroyed. At the apex of the root, a focus of bone tissue destruction of an irregular shape with uneven, unclear contours is determined. As a result of the resorption of cement and dentin, the root surface that comes out onto the contour is eaten away, sometimes the root of the tooth becomes shorter.

Chronic granulomatous periodontitis. Depending on the morphological features, granulomatous periodontitis is divided into dental granuloma, complex dental granuloma and cystogranuloma. In a complex granuloma, along with granulation tissue, there is a proliferation of epithelial strands, and it turns into a cystogranuloma. As a result of dystrophy and disintegration of the epithelium, a cavity is formed, lined from the inside with epithelium. On the radiograph, a focus of enlightenment of a round or oval shape with clear, even, sometimes sclerotic contours is determined at the apex of the tooth. The cortical plate of the socket in this area is destroyed. Sometimes hypercementosis develops and the apex acquires a club-shaped form. It is not possible to distinguish a simple granuloma from a cystogranuloma radiologically. However, it is believed that if the size of the focus of destruction is more than 1 cm, the presence of a cystogranuloma is more likely.

Chronic fibrous periodontitis. This type of periodontitis occurs as a result of acute or other chronic forms of periodontitis; it can also develop with long-term traumatic effects on the tooth. In this case, as a result of productive reactions, the periodontium is replaced by coarse fibrous structures of ruby tissue; thickening of the periodontium, excessive formation of cement (hypercementosis) in the apex or over the entire surface of the tooth occur.

The radiograph at the root apex shows a widened periodontal space. The compact plate of the dental alveolus is preserved, sometimes sclerosed. The root at the apex is club-shaped thickened due to hypercementosis.

When projecting some anatomical formations onto the root apex (incisive and mental foramina, large bone cells), difficulties arise in distinctive recognition. The integrity of the closing cortical plate of the socket makes it possible to exclude the diagnosis of chronic granulomatosis and granulating periodontitis. When using radiography with a change in the course of the central beam of rays, as a rule, anatomical formations on these images are projected separately from the root apex.

Chronic low-activity inflammatory processes can cause excessive bone tissue production with the formation of small foci of sclerosis. This is most often observed at the roots of the lower molars. When analyzing images, difficulties arise in differentiating these foci from small osteomas or root fragments.

The diagnosis of chronic periodontitis in the acute stage is established on the basis of clinical manifestations of acute periodontitis and radiographic picture of chronic periodontitis (granulating or granulomatous). Chronic fibrous periodontitis in the acute stage is sometimes regarded as acute periodontitis.

A fistula tract located parallel to the long axis of the root is visible on the radiograph as a narrow strip of enlightenment extending from the apical focus of destruction to the alveolar edge of the jaw. In another direction, the fistula tract is usually not visible on the image.

Repeated radiographs are most often performed during treatment with a needle to determine patency and at the end - to assess the quality of root canal filling. After mechanical and chemical treatment of the root canals, root needles are inserted into them and an X-ray is taken to assess the patency of the canal. The X-ray shows insufficient opening of the tooth cavity, overhangs, in particular over the mouth of the root canal, thinning and perforation of the walls of the cavity, root, bottom, the presence of a broken instrument in the canal. Gutta-percha pins are clearly visible in the canals. To detect perforation, X-rays are performed with an inserted root needle. The false passage is better visible with its medial-lateral direction, worse - with a buccal-lingual direction. An indirect sign of perforation is the destruction of the adjacent cortical plate of the socket.

To determine changes in the size of periapical lesions after treatment, it is necessary to perform repeated identical radiographs that exclude projection distortions. Identity of images of the frontal teeth is ensured by performing direct panoramic radiographs under standard examination conditions (patient position and tube in the oral cavity). To examine premolars and molars, lateral panoramic radiographs and orthopantomograms are performed. Complete or partial restoration of bone tissue in most patients occurs within the first 8-12 months after treatment.

In case of inadequate root canal filling, chronic periodontitis may become aggravated. In these cases, an X-ray is necessary to assess the degree of canal filling and the nature of the filling material.

X-ray diagnostics of chronic periodontitis in children. In small children, even moderate caries can be complicated by chronic periodontitis. Primary chronic granulating periodontitis is predominantly encountered, localized in the molars in the bifurcation area.

Due to the close proximity of the rudiments of permanent teeth, especially molars, a number of complications may arise:

1. death of the follicle due to the growth of granulation tissue into the growth zone;
2. disruption of enamel calcification due to infection penetrating the follicle;
3. displacement of the rudiments of permanent teeth;
4. acceleration of the eruption of permanent teeth;
5. development of follicular cyst.

In children with chronic periodontitis of the lower molars, panoramic radiographs sometimes reveal ossified periostitis in the form of a linear shadow parallel to the cortical layer along the lower edge.

In children and adolescents, the growth zone in the area of the unformed apex should not be confused with a granuloma. In the growth zone, the periodontal gap is of uniform width, the compact plate of the socket is not damaged, the tooth has a wide root canal.

X-ray diagnostics of periodontal diseases

The complex of periodontal tissues - the periodontium - includes the circular ligament of the tooth, gums, alveolar bone tissue and the periodontium.

When examining the periodontium, preference is given to panoramic tomography and interproximal images. When standard examination conditions are met, the methods ensure that identical images are taken, which are necessary, in particular, to assess the effectiveness of the treatment measures being taken. Panoramic radiographs are also informative, although their execution is associated with a high radiation load.

Intraoral contact radiographs taken in compliance with isometric rules create a false impression of the state of the cortical endplate due to the fact that the buccal and lingual sections are projected separately. Taking dynamic contact radiographs sometimes leads to an incorrect assessment of the treatment measures taken.

The first radiological symptoms of changes in the interalveolar septa are not early, therefore radiological examination cannot be a preclinical diagnostic measure.

Gingivitis. No changes in the interdental septa are observed. In ulcerative necrotic gingivitis in children and adolescents, the radiograph shows widening of the marginal sections of the periodontal gap and osteoporosis of the apices of the cortical plates of the interalveolar septa.

Periodontitis. When the periodontium is affected in the area of one or several teeth, limited or local periodontitis is diagnosed; when the periodontium of all teeth of one jaw or both jaws is involved, diffuse periodontitis is diagnosed.

Local periodontitis. Local periodontitis is characterized by the destruction of the interdental septum of varying severity. The radiograph usually shows the cause of its occurrence: "overhanging" fillings, incorrectly made artificial crowns, foreign bodies, large marginal carious cavities, subgingival deposits. The depth of the periodontal pocket reaches 3-4 mm.

The main symptoms of diffuse generalized periodontitis are osteoporosis and a decrease in the height of the interdental septa. Depending on their severity, the following degrees (stages) are distinguished radiologically:

• initial - cortical closing plates of the apices of the interdental septa are absent, osteoporosis of the interdental septa without a decrease in height;
• I - reduction of the height of interdental septa by 1/5 of the root length;
• II - the height of the interdental septa is reduced by 1/2 the root length;
• III - the height of the interdental septa is reduced by 1/3 of the root length.

The spread of inflammation to the periodontium is radiologically manifested as widening of the periodontal gap in the marginal areas. With complete destruction of the cortical plate of the socket around the root, "eaten away" spongy bone with uneven contours is visible.

In different groups of teeth of the same patient, a decrease in the height of the entire interalveolar septum (horizontal type) or destruction of the septum in one tooth is observed, while the decrease in its height in the adjacent tooth is not so significant (vertical type).

The severity of destructive changes in the marginal sections of the alveolar processes and the degree of tooth mobility are not always comparable. In this case, the ratio between the sizes of the root and crown is important: teeth with long roots and multi-rooted teeth with diverging roots retain stability longer even with pronounced bone changes.

Repeated radiographs allow us to judge the activity of the course or stabilization of the process. The appearance of clear contours of the marginal sections of the alveolar processes, stabilization of osteoporosis or normalization of the radiographic picture indicate a favorable course of the process.

In patients with diabetes, changes in the marginal areas are similar to those observed in periodontitis.

Periodontosis. With periodontosis, a sclerotic restructuring of the bone pattern occurs - the bone marrow spaces become smaller, individual bone beams are thickened, the pattern acquires a fine-meshed character. In elderly people, a similar restructuring is observed in other parts of the skeleton.

The degree of reduction in the height of the interdental partitions is the same as with periodontitis. In the case of an inflammatory process, signs of periodontitis and periodontosis are revealed on the radiograph.

Periodontolysis develops with a rare genetically inherited disease - keratoderma (Papillon-Lefevre syndrome). Progressive resorption of the marginal sections of the alveolar process leads to tooth loss. The disease begins during the eruption of baby teeth, causing them to fall out. Temporary stabilization is replaced by progressive osteolysis of the alveolar process during the eruption of permanent teeth.

Histiocytosis X. Of the three types of histiocytosis (eosinophilic granuloma, or Taratynov's disease, Hand-Schüller-Christian disease, and Letterer-Siwe disease), eosinophilic granuloma is the most common. The etiology of these diseases is still unknown. It is believed that they are different forms of the same process. The morphological substrate is specific granulomas that cause destruction of the bone sections involved in the process. The disease is painless, sometimes with an increase in body temperature. When the jaws are affected, the radiographic picture sometimes resembles that of periodontitis.

Eosinophilic granuloma most often develops in children and adolescents (under 20 years of age), men are ill 6 times more often. Mostly flat bones (skull, pelvis, ribs, vertebrae, jaws) and femurs are affected. Histologically, intraosseous proliferates (granulomas) of histiocytic, plasmacytic cells and eosinophils are detected. In later stages, xanthomatous changes occur with the accumulation of cholesterol and Charcot-Leyden crystals in the cytoplasm. In the area of former foci of destruction, with a favorable course of the disease, scar tissue and sometimes bone are formed.

With eosinophilic granuloma, as a rule, changes are found not only in the jaws, but also in the flat bones of the cranial vault - round, clear defects, as if punched out with a punch. In the jaws, granulomas often occupy a marginal position, involving the upper and lower alveolar processes in the pathological process - teeth devoid of bone structure, as if hanging in the air ("floating teeth"). After the loss of teeth, the sockets do not heal for a long time. In children, granulomas located near the periosteum can cause a picture of ossifying periostitis.