CARIES OF TOOTH

From Big Medical Encyclopedia

CARIES OF TOOTH (caries dentis; lat. caries rotting) — the pathological process which is shown demineralization and the progressing destruction of solid tissues of tooth with formation of defect in the form of a cavity.

For the first time data about To. h. meet apprx. 3000 years BC. Comparison of results antropol, researches with modern data on prevalence To. h. confirms growth of incidence of teeth at the modern person. Researches in the different countries showed that incidence To. h. sharply increased in the countries of Europe and America approximately from 18 century that connect with considerable change of the environment, conditions of life and character of food. I. G. Lukomsky as a result of studying of the skulls found in the USSR in barrows 9 — 12 vv and at cemeteries 15 — 17 centuries, found from 0 to 8,2% of the teeth affected with caries. According to modern data, prevalence To. h. in some districts of the globe reaches 100%.

Epidemiology

Studying of a porazhayemost To. h. various groups of the population it is carried out for assessment of requirement in stomatol. the help and detection of dependence To. h. from environmental factors. According to the WHO recommendation, at assessment of a prevalence of the population To. h. define three main indicators: prevalence, intensity of defeat, gain of intensity. Prevalence To. h. is defined by number of persons at whom at inspection presence of one or the teeth which were more affected with caries, sealed up or absent is revealed; this indicator is expressed in % to total number inspected (at children — separately for milk and second teeth).

Indicator of intensity of defeat (KPU) — a median number of the teeth affected with caries and its complications (K), sealed up (P) and extracted concerning caries (U) on one inspected. This indicator for milk teeth (kp) is determined by the number of the teeth affected with caries and destroyed and sealed up; the absent teeth are not considered. For some special researches, in particular for assessment of effect of the tested prophylactics, studying of resistance to caries of different surfaces of teeth, the specified indicator of intensity of defeat of surfaces of teeth is applied.

The gain of intensity of defeat is defined by quantity of again revealed cases of damage of teeth caries for a certain span; this indicator is established by repeated inspection of the same group at an interval of 1 year and comparisons of the revealed indicators of the KPU.

Uneven prevalence is revealed To. h. in different klimatogeografichesky zones of the globe. It is very high (to 100%) in the countries sowing. parts of Europe, North America; slightly lower — in the central areas of these continents, is much lower (to 50%) — in tropical and equatorial zones of Africa, Southeast Asia and on islands of the Pacific Ocean (except for the large cities). Prevalence To. h. in the USSR it is also uneven. A. I. Rybakov and G. V. Baziyan (1973) provide the following data on frequency To. h. young men and girls have 16 — 19 years: Przhevalsk and Tashkent — 56,5%, Kolomna — from 56,5 to 63,3%, Ur-Tyube — 67,1%, Minsk — 74,6%, Petrozavodsk — 92,8%, Leningrad — 93,3%, Murmansk — 99,8%. As a rule, prevalence and intensity of damage of teeth caries are higher at urban population, than at rural.

Different prevalence To. h. explain with a number of factors: klimatogeografichesky conditions (climate, macro - and microelements of the soil and water), social conditions (a condition of life and work), character of food (vitamins, a ratio of carbohydrates, proteins and fats).

An etiology and a pathogeny

Since antiquity and the Middle Ages a role of the reason To. h. attributed to the special worms destroying teeth, the «bad juice» arriving from blood or food. The beginning of scientific studying of a question is connected with development of chemistry in 18 century when solvent action to - t on enamel of teeth was shown. With development of bacteriology searches of specific microbic activators K were conducted. h. In 19 century these directions combined in the form of the chemical and parasitic theory which is fullestly developed by U. Miller (1881), edges used recognition during a number of decades. Late development of physics promoted emergence physical. - chemical theories To. h. In particular, D. A. Entin (1938) considered changes physical. - chemical properties in system solid tissues of tooth — a pulp as a basis of carious process. I. G. Lukomsky (1955) considered that carious process is a consequence of trophic disturbances in tissues of tooth, in particular in a pulp. A. E. Sharpenak (1958) suggested that at the heart of emergence To. h. the disturbance of protein metabolism of enamel caused by a lack of food of protein and especially irreplaceable amino acids — arginine and a lysine lies.

In sovr, the Soviet stomatology idea that emergence To gained distribution. h. it is caused by the combined exogenous and endogenous influences, and its pathogeny is defined by interaction of the general and local factors.

These representations found expression, in particular, in A. I. Rybakov's concept (1971). Age aspects of development of dentoalveolar system are the basis for this concept; at each stage of development of an organism the major internal and exogenous factors which interaction can lead to emergence of carious process are allocated. During the pre-natal period the importance is allocated for a genetic factor, disturbance of formation of internals and systems of an organism, including bodies of an oral cavity, insufficient receipt of some microelements and vitamins. In the period of the childhood and youth To. h. it can be caused by influence of endocrine factors in connection with puberty, the postponed diseases, an abnormal liver function, decrease in resistance of tissues of tooth, a lack of fluorine, disturbance of salivation and environmental change of an oral cavity. During from 20 to 40 years the accompanying diseases have a certain value (went. - kish. path, liver, endocrine system) and diseases of dentoalveolar system. After 40 years disturbance of activity of internals and systems (decrease of the activity of gonads, expressiveness of stressful reactions, insufficiency of the insulyarny device) gains value.

Many exogenous and internal causes exerting impact on emergence and development To are established. h. Alimentary first of all belongs to exogenous factors: deficit of proteins, vitamins, especially groups B and D, mineral salts, first of all calcium and phosphorus, a number of microelements (fluorine, strontium, molybdenum, etc.), excess consumption of the carbohydrates which are easily fermented in an oral cavity, fats and some microelements (in particular, selenium, magnesium, cadmium, lead). Microflora of an oral cavity is of great importance «(see. Roth, oral cavity ), especially bacterial structure of a dental plaque (see. Teeth, biochemistry ). An essential role is played by decrease in pH to 4,5 — 5,5 in a dental plaque on certain sites of a surface of enamel of teeth; pH of lump of oral liquid at the same time can not change at the expense of rather high buffer capacity of saliva.

Among endogenous an important role is played by the genetic and other factors influencing a bookmark and formation of dental germs, degree of their mineralization and structural features of enamel of tooth. Influence of genetic factors can be to a certain extent weakened by rational conditions in which the child develops.

Emergence To. h. at children at early age (2 — 3 years) it is connected with disturbances in the antenatal period (diseases of mother, especially disturbances of exchange, abuse of nek-ry pharmaceuticals during pregnancy, toxicoses, etc.). Factors against the background of which arises To. h., can be defective food at artificial feeding and diseases of newborns. In the subsequent at children join the stated above factors also exogenous among which leaders in emergence To. h. are unbalanced food (especially excess of carbohydrates) and other reasons characteristic for To. h. at adults. Level of a porazhayemost of teeth caries depends, in particular, on processes accelerations (see), the cut is one of manifestations an early teething; often painters are not completely created: fissures are not enameled, and enamel is insufficiently mineralized.

It is established that with age incidence To. h. goes down; it is connected with age increase in resistance of enamel owing to gradual increase in a mineralization, consolidation of a crystal lattice of enamel, reduction of organic components, etc.

In a pathogeny allocate two basic groups of factors — the general and local: disturbance of the general metabolic system of interstitial exchange of an organism, including exchange in calciphied fabrics with their regulatory mechanisms, and disturbance in local system (sialadens — saliva — oral liquid — a dental plaque — a pellicle — tissues of tooth — parodont). Role of the general and local pathogenetic factors at different stages K. h. it is not identical.

In the precarious period the large role is played by the general (background) factors, and then, in process of development patol, process in tissues of tooth — the local factors operating against the background of the general changes defining resistance of enamel of tooth.

Emergence To. h. perhaps at different options of interaction of the general and local cariogenic factors which as well as resistance of solid tissues of tooth, can be different intensity and change during life depending on conditions. But anyway the effect of cariogenic factors consists in creation of conditions which cause the progressing demineralization of tissues of tooth.

The normal structure and functions of enamel are provided with a dynamic equilibrium of processes of demineralization and remineralization. If conditions under which this balance is broken are created and there is a dominance of process of demineralization, there comes destruction of enamel, formation of a so-called carious spot. Progressing of this process leads to formation of a carious cavity.

The mechanism of demineralization of enamel is that on the limited site of a surface of tooth in a dental plaque as a result of fermentation are formed by microorganisms of sugars milk, acetic, Pyroracemic and others to - you, and concentration of hydrogen ions goes down to a critical level (pH 5,5). Owing to the fact that enzymes of microorganisms of a dental plaque lyse a pellicle and a cuticle of enamel to - you, formed in a dental plaque, directly influence mineral substances of enamel. At long maintenance of a critical level of H+ (or its intermittent character) and in the presence of the general background of the cariogenic situation which led to decrease in resistance of enamel on the respective site dissolution of crystals of apatite, and also less resistant enamelogenesis (sites of strips of Rettsius) begins. It leads to penetration to - t in a subsurface layer where there are most expressed changes at the first stages of carious process; the zone of the happening demineralization extends parallel to the surface of tooth. Smaller expressiveness of demineralization in a surface layer of enamel depends on features of its structure, and also on receipt in it mineral components from saliva.

Further education organic to - t on the surface of enamel leads to gradual increase in microspaces, penetration of microorganisms which continue a kislotoobrazovaniye in the demineralized site of enamel; process of demineralization begins to extend also in depth, forming the cone-shaped center of defeat. Destruction of dentine happens with direct participation of microorganisms which proteolytic enzymes influence shoots of fibrilloblasts and the main substance of dentine (collagen); acid-forming microorganisms dissolve inorganic matters of dentine.

Change of the main fiziol, processes in enamel of tooth begins with disturbance of permeability, solubility and ion exchange. Disturbance of these processes is closely connected with decrease in protective function of saliva and a pellicle of tooth. Reduction in saliva of quantity of a lysozyme, immunoglobulins and concentration of the ionized calcium, phosphorus, change of a ratio of calcium and phosphorus (lower than 1: 1,3), fluorine and other elements, decrease in pH is led to disturbance of processes of remineralization of enamel of tooth; its permeability and solubility increases, receipt decreases and escaping it calcium ions, phosphorus both others macro - and microelements increases. To disorders of remineralization of enamel give also disturbances of protein metabolism in tissues of tooth, first of all not collagenic proteins and glycoproteins.

Thin, more permeable surface layer of enamel together with a pellicle of tooth and a layer of a dental plaque are as if boundary educations between two phases: liquid (oral liquid) and firm (tissues of tooth); at destructions of a pellicle solubility of enamel sharply increases, its resistance in relation to aggressive pathogenic factors respectively decreases.

Primary (starting) moments of carious process is the solubilization of enamel caused by the listed above mechanisms. It is possible to assume that primary mechanisms of carious process begin at molecular level with disturbance of direct chemical communication between mineral (crystals of a hydroxyapatite) and organic the fractions of enamel (proteinaceous matrixes of enamel columns) connected through phosphorus-radio and NH2 bonds. Then the combined disturbances of mineral and protein metabolism with a prevalence at an early stage of process of demineralization, at a late stage — proteolysis develop. At elimination of cariogenic factors and preservation of a proteinaceous matrix of enamel columns stabilization of carious process and even its involution is possible (at a stage of a spot).

Since caries of enamel in a pulp of tooth find a hyperpermeability of walls of vessels with an exit of a liquid part of blood in fabric, changes of hydrodynamics of an intercellular lymph, etc. These changes affect circulation of dentinal and enamel liquids, permeability of enamel and dentine; proteinaceous and synthetic function of fibrilloblasts is broken. At a stage of average caries find a hyperpermeability in the direction from a carious cavity to a pulp of tooth; especially it comes to light at deep caries when in a pulp the phenomena of irritation of fabric accrue; it is quite often possible to find signs of an inflammation with the expressed vascular component.

Biochemical changes of solid tissues of tooth, a pulp and oral liquid precede clinical, morfolichesky and elektronnomikroskopichesky manifestations of process To. h. Initial biochemical changes arise on border between the surface of enamel and the basis of a dental plaque. The integrity of enamel is broken as a result of metabolic activity of microorganisms of a dental plaque. The mechanism of biochemical shifts during the developing of caries of enamel in a stage of a spot is in what coming to an oral cavity easily fermented sugar is changed by metabolism of microbic flora of a dental plaque and saliva. The sucrose coming to a dental plaque is split on glucose and fructose by enzymes of hl. obr. streptococci. Enzymes of microorganisms synthesize from glucose biopolymer a glyukon-dextran, in Krom glucosic units are connected an alpha, 1 — 6-or an alpha, by 1-3 bonds; in the latter case the water-insoluble muton, existence to-rogo in a dental plaque is formed defines pathogenicity of a mutant streptococcus. From molecules of fructose fruktan-lavan is synthesized. Both biopolymers are split by cariogenic bacteria of a dental plaque with education to - t. In processes of synthesis and metabolism of dextrans and lavans in a dental plaque also others are formed milk, acetic, Pyroracemic, apple, oil, propionic to - you. It is established that concentration milk to - you in a dental plaque at the persons subject To. h., above, than at persons, resistant to caries and that if tooth is not covered with a dental plaque, caries does not develop. In the absence of a dental plaque the decrease of solid tissues of tooth of not carious origin — an erosion, a necrosis can develop (see. Teeth ).

The dental plaque which is constantly formed on teeth in the course of their functioning gains pathogenic properties under following conditions: 1) accumulation of considerable mass of microorganisms in deepenings, fissures, in cervical sites of tooth; 2) the concentration of microorganisms in certain sites reaching 500*10 6 in 1 mg of a dental plaque; 3) accumulation milk, lemon and others to - t; 4) braking of diffusion of neutralizing agents in a dental plaque.

In emergence of initial changes in tooth the important role belongs to a pellicle, edges can influence formation of colonies of certain microorganisms and in certain cases break transport of substances from saliva to enamel and vice versa. K-you, produced by microorganisms, diffuse through a pellicle and dissolve crystals of enamel; ions of the dissolved mineral components of enamel get through a pellicle into saliva. In chemical structure of a pellicle at initial To. h. there are changes consisting in sharp increase in amount of the proteinaceous and connected carbohydrates (from 2,5% to 4%), the amount of free hexoses increases twice; other carbohydrate components of glycoproteins (a hexosemine, uranium and sialine to - you, ketosucrose, a fukoza) increase slightly.

In a stage of a white carious spot the general maintenance of proteinaceous components of an organic matrix increases almost twice. Content of free amino acids and oligopeptid increases three times, the level of insoluble protein is not changed.

Increase in protein content in a white spot happens due to increase in fraction of soluble Solk and high-molecular peptides. In the pigmented spot the general protein content remains at the same level, but the amount of water-soluble protein decreases, the fraction of free amino acids increases by eight times in comparison with intact enamel and 2,5 times above, than in a white carious spot. Inorganic phosphorus is lowered in a white carious spot by 73%; content of carbohydrates in comparison with intact enamel increases in organic matter by 12 times, the maintenance of lipids decreases. The surface of enamel of a white carious spot contains 2 — 3 times more fluorine, than in other sites of carious enamel. In carious enamel the smaller amount of nitrogen, than in protein of intact enamel, bigger number of amino acids and in bigger quantity is defined. In collagen of dentine ratios acid (asparaginic, glyutaminovy amino acids) and the main (a lysine, a histidine and arginine) the amino-acid remains are broken. It leads to structural change of collagen, disruption of communication between a proteinaceous matrix and mineral component. In a pulp processes of exchange amplify; the maintenance of a glycogen increases at average and deep caries.

Some researchers tried to connect To. h. with change of content of crude protein of saliva. In the mixed saliva at multiple To. h. content of crude protein fluctuates during the day. In the mixed saliva of the persons having carious teeth the tendency to increase in content of the majority of free amino acids (tryptophane, threonine, glyutaminovy, asparaginic to - t, a lysine, phenylalanine, tyrosine) is shown while concentration of the reducing substances (sugar) does not depend on existence or lack of carious process. Activity of enzymes of saliva and a dental plaque in many respects defines character and speed of emergence patol, process in solid tissues of tooth. The significant role belongs to enzymes of saliva of carbohydrate and phosphorus exchange as they are directly involved in anaerobic glycolysis of carbohydrates, processes of development to - t, processes of a mineralization and remineralization of enamel. At the children suffering multiple To. h., activity of acid and alkaline proteases in the mixed saliva increases and concentration of protein in saliva increases.

Microflora

Shifts as a part of constant microflora of an oral cavity are defined before a wedge, manifestations To. h. At all stages of carious process the vysevayemost of acid-forming and acid resisting strains of a streptococcus and lactobacilli increases. The greatest number of microorganisms is sowed from a dental plaque and surface layers of carious dentine (3*10 8 on 1 g of material). In deep layers of carious dentine flora is less plentiful (10 5 on 1 g). Essential distinctions between streptococci of oral liquid, a dental plaque and various layers of carious dentine are established. Streptococci of saliva on cultural, biochemical, and antigenic properties are identified as Streptococci salivarii, and streptococci of carious dentine are close to streptococci of group D (enterococci). At persons with To. h. increase in biochemical activity of streptococci and lactobacilli, vegetans on the surface of teeth is established; they produce hyaluronidase, acid phosphatase, a neuraminidase, DNA-ase, lizotsimopodobny enzyme. From enamel and dentine at To. h. allocate strains of the anaerobic microorganisms (streptococci, staphylococcus, actinomycetes, nokardiya) dissolving in vitro the denatured collagen. In dentinal tubules often vegetirut Bacteroides melaninogenicus, the lyseing native collagen, and the leptotrikhiya producing chondroitin-sulphatase.

From a dental plaque of the persons predisposed to To. h., strains of the microorganisms (Streptococcus mitis, Streptococcus sanguis, Streptococcus mutans, Fusobacteria) synthesizing from the refined carbohydrates yodofilny high-molecular polysaccharides like a dextran, lavan and amylopectin are allocated. The highest products of these almost insoluble polysaccharides are revealed at strains of a mutant streptococcus at cultivation of in vitro in strictly anaerobic conditions on Wednesdays with sucrose. Selective tropism of a mutant streptococcus to the surface of enamel at the expense of a producing adhesive extracellular polysaccharides, and also high biochemical, activity of these microorganisms is regarded by a number of researchers as a factor of cariogenicity. A number of researchers specifies that for emergence To. h. associative activity of a mutant streptococcus with lactobacilli, veylonella and other microorganisms is necessary.

It is established that in immune responses the big role belongs to saliva, a dental plaque, a secret of a mucous membrane of a gingiva and blood serum. In these biol, liquids kariyesimmunny people have some of immunoglobulins of a class A, an antiserum capacity against cellular and intracellular glikanopodobny polysaccharides.

At people with multiple To. h. in saliva and blood serum indicators of nonspecific resistance decrease (a lysozyme, beta lysines, properdin, phagocytosis, etc.) that is combined with disturbance of structure of microflora of an oral cavity. In initial stages To. h. the microbic obsemenennost of an oral cavity raises, the structure of microflora changes further that is characterized by settling of an oral cavity tranzitorny species of microorganisms (Pseudomonas, Klebsiella, Escherichia).

Numerous observations of interrelation between decrease in some factors of antimicrobic protection in saliva, change in quantitative and qualitative structure autoflor and number of the teeth which are again affected for a certain term caused creation of the tests revealing predisposition of people to caries and a degree of activity of carious process. Laktobatsillen-test it is based on mikrobiol, calculation of lactobacilli in tests of saliva; Snider's test is based on definition of time of approach and size of a zone of decolourization of a medium around bacterial clumps; the test of Rikkles — on definition of degree of a kislotoobrazovaniye on discoloration after crops of saliva on the Wednesday containing sucrose and mixed indicator.

Pilot models

Concepts of an etiology and a pathogeny are confirmed by animal experiments at which, as well as at people, it is possible to receive the main stages of caries of tooth: stage of a spot, caries of enamel, average and deep (perforative) caries. Main model K.z. at rats, hamsters and mice is the alimentary, caused by increase in contents in a diet of the carbohydrates which are easily fermented in an oral cavity, especially sucrose (to 25 — 65%). The most widespread cariogenic diets — so-called sakharozo-casein, napr, offered in 1954 by I. A. Begelman and soavt, (sucrose — 54%, casein and sukharny powder — on 18,5%, vegetable oil — 5%, salt mix — 4% and polyvitamins at the rate of 1 tablet on 100 g of a diet), or sucrose — 66%, milk skim milk — 32%, a dry liver — 2%. The cariogenic effect of a diet in certain limits is directly proportional to amount of the sucrose which is contained in a diet. Sucrose possesses cariogenic action only at receipt in an organism of young animals (20 — 30-day age, weighing 20 — 40 g) through a mouth. Administration of sucrose via the probe, a fistula of a stomach, intraperitoneally, intravenously or subcutaneously almost excludes cariogenic effect. Similar results observed in experiences on parabiozirovanny (sewed together) rats at their separate feeding: To. h. arose only at the animal receiving cariogenic food through a mouth.

At adult puberal rats (6 — 8 months, the weight of St. 100 g) To. h. does not arise even at the content of sucrose in a cariogenic diet to 66%. At young gnatobiotichesky (sterile) animals at contents them on a cariogenic diet To. h. also does not arise. However introduction to a mouth to sterile rats of culture of the enterococci allocated from carious cavities of control rats leads to snowballing at them To. h.

Action of a cariogenic diet depends not only on amount of the easily split carbohydrates, but also on their ratio with other ingredients. Increase in a diet of the proteins containing irreplaceable amino acids (especially a lysine), digestible fats, vitamins (especially groups B, D), mineral salts (first of all calcium and phosphorus) and microelements (especially fluorine, molybdenum, copper, vanadium, strontium) can sharply reduce cariogenic effect. The effect of such diets depends also on physical. properties of ingredients; e.g., administration of sucrose in water solution reduces its action in comparison with crystal. The rough, rigid diet (with casein, corn, rice, wheat of coarse grinding) does not promote bystry emergence To. h., but considerably accelerates deleting of crowns of teeth with the begun defect of enamel.

During the receiving experimental To. h. using saccharose diets the general disbolism, first of all carbohydrate were observed that is confirmed by researches of a sugar content in blood and a glycosuria. During the keeping of rats on a cariogenic diet their immune responsiveness goes down. A role of immune factors in a pathogeny experimental To. h. it is confirmed at experimental therapy of rats, in particular using fluorinated drugs; at the same time indicators immunol. reactivity were normalized in parallel with reduction of a porazhayemost of teeth caries. The anti-pulpal cytotoxic serum entered to rats in the stimulating and oppressing doses, respectively causes activation and lowering of the level of exchange processes (especially protein metabolism) in solid tissues of tooth that also demonstrates participation of immune mechanisms in regulation of resistance of its solid fabrics.

Also the role of genetic factors was investigated. Lines of the rats susceptible and resistant to induction were received To. h. Hereditary qualities of a susceptibility or resistance to To. h. remain at posterity after crossing of both lines. However in the course of generation of populations under the influence of environmental factors hereditary qualities can change. E.g., lines of rats and hamsters, susceptible to caries, through several generation have a resistant resistance and the maintenance of animal these lines on a cariogenic diet does not lead to emergence To. h.

Though in the majority of cariogenic diets protein content and mineral salts fluctuates in limits fiziol, norms, in solid tissues of tooth, a bone skeleton and in other body tissues in general at the level of interstitial exchange arise the combined disturbances of protein and mineral metabolism. Essential changes of exchange of the glycoproteins which are carrying out as if acetylene bond between proteins, carbohydrates and mineral components and actively participating in processes of a mineralization of calciphied fabrics are found.

Also researches of interrelation were conducted To. h. with funkts, frustration of endocrine system. The extirpation or oppression of function thyroid, parathyroid, gonads considerably increase efficiency of a cariogenic diet; administration of somatotropic hormone, parathormone, thyrocalcitonin and other hormones causes decrease in a prevalence of teeth caries. Depression of function of sialadens or their extirpation leads to increase in a porazhayemost of teeth caries during the keeping of animals on a cariogenic diet; converse effect is gained introduction animal extract of a parotid sialaden — a parotin.

Thus the role of disbolism, genetic and immune factors, and also functional frustration of endocrine system in development is confirmed To. h.

Pathological anatomy

Distinguish early and late phases morfol, changes at To. h. The early phase is characterized by formation of a spot of enamel (white and pigmented), late — formation of different depth of a cavity in solid tissues of tooth (superficial, average and deep caries).

Fig. 1. Shlif of enamel of tooth at caries of enamel in a stage of a white carious spot: 1 — a body of defeat; 2 — a transparent zone; 3 — a dark zone. Polarization microscopy; h45.

Stage of a spot. Loss of natural color is caused by subsurface demineralization of the enamel causing change of its optical properties. During the studying of shlif of the teeth affected with caries in a stage of a white spot in the carious center determine three zones by the polarizing microscope: body of defeat, dark and transparent zones (fig. 1); emergence of these zones is caused by formation of microspaces, various on the volume and quantity in each zone.

Fig. 2. Shlif of tooth at caries of enamel in a stage of the pigmented spot: demineralization of a subsurface layer; the periblast (1) of enamel is kept; the subsurface layer (2) is demineralized. Microroentgenogram; X 45.

The pigmented spot (light brown) differs from a white spot in the big amount and depth of defeat. On shlifa of tooth at the pigmented spot considerable changes in a subsurface layer of enamel, in a periblast demineralization come to light is absent (fig. 2). Defeat does not exceed a half of thickness of enamel in the beginning, then takes all enamel in depth. At elimination of cariogenic factors and stabilization of process the spot gains dark brown or black color.

Fig. 3. The diffraction pattern of enamel of tooth at caries in a stage of a spot: expansions of interprismatic spaces are visible (it is specified by shooters); x 38 400

Electronic microscopic examination of carious process in a stage of a spot reveals early changes in patol, the center which for klyuchatsya in loss of inorganic matter on the periphery of prisms, weakening of intercrystal bonds in enamel, disturbance of strict orientation of crystals and change of their form and the sizes. Gistokhim, methods revealed degradation of mucopolysaccharides of interprismatic organic matter. In the field of defeat expansion of interprismatic spaces (fig. 3) is observed, contours of enamel columns are designated more accurately, their cross striation is sharply expressed, Rettsius's lines are defined more accurately. Increase of destructive changes leads to a chaotic arrangement of enamel columns, their fragmentation and, finally, to transformation of enamel substance into the unstructured, softened weight sated with colonies of microbes.

Stage of a carious cavity. In process of distribution patol, process on deeper layers of enamel defeat, shaped the triangle or a cone turned by the basis to the surface of tooth forms. The part of enamel which underwent destruction is torn away therefore in enamel the cavity with uneven contours is formed. Destruction of enamel and dentinal border, penetration of microbes into dentinal tubules causes development of caries of dentine. Spread of caries on dentine is followed by dystrophy of tomsovy fibers; in dentinal tubules accumulation of microbes is defined. Under the influence of emitting proteolytic enzymes and acid-forming microbes there is a dissolution of a proteic matter and demineralization of dentine. This process happens in a circle of tubules in the beginning that is expressed by their uneven expansion, then process extends also to other sites of dentine. By data gistokhy. researches, direct object of influence of bacterial proteases in dentine is its collagenic basis.

Fig. 4. A tissue specimen of tooth at carious defeat of dentine: expansion of dentinal tubules (1) on peripheries of a carious cavity, their accurate and figurative swelling is expressed (2): coloring hematoxylin-eosine; X 200.

In the field of carious defeat dentinal tubules are expanded, a part are chetkoobrazno blown up (fig. 4), in places merge, forming micro and the macrocavities containing the necrotic masses and plentiful accumulation of microbes. Further rejection of considerable mass of nekrotizirovanny dentine and deepening of a cone-shaped cavity with uneven walls is observed. On the periphery of a carious cavity towards a pulp of tooth dentinal tubules extend and deformed; they are intensively painted by hematoxylin in the form of dark strips. More deeply the layer condensed transparent (a zone of a hyper mineralization) dentine with considerably the narrowed dentinal tubules is located and is even deeper — a layer of not changed dentine. At late stages of process also this layer of dentine therefore communication of a carious cavity with a pulp cavity (the penetrating caries) is established collapses.

Fig. 5. Shlif of a crown of tooth at fissure caries: the carious cavity (1) with the hanging edge of enamel is visible, from a pulp cavity — formation of a layer of replaceable dentine (2).

At caries in a pulp of tooth observe a wide range of the reactive and dystrophic changes testimonial of a close functional linkage of solid and soft tooth tissues: pycnosis of kernels of fibrilloblasts, an atrophy, disorganization and vacuolation of a layer of fibrilloblasts, a reticular atrophy and cystous transformation of a pulp, adjournment in a pulp of petrifikat and formation of replaceable dentine. Reactive formation of replaceable (irregular) dentine happens directly under a carious cavity in solid tissues of tooth (fig. 5). Products of this layered, with incorrectly located tubules of dentine are more expressed when carious process develops slowly. Formation of replaceable dentine to some extent distances the term of perforation of a bottom of carious defect, but is new prevents it since caries extends further also to replaceable dentine, and the speed of carious process usually surpasses rates of formation of reparative dentine.

Classification

Distinguish To. h. on localization, depth of defeat, character a wedge, currents, etc. Depending on the struck fabric allocate caries of enamel, dentine, cement; on localization — caries of fissures ny, caries of the adjoining surfaces (aproksimalny, or contact) and cervical. Classification by localization defines a method of formation of carious cavities for preparation for sealing.

On depth of defeat distinguish: initial To. h. (in a stage of a spot); superficial — defect of enamel without disturbance of enamel dentinal border; average caries — disturbance of enamel and dentinal border, but in the presence of a considerable layer of solid dentine at the bottom of a carious cavity; deep To. h. — over a pulp the insignificant layer of the dentine which is often softened and pigmented remains. This classification defines a method of Treatment.

All types To. h. it is accepted to combine in the absence of clinically defined changes in a pulp the concept «simple, or uncomplicated, caries». In a wedge, practice in cases if there is a carious cavity on border with earlier imposed seal, also the term «secondary caries, or recurrent» is applied.

Some authors allocate acute and hron, forms K. h. Acute caries is characterized by bystry distribution of process to depth and to breadth of solid tissues of tooth; processing of a cavity at treatment is followed by usually sharp morbidity of dentine. Hron, caries proceeds slowly; carious fabrics are pigmented, dense, hardly give in to removal by the excavator, morbidity of dentine during the processing is insignificant or is almost absent. The specified division is hardly justified since demineralization of tissues of tooth and formation of a cavity happens within several weeks and even months; such term does not keep within a concept acute patol, process.

Depending on intensity of carious defeat distinguish single (separate teeth) and multiple damages of teeth; besides, allocate systemic lesion when are surprised all or almost all teeth, it is frequent with localization of process at a neck of tooth.

A clinical picture

At survey of an oral cavity for identification of carious teeth it must be kept in mind that at cutters, canines and premolar tooths contacting surfaces usually are surprised, on painters caries arises on a chewing surface, especially at young people (so-called fissure caries) more often; with age owing to deleting of a chewing surface of teeth there is caries on contacting surfaces, at necks of teeth more often. It is established also that the teeth symmetrized usually are surprised (on the right and left side of a jaw).

Initial caries (in a stage of a spot) usually proceeds asymptomatically and it is found only at attentive survey. Enamel tarnishes, becomes opaque, there is white (pretty) or pigmented (from brown till black color) a spot, a surface to-rogo smooth. And on electric current tooth reacts to temperature irritations within norm. White and light brown carious spots are a wedge, manifestation of the progressing or intermittent demineralization of enamel and therefore the remineralizing therapy is required; brown and black carious spots are a sign stopped patol, process.

Superficial caries it is characteristic quickly passing pain from the sweet getting on tooth, acid, salty, sometimes from mechanical irritants. At survey, usually during the sounding, superficial defect with a rough surface is found. Sometimes sounding happens slightly painfully. In certain cases visually only the carious spot is defined, but sounding allows to establish existence of a cavity. The pulp of tooth reacts to irritation electric current within norm.

Average caries proceeds, as a rule, without serious consequences. Sometimes there is short-term pain from irritants, is more often than mechanical. At survey and sounding the carious cavity filled with the remains of food and the softened pigmented dentine comes to light. The pulp of tooth reacts to irritation electric current within norm.

Deep caries represents the last stage of uncomplicated caries. Pain arises from mechanical, chemical and temperature irritants, but after their elimination pain quickly disappears. A carious cavity of the considerable size, at the bottom of the dentine its softened, pigmented. Sounding of a bottom of a cavity is painful, especially in the field of horns of a pulp. In certain cases clinically defined signs of irritation of a pulp can be observed. Reaction of a pulp of tooth to irritation electric current is more often within the norm but maybe lowered (10 — 12 mk). In cases of uncured caries microorganisms get into a pulp of tooth or the bottom of a carious cavity is perforated and there is a complication — an inflammation of a pulp of tooth — pulpitis (see).

Feature of caries of milk teeth more bystry is, than in second teeth, a current patol, process. Destruction of enamel happens on the considerable surface of tooth, process quickly reaches enamel and dentinal border; caries of dentine quickly goes deep. It is caused by the fact that the enamel cover of milk teeth is much thinner, than constants, in dentine there are low-mineralized wide zones reaching a pulp; in milk teeth adjournment of secondary dentine is slowed down. At a number of infectious diseases, the exhausting children, at rickets, avitaminosis, alimentary diseases there is an intensive damage of both milk, and second teeth caries. Enamel collapses on the considerable surface of tooth; in rather short time crowns of other teeth are surprised, the pulp of tooth with the subsequent its necrosis is involved in process. Such intensive destruction of teeth can stop at improvement of the general condition of the child. More often milk painters are surprised caries, canines are more rare. In teeth of a milk bite aproksimalny caries, and then cervical meets more often.

At pregnant women (both at normal, and at patholologically the proceeding pregnancy) emergence of multiple pretty spots in a cervical part of tooth is sometimes observed, on site them defects of enamel are soon found. These defects tend to distribution on the vestibular surface of teeth, being followed by sharp morbidity. Such phenomenon is connected with a lack of mineral substances of an organism of future mother.

Diagnosis

At a stage of the formed cavity the diagnosis is usually simple. However it is not always easy to distinguish caries in a stage of a spot from diseases of solid tissues of tooth of not carious character. The carious spot should be differentiated with changes at a hypoplasia of enamel and a fluorosis of teeth (see. Teeth ). Unlike caries, at a hypoplasia and a fluorosis of a spot multiple are also localized on the vestibular surface and hillocks of teeth, a bottom of defeat firm. For the purpose of diagnosis it is possible to apply a method of vital coloring of teeth: after removal of a soft dental plaque and drying of tooth on the site of enamel changed in color for 3 min. impose a tampon from 2% solution of methylene blue; the carious spot is painted, and color of a spot at a hypoplasia and a fluorosis does not change.

Superficial To. h. differentiate with a hypoplasia and an erosion of enamel (erosion have the bowl-shaped form and are localized more often on the vestibular surface of foreteeth), average caries — with wedge-shaped defect, for to-rogo the wedge-shaped deepening with a firm bottom and walls located at a neck of teeth is characteristic. Quickly passing morbidity from irritants distinguishes deep caries from acute pulpitis (see), the main symptom to-rogo is the spontaneous or long not passing pain from irritants. Use also an electric pulp test (see. Elektrodiagnostika ) or rentgenol, a research (see. Teeth, methods of a research ).

Treatment

the General treatment is directed to increase in reactivity of an organism and normalization of activity of systems and bodies, decrease in action of cariogenic factors. It is especially important at multiple To. h. at children and pregnant women. A component of complex treatment is sanitation of an oral cavity and teeth (see. Sanitation of an oral cavity ), restriction in food of carbohydrates and sweet flour products.

Topical treatment variously depending on a stage patol, process. At initial To. h., in a stage of a white or light brown spot, the means strengthening a mineralization of enamel are offered (10% solution of a gluconate of calcium, 10% solution of the acidified calcium phosphate in the form of applications). Apply according to the following scheme. The surface of tooth is cleared of a dental plaque a cotton plug with hydrogen peroxide, dried up a gauze napkin and a stream of warm air, impose the cotton plug moistened with the specified remineralizing liquid (duration, applications of 10 — 15 min.). Then on the same surface impose the cotton plug moistened 2 — 4% with solution of sodium fluoride for 1 — 2 min. Criterion of a positive take is total disappearance of a spot or emergence of gloss of enamel after 15 — 20 applications.

Superficial caries on smooth surfaces of second teeth of children and teenagers in most cases does not need to be sealed up. Use of applications with the remineralizing solutions, a fluoric varnish is shown. At localization of caries in fissures and on the adjoining surfaces of second teeth sealing is obligatory. At the same time by means of borons delete the hanging edges of enamel, create a cavity with the subsequent tooth filling (see). Sealing superficial is in certain cases possible To. h. without processing of a cavity boron, at the same time apply composition sealing materials (see).

At average and deep To. h. processing of a cavity boron for the purpose of removal of a softened dentine and giving of a cavity of the corresponding form is obligatory. At treatment of deep caries it is necessary to consider thickness of okolopulparny dentine, a condition of a pulp. In order to avoid opening of a horn of a pulp preparation of a carious cavity is made carefully; the softened dentine at the bottom of a cavity is deleted with excavators (see. Dental tools ). At deep caries, especially at children, preservation of a small layer of a softened dentine at the bottom of a cavity is admissible. For impact on microflora of the infected dentine and protection of a pulp is applied to lay down. laying. For this purpose after preparation the cavity is dried up by warm air, on a bottom it is imposed evgenolovy paste or paste on the basis of drugs of calcium (calcine-paste and kalmetsin); paste is covered with artificial dentine and impose a constant seal. The temporary seal for 10 — 12 days is imposed when on a wedge, signs can assume the beginning inflammation of a pulp.

Preparation of a carious cavity is an important stage of treatment since correctness of preparation and formation of a cavity provides reliable fixing of a seal. Careful preparation of a carious cavity and high quality of sealing material practically exclude a recurrence of caries. However at excision patholologically of the changed fabrics the sparing relation to healthy tissues of tooth is necessary. Preparation consists of the following stages: anesthesia, disclosure of a carious cavity, expansion of a cavity (removal of the softened and pigmented dentine), formation of a cavity under a seal.

Anesthesia is carried out by an injection to peridental fabrics of 2% of solution of novocaine, Trimecainum, etc. (see. Anesthesia local ); apply also electroanesthesia by means of the device EL OZ-l. For premedication appoint tranquilizers; in certain cases apply gas (e.g., nitrous oxide) or an intravenous anesthesia. The anesthesia is carried out by anesthesiologists in specially equipped office. Application anesthesia is carried out by mestnoanesteziruyushchy means: 75% fluoric paste (across Lukomsky), Platonov's liquid (No. 1: Dicaini 0,05, Phenoli puri 1,0, Aq. destillatae 3,0; No. 2: Dicaini 0,05, Spiritus acetylici 95 of %, Chloroformii aa 1,0). Both liquids before the use mix in equal quantities and apply on a carious cavity for 3 — 5 min. that reduces morbidity during preparation.

Fig. 6. The scheme of classification of carious cavities on Bleka: 1 — the I class — caries in the field of natural deepenings and fissures; 2 — the II class — caries of the adjoining surfaces of premolar tooths and painters; 3 — the III class — caries of the adjoining surfaces of cutters and canines (cutting edges are kept); 4 — the IV class — caries of contact surfaces of cutters and canines with disturbance of a corner of a cutting edge; 5 — the V class — cervical caries.

At preparation of solid tissues of tooth it is accepted to be guided by classification of B of lek (fig. 6), according to a cut carious cavities subdivide into five classes: 1) caries in fissures and natural deepenings; 2) caries of proximal surfaces of premolar tooths and painters; 3) caries of proximal surfaces of cutters and canines at preservation of cutting edges; 4) caries of proximal surfaces of cutters and canines at disturbance of corners of a cutting edge; 5) cervical caries. At the first stage of processing of a carious cavity delete the hanging edges of enamel; preservation of edges of enamel is allowed during the processing of a lip surface of cutters and canines for cosmetic reasons.

The shape of cavities of the 1st class is defined by a form of natural deepenings in which caries is localized; the cavity of the 1st class can be triangular, in the form of a rhombus, crosswise. The created cavities of the 2nd class can be different depending on whether the sufficient layer of healthy dentine what access to a carious cavity, will affect by caries one of the adjoining teeth remained or both are struck adjoining tooth etc. Cavities of the 3rd class can also be several versions; when teeth stand very densely and there is no access to a carious cavity, it is necessary to delete a part of healthy fabrics from a palatal surface. At a carious cavity of the 4th class, except the main, the additional cavity forms. An indispensable condition is formation of a bottom the main y an additional cavity at right angle within dentine. At cervical caries (the 5th class) formation of a cavity is difficult because of proximity of a pulp of tooth and a gingiva; shape of a cavity more often oval; it is necessary to aim that its bottom and walls were created at right angle. At so-called circular caries >the cavity forms on all circle of tooth; in this case strong points (notches) shall be created.

The forecast

At treatment To. h. sealing forecast usually favorable. However in certain cases near a seal there is a carious cavity (secondary, or recurrent, caries). More often it is a consequence of the wrong preparation of a carious cavity; at children developing of caries can be a consequence of changes in tissues of tooth and saliva during the weakening of an organism. Loss of a seal is usually connected with disturbance of a technique of preparation of fabrics or technology of sealing. At treatment initial To. h. by method of remineralization a recurrence is possible; in this regard the general and repeated topical treatment in 4 — 6 months

Prevention

Prevention of caries of tooth is necessary it is necessary to begin with care about health of future mother; the leading role belongs to the good balanced nutrition of the pregnant woman and the feeding woman. The correct feeding of the child also creates premises of full development of tissues of tooth, resistance to caries.

In the preventive purposes, and especially at multiple To. h., A. I. Rybakov (1967) recommended special diets taking into account the content of fluorine in drinking water.

Diet And (not less than 3500 kcal) — at the content of fluorine less than 1 mg/l: 120 g of protein, 100 g of fats, 400 g of carbohydrates and mineral salts (calcium, phosphorus), microelements (fluorine, manganese), vitamins B 1, C, D.

A diet of B (apprx. 3000 kcal) — for the persons living in areas where drinking water contains normal amount of fluorine: 90 g of protein, 50 g of fats, 300 g of carbohydrates; the diet shall be rich with salts of calcium, phosphorus and microelements (copper, a kick), vitamins B 1 , B 6 , C, exclude sweets, tinned fruit, food shall not be exposed to long culinary processing, inclusion of crude vegetables is obligatory.

The most expressed anticarious action fluorine, especially during the periods of a mineralization, eruption and maturing of teeth possesses. In the anticarious purposes enter fluorine with drinking water and food stuffs into an organism, and also influence directly enamel. The mechanism of effect of fluorine is explained by the fact that in enamel the fluorapatite steadier against influence to - t is formed of a hydroxyapatite. Fluoration of water (see) to optimum level (1 mg/l) is a mass and efficient anticarious action; this method is recommended to WHO for distribution in all countries. Decrease in incidence To. h. at fluoration of water about 30 — 50% are reached on average (according to different data). Fluorine can be entered as nutritional supplement into salt, milk, and also in the form of tablets at the rate of 1,5 — 2 mg a day.

Locally apply fluorides in the form of applications, rubbing in of pastes and solutions, rinsing, a covering of teeth gel and a varnish. Produce also fluorinated chewing gums. 0,1 — 0,2% solutions of sodium fluoride are applied to rinsing of an oral cavity (see. Fluorine, drugs ).

In 1936 I. G. Lukomsky suggested to process teeth of 75% fluoric paste two times a year (a so-called flyuorization of teeth). This method was applied a nek-swarm time of hl. obr. in children's policlinics, but its shortcoming consists in big labor input. Afterwards this method was simplified thanks to production of fluorinated varnishes which use demands small expense of time at considerable efficiency. The varnish is applied with a thin coat on the dried-up surface of tooth; within several hours it keeps on teeth that provides diffusion of ions of fluorine in enamel. Also fluorinated toothpastes are offered. Results of overseeing by effect of such pastes are contradictory, however most of authors notes anticarious effect. In the preventive purposes of a fissure of healthy painters and premolar tooths process so-called silant: at a careful covering silant To. h. in fissures does not arise (observations up to three years).

Importance in prevention To. h. belongs to hygiene of an oral cavity since formation of a soft plaque and a delay of the remains of food in interdental spaces and at necks of teeth are essential cariogenic factors. Removal of a dental plaque by means of a toothbrush is the most effective. For clarification of interdental spaces of the movement of a toothbrush shall be along an axis of tooth; duration of toothbrushing apprx. 3 min. It is recommended to carry out toothbrushing in the morning and in the evening. Children should be accustomed to toothbrushing with 2 — 3-year age, and from 4 years they shall brush regularly teeth twice a day. It is recommended to use toothpicks from synthetics or from a tree. Not only doctors, but also tutors of kindergartens and teachers of schools shall pay to questions of hygiene of an oral cavity attention. A certain value in maintenance of an oral cavity in a gigabyte. a state it is given to firm food (crude vegetables, fruit), during the chewing the cut occurs self-cleaning of teeth. It is important that chewing was carried out on both sides of jaws.

Sanitation of an oral cavity (see) it is carried out in stomatol, policlinics, departments and offices, at the enterprises, in collective farms, state farms, preschool institutions, schools, higher education institutions and technical schools as medical examination of organized collectives.



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E. V. Borovsky; G. V. Baziyan (epid.), L. V. Morozova (mikr.), V. V. Panpiarovsky (stalemate. An.), M. M. Persits (biochemical), A. A. Prokhonchukov (stalemate. physical.).

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