Otitis

The concept of permeability of mineralization of enamel demineralization. WITH

Enamel, the tissue covering the crown of the tooth, is the hardest in the body. On the chewing surface its thickness reached 1.5-1.7 mm; on the lateral surfaces it is much thinner and disappears towards the neck, at the junction with the cement.

*Enamel structure. The main structural formation of enamel is enamel prisms with a diameter of 4-6 microns. The length of the prism corresponds to the thickness of the enamel layer and even exceeds it due to the tortuous direction. Enamel prisms, concentrating into bundles, form S-shaped bends. As a result, optical inhomogeneity (dark or light stripes) is revealed on enamel sections: in one area the prisms are cut in the longitudinal direction, in the other - in the transverse direction (Gunter-Schräger stripes). In addition, on sections of enamel, especially after treatment with acid, lines are visible that run in an oblique direction and reach the surface of the enamel, the so-called lines of Retzius. Their formation is associated with the cyclical mineralization of enamel during its development.
The enamel prism has a transverse striation, which reflects the daily rhythm of complications of mineral salts. The cross-section of the prism itself is, in most cases, arcade- or scale-shaped, but can be polygonal, round, or hexagonal.
In the tooth enamel, in addition to the indicated formations, there are lamellae, fascicles and spindles. Lamellae (plates) penetrate the enamel to a considerable depth, enamel bundles - to a lesser depth. Enamel spindles - processes of odontoblasts - penetrate the enamel through the dentin-enamel junction.
The main structural unit of a prism is considered to be crystals of apatite-like origin, tightly adjacent to each other, but located at an angle. The structure of the crystal is determined by the size of the unit cell.
*Chemical composition. Teeth consist of apatites of many types, but the main one is hydroxyapatite - Ca10(PO4)6(OH)2. Inorganic substance in enamel is represented (%) by: hydroxyapatite - 75.04; carbonate apatite -12.06; chlorapatite - 4.39; fluorapatite - 0.63; calcium carbonate - 1.33; magnesium carbonate-1.62. In the composition of chemical inorganic compounds, calcium is 37%, and phosphorus is 17%.
The condition of tooth enamel is largely determined by the Ca/P ratio as the elements that form the basis of tooth enamel. This ratio is not constant and can change under the influence of a number of factors. Healthy enamel of young people has a lower Ca/P ratio than the enamel of adult teeth; this indicator also decreases with demineralization of the enamel. Moreover, significant differences in the Ca/P ratio within the same tooth are possible, which served as the basis for the statement about the heterogeneity of the structure of the tooth enamel and, therefore, the unequal susceptibility of different areas to caries.

For apatites, which are tooth enamel crystals, the molar Ca/P ratio is 1.67. However, as currently established, the ratio of these components can change both downward (1.33) and upward (2.0). At a Ca/P ratio of 1.67, crystal destruction occurs when 2 Ca2+ ions are released; at a ratio of 2.0, hydroxyapatite is able to resist destruction until 4 Ca2+ are replaced, while at a Ca/P ratio of 1.33 its structure is destroyed. According to existing concepts, the Ca/P coefficient can be used to assess the condition of tooth enamel.
microelements in the enamel are distributed unevenly. The outer layer contains a high content of fluorine, lead, zinc, and iron, with a lower content of sodium, magnesium, and carbonates in this layer. Strontium, copper, aluminum, and potassium are distributed evenly among the layers.
Each enamel crystal has a hydration layer of bound ions (OH~) formed at the crystal-solution interface. It is believed that thanks to the hydration layer, ion exchange occurs; it can occur through a heteroionic exchange mechanism, when a crystal ion is replaced by another ion of the medium, and through an isoionic exchange mechanism, when a crystal ion is replaced by the same ion of the solution.
In addition to bound water (hydration shell of crystals), the enamel contains free water, dissipated in microspaces. The total volume of water in the enamel is 3.8%. The movement of the liquid is due to the capillary mechanism, and molecules and ions diffuse through the liquid. Enamel fluid plays a biological role not only during the development of enamel, but also in the formed tooth, providing ion exchange.
The organic matter of enamel is represented by proteins, lipids and carbohydrates. The following fractions were determined in enamel proteins: soluble in acids and EDTA - 0.17%, insoluble - 0.18%, peptides and free amino acids - 0.15%. According to the amino acid composition, these proteins, the total amount of which is 0.5%, have characteristics of keratins. Along with protein, lipids (0.6%), citrates (0.1%), and polysaccharides (1.65 mg of carbohydrates per 100 g of enamel) were found in the enamel.
Thus, the enamel contains: inorganic substances - 95%, organic - 1.2% and water - 3.8%.

*Functions of enamel. Enamel is the avascular and hardest tissue of the body; it protects dentin and pulp from external mechanical, chemical and temperature irritants. Only thanks to this, the teeth fulfill their purpose - they bite off and grind food. The structural features of enamel were acquired during the process of phylogenesis.

*The phenomenon of enamel permeability tooth is carried out due to the washing of the tooth (enamel) from the outside with oral fluid, and from the pulp - tissue and the presence of spaces in the enamel filled with liquid. Dental lymph can pass through the enamel, neutralizing lactic acid and gradually increasing the density due to the mineral salts contained in it. Enamel permeable in both directions: from the enamel surface to dentin and pulp and from pulp to dentin and enamel surface. On this basis, tooth enamel is considered a semi-permeable membrane. Permeability is the main factor in the maturation of tooth enamel after eruption. The normal laws of diffusion manifest themselves in the tooth. In this case, water (enamel liquid) passes from the side of low molecular concentration to the side of high, and molecules and dissociated ions - from the side of high concentration to low. In other words, calcium ions move from saliva, which is oversaturated with them, into the enamel fluid, where their concentration is low.
Currently, there is indisputable evidence of the penetration of many inorganic and organic substances into the enamel and dentin of the tooth from saliva. It was shown that when a solution of radioactive calcium was applied to the surface of intact enamel, it was found in the surface layer within 20 minutes. With longer contact of the solution with the tooth, radioactive calcium penetrated the entire depth of the enamel to the enamel-dentin junction.
The revealed patterns of penetration of calcium and phosphorus into tooth enamel from saliva served as a theoretical prerequisite for the development of a method of enamel remineralization, which is currently used for the prevention and treatment of early stages of caries.
The level of permeability can change due to a number of factors. So, this figure decreases with age. Electrophoresis, ultrasonic waves, and low pH increase the permeability of enamel. It also increases under the influence of the enzyme hyaluronidase, the amount of which in the oral cavity increases in the presence of microorganisms and dental plaque. An even more pronounced change in enamel permeability is observed if sucrose has access to dental plaque. To a large extent, the degree of entry of ions into the enamel depends on their characteristics. Monovalent ions have greater penetrating power than divalent ions. The charge of the ion, pH of the medium, enzyme activity, etc. are important.

The study of the distribution of fluoride ions in enamel deserves special attention. When applying a solution of sodium fluoride, fluoride ions quickly enter a shallow depth (several tens of micrometers) and, as some authors believe, are included in the crystal lattice of the enamel. It should be noted that after treating the enamel surface with a sodium fluoride solution, its permeability sharply decreases. This factor is important for clinical practice, as it determines the sequence of tooth treatment during remineralization therapy.
Maturation of tooth enamel and fluoride prophylaxis

Maturation means an increase in the content of calcium, phosphorus, fluorine and other components and an improvement in the structure of tooth enamel.

In the enamel after tooth eruption, calcium and phosphorus accumulate, most actively in the first year after tooth eruption, when calcium and phosphorus are adsorbed in all layers of various zones of the enamel. Subsequently, the accumulation of phosphorus, and after 3 years of age - calcium, sharply slows down. As the enamel matures and the content of mineral components increases, the solubility of the surface layer of enamel, in terms of the release of calcium and phosphorus into the biopsy material, decreases. An inverse relationship has been established between the calcium and phosphorus content in enamel and the degree of caries damage. The surface of the tooth, where the enamel contains more calcium and phosphorus, is much less likely to be affected by caries than the surface of the tooth, the enamel of which contains less of these substances.
Fluoride plays an important role in the maturation of enamel, the amount of which gradually increases after tooth eruption. The additional introduction of fluoride reduces the solubility of enamel and increases its hardness. Other microelements that influence the maturation of enamel include vanadium, molybdenum, and strontium.

The mechanism of enamel maturation has not been sufficiently studied. It is believed that in this case changes occur in the crystal lattice, the volume of microspaces in the background decreases, which leads to an increase in its density. Data on enamel maturation are important in caries prevention, since they can be used to determine the optimal timing of treatment with remineralizing drugs. If there is a lack of fluoride in drinking water, it is precisely during the period of enamel maturation that additional fluoride administration is necessary, both internally and locally, which can be done by rinsing with fluoride-containing solutions, brushing teeth with fluoride-containing pastes and other methods.

The maturation of enamel is an increase in the content of calcium and phosphorus, a decrease in the content of organic substances in it and an improvement in its structure, which continues throughout life. Therefore, in older people, compared to younger people, teeth are more resistant to the action of demineralizing solutions. Erupted teeth are low-mineralized; they immediately begin to accumulate calcium and phosphorus, which is especially intense during the first year after eruption. Then the accumulation of phosphorus slows down, and 3 years after the tooth erupts, the accumulation of calcium in it slows down, but it still continues throughout life. The amount of fluoride in the enamel also gradually increases after tooth eruption. At the same time, the density of the enamel increases, and the volume of microspaces decreases.

In an unerupted tooth, calcium and phosphorus are distributed evenly, and after the tooth erupts, there is a gradual accumulation of higher concentrations of inorganic substances in the surface layer of enamel, which becomes denser and more resistant to the action of organic acids. Consequently, the most active process of tooth maturation occurs in the period from 1 to 3 years after its eruption, and especially in the first 12 months. Therefore, during this period it is necessary to create optimal conditions for mineralization through remineralizing therapy with calcium and phosphorus preparations. Fluoride preparations compact the surface layer of enamel, preventing the further entry of calcium and phosphorus, so they are not recommended for use within the specified time frame or are used in limited quantities. Saliva, supersaturated with calcium and phosphorus, ensures the maturation of the enamel, thereby providing the special protective properties of its surface layer. Unfavorable conditions in the oral cavity during the intensive process of tooth maturation (the predominance of cariogenic microflora, the presence of bacterial plaque, an excess of refined carbohydrates and a decrease in the concentrations of calcium and phosphorus in food, hyposalivation, etc.) prevent the maturation of the enamel, resulting in it does not acquire the necessary resistance to the action of cariogenic factors. Under the influence of the mineralizing potential of saliva, as well as due to the diffusion of minerals from the pulp, remineralization of tooth enamel can occur. Considering the above, remineralizing therapy is advisable in the initial stages of caries. As the enamel matures, an increasing amount of mineral substances, mainly low molecular weight calcium compounds, are deposited on its surface, which fill the gaps between the prisms. They create the so-called on its surface. “prism-free layer”, characterized by high density. During the maturation process, the enamel crystal lattice becomes denser, the volume of microspaces decreases, and the content of mineral elements increases. The consequence of the above changes is an increase in enamel resistance and a decrease in its solubility in acids.

The permeability of enamel is one of its most important properties. The mechanism of enamel permeability is associated with the presence in its structure of microspaces filled with water, through which various substances can penetrate depending on the size of their molecules and the ability to bind to the crystal lattice of apatites. Enamel is permeable in both directions: from the pulp side and from the saliva side. In this case, molecules and ions move from a medium with a higher concentration towards a lower concentration. The main route of entry of various substances into tooth enamel is from saliva. The permeability of enamel determines its maturation after teething. When radioactive calcium is applied to the surface of the enamel, it is detected in its surface layer after 20 minutes. Penetrating from saliva, calcium ions are deposited in the outer layers of the enamel and then slowly diffuse into the deeper layers. Experiments with radioactive phosphorus showed the possibility of its penetration into the enamel both from saliva and from the pulp. Fluorine comes from saliva into the microspaces of the enamel, but due to its high reactivity, it quickly binds to the apatites of the surface layer, compacting it. As a result, the permeability of the enamel is sharply reduced. This fact is very important, since it determines the sequence of tooth treatment during remineralization therapy: first, calcium and phosphorus must be administered, and then fluoride preparations. Radioactive iodine ions, when applied to the surface of the enamel, quickly penetrate the enamel, dentin, pulp and are found in the thyroid gland after 2 hours. From saliva, not only mineral but also organic substances penetrate into the tooth enamel: amino acids, vitamins, monosaccharides, dyes, toxins and others. Using radioactive labels, it was shown that amino acids penetrate into the enamel from saliva, but they are not found in proteins, which indirectly indicates the absence of metabolism of organic substances in tooth enamel.

Enamel is more permeable to monovalent ions than to divalent ones. The permeability of enamel depends on the rate of salivation: the higher it is, the less permeability. Enamel permeability is increased by monosaccharides, acetylcholine, organic acids, sucrose, alcohol, hyaluronidase, as well as electrophoresis, ultrasound, and bacterial plaque. The permeability of enamel decreases under the influence of saliva supersaturated with calcium and phosphorus salts, as well as fluoride preparations. The enamel of human teeth has significantly lower permeability than the enamel of animal teeth. The permeability of the enamel of different teeth and different surfaces of the same tooth is not the same. It increases from incisor to molar. The permeability of the enamel of unerupted teeth is higher than that of primary teeth, and the permeability of the enamel of primary teeth is higher than that of permanent teeth. With age, the permeability of the enamel of permanent teeth decreases. However, the enamel of extracted teeth is also permeable to certain ions and dyes.

High permeability of enamel contributes to the development of caries. Therefore, by influencing the permeability of enamel, it is possible to develop optimal conditions for preventing the development of dental caries and treating it at the stage of focal demineralization of the enamel. It is also necessary to take into account the fact that the shorter the period of tooth maturation, the less its permeability and the higher its resistance to caries.

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The permeability of the enamel of baby teeth and permanent unformed teeth is much higher than the permeability of permanent formed teeth. Plaque increases the level of enamel permeability. Enamel is a tissue of ectodermal origin that undergoes calcification. It is acellular tissue and lacks blood vessels and nerves. After the enamel completes its formation and calcification, it loses its ability to grow. The enamel is not capable of regeneration and the damage that occurs in it is not eliminated. The disappearance of a white subsurface carious spot is not associated with enamel regeneration, but occurs under the influence of remineralizing solutions, when salts of calcium, phosphorus, fluorine, etc. are artificially introduced into the enamel. Most of the enamel hydroxyapatite crystals are complex formations - enamel prisms, which begin at the enamel-dentin junction and go to the enamel surface, bending repeatedly in the form of a spiral. The permeability of enamel is given great importance in connection with the processes of formation and maturation of hard dental tissues in normal conditions, and de- and remineralization in pathologies. Enamel permeability is related to the maturation of the tooth after eruption (both primary and permanent). Tooth enamel is permeable to many inorganic elements (calcium, phosphorus, fluorine, iodine, etc.) and organic substances (amino acids, carbohydrates, vitamins, etc.). Saliva is a source of nutrients for enamel. However, the intensity of ion exchange and mineralization of enamel is most pronounced in childhood and young age, and decreases with age. At the earliest stages of caries, the permeability of enamel increases sharply (especially in baby teeth). Increased enamel permeability is a sign of progressive demineralization of hard tooth tissues, but thanks to this property, the reverse process develops - remineralization, which helps to stop caries. The surface (outer) layer of enamel has special physical and chemical properties that distinguish it from the underlying layers. It is more resistant to acids. Apparently, this is due to a higher content of calcium and phosphorus in the surface layer. Moreover, the content of these main mineral macroelements remains constantly high in the outer layer, since after teething the main use is

The source of substances entering the enamel is saliva.

A high fluorine content is also determined in the outer layer, 10 times more than in the underlying layer. Strong cariesstatic agents include fluorine, phosphorus, and medium ones include molybdenum, vanadium, copper, boron, lithium, and gold. Selenium, cadmium, manganese, lead, and silicon are considered cariogenic. The intensity of caries in different age periods is not the same: more often caries develops soon after tooth eruption (sometimes in the first months). In childhood, the resistance of dental tissues to cariogenic factors is low, therefore, during this period of life, the activity of caries is higher. Unfavorable conditions in the oral cavity soon after teething, when the enamel has not yet fully matured and formed, prevent the maturation of the enamel, i.e. enamel is formed that does not have sufficient resistance to the action of cariogenic factors. Unfavorable conditions in the oral cavity include changes in microflora, excessive consumption of sweets, hyposalivation, insufficient fluoride intake, etc. Enamel solubility. When caries occurs acid dissolution enamels. The chewing surface is less soluble, and in the area of the tooth neck the enamel is more soluble [Leontyev V.K., 1977]. In dentistry, the solubility of enamel in acids - lactic, acetic, pyrogramic, etc. - as agents involved in the demineralization process is of particular importance. Calcium and phosphorus salts added to the demineralizing solution reduce the rate of enamel dissolution, and carbonate promotes the dissolution of enamel and slows down remineralization. Fluoride is of particular importance in the solubility of enamel. Introducing itself into the crystal lattice of enamel, it displaces hydroxyl, replacing it, resulting in the formation of hydroxyfluorapatite - a stable compound that provides reduced solubility of enamel and resistance to caries. Reduced solubility is one of the leading factors in the anticariasis effect of fluorine. Aluminum, zinc, molybdenum reduce the solubility of enamel, and sulfates increase it. It is very important to determine the intravital solubility of enamel, which can be used to assess its ability to demineralize and resistance to caries. Hereditary factors play an important role in determining the level of solubility. V.G. Suntsov (1988) established that the structure and properties of the surface layer of enamel of milk and permanent teeth depend on the characteristics of the anlage and development of all factors influencing ontogenesis. Saliva is of great importance in maintaining the physiological balance of the processes of mineralization and demineralization in the enamel and is the most important factor in maintaining homeostasis of the oral cavity. The most important function of saliva - mineralizing - is based on mechanisms that, on the one hand, prevent the release of its constituent components from the enamel; on the other hand, facilitating the flow of such components from saliva into the enamel. This achieves a state of dynamic equilibrium of the enamel composition.

The interaction of two processes - the dissolution of enamel hydroxyapatite crystals and their formation - ensures the maintenance of equilibrium between the enamel and the biological fluid surrounding it.

The solubility of hydroxyapatite is largely determined by the concentration of calcium, inorganic phosphate and pH of the medium. Calcium is in free
and bound state. Free
or ionized calcium co-
accounts for about 55% of its total
quantities. 30% of calcium is due to
proteins and 15% with anions - phospho-
phates, citrate, etc. In saliva
retains calcium 2 times less,
than in the blood. On average, the pH of saliva is neutral and ranges from 6.5-7.5. The demineralizing effect of enamel is observed at pH< 6,0. Однако такая реакция слюны бывает очень редко. Кислая среда может определяться в кариоз-ных полостях, налете, после по-падания в полость рта углеводов, но это локальное снижение рН обусловлено жизнедеятельностью микрофлоры налета, кариозных полостей. Кислоты, продуцируе-мой в этих участках, недостаточ-но для понижения рН всей массы слюны. Следовательно, в патогенезе ка-риеса зубов имеет значение именно локальное понижение рН. Снижение функциональной ак-тивности слюнных желез приводит к тому, что зубы меньше омывают-ся слюной, повышается раствори-мость и снижается ее реминерали-зующий эффект; ухудшается само-очищение полости рта, способст-вующее развитию микрофлоры; уменьшается выделение минераль-ных веществ со слюной у кариес-восприимчивых людей, что отрица-тельно влияет на гомеостаз полости рта. Формирование молочных зачат-ков происходит во внутриутробном периоде и во многом зависит от те-чения беременности, перенесенных беременной заболеваний, характера ее питания. Нарушение формирования твер-дых тканей молочных зубов в этот период является предрасполагаю-щим фактором для развития мно-жественного кариеса молочных зу-бов. Твердые ткани молочных зубов менее минерализованы, чем посто-янных. Эмаль - самая твердая часть че-ловеческого тела. Эмаль молочных зубов на 94-96 % состоит из неор-ганических веществ, органических веществ в ней больше (3,5-5,5 %), а воды меньше (около 0,5 %). Эмалевый покров и слой дентина молочных зубов тоньше, особен-но тонок слой дентина в зоне ро-гов пульпы. Дентинные канальцы шире и тоньше таковых посто-янных зубов. Пульповая камера значительно объемнее (недоста-точно развитие вторичного ден-тина). Просвет дентинных трубочек (ка-нальцев) в молочных и постоян-ных несформированных зубах зна-чительно шире, чем в постоянных сформированных. Эту особенность строения дентина необходимо учи-тывать при использовании некото-рых пломбировочных материалов в детском возрасте. Рога пульпы молочного и посто-янного несформированного зуба по сравнению с постоянными зубами значительно больше углубляются в дентин, поэтому необходима боль-шая осторожность при препариро-вании кариозных полостей в таких зубах. In the development of vital activity of the pulp of a baby tooth, two periods are distinguished: pulp formation

(coronal and root) and reverse development of the pulp of baby teeth, corresponding to the period of root resorption. When root resorption begins, the number of cellular elements decreases, and the intercellular substance increases.

Through the root canal and the relatively wide apical foramen, the pulp of the baby tooth is closely connected with the periodontium. This communication between the pulp and the periodontium contributes to the rapid transition of the inflammatory process from the pulp to the periodontium. The incidence of caries in certain groups of teeth and their surfaces. The degree of damage to primary and permanent teeth is not the same. Among primary teeth, molars are most often affected, followed by incisors and canines. Moreover, damage to the molars on the lower jaw, and to the frontal teeth - on the upper jaw, is more often observed. Of the permanent teeth in children, caries most often occurs in the first molars. The first place in the localization of carious cavities in primary teeth is occupied by contact (approximal surfaces), then cervical and, finally, chewing surfaces. Carious cavities on the approximal surfaces of teeth are often adjacent, which creates certain difficulties in diagnosis during filling. Caries on the free surfaces of primary teeth (labial, cheek, lingual) is extremely rare. In permanent teeth, the first place in frequency is occupied by caries of chewing surfaces, and the second place by approximal surfaces. 5.2.1. Peculiaritiescaries developmentatchildren Caries in children at different age periods occurs differently. The course of caries in primary teeth is influenced by anatomical and physiological characteristics, the general resistance of the child’s body and the high reactive properties of childhood. Multiplicity of lesions. The carious process affects a large number of teeth - 8, 10 or more, sometimes all 20 teeth are affected. One tooth may have several carious cavities localized on different surfaces. Such caries is also called acute, acute, blooming, galloping. All this is multiple caries, destroying the child’s dental system. Such caries often develops after acute infectious diseases (measles, scarlet fever, tonsillitis, etc.), which were severe; sometimes after an illness a child develops many new carious cavities. Some chronic diseases (tonsillitis, chronic diseases of the bronchopulmonary system, etc.) are also accompanied by multiple caries. Multiple caries affects all surfaces of the teeth, in a short time the crowns are completely destroyed, the pulp becomes necrotic and only the roots remain in the jaw; the lesion occurs sequentially and spreads to all teeth soon after eruption, and by 3-4 years the child is left without teeth. Multiple caries in some diseases. A pressing problem among young children is still rickets, the prevalence of which in the first year of life remains high and, according to the results of large-scale epidemiological studies,

falls within the range of 55-70%. The basis of rickets is disturbances in phosphorus-calcium metabolism and the system that regulates phosphorus-calcium homeostasis (vitamin D metabolites, parathyroid and thyroid glands). After severe forms of rickets, a “hypocalcemic titer” of the child is often formed, characterized by clinical manifestations of hypocalcemia for many years (“juvenile osteopathies”).

It can be considered that the dentofacial system in rickets is the target organ and there is a pathogenetic connection between rickets and disturbances in the formation of the dentofacial system, insufficient mineralization of teeth and deviations in the formation of permanent teeth, retarded jaw growth and anomalies bite, early and multiple dental caries (Fig. 5.17). Down's disease is characterized by a significant retardation of the child in physical and mental development, dysfunction of many endocrine glands. The appearance of the child is typical immediately after birth. The pairing and sequence of teething are disrupted; in some children, milk teeth erupt late, sometimes by 4-5 years; there is multiple damage to all teeth, even the most caries-resistant ones, both milk and permanent. Damage to various tooth surfaces is noted, including an atypical course of caries on the lingual surfaces, in the area of the cutting edge of the incisors, etc. The following factors play a role in the development of multiple caries in Down syndrome: high susceptibility to childhood infections, diseases of the upper respiratory tract and very poor oral hygiene. The speed of spread of the process- one of the main especially- Fig. 5.17. Multiple caries in a patient with rickets. of caries in milk teeth. Caries in primary teeth develops faster than in permanent teeth, quickly reaches the enamel-dentin junction, penetrates into dentin and spreads therein (penetrating caries). This is due to the thin enamel cover and the special structure of dentin, which has low-mineralized zones reaching the pulp. Low pulp activity plays a certain role. Therefore, in childhood, especially in weakened young children, the carious process develops very quickly from the initial forms to complications in the form of pulpitis and periodontitis, the dentin is softened, light yellow, and can be easily removed with an excavator whole layers. The carious process seems to penetrate through hard tissues (enamel, dentin) and quickly spreads to the pulp. Circular caries. Caries of primary anterior teeth, starting on the labial surface in the cervical area, spreads around the entire crown, capturing the proximal and lingual surfaces (Fig. 5.18). The process deepens, and the crown easily breaks off at the level of circular caries, leaving only the roots (Fig. 5.19-5.21).

Rice. 5.18. Circular caries of primary incisors. Rice. 5.19. Fracture of the crown after circular caries. Rice. 5.20. Caries on the contact surfaces of primary incisors. Such caries often occurs soon after teething and primarily affects the upper frontal incisors, less often the canines. Circular caries of primary teeth is very similar to the so-called radiation caries, which rapidly develops cervically as a complication after radiation therapy for neoplasms and leads to rapid tooth loss. It is believed that the following factors are important in the development of circular caries of primary teeth: the crowns of primary teeth are mineralized in utero, and their structure depends on the course of the mother’s pregnancy. The neck of the baby tooth mineralizes soon after the birth of the child, when his body transitions to new conditions of existence: the nature of nutrition changes - intraplacental to natural or, unfortunately, more often to artificial feeding. Nutritional conditions, living conditions of his life, diseases that can develop immediately after birth, acute respiratory infections, dyspepsia and other diseases can adversely affect mineralizing dental tissues. During this period, the neck of the tooth is the most weakened area of the tooth; as a result, its mineralization is incomplete, and it subsequently turns out to be susceptible to the development of caries. Circular caries occurs mainly in premature babies, with malnutrition, rickets, tuberculosis, and in children who are bottle-fed. In these cases, calcium salts may be released from already mineralized tissues. Circular caries is characterized by rapid spread of the process in the direction of the pulp. It should be noted that children almost never present with acute pulpitis due to circular caries. There are two possible outcomes here: the first is when the death of the pulp occurs in a child with reduced body resistance

without any clinical manifestations and chronic periodontitis gradually develops; the second is when, during circular caries, the root pulp is isolated from the coronal pulp due to replacement dentin, the tooth crown breaks off along with the coronal pulp, and the root pulp remains viable and retains intact periodontium. The root pulp is tightly “walled up” with pigmented dentin, and the tooth, in the presence of such caries and living pulp, continues to “serve” the child for some time. This option is less common in children.

Caries along the plane (planar caries). With this form, the carious process does not spread deep, but along the surface, forming an extensive shallow carious cavity (see Fig. 5.21). If the process develops quickly, the tooth soon collapses. But sometimes caries develops slowly along the plane: the dentin is brown or dark brown in color, dense. This is one of the forms of chronic caries, which is also called stationary, or suspended. With planar caries, part of the enamel and dentin may be missing without the formation of a cavity in both molars and incisors. But slow progression of caries in children is rare; rapid demineralization develops much more often. Based on the leading manifestations of caries - the number of carious teeth and cavities, their localization, the increase in caries after a year - the degree of activity of the process is determined. When comparing individual clinical signs in children with different degrees of caries activity, differences in the development of the pathological process are revealed. Based on this, Prof. T.F. Vinogradova identified 3 groups according to the degree of caries activity:

Rice. 5.21. Caries along the plane. Group I - compensated temperature
caries treatment (I degree); II group - subcompensated-
caries (II degree); III group - decompensated-
caries (III degree). With a decompensated form of caries, the child has many affected teeth, including pulpless ones; carious cavities have sharp edges and an abundance of wet dentin; damage to almost all groups of teeth is observed; there are many chalk spots. When examining previously placed fillings, their defects and relapse of caries are discovered. This classification is widely used in pediatric therapeutic dentistry. Clinically, in children, as in adults, caries is divided into spots (macula cariosa), superficial (caries superficialis), medium (caries media) and deep (caries profunda). The first two forms of caries are combined into initial caries. Caries in the spot stage can be detected in children of a very early age, literally from 6-8 months. In children, the upper incisors are more often affected; chalky spots appear without a natural shine at the neck of the tooth, small at first, and then spreading over the entire vestibular surface of the crown.

Caries in the spot stage is asymptomatic and is detected only during a preventive examination by a doctor or an attentive mother.

Sometimes carious spots in children are discovered after removing white sticky plaque from the enamel surface. With an intensive course, carious spots are light, without clear boundaries, as if blurred, prone to constant progression. The larger the area of the spot, the more intense the course of the pathological process and the sooner a carious cavity is formed (superficial caries), therefore the size of the carious spot is important for determining the severity of the process. With slowly occurring demineralization, prone to stopping the pathological process, carious spots are pigmented, but they are much less common in children. As soon as roughness begins to be detected during probing, this means that superficial caries develops and a cavity forms within the enamel. Children are characterized by the formation of small carious cavities against the background of a large carious chalk spot. Not all carious spots can be detected during examination: it is difficult to identify carious spots on proximal surfaces, especially when they are located on adjacent teeth. Sometimes a carious spot is covered by a large layer of soft plaque. Subsurface carious spots are difficult to detect. This can only be done after thoroughly drying the tooth surface. Carious spots on permanent teeth should be distinguished from the spotted form of systemic hypoplasia and fluorosis. Most often, carious spots form on the neck of the tooth. With systemic hypoplasia, damage to teeth of the same period of formation (mineralization) is observed and the process develops in one plane. Spots, clearly defined, are often located in the middle of the vestibular surface or closer to the cutting edge. With fluorosis, there is damage to teeth of different periods of formation; There are multiple white or brown spots of different sizes, which can be located on any surface of the tooth. The higher the fluoride content in the water, the larger the size of the spots and the nature of the changes in the enamel. In childhood, systemic hypoplasia occurs very often, especially in children who have suffered acute or chronic diseases (dyspepsia, dysentery, rickets, etc.) during the period of mineralization of the crowns of permanent teeth. Foci of endemic fluorosis are also quite common. Children who may simultaneously have caries and fluorosis, caries and systemic hypoplasia often come to the clinic for consultation. In some cases, one child may have carious spots, systemic hypoplasia, and a spotted form of fluorosis. This is due to the formation (mineralization) of enamel, which depends on the age of the child, the fluoride content in drinking water, and diseases suffered during this period. Carious spots on baby teeth are sometimes differentiated from hypoplasia of baby teeth. Chalk spots with hypoplasia of primary teeth appear in those areas that are formed in one period. Hypoplasia of primary teeth is detected more often in premature children. Superficial caries. In young children, this form of caries is rare; more often there is a combination of a large carious spot, against the background of which softening of the tissue and

A small carious cavity is formed within the enamel. The softened enamel is removed with a little effort using an excavator. Most children do not complain. Sometimes short-term pain occurs from sweet, sour, salty foods. A small carious cavity with superficial caries should be differentiated from the grooved, cup-shaped form of systemic hypoplasia, the erosive form of fluorosis, and intermediate caries.

Teeth are living organs with metabolic processes constantly occurring in them. Many people have probably heard more than once about such a phenomenon as the acid-base balance, which must be restored every time after eating. This is explained by the fact that the pH in the oral cavity becomes acidic after eating. To neutralize this condition, the process of “washing out” microelements from tooth enamel into the oral cavity begins to become more active. This process is called demineralization; if it becomes dominant over the processes of remineralization, then defects appear in the enamel, which subsequently open the way for the development of caries.

This is a pathological process in which the hard tissues of the teeth soften with accompanying demineralization. A cavity gradually forms in the tooth. The development of caries can be influenced by external and internal causes. It is characterized by the following stages:

Stains.
Surface.
Average.
Deep.

When a violation of the enamel is in the stain stage, this can be easily noticed by its lost color - it becomes dull with the loss of its characteristic shine. In this case, there is no roughness on the surface - it is absolutely smooth. At this stage, caries is practically invisible, so in order to identify its early form, the methylene blue staining method is used. First you need to remove plaque from the enamel, for which you use a thick swab treated with hydrogen peroxide. If there is an initial manifestation, then this area of enamel treated with dye, due to increased permeability, will turn blue. And accordingly, the white spot, which is not of carious origin, will remain unchanged.

When caries is detected, the white spot stage must be treated. This therapy consists of the following:

A diet is prescribed that is rich in vitamins, proteins, mineral salts and other useful and necessary substances.
Remineralizing therapy is carried out, which is based on the use of products containing sufficient amounts of calcium and fluoride.

Currently, in dentistry, much attention is paid to an integrated approach to the treatment of dental caries. If earlier the emphasis was mainly placed only on filling and improving methods for eliminating carious cavities, now it is no less important to influence the factors and other circumstances of its formation. Research has established that the main cause of caries formation is the presence of a specific “streptococcus mutans”. This microorganism is capable of releasing acids during its life processes, which provoke the process of tooth enamel losing mineral substances. As a result, demineralization leads to the formation of caries. To prevent such complications, teeth are remineralized.

This treatment method consists of filling tooth enamel with essential minerals. Since phosphorus and calcium are the main elements of tooth structure, they form the basis of remineralizing compounds. In this case, fluorine influences the formation of acid-resistant forms of the main substance of tooth enamel - apatite.

To increase the effectiveness of the procedure, it is combined with the use of fluoride-containing products. In most cases, fluorides are recommended after completion of the remineralization course to reduce the release of calcium from tooth enamel. Drugs intended for therapy are produced in different forms, these can be varnishes, gels, and special pastes. Solutions of mineral substances are also used in the form of applications to the points of problem teeth and calcium preparations for internal use.

Based on the above, we can come to the conclusion that remineralization therapy is the process of professional treatment of enamel with special preparations that aim to normalize its mineral composition. It helps get rid of small defects that were caused by demineralization; in addition, it serves as a strong prophylactic agent that prevents damage to the enamel as a result of leaching of calcium and phosphorus from hard dental tissues.

Why is remineralization needed?

In the oral cavity, the process of formation of certain chemical reactions continuously occurs, the pH level changes; the presence of various microorganisms that lead their lives in dental plaque also contribute to the overall picture. The appearance of dental plaque, a lack of minerals that enter the patient’s body with food, and disturbances in the acid-base balance often provoke the process of the enamel releasing the components it needs, in particular minerals. All this ultimately leads to the beginning of demineralization, as a result of which the enamel gradually becomes thinner and thinner, forming a carious cavity.

At the same time, this process is quite lengthy, and the tooth is destroyed due to the process not starting immediately. First, demineralized lesions form - the color and structure of the enamel changes, making it much more vulnerable to activating caries. And it should be noted that this stage of the so-called white spot of the carious process may well be reversible.

But for this it is necessary to timely saturate the enamel with important elements such as calcium, phosphorus and fluorine. For this purpose, there is a procedure called remineralization. Using this method, you can not only completely restore the enamel, but also reduce the susceptibility of teeth to caries. The benefits of remineralization therapy are outlined in the list below:

Provides protection of teeth from caries as an excellent preventive procedure.
It is highly effective at the onset of caries development, contributing to the preservation of teeth; cures caries without the use of mechanical interventions.
Excellent in eliminating hypersensitivity, as it is a consequence of dental demineralization.
Helps replenish the loss of minerals in tooth enamel as a result of the whitening procedure. It also increases the content of minerals lost during the treatment of orthodontic diseases, in adolescence, when they are intensively consumed during the active growth of the patient, pregnancy due to the high need of the fetus for minerals.

Indications for the procedure

Remotherapy is a kind of urgent assistance in dental practice, which returns wasted minerals to the teeth and preserves the normal condition of the teeth, making them more resistant to negative influences and other undesirable factors. Currently, there are certain indications for this therapy:

With increased sensitivity of tooth enamel.
Initial caries, the so-called “white spot” stage.
For minor multiple carious formations.
Lesions of tooth enamel of a non-carious nature, expressed by fluorosis, enamel hypoplasia, wedge-shaped defect and some others.
The patient suffers from pathological tooth wear.
As a consolidating procedure after sessions to remove plaque and tartar.
After whitening, during the treatment of orthodontic diseases and after its completion, during breastfeeding and some other procedures and conditions in order to replenish the mineral composition of the enamel.

Enamel permeability: what is it?

Research in this area shows that the level of permeability of tooth enamel can be influenced by a number of factors, for example, the following:

Age. It should be noted that with age this indicator does not increase, but rather decreases.
Application of electrophoresis.
Ultrasonic waves help increase the permeability of tooth enamel.
A significant factor for permeability is low pH.
Hyaluronidase enzyme. The permeability of enamel increases under its influence, the amount of which, in turn, becomes greater in the oral cavity in the presence of dental plaque and microorganisms developing in it.
Sucrose. Permeability becomes more pronounced if sucrose is added to the microorganisms in dental plaque.

A few words need to be said about some elements that play an important role in the processes of remineralization. Thus, the flow of ions into tooth enamel is highly influenced by the characteristics of the ions. For example, divalent ions have less penetrating power than monovalent ions. Of great importance in this is also the charge of the ion, pH of the environment and enzyme activity. At the same time, special attention is required to study how fluoride ions distribute in tooth enamel. When applied, a solution of sodium fluoride allows fluoride ions to quickly reach a small depth and, according to some researchers, to be incorporated into the crystal lattice. It is necessary to note that the surface of tooth enamel treated with such a solution becomes low permeable.

Technology

This procedure is considered completely painless and does not require any special effort or time. And the effect of its use is always very high. And you can be sure that the teeth of both adults and children will be kept healthy and beautiful. There are several methods of remineralization; each method may have its own procedure. At the same time, there are also moments that are characteristic of all. The following is just a general methodology, but it gives a clear idea of how this should all happen:

The procedure is performed only on absolutely clean tooth enamel.
If there are indications, it is carried out with mandatory professional sanitation of the oral cavity.
Remineralizing therapy sessions are individually selected for each patient.
Selecting a suitable gel
A soft tray special for this procedure is selected and the gel is introduced into it.
A mouthguard with gel is installed in the oral cavity on prepared (air-dried) teeth.
Apply the gel for four minutes. After completing the procedure, it is not recommended to eat, rinse, or drink for an hour. It is advisable to carry out these procedures at least once a year, and preferably twice.

Remineralization in children

Initial caries includes two forms: in the spot stage and superficial. In the first case, the child develops white, chalky-colored spots of different shapes and sizes on the teeth (in most cases, the upper incisors). There is usually no pain in this case. Spots that do not initially have any defined boundaries begin to grow steadily over time and ultimately lead to the formation of carious cavities. This will already be the stage of superficial caries.

In some cases, its occurrence and the appearance of a carious cavity can be determined by the formation of rough spots on the surface, while the tooth enamel becomes softer and can be removed using a tool. For the most part, the little patient does not experience pain, however, in some cases this phenomenon may be characterized by increased sensitivity to cold and hot food, as well as to other irritants.

Using remineralization, introducing the missing mineral components, usually a combination of the main three minerals, it is possible to achieve (although, admittedly, this does not happen often) the disappearance of the stain, or to stop the demineralization process that has begun.

For remineralization, the following drugs and solutions are used:

calcium gluconate (10 percent);
Remodenta (3 percent), which does not contain fluorine;
acidified calcium phosphate (2 and 10 percent solutions);
sodium fluoride (2 percent);
gel (one percent) containing fluoride;
gel (with pH 6.5-7.5 and 5.5) containing calcium and phosphate.

It also includes:

Diplene F – dental adhesive film. It must be glued to the baby’s tooth before bedtime, after brushing the teeth. Overnight, the film will completely dissolve, and fluoride ions will take their place in the crystal lattice of tooth enamel.
Fluoride varnish. When applying it, you must adhere to food intake restrictions for at least three hours.

It is very important that during remineralization therapy the child maintains daily oral hygiene, brushes his teeth at least twice a day and eats as little sweets as possible. Quite often, especially when the tooth enamel is not yet sufficiently mineralized in young patients, the remineralizing procedure turns out to be timely and effective. It makes it possible to slow down the onset of caries development. After six months, you can already notice how the tissues have thickened.

Application methods

Due to the weak genesis of hard dental tissues, which usually occurs during intrauterine development due to the influence of negative factors on the mother’s body and child, erupting teeth no longer have the optimal mineral composition in the enamel. Therefore, there is a need to carry out active remineralization in order to prevent caries.

When treating temporary teeth, a fairly popular method of silvering with 30% AqNO3 can be used. The procedure gives very good results in most cases. It is recommended to carry out treatment in three sessions with day breaks, then repeat the procedure after three months and after six.

Remineralizing therapy uses the Borovsky-Leus method. It includes five-minute applications (two or three times) of 10 percent calcium gluconate, then three minutes of two percent sodium fluoride. The procedures are performed until the focal spots disappear. The course of treatment continues, taking into account the activity of dental caries, usually for ten days. It is recommended that children with initial stages of caries undergo this therapy at least twice a year, but if stage 3 is observed, every three months.

Studies conducted over a number of years have shown that the use of this method gives good results and significantly reduces the percentage of caries.

Method of T. Vinogradova:

Apply a solution of calcium gluconate (10 percent) for three minutes.
Rinse or bathe the mouth with a sodium fluoride solution for one or two minutes, or coat the tooth enamel with fluoride varnish as an alternative.

P. Leus method:

Using electrophoresis with calcium gluconate (10 percent) for three to five minutes.
Application of an application with a 2 percent sodium fluoride solution for two minutes. The course of treatment is three times with weekly breaks.

The drug includes the following composition (percentages in brackets):

calcium (4.4), phosphorus (1.4);
magnesium (0.15), potassium (0.20);
sodium (6.0), chlorine (30.0);
organic matter (44.0);
microelements (up to 100).

Remodent is usually used for rinsing procedures, applications (3 percent solution), and for cleaning with toothpaste, which contains three percent of the drug by weight.

Before using the application, you need to brush your teeth well with an oral hygiene paste, after which tampons treated with remodent are applied for a quarter of an hour. During the year, experts advise carrying out three to five procedures. After each session, you should not eat or brush your teeth for two hours. Use 10 ml of solution as a rinse (lasting up to five minutes).

The effectiveness of the drug as a prophylactic agent can reach 50 percent. The effectiveness is most pronounced on chewing surfaces.

Gel for teeth

Remineralization therapy is an effective and physiological way to treat and prevent caries. There is an excellent gel R.O.C.S. Medicals Minerals, which will strengthen teeth with minerals using a mouth guard. It will also improve the shine and color of teeth without the help of aggressive whitening agents, this is especially important for those patients who are contraindicated for teeth whitening. Features of the composition:

is a source of highly digestible compounds of magnesium, calcium and phosphorus;
special additives give it adhesive properties;
forms an invisible film on the enamel;
promotes active gradual penetration into dental tissues;
the presence of xylitol increases its remineralizing effect

In conclusion

Summarizing the above, we can come to the conclusion that remineralization therapy is a truly effective method for preventing caries in the initial stages. It is able to compensate for the loss of minerals from tooth enamel and bring their saturation to an optimal level. This will significantly increase the resistance of tooth enamel to various acids. In addition, this method is completely painless, which is aimed at ensuring that teeth are always beautiful and healthy.

Remineralizing therapy is usually carried out in courses of treatment. Depending on the condition of the teeth, the specialist will prescribe the required annual number of procedures. It can be performed on both adult patients and children. The technique of application is that the patient applies special pastes and varnishes to the entire dentition.

Section 2. Dental caries

001. Ca 10 (PO 4)6(OH) 2 is

1) carbonapatite

2) chlorapatite

4) whitlockite

5) hydroxyapatite
002. Hard tissues of the tooth are characterized by a calcium-phosphorus ratio

3) 2,1
003. Solubility of dental enamel hydroxyapatite

when the pH of the oral fluid decreases

1) increases

2) decreases

3) does not change
004. Enamel microhardness in caries at the spot stage

1) decreases

2) increases

3) does not change
005. Enamel permeability increased

1) in the white spot stage

2) with fluorosis

3) with hypoplasia

4) upon abrasion
006. Ion exchange processes, mineralization and demineralization

provides

1) microhardness

2) permeability

3) solubility
007. For dental caries in the white spot stage, protein content

in the lesion body

1) increases

2) decreases

3) does not change
008. For dental caries in the white spot stage, calcium content

in the lesion body

1) increases

2) decreases

3) does not change

009. For dental caries in the white spot stage, phosphorus content

in the lesion body

1) increases

2) decreases

3) does not change
010. For dental caries in the white spot stage, fluoride content

in the lesion body

1) increases

2) decreases

3) does not change
011. Enamel hydroxyapatite formula

1) SaNRON 4

2) Ca 10 (PO 4) 6 (OH) 2

3) Ca 10 (PO 4) 8 (OH) 2

012. With average caries, probing the cavity is painful

1) along the edge of the enamel

2) along the enamel-dentin junction

3) along the bottom of the carious cavity

013. Phosphoric acid permeability of enamel

1) increases

2) lowers

3) does not change

014. Sodium fluoride enamel permeability

1) increases

2) lowers

3) does not change

015. Saline solution permeability of enamel

1) increases

2) lowers

3) does not change

016. Lactic acid permeability of enamel

1) increases

2) lowers

3) does not change

017. Calcium gluconate solution enamel permeability

1) increases

2) lowers

3) does not change

018. Remodent solution, enamel permeability

1) increases

2) lowers

3) does not change

019. Remineralization of tooth enamel is determined by its

1) microhardness

2) permeability

3) solubility
020. The most characteristic clinical symptom

with caries of different stages - pain

1) spontaneous

2) persisting after removal of the stimulus

3) only in the presence of a stimulus
021. The cavity with superficial caries is localized within

2) enamel and dentin

022. The cavity with average caries is localized within

2) enamel and dentin

3) enamel, dentin and predentin
023. The cavity with deep caries is localized within

2) enamel and dentin

3) enamel, dentin and predentin
024. Methods for diagnosing caries at the spot stage

1) staining and EDI

2) radiography and EDI

3) radiography and thermal diagnostics

4) thermal diagnostics and fluorescent stomatoscopy

5) fluorescent stomatoscopy and staining
025. Vital staining method reveals lesions

demineralization of enamel

1) with enamel erosion

2) for caries in the white spot stage

3) with a wedge-shaped defect

4) with hypoplasia

5) for caries in the pigmented spot stage
026. For vital staining of tooth enamel when diagnosing caries

use

1) erythrosine

3) methylene blue

4) potassium iodide

5) Schiller–Pisarev solution

027. Remineralizing therapy involves

entry of substances into the site of demineralization

1) mineral

2) organic

028. Deep caries is differentiated

1) with average caries

2) with chronic pulpitis

3) with chronic periodontitis

4) with fluorosis

029. Etching the enamel ensures contact with the tooth enamel

with composite material according to the principle

1) micro clutches

2) chemical interaction

3) adhesion

030. Sealants are used for prevention

1) caries

2) fluorosis

3) hypoplasia

031. For better retention of the composite material

the enamel is prepared by

1) fluoridation

2) creating a fold

3) acid pickling

032. Restorative filling materials include

1) zinc-eugenol paste

2) glass ionomer cement

3) potassium hydroxide

4) composite materials

5) compomers

033. List the methods of filling cavities

1) sandwich technique

2) step-back

3) tunnel method

034. The composition of the composite material includes

1) phosphoric acid

2) filler

035. For etching enamel before filling

the composite material uses acid

1) salt

2) fluorescent

3) orthophosphoric

036. Glass ionomer cement is used

1) for aesthetic filling

2) for filling temporary teeth

3) for fixing pin structures

4) to create a tooth stump for a crown
037. Groups of composite materials include

1) microphylls

2) macrophylls

3) hybrid

4) neutrophils
038. Bonding systems include

1) primer

2) acid

3) adhesive

4) polishing paste
039. Color of filling material for aesthetic restoration

should be selected under the following conditions

1) in the dark on a dried tooth surface

2) under artificial light

after etching the tooth surface with acid

3) in natural light on a damp tooth surface
040. For the restoration of the frontal group of teeth it is used

1) amalgam

2) microfilled composites

3) cement phosphate

4) dentin paste
041. Used for sandwich filling technique

combination of materials

1) phosphate cement + amalgam

2) glass ionomer cement + composite

3) apexit + dentin paste
042. For polishing the surface of a filling made of composite material

use

1) finely dispersed diamond turbine burs

2) Gates burs

3) silicone polishers

4) SoftLex wheels

5) carbide finishes
043. For filling cavities of class 1 and 2 according to Black, use

1) microfilled composites

2) hybrid composites

3) packable composites

044. Composite materials by type of polymerization

are divided into

1) light-hardening

2) chemical curing

3) double curing

4) infrared curing
045. In the chewing group of teeth when filling according to class 2 according to Black

contact point is created

1) planar

2) point

3) stepped
046. When applying a one-component bonding system

the dentin surface should be

1) overdried

2) slightly damp

3) abundantly moisturized
047. Causes of post-filling pain after use

light-curing composites can be

1) applying bonding to overdried dentin

2) violation of polymerization technique

3) use of abrasive paste when polishing the filling
Match
048. Type of filling material Black class

1) flowable composite a) 1 (large cavity)

2) packable composite b) 2

3) microfilled composite c) 3, 4

d) 5
Please indicate the correct sequence
049. Stages of filling a cavity with composite materials

1) applying bonding

2) applying cushioning material

3) etching of enamel

4) polishing the filling

5) adding filling material
050. Distribute filling materials

as their aesthetic properties increase

1) composites

2) compomers

3) glass ionomers