DENTAL CALCULUS (calculus dentalis) — the mineralized amorphous or crystal deposits on the surface of tooth in a neck.
There is a number of theories of education 3. to., however the pathogeny is finally not found out. One authors consider that settling-out of calcium phosphate comes from saliva owing to loss by it of carbonic acid and increase in a pH value of saliva; other authors explain sludge formation with release of ammonia from urea that also promotes increase in a pH value of saliva at reduction in the rate of salivation (especially during sleep). Some authors note a role of surfactants in education 3. to. There are also fosfatazny theory and the so-called theory of crystallization.
The contributing factors in education 3. to. are the increased speed of salivation, change physical. - chemical properties of saliva (viscosity, etc.) and exchange processes in an organism, caused by disturbance of food and various diseases (hl. obr. went. - kish. path, liver, etc.), nek-ry pharmaceuticals, including antibiotics; 3 are especially intensively deposited. to. at smokers.
In relation to a gingiva distinguish naddesnevy and subdingival 3. to. Naddesneva 3. to. is located above gingival edge, has color from yellow-white to brown and black-brown, often it is not painted. Pigmentation 3. to. it is caused by disintegration of uniform elements of blood in a dentogingival pocket and emergence of hemoglobin, change of chemical composition of saliva and liquid of a dentogingival pocket, and also influence of nicotine. Naddesneva 3. to. usually friable, fragile, easily acts special tools; it is postponed on the teeth which are near output channels of big sialadens (the lingual surfaces of the lower foreteeth, the buccal surfaces of upper big molars) and also for surfaces of dentures in the absence of care of them. Hardness 3. to. depends on many factors, including on prescription of its education; the chemical structure depends on the place of education 3. to. in an oral cavity.
Subdingival 3. to. forms below gingival edge (fig.), in the area patol, a dentogingival pocket (see. Desna ), has dark brown color, hardness it is much higher, than naddesnevy 3. to. As it is formed by precipitation of inflammatory exudate and components of blood serum of vessels of a dentogingival pocket, it call «serumal». It is formed at various distances from output channels of big sialadens, has identical chemical structure irrespective of the place of education in an oral cavity; it is considered that saliva does not participate in its education.
Both look 3. to. have identical amino-acid structure and sloistokontsentrichesky structure; the chemical structure is variable; apprx. 80% make inorganic components from which contain in the greatest number calcium, magnesium, phosphorus, carbonates and microelements. According to Jenkins and Spiyers (G. N. Jenkins, Spiers, 1954), the content of fluorine is 3. to. above, than in the surface of enamel of second teeth at the same individual. The X-ray crystallographic analysis revealed that in 3. to. a lot of substance, similar to apatite and other crystal forms of calcium phosphate, including brushite, beta tricalcium phosphate, and a nek-swarm amount of the magnesium replacing calcium, and also oktakaltsiyfosfat contains. It is established that a ratio of various crystal forms in 3. to. changes depending on biogeochemical conditions of the environment. The organic component (matrix) is a derivative of saliva and bacteria, is presented preferential by the glycoprotein containing from 12 to 20% of carbohydrates.
3. to. forms by impregnation of a soft dental plaque (see. Teeth, biochemistry of teeth ) and magnesium which get into a jellylike matrix of a dental plaque and are besieged by mineral components of saliva, generally calcium phosphates on soft tooth deposits with formation of brushite, octacalcium of phosphate, apatite. At the same time in a matrix of a dental plaque the ratio between organic and mineral fraction in favor of the last changes that leads to emergence of the centers (kernels) of a mineralization, depolymerization of organic matter of a matrix, its decrease, loss of water, hardening of a dental plaque and education 3. to. — the mineralized dental plaque. Mineralization of a soft dental plaque and education 3. to. occurs in 12 days. An essential role in education 3. to. belongs to bacteria (Leptotrichia buccalis). In 3. to., covered with a dental plaque, activity of phosphatases, leucineaminopeptidase and other enzymes is defined.
3. to. renders irritant action on a gingiva, is one of the reasons ulitis (see). The subdingival stone renders bigger irritant action, than naddesnevy 3. to., strengthening an inflammation and exudation, destroying an epithelium of a dentogingival pocket, promotes distribution of inflammatory process on periodontium (see). Careful removal 3. to. is the main condition of the prevention and treatment of an ulitis and enters complex treatment periodontosis (see).
3. to. delete with special tools by mechanical stripping with preliminary application of tampons with hydrogen peroxide. Ultrasonic installation like Ultrastom, Kavitron is sometimes applied (see. Ultrasonic therapy, equipment ).
Prevention consists in respect for hygiene of an oral cavity, ensuring good nutrition with inclusion in a diet of crude vegetables and fruit.
See also Sanitation of an oral cavity .
Bibliography: Kolesov A. A. To a question of formation of dental and salivary calculi, Stomatology, No. 3, page 40, 1957; P e r-with and M. M. c, Kolesnik A. G. Ilheus P. A. Dental plaque, education, properties, structure and value, in the same place, No. 1, page 90, 1971, bibliogr.; Jenkins G. N. The physiology of the mouth, Oxford, 1970; M a n d e 1 I. D. Biochemical aspects calculus formation, J. Periodont. Res., v. 9, p. 211, 1974.
E. V. Borovsky, M. M. Persits.