Periodontist- a complex of closely interconnected tissues surrounding and fixing the teeth (gums, periosteum, bones of the alveolar process, periodontium and cement covering the root of the tooth). The biological and pathological relationship of the tissues that fix the teeth has been established for a long time.
Periodontal tissues are an embryological, physiological and pathological unity. There is a close relationship between the development, functions and diseases of the periodontium, despite the different structures of its constituent elements.
An embryological connection is indicated by the fact that all periodontal tissues (with the exception of the gums) develop from the connective tissue surrounding the tooth germ and share a common blood supply. The physiological connection is manifested in the fixing function of periodontal tissues. When a tooth is lost, the entire periodontium is resorbed. The pathological connection is manifested in the fact that the pathological processes that occur in individual periodontal tissues, as a rule, quickly pass to the rest of its parts. Periodontium is a functional, physiological and pathological concept rather than an anatomical one.
The division of the masticatory apparatus into teeth and periodontium and the separation of the concept of periodontium violates the concept of the tooth as an anatomical unit, since the cement covering the root of the tooth (although it is closely related to the tooth) should still be attributed to the periodontium, because its development differs from the development of other hard tissues tooth - enamel and dentin. Enamel and dentin develop from the tooth germ, and cementum from the connective sheath surrounding the tooth germ. The function of the cement consists of fixing the tooth, in which the fibers of the periosteum fixing the tooth are attached. Thus, the pathological processes of cementum are associated with periodontal diseases.
Periodontium is a connective tissue located between the wall of the dental alveoli and the surface of the tooth root in the so-called periodontal gap. The periodontal connective tissue is directly connected with the jaw bone, through the apical opening - with the pulp of the tooth, and at the edges of the tooth socket - with the gum and periosteum of the jaw
The functions of the periodontium. The periodontium performs a variety of functions: support-retaining, distributing pressure, chewing pressure regulator, plastic, trophic, etc.
The periodontium fixes the teeth in the jaw. Force acts on the teeth both during chewing and without chewing load, in other functional states. These forces are trying to move the teeth from their place.
The periodontium transfers the forces acting on the teeth to the jawbones. Forces arising from the contraction of the masticatory muscles are called masticatory forces.
The transfer of masticatory forces is carried out primarily through the periodontal fibers, which are located in different directions in such a way that they tightly fix the tooth in the tooth cell. They mainly stretch in an oblique direction at an angle of 45 ° towards the top of the root - the tooth, as it were, hangs in the alveolus. In the region of the neck of the tooth, these fibers take an almost horizontal direction and, intertwining with the bundles of fibers coming from the top of the alveolar septum and the gums, form a circular ligament covering the neck of the tooth in the form of a ring.
In the apical part of the root, as well as in the cervical part of the periodontium, a certain number of fibers run in the radial direction, which prevents and limits the lateral movements of the tooth. The vertical arrangement of the fibers at the bottom of the alveoli in the apical section of the periodontium prevents the teeth from moving out of the hole.
The slightly wavy course of the bundles of periodontal collagen fibers makes possible a slight displacement of the teeth: under the load acting on the teeth, the fibers do not stretch, but straighten, tighten. Under the influence of a sudden high force, the fibers can break, and part of the cement can break off from the dentin. The direction of the force acting on the tooth may be parallel to the longitudinal axis of the tooth; this force pushes the tooth into the alveolus. In most cases, however, the acting force forms a larger or smaller angle with the longitudinal axis of the tooth and exerts a tilting effect on the tooth.
The pressure falling on any tooth extends not only through its roots to the alveolar process, but also through interdental contacts to adjacent teeth.
The distribution of chewing force is also facilitated by the fact that the large molars are inclined in the medial direction, and therefore the forces acting during chewing along their longitudinal axis are partly transferred to small molars and incisors.
Thus, these teeth take part of the load of the large molars. With the loss of each individual tooth, the tooth adjacent to it loses its support, leans towards the formed gap. Therefore, the extraction of teeth is highly undesirable in terms of their fixation.
Proper contact of the teeth and lateral (proximal) surfaces is also an essential factor in the distribution of chewing force. Is her contact with contact points broken
(displaced towards the neck of the tooth or laterally), the action of chewing force can cause displacement of the teeth (Fig. 2).
Chewing movements, creating increased pressure in the periodontium, cause the emptying of blood vessels. A decrease in the volume of blood in the periodontal vessels reduces the width of the periodontal gap and contributes to the immersion of the tooth into the hole. When pressure is not applied to the periodontium, the vessels fill with blood, and the periodontal gap is restored to its previous size, pushing the tooth and returning it to its original position. Thus, a change in the width of the peridontal gap ensures the physiological mobility of the tooth, and a change in the volume of the vascular bed creates a partial cushioning of the masticatory pressure that the tooth experiences during the closing of the dentition and chewing food.
This is also facilitated by a less sweaty arrangement of periodontal fibers and a significant amount of loose connective tissue in the region of the apex of the tooth root.
The force of chewing pressure on the tooth is regulated by mechanoreceptors - the terminal branches of the bushy nerve endings located in the periodontium. The receptors give a signal, in particular, to the masticatory muscles. This regulates the force of chewing pressure on the teeth.
The plastic function of the periodontium is carried out by the cellular elements present in it. So, cementoblasts take part in the construction of secondary cement, osteoblasts in the formation of bone. Thus, tissues lost as a result of physiological or pathological processes are restored.
A well-developed network of vessels (periodontal capillaries have a tortuous course like glomeruli) and periodontal nerves determines its trophic function - feeding the cement of the tooth and the walls of the alveoli.
In addition to these functions, the periodontium is involved in the growth, eruption and change of teeth, and also performs barrier and sensory functions.
The duration of the load on the teeth created by chewing and swallowing is on average about half an hour a day (no more than 2 hours). During sleep, the lower jaw usually drops, so that the teeth do not touch, there is no load on the dental bed. The magnitude of chewing force usually varies between 50 and 100 kg, sometimes it can be much more. The action of the force depends on the size of the root covered with gums and fixed to the tooth cell as a clinical concept. The longer the “clinical root”, the stronger the support of the tooth and only a significant force can displace it. On the other hand, the larger the "clinical crown" compared to the "clinical root", the less force can displace the tooth from the tooth cell. The forces acting under functional loading rebuild the bone.
The bone tissue of the alveolar processes of the jaws consists of a compact and spongy substance. Bone marrow cavities of various sizes are filled with fatty bone marrow. The basis of bone tissue is a protein - collagen. A feature of the bone matrix is the high content of citric acid, necessary for mineralization, as well as alkaline and acid phosphatase enzymes involved in the formation of bone tissue.
In the alveolar process, gradual formation and destruction of bone occurs. This process depends on the forces acting on the tooth and on the general condition of the body. Under normal conditions, there is a physiological balance between the formation and destruction of bone, i.e., the lost bone is replaced by a new one. An increase in pressure within physiological limits promotes bone formation. Calcified, thick bony trabeculae develop around a well-functioning tooth. In the bone, the course of bone trabeculae corresponds to the direction of the forces acting on the bone, while the bone fixes the tooth most strongly. A decrease in pressure (for example, with a decrease in chewing) leads to a change in bone trabeculae to a decrease in their number and their atrophy. Morphofunctional disorders in the jawbone can have different severity. With the loss of teeth that do not have antagonists and do not perform a chewing function, only the number of bone trabeculae around the tooth decreases, but the tooth cell itself does not atrophy.
Atrophy is observed after the loss of one or more teeth, in pathological conditions (periodontal disease, periodontitis, diabetes mellitus, etc.), as well as in people over the age of 60 years. Atrophy after tooth extraction occurs immediately and first manifests itself in a decrease in the height of the tooth socket by one third. In the future, atrophy proceeds more slowly, but does not stop, but only slows down somewhat.
In the formation of the internal structure of the bone, a certain role is played not only by mechanical factors, but also by other influences from the body. The formation of a new bone depends not only on the tension and the magnitude of the forces acting on the bone, but also on the general condition of the body, on past general and local diseases, on the intensity of metabolism, etc.
The resistance of the periodontium to the load in ontogenesis increases sequentially, in accordance with the growth and development of all elements that make up the dentoalveolar system. However, the maximum vertical endurance of the periodontium, determined by a gnatodynamometer, does not characterize all the forces that arise during chewing and are made up of successive rhythmic crushing and grinding movements of the lower jaw. Under physiological conditions, the periodontium has a significant reserve of reserve forces, without which the chewing process would be impossible.
The load on the periodontium that occurs during chewing depends on the nature of the food, muscle strength, type of closure of the jaws, but almost always only a part of the possible periodontal endurance is used during chewing. The reserve forces of the periodontium can be increased by training the chewing apparatus (for example, by chewing rough food).
With periodontal diseases, its physiological reserves gradually disappear, functional deficiency develops, leading to tooth loss.
Physiological changes in teeth and periodontium. The shape, structure of the teeth and the condition of the periodontium are not constant, they change under the influence of various functional conditions. These changes are manifested in the erasure (abrasion) of the teeth, in the appearance of their mobility, in the occurrence of a pathological bite, in the exfoliation of the epithelium and in the atrophy of the tooth cells (Fig. 3).
Rice. 3. Erasure of the crown of the tooth at different ages.
Erasing occurs both on the chewing and on the lateral (proximal) surfaces. As a result of abrasion, the chewing surfaces of the teeth are gradually polished, the steepness of their tubercles decreases, the grooves of the chewing surface become smaller and gradually disappear. As a result of such abrasion, the bite becomes deeper, a much larger part of the chewing surfaces is in contact.
Erasure depends on the type of chewing, on the composition of the food and on the state of the bite. So, with a direct bite, the chewing surfaces of molars and premolars and the cutting edges of incisors and canines are erased faster, with a deep bite, the lingual surface of the anterior teeth of the upper jaw and the vestibular teeth of the lower jaw. Individual teeth or groups of them are subjected to rapid abrasion with an oblique or mixed bite. With the loss of any group of teeth, the remaining teeth are intensively erased as a result of overload. According to the degree of erasure, conclusions can be drawn regarding the age of a person. Until the age of 30, it is limited to enamel. By about 40-60 years of age, the enamel of the tubercles is erased to the dentin, which is visible in its yellowish color; it becomes shiny and pigmented.
Rice. 4. Four stages of teething.
Attachment of the epithelium: 1 - only on the enamel; 2 - on enamel and on
cement; 3 - only on cement (covers the entire root);
4 - on cement (the cervical part of the root is free).
The crown of the tooth is slightly shortened. By the age of 70, abrasion approaches the pulp cavity (Fig. 3).
Severe wear of all teeth leads to a decrease in bite, resulting in pain in the temporomandibular joint.
As a result of erasing the proximal surface of the teeth, the nature of their contact changes. Interdental contact points are ground off, contact surfaces are formed. The appearance of the contact surface to a certain extent prevents the increase in interdental spaces and, as a result, the ingress of food masses there.
The erasure of the lateral surfaces causes the mobility of the teeth and their displacement in the medial direction. As a result of erasure, the dental arch shortens by approximately 1 cm by the age of 40.
The eruption of teeth and their position in the dental arch is called active dentition. The protrusion of teeth from the jawbones continues throughout life, although it can be significantly slowed down. Continuous eruption may be accompanied by bone formation at the margin of the alveolus and continuous cementation at the root of the tooth.
Attachment of the epithelium during eruption is observed at the border of the middle and lower thirds of the crown of the tooth. The site of attachment of the epithelium, however, is not permanent and, over time, moves very slowly towards the root apex. Due to this, an increasing part of the crown of the tooth, and then the root, appears in the oral cavity. This process is called passive eruption.
According to the position of attachment of the epithelium, 4 stages of tooth eruption are distinguished (Fig. 4). In the first stage, the epithelium is attached only to the tooth enamel. The gums thus cover approximately one third of the enamel. The clinical crown is smaller than the anatomical one. This stage continues from the time of tooth eruption until about 25 years of age. In the second stage, the attachment of the epithelium is present not only on the enamel, but also partly on the cementum. However, the clinical crown is still smaller than the anatomic one. This picture is usually observed at the age of 25-35 years. During life, the separation of the epithelium from the enamel continues, its attachment is shifted to the cementum, but it does not yet completely cover the root. The clinical crown coincides with the anatomical one. This situation corresponds to the third stage and is observed approximately at the age of 35-45 years. In the fourth stage, the attachment of the epithelium shifts towards the apex of the root, and therefore part of the root remains free. The clinical crown is larger than the anatomical one. The combination of these signs is typical for people over 45 years old. Thus, according to the stages of passive eruption, conclusions can be drawn regarding the age of a person.
Periodontal tissues undergo constant restructuring - the destruction and formation of cells and fibers. A continuous layer of cementum is found on the roots of a functioning tooth. New fibers are formed in place of dead periodontal fibers. Only a properly functioning tooth shows a characteristic distribution of periodontal fibers. If chewing force does not act on the tooth and it loses its antagonist, then in place of obliquely passing dense fibrous connective tissue, loose connective tissue is formed parallel to the surface of the tooth. If the function of the tooth is resumed (the antagonist is replaced), then the original structure of the periodontal fibers is restored, and a gradual restructuring occurs in the bone in accordance with the chewing force. As long as regeneration is in a state of equilibrium and compensates for damage, the periodontium remains intact. If destruction prevails over restoration, periodontal death occurs.
Periodontium (parodontium; from Greek para - about and odous, odontos - tooth) is a complex of tissues surrounding the tooth. The composition of the periodontium includes the gum, alveolar bone, pericementum and the tooth as a whole. The term "periodontium" (synonymous with amphodont) emphasizes the functional and genetic unity of the tissues surrounding the tooth.
In the absence of treatment, due to the progression of inflammatory destruction, the supporting elements of the tooth die. The chewing load, which is physiological, under such conditions turns out to be excessive and acquires the value of an additional pathogenic moment, which intensifies the inflammatory reaction and accelerates the destruction of the ligamentous and bone supporting apparatus up to the complete loss of teeth from their supporting bed.
This process of progressive destruction of the periodontium is characterized by the fact that the moments of exacerbation alternate with periods of spontaneous (sometimes quite long) subsidence.
After the ligamentous apparatus between the tooth and the gum is destroyed and the retaining components are replaced by an inflammatory infiltrate of mononuclear leukocytes and plasma cells, periodontal pockets (PCs) appear. Primarily they are formed only in the area of individual teeth, on some of their surfaces. As the duration of the disease increases, PCs of different depths are found in the area of all teeth.
The given scheme of the beginning and development of the pathological process in the periodontium due to accumulations of microbial plaque and its progressive transition from superficial damage (gingivitis) to inflammation of the bone and periodontal structures located below the gum (periodontitis) is not in all cases legitimate. Gingivitis does not always turn into periodontitis. Moreover, there are cases of self-recovery with gingivitis.
GOU VPO Saratov Medical University.Department of Therapeutic Dentistry
Periodontal diseases.
Methodological guide for students, interns and residents of the dental profile.
.TOPIC: ANATOMY AND PHYSIOLOGY OF THE PERIODONT. FUNCTIONS OF THE PERIODONT.
Targets: to study the structure of all tissues that make up the periodontium, and the functions of the periodontium.
Required initial level of knowledge:
1) The structure of the mucous membrane of the gums.
2) The structure of the bone tissue of the alveoli.
3) The structure of the periodontium.
4) The structure of cement.
Questions to prepare for the lesson:
1) What is a periodontium?
2) The tissues that make up the periodontium.
3) Gingival mucosa, normal appearance of the gingival mucosa.
4) Gingival zones: marginal gingiva, alveolar gingiva, sulcular gingiva,
transitional fold.
5) Layers of the gums.
6) Histological structure of the gingival epithelium, its blood supply and innervation.
7) Histological structure of the lamina propria of the gingival mucosa, its blood supply, gingival microvasculature, plasma capillaries, innervation.
8) Gingival sulcus (sulcular gingiva), depth, histological and clinical gingival sulcus, biological gingival width: epithelial attachment, connective tissue attachment; features of blood supply and innervation.
9) Gingival fluid. Local immunity of the oral cavity (cellular and humoral, secretory immunoglobulin A).
10) Ligament apparatus of the gums.
11) Periodontium, the direction of the periodontal fibers, the shape and width of the periodontal gap. Periodontal composition: fibers, ground substance, cells (fibroblasts, cementoblasts, histiocytes, mast, plasma cells, osteoblasts, osteoclasts, epithelial cells, mesenchymal cells), blood supply, innervation.
12) Cement (primary, secondary), composition, blood supply, innervation.
13) Bone tissue of the alveoli, structure of the alveoli, lamellar bone, spongy substance, bone marrow, direction of trabeculae, bone tissue cells (osteoblasts, osteoclasts, osteocytes), blood supply, innervation.
14) Age-related changes in the periodontium.
15) Periodontal functions: trophic, support-retaining, shock-absorbing, barrier (external and internal barrier), plastic, reflex regulation of masticatory pressure.
Lesson equipment.
Table No. 71. "The structure of the periodontium."
Table No. 72
Table No. 59. "Gingival attachment."
Table No. 73. "Blood supply of the gingival papilla."
Table No. 90. "The structure of the bone tissue of the interdental septa of the lateral teeth."
Table No. 100. "The structure of the bone tissue of the interdental septa of the front teeth."
PERIODONT- This is a complex of tissues surrounding the tooth, constituting a single whole, having a genetic and functional commonality.
The term "periodontium" comes from the Greek words: para - around, about; and odontos - tooth.
Tissues that make up the periodontium:
gum,
bone tissue of the alveoli (together with the periosteum),
periodontium,
tooth (cement, root dentin, pulp).
GUM- mucous membrane covering the alveolar processes of the jaws and covering the necks of the teeth. Fine the mucous membrane of the gums is pale pink in color, its surface is uneven, similar to an orange peel (the so-called "steepling") due to small retractions that form at the site of attachment of the gums to the alveolar bone by bundles of collagen fibers. With inflammatory edema, the irregularities of the mucous membrane of the gums disappear, the gum becomes even, smooth, shiny.
gum zones:
marginal gingiva, or free gingival margin;
alveolar gum, or attached gum;
sulcular gum, or gingival sulcus;
transitional fold.
Alveolar gum- gum covering the alveolar process of the jaws, 1-9 mm wide.
Sulcular gingiva(gingival sulcus) - a wedge-shaped space between the surface of the tooth and the marginal gum, a depth of 0.5-0.7 mm.
gingival sulcus lined with striated epithelium, which is attached to the enamel cuticle. The place where the epithelium attaches to the enamel is called gingival attachment. Gingival attachment is considered as a functional unit consisting of 2 parts:
epithelial attachment, or junctional epithelium, which forms the bottom of the gingival sulcus, is located above the enamel-cement junction on the enamel. The width of the epithelial attachment ranges from 0.71 to 1.35 mm (average -1 mm);
connective tissue fibrous attachment, which is at the level of the enamel-cement joint on the cement. The width of the connective tissue attachment ranges from 1.0 to 1.7 mm (average 1 mm).
Depth anatomical gingival sulcus less than 0.5 mm, determined only histologically.
Clinical gingival sulcus a depth of 1-2 mm is determined by probing.
The epithelial attachment is weak and can be destroyed by probing or working with other instruments. For this reason, the clinical depth of the gingival sulcus is greater than the anatomical depth. Disruption of the connection between the attachment epithelium and the enamel cuticle indicates the beginning of the formation of a periodontal pocket.
Histological structure of the gums.
Histologically, the gum consists of 2 layers:
stratified squamous epithelium,
own plate of the mucous membrane of the gums (lamina propria).
The structure of the stratified squamous epithelium of the oral cavity:
basal layer- consists of cylindrical cells located on the basement membrane;
spiny layer- consists of polygonal-shaped cells, which are interconnected using hemidesmosomes;
granular layer– cells are flat, contain grains of keratohyalin;
stratum corneum- cells are flat, without nuclei, keratinized, constantly desquamated.
In the cytoplasm of cells of all layers of the epithelium (except for the stratum corneum) there are a large number of tonofilaments. They define turgor gums, which resists the mechanical load on the mucous membrane and determines its extensibility. With age, the number of tonofilaments increases by 3 times. The epithelium of the marginal gingiva keratinizing, which makes it more resistant to mechanical, temperature and chemical influences during meals.
Between the cells of the stratified squamous epithelium is an adhesive ground substance connective tissue (matrix), which includes glycosaminoglycans(including hyaluronic acid). Hyaluronidase(microbial and tissue) causes depolymerization glycosaminoglycans the main substance of the connective tissue, destroying the bond of hyaluronic acid with the protein, the hyaluronic acid molecule changes its spatial configuration, as a result of which the pores increase, and the permeability of the connective tissue for various substances, including microbes and their toxins, increases.
Histological structure of the attachment epithelium.
The epithelium of the attachment consists of several (15-20) rows of oblong cells located parallel to the surface of the tooth. There are no blood vessels and nerve endings in the epithelium of the gingival mucosa.
Histological structure of the lamina propria of the gingival mucosa.
own record is a connective tissue formation, consists of two layers:
superficial (papillary),
deep (mesh).
mesh layer formed by denser connective tissue (contains more fibers).
Connective tissue composition:
ground substance- intercellular matrix (35%), formed by macromolecules of proteoglycans and glycoproteins. The main glycoprotein is fibronectin, which provides the connection of the protein with the cellular matrix. Another type of glycoprotein laminin- provides attachment of epithelial cells to the basement membrane.
fibers(collagen, argyrophilic) - 60-65%. Fibers are synthesized by fibroblasts.
cells(5%) - fibroblasts, polymorphonuclear leukocytes, lymphocytes, macrophages, plasma cells, mast cells, epithelial cells.
The gums are supplied with blood from the subperiosteal vessels, which are the terminal branches of the hyoid, mental, facial, great palatine, infraorbital and posterior superior dental arteries. There are many anastomoses through the periosteum with the vessels of the alveolar bone and periodontium.
Microcirculatory bed gums are represented by: arteries, arterioles, precapillaries, capillaries, postcapillaries, venules, veins, arterio-venular anastomoses.
Features of the capillaries of the mucous membrane of the gums.
The capillaries of the gingival mucosa are characterized by:
the presence of a continuous basement membrane,
the presence of fibrils in endothelial cells,
lack of fenestration of endothelial cells. (All this indicates a large exchange between blood and tissues).
the diameter of the capillaries is 7 microns, that is, the capillaries of the gums are true capillaries.
in the marginal gingiva, the capillaries look like capillary loops (“hairpins”) arranged in regular rows.
in the alveolar gum and transitional fold there are arterioles, arteries, venules, veins, arterio-venular anastomoses.
Blood flow intensity in the gums is 70% of the blood flow intensity of all periodontal tissues.
The partial pressure of oxygen in the capillaries of the gums is 35-42 mm Hg. The gingival mucosa also contains non-functioning capillaries, which contain only blood plasma and do not contain red blood cells. These are the so-called plasma capillaries.
Features of blood flow in the region of the periodontal sulcus.
In the region of the gingival sulcus, the vessels do not form capillary loops, but are arranged in a flat layer, being postcapillary venules, the walls of which have increased permeability, through them there is an extravasation of blood plasma and its transformation into gum fluid. Gingival fluid contains substances that provide local immune protection of the oral mucosa.
Local immunity of the oral cavity is a complex multi-component system, including specific and non-specific components, humoral and cellular factors that protect oral and periodontal tissues from microbial aggression.
Humoral factors of local immunity of the oral cavity:
lysozyme- causes depolymerization of polysaccharides of the cell wall of microorganisms;
lactoperoxidase- forms aldehydes, which have a bactericidal effect;
lactoferrin- competes with bacteria for iron, providing a bacteriostatic effect;
mucin- promotes adhesion of bacteria to epithelial cells;
β-lysines- act on the cytoplasm of microorganisms, contributing to their autolysis;
immunoglobulins(A, M, G) - get from the blood serum by passive diffusion through the intercellular spaces of the gingival sulcus and through the epithelial cells. The main role is played immunoglobulin A(IgA). The secretory component S c of immunoglobulin A is synthesized by the epithelial cells of the excretory ducts of the salivary glands. Immunoglobulin A binds to the secretory component in the oral fluid and is fixed on epithelial cells, becoming their receptor, and imparts immunospecificity to the epithelial cell. Immunoglobulin A binds to a bacterial cell, thereby preventing bacteria from settling on the surface of the teeth, and reduces the rate of plaque formation.
polymorphonuclear leukocytes- are released as part of the gingival fluid from the gingival sulcus in an inactive state. Neutrophilic leukocytes have special Fc and Cz receptors for connection with the bacterial cell. Leukocytes are activated in conjunction with antibodies, complement, lactoferrin, lysozyme, peroxidase.
monocytes (macrophages)- phagocytize oral microorganisms, secrete substances that stimulate leukocytes.
epithelial cells gum mucosa - have special Fc and Cz receptors for connection with a microbial cell.
mucin saliva - promotes adhesion of microbial cells and fungi to the surface of the epithelial cell. Constant peeling epithelial cells with microorganisms blocked on them promotes the removal of microbes from the body and prevents them from entering the gingival sulcus and deeper into the periodontal tissue.
Nerve fibers gums (myelinated and unmyelinated) are located in the connective tissue of the lamina propria.
Nerve endings
free- interoreceptors (tissue),
encapsulated(balls), which with age turn into small loops. These are sensitive receptors (which respond to 2 types of stimuli - pain and temperature) - the so-called polymodal receptors. These receptors have a low threshold of irritation, which goes to poorly adapting neurons of the nuclei of the V pair (trigeminal nerve). Sensory receptors respond to pre-pain irritation. The greatest number of these receptors is located in the marginal zone of the gums.
The bone tissue of the alveoli consists of the outer and inner cortical plates and the spongy substance located between them. The spongy substance consists of cells separated by bone trabeculae, the space between the trabeculae is filled with bone marrow (red bone marrow in children and young men, yellow bone marrow in adults). A compact bone is formed by bone plates with a system of osteons, permeated with channels for blood vessels and nerves.
Direction of bone trabeculae depends on the direction of action of the mechanical load on the teeth and jaws during chewing. Bone of the lower jaw has a fine-mesh structure with predominantly horizontal the direction of the trabeculae. Bone top jaws has a large-celled structure with predominantly vertical the direction of the bony trabeculae. Normal bone function determined by the activities of the following cellular elements: osteoblasts, osteoclasts, osteocytes under regulatory influence nervous system, parathyroid hormones (parathormone).
The roots of the teeth are fixed in the alveoli. The outer and inner walls of the alveoli consist of two layers of compact substance. The linear dimensions of the alveoli are less than the length of the tooth root, so the edge of the alveolus does not reach the enamel-cement joint by 1 mm, and the tip of the tooth root does not adhere tightly to the bottom of the alveolus due to the presence of periodontium.
Periosteum covers the cortical plates of the alveolar arches. The periosteum is a dense connective tissue, contains many blood vessels and nerves, and is involved in bone tissue regeneration.
The chemical composition of bone tissue:
1) mineral salts - 60-70% (mainly hydroxyapatite);
2) organic matter - 30-40% (collagen);
3) water - in a small amount.
The processes of remineralization and demineralization in bone tissue are dynamically balanced, regulated by parathyroid hormone (parathyroid hormone), thyrocalcitonin (thyroid hormone) and fluorine also have an effect.
Features of the blood supply to the bone tissue of the jaws.
The blood supply to the bone tissue of the jaws has a high degree of reliability due to collateral blood supply, which can provide 50-70% of pulsed blood flow, and another 20% from the masticatory muscles enters the jaw bone tissue through the periosteum.
Small vessels and capillaries are located in the rigid walls of the Haversian canals, which prevents a rapid change in their lumen. Therefore, the blood supply to the bone tissue and its metabolic activity are very high, especially during the period of bone tissue growth and fracture healing. In parallel, there is also a blood supply to the bone marrow, which performs a hematopoietic function.
The vessels of the bone marrow have wide sinuses with slow blood flow due to the large area cross section sinus. The walls of the sinus are very thin and partially absent, the capillary lumens are in wide contact with the extravascular space, which creates good conditions for free exchange of plasma and cells (erythrocytes, leukocytes).
There are many anastomoses through the periosteum with periodontium and gingival mucosa. The blood flow in the bone tissue provides nutrition to the cells and the transport of minerals to them.
The intensity of blood flow in the bones of the jaws is 5-6 times higher than the intensity in other bones of the skeleton. On the working side of the jaw, the blood flow is 10-30% greater than on the non-working side of the jaw.
The vessels of the jaws have their own myogenic tone to regulate blood flow in the bone tissue.
Nerve vasomotor fibers run along the blood vessels to regulate the lumen of the vessels by changing the tonic tension of smooth muscles. To maintain the normal tonic tension of the vessels, 1-2 impulses per second go from the cerebral cortex.
Innervation of the vessels of the lower jaw carried out by sympathetic vasoconstrictor fibers from the upper cervical sympathetic ganglion. The vascular tone of the lower jaw can quickly and significantly change when the lower jaw moves during chewing.
Innervation of the vessels of the upper jaw carried out by parasympathetic vasodilating fibers of the nuclei of the trigeminal nerve from the Gasser ganglion.
The vessels of the upper and lower jaws can simultaneously be in various functional states(vasoconstriction and vasodilation). The vessels of the jaws are very sensitive to the mediator of the sympathetic nervous system - adrenaline. Due to this, the vascular system of the jaws has shunting properties, that is, it has the ability to quickly redistribute blood flow using arterio-venular anastomoses. The shunting mechanism is activated during sudden changes in temperature (during meals), which is a protection for periodontal tissues.
PERIODONTIUM(desmodont, periodontal ligament) is a tissue complex located between the inner compact plate of the alveolus and the cementum of the tooth root. The periodontium is a formed connective tissue.
Periodontal gap width is 0.15-0.35 mm. The shape of the periodontal gap is an "hourglass" (there is a narrowing in the middle part of the root of the tooth), which gives the root more freedom to move in the cervical third of the periodontal gap and even more - in the apical third of the periodontal gap.
Composition of periodontium. The periodontium consists of:
fibers (collagen, elastic, reticulin, oxytalan);
cells,
intercellular ground substance of connective tissue.
Allocate 4 zones of periodontal fibers:
in the cervical region - the horizontal direction of the fibers,
in the middle part of the root of the tooth - an oblique direction of the fibers, the tooth is, as it were, suspended in the alveolus,
in the apical region - the vertical direction of the fibers,
in the apical region - the vertical direction of the fibers.
Periodontal cells:
fibroblasts- participate in the formation and breakdown of collagen fibers that are part of the main substance of the connective tissue.
histiocytes,
mast cells,
plasma cells(perform the function of immune defense of tissues),
osteoblasts(synthesize bone tissue)
osteoclasts(involved in bone resorption)
cementoblasts(participate in the formation of cement),
epithelial cells(the remnants of the tooth-forming epithelium - the islets of Malasse - under the influence of pathogenic factors, cysts, granulomas, tumors supposedly can form from them);
mesenchymal cells- (poorly differentiated cells, from which various connective tissue cells and blood cells can be formed).
Normally, the root of a tooth has inclined position in the alveolus at an angle of 10 o. Under the action of a force at an angle of 10 about to the longitudinal axis of the tooth, there is a uniform distribution of stresses throughout the periodontium.
At increasing the angle of inclination tooth up to 40 about increases the stress in the marginal periodontium on the pressure side. The elasticity of collagen fibers and their inclined position in the periodontium contribute to the return of the tooth to its original position after the chewing load is removed. Physiological tooth mobility is 0.01 mm.
Features of the periodontal blood supply.
Periodontal vessels are glomerular in nature, located in the niches of the bone wall of the alveoli. The capillary network runs parallel to the surface of the tooth root. There are a large number of anastomoses between periodontal vessels and vessels of bone tissue, gums, bone marrow, which contributes to the rapid redistribution of blood during compression of periodontal vessels between the root of the tooth and the wall of the alveolus during masticatory pressure. When the periodontal vessels are compressed, foci of ischemia. After the chewing load is removed and ischemia is eliminated, reactive hyperemia, which is small and short, which helps the tooth return to its original position.
With an inclined position of the tooth root in the alveolus at an angle of 10 about when chewing in the periodontium, 2 foci of ischemia occur, with opposite localization (one in the cervical region, the other in the apical region). Areas of ischemia occur in various places of the periodontium due to movements of the lower jaw during chewing. After the chewing load is removed, reactive hyperemia occurs in two opposite areas and contributes to the establishment of the tooth in its original position. The outflow of blood is carried out through the intraosseous veins.
Periodontal innervation is carried out from the trigeminal nerve and the upper cervical sympathetic ganglion. In the apical region of the periodontium are mechanoreceptors (baroreceptors) between bundles of collagen fibers. React to touch to the tooth (pressure). Mechanoreceptors are activated in the phase of incomplete jaw closure, providing a reflex chewing process. With very hard food and very strong closure of the dentition, the pain threshold of irritation of the periodontal mechanoreceptors is overcome, and a protective reaction is activated in the form of a sharp opening of the mouth due to inhibition of sending impulses to the masticatory muscles (periodontitis-muscular reflex is suppressed).
Cement- hard tissue of mesenchymal origin. Covers the root of the tooth from the neck to the top. Provides attachment of periodontal fibers to the root of the tooth. The structure of the cement resembles coarse fibrous bone tissue. Cement consists of a base substance impregnated with calcium salts and collagen fibers. The thickness of the cement in the area of the neck of the tooth is 0.015 mm, in the area of the middle part of the root of the tooth - 0.02 mm.
Types of cement:
primary, acellular- Formed prior to tooth eruption. Covers 2/3 of the length of the root dentin in the cervical area. Primary cement consists of the ground substance and bundles of collagen fibers running parallel to the axis of the tooth in the radial and tangential directions. The collagen fibers of the cementum continue into the Sharpei fibers of the periodontium and the collagen fibers of the bone tissue of the alveoli.
secondary, cellular- formed after the eruption of the tooth when the tooth enters into occlusion. Secondary cementum is layered on the primary cementum, covers the dentin in the apical third of the tooth root and the interroot surface of multi-rooted teeth. The formation of secondary cement continues throughout life. The new cement is layered on top of the existing cement. Cells involved in the formation of secondary cementum cementoblasts. The surface of the cement is covered with a thin, not yet calcified cementoid layer.
collagen fibers,
adhesive base material
cells cementoblasts- stellate process cells, located in the cavities of the main substance of the cement in individual lacunae. With the help of a network of tubules and processes, the cementoblasts are connected with each other and with the dentinal tubules, through which the diffusion of nutrients from the periodontium is carried out. Cement has no blood vessels and nerve endings. The thickness of the secondary cement in the area of the neck of the tooth is 20-50 microns, in the area of the root apex - 150-250 microns.
Questions of test control.
1. Periodontium is:
a) tooth, gum, periodontium. 1 answer
b) tooth, gum, periodontium, alveolar bone.
c) tooth, gum, periodontium, alveolar bone, root cementum.
2. Alveolar gum is:
b) gum surrounding the tooth 1 answer
3. Marginal gum is:
a) gingival papilla and gum around the tooth.
b) the gum surrounding the tooth. 1 answer
c) gum covering the alveolar process.
4. Normally, the epithelium does not keratinize:
a) gingival sulcus.
b) papillary gums. 1 answer
c) alveolar gums.
5. Alveolar gum consists of:
a) epithelium and periosteum.
b) epithelium and mucosa proper 1 answer
c) epithelium, proper mucosal and submucosal layers.
6. With intact periodontium, the gingival sulcus contains:
a) microbial associations.
b) exudate. 1 answer
c) gingival fluid.
d) granulation tissue.
7. With intact periodontium, the gingival sulcus is determined:
a) clinically.
b) histologically. 1 answer
c) X-ray.
Independent work of students.
Students receive patients with periodontal diseases, examine the gums, identify gum zones and determine the presence of a normal state or pathological changes in periodontal tissues. It is necessary to correctly determine the zones of the gums, determine the color of the gums, the presence or absence of edema of the mucous membrane of the gums, determine the depth of the gingival sulcus and the integrity of the dentogingival attachment.
Answers to test control questions:
1b, 2c, 3b, 4a, 5b, 6c, 7c.
Main literature.
1. Borovsky E.V. Therapeutic dentistry. M.: Techlit.-2006.-554s.
2. Danilevsky N.F., Magid E.A., Mukhin N.A. etc. Periodontal diseases. Atlas. M.: Medicine.-1993.-320s.
3. Periodontal diseases edited by prof. L.Yu. Orekhova. M.: Poli-MediaPress.-2004.-432p.
4. Lukinykh L.M. etc. Periodontal disease. Clinic, diagnosis, treatment and prevention. N.Novgorod: NGMA.-2005.-322p.
Additional literature.
1. Ivanov V.S. Periodontal diseases. M.: MIA.-1998.-295s.
2. Balin V.N., Iordanishvili A.K., Kovalevsky A.M. Practical periodontology. St. Fri.: "Peter".-1995.-255p.
3. Loginova N.K., Volozhin A.I. Pathophysiology of the periodontium. Teaching aid. M.-1995.-108s.
4. Kuryakina N.V., Kutepova T.F. Periodontal diseases. M.: Medkniga. N.Novgorod. NGMA.-2000.-159p.
5. Storm A.A. Periodontology - yesterday, today and...// Periodontology.-1996.-№1.-P.26.
6. Straka M. Periodontology–2000. // New in dentistry.-2000. -No. 4.-S.25-55.
7. Kirichuk V.F., Chesnokova N.P. and other Physiology and pathology of the periodontium. Tutorial. Saratov: SGMU.-1996.-58p.
Therapeutic dentistry. Textbook Evgeny Vlasovich Borovsky
9.3. STRUCTURE OF PARODONTAL TISSUES
The periodontium unites a complex of tissues that have a genetic and functional commonality: gum with periosteum, periodontium, alveolar bone and tooth tissues.
Gum. The gum is divided into free, or interdental, and alveolar, or attached. The marginal part of the gum is also isolated.
free(interdental) is called the gum, located between adjacent teeth. It consists of labial and lingual papillae, which form an interdental papilla, which has the shape of a triangle, with its apex facing the cutting (chewing) surfaces of the teeth, and fills the space between adjacent teeth.
Attached(alveolar) is the part of the gum that covers the alveolar process. From the vestibular surface, the alveolar gum at the base of the alveolar process passes into the mucous membrane covering the body of the jaw and the transitional fold; from the oral surface, the alveolar gum passes on the upper jaw into the mucous membrane of the hard palate, and on the lower jaw - into the mucous membrane of the floor of the oral cavity. The alveolar gum is fixedly attached to the underlying tissues due to the connection of the fibers of the mucous membrane itself with the periosteum of the alveolar processes of the jaws.
Rice. 9.2. Circular ligament of the tooth. Micrograph.
Marginal denote the part of the gum adjacent to the neck of the tooth, where the fibers of the circular ligament of the tooth are woven, which, together with other fibers, forms a thick membrane designed to protect the periodontium from mechanical damage (Fig. 9.2). The free gum, which is covered by the gingival papilla, is adjacent to the surface of the tooth, separated from it by the gingival groove. The bulk of the tissue of the free gums are collagen fibers, but, in addition to them, elastic fibers are also found. The gum is well innervated and contains various types of nerve endings (Meissner bodies, thin fibers included in the epithelium and related to pain and temperature receptors).
The tight fit of the marginal part of the gum to the neck of the tooth and resistance to various mechanical influences are explained by turgor, i.e., interstitial pressure caused by a high-molecular interfibrillar substance.
The gum is formed by stratified squamous epithelium, its own membrane (lamina propria); the submucosal layer (submucosa) is not expressed. Normally, the gingival epithelium is keratinized and contains a granular layer, in the cytoplasm of cells of which there is keratohyalin. The keratinization of the gingival epithelium is considered by most authors as a protective function due to its frequent mechanical, thermal, chemical irritation during chewing.
An important role in the protective function of the gingival epithelium, especially in relation to the penetration of infection and toxins into the underlying tissue, is played by glycosaminoglycans (GAGs), which are part of the adhesive between the cells of the stratified squamous epithelium. It is known that acidic GAGs (chondroitin sulfuric acid A and C, hyaluronic acid, heparin), being complex macromolecular compounds play an important role in trophic function of connective tissue, in the processes of tissue regeneration and growth.
Neutral GAGs(glycogen) are found in the gingival epithelium. Glycogen is localized mainly in the cells of the spiny layer, its amount is insignificant and decreases with age. Neutral GAGs are also found in the vascular endothelium, in leukocytes located inside the vessels. Ribonucleic acid (RNA) is found mainly in the cytoplasm of epithelial cells of the basal layer and plasma cells of the connective tissue.
Sulfhydryl groups of superficial keratinized layers of the epithelium were found in the cytoplasm and intercellular bridges. With gingivitis and periodontitis, sulfhydryl groups inside the cells disappear due to edema and loss of intercellular bonds. In the periodontium, neutral GAGs are detected along the bundles of collagen fibers along the entire line of the periodontium; there are few of them in the primary cementum; in a slightly larger amount they are found in the secondary cement; in bone tissue, they are located mainly around osteon channels.
Distribution study acid GAGs in periodontal tissues showed their presence in the gums, especially in the area of connective tissue papillae, basement membrane; there are few of them in the stroma (collagen fibers, vessels), mast cells contain acidic GAG. In the periodontium, acidic GAGs are located in the walls of the vessels, along the bundles of collagen fibers along the entire periodontal membrane, with some increase in their content in the area of the circular ligament of the tooth. GAGs are constantly found in cement, especially secondary cement. Acid GAGs in bone are found around osteocytes, at the border of osteons.
Currently, there are indisputable data on the significant role of the hyaluronic acid - hyaluronylase system in the regulation of the permeability of capillary-connecting structures. Hyaluronidase produced by microorganisms (tissue hyaluronidase) causes depolymerization of GAGs, destroys the bond between hyaluronic acid and protein (hydrolysis), thereby dramatically increasing the permeability of the connective tissue, which loses its barrier properties. Therefore, GAG protects periodontal tissues from the action of bacterial and toxic agents.
Among the cellular elements of the connective tissue of the gums, fibroblasts are most common, less often - histiocytes and lymphocytes, and even less often - mast and plasma cells. Cellular composition connective tissue the mucous membrane of the human oral cavity is as follows [Gemonov V.V., 1983] as a percentage:
Mast cells in normal gums are grouped mainly around the vessels, in the papillary layer of its own membrane (Fig. 9.3). Although much research has been devoted to mast cells, their function has not been fully elucidated. It should be mentioned that they contain heparin, histamine and serotonin; they are related to the production of proteoglycans.
The structure of the gingival junction. Quite a lot of work has been devoted to the study of this formation, mainly because the first inflammatory changes are localized precisely in the area of the dentogingival junction. It is generally accepted that the gingival epithelium consists of oral, sulcus (slit) epithelium and connective, or attachment epithelium (Figure 9.4). The oral epithelium is a stratified squamous epithelium; the sulcular epithelium is intermediate between the stratified squamous and junctional epithelium. Although the junctional and oral epithelium have a lot general, histologically they completely different. The mechanism of connection of the epithelium with the tissues of the tooth is still not fully understood.
Electron-microscopically established that the surface cells of the junctional epithelium have multiple hemidesmosomes and are associated with apatite crystals of the tooth surface through a thin granular layer of organic material (40-120 nm).
Figure 9.3. Mast cells of the gums. Micrograph.
Rice. 9.4. The structure of the gums (diagram).
1 - epithelium of the oral cavity; 2 - furrow epithelium (slit), 3 - junction epithelium (attachment epithelium); 4 - enamel; 5 - gingival groove, 6 - attached gum; 7 - free gum.
AT last years It has been established that the basement membrane and hemidesmosomes are the most important factors in the mechanism of attachment of the junctional epithelium to the tooth.
The epithelial attachment consists of several rows of oblong cells located parallel to the tooth surface. It was radiographically established that the cells of the epithelial attachment contain proline and are mixed every 4–8 days, i.e., much faster than the cells of the gingival epithelium. The cuticular layer on the enamel is rich in neutral GAGs and contains keratin.
The depth of the gingival sulcus is usually less than 0.5 mm, its base is located where there is an intact connection of the epithelium with the tooth.
Clinical sulcus is a gap between a healthy gum and the surface of the tooth, which is detected with careful probing. The clinical sulcus is always deeper than the anatomical sulcus, its depth is 1–2 mm. The presented modern data indicate the presence of certain regenerative capabilities of the dentogingival junction. Violation of the connection between the epithelial attachment and the cuticular layer of enamel indicates the beginning of the formation of a periodontal pocket.
Gingival fluid is an important part of the defense mechanism of the marginal periodontium due to the immunological properties of the exudate and phagocytic activity. The release of fluid from the gingival pocket is insignificant, it increases with mechanical stimulation and inflammation. Any injected substances (including drugs) are rapidly eliminated if not mechanically retained. This should be borne in mind when prescribing drug therapy for gingival pockets - in order to create a long-term contact, they must be held in place with a gingival bandage or paraffin.
Undoubtedly, the described formations that carry certain functions cannot be considered in isolation, without connection with the influence of local and general factors.
The tissues of the periodontium proper. They include collagen, elastic fibers, blood and lymphatic vessels, nerves, cellular elements characteristic of connective tissue, elements of the reticuloendothelial system (RES). The size and shape of the periodontium is not constant. They can vary depending on age and various pathological processes localized both in the organs of the oral cavity and beyond.
The periodontal ligamentous apparatus consists of a large number of collagen fibers arranged in the form of bundles, between which there are vessels, cells, intercellular substance (Fig. 9.5). The main function of periodontal fibers is the absorption of mechanical energy that occurs during chewing, its uniform distribution on the bone tissue of the alveoli, the neuroreceptor apparatus and the periodontal microvasculature.
Rice. 9.5. The structure of the periodontium is normal. x 200.
1 - cell-free cement, 2 - cementoblast, 3 - periodontal collagen fibers,
The cellular composition of the periodontium is very diverse. Fibroblasts, plasma, mast cells, histiocytes, cells of vasogenic origin, RES elements, etc. are found in the periodontium. They are located mainly in the apical part of the periodontium near the bone and are characterized by a high level of metabolic processes.
In addition to these cells, epithelial remnants should be named - clusters of cells scattered throughout the periodontium (Fig. 9.6). Most authors refer them to the remnants of the tooth-forming epithelium. These formations can be in the periodontium for a long time, without showing themselves. And only under the influence of any reasons (irritation, the influence of bacterial toxins, etc.) can cells become a source of pathological formations - epithelial granulomas, cysts, epithelial cords in periodontal pockets, etc.
In the structural elements of the periodontal, such enzymes of the redox cycle as succinate dehydrogenase, lactate dehydrogenase, NAD- and NADP-diaphorases, glucose-6-phosphate dehydrogenase, as well as phosphatases and collagenase are detected.
Bone of the interdental septum. It consists of a compact bone substance that forms the Cortical plate, which consists of bone plates with a system of osteons. The compact bone of the edge of the alveolus is penetrated by numerous perforating canals through which blood vessels and nerves pass. Spongy bone is located between the layers of compact bone, and yellow bone marrow is located between its beams.
Rice. 9.6. Malasse cells in the periodontium. x 280 .
On the one hand, periodontal fibers pass into the cementum of the root, on the other hand, into the alveolar bone. Cement in structure and chemical composition is very similar to bone, but for the most part (along the length of the root) it does not contain cells. Only at the apex cells appear, located in the lacunae associated with the tubules, but not in such a correct order as in the bone tissue (cellular cement).
The bone tissue of the alveolar process practically does not differ in structure and chemical composition from the bone tissue of other parts of the skeleton. For 60–70% it consists of mineral salts and a small amount of water, and for 30–40% - of organic substances. The main component of organic matter is collagen. The functioning of bone tissue is mainly determined by the activity of cells: osteoblasts, osteocytes and osteoclasts. In the cytoplasm and nuclei of these cells, the activity of more than 20 enzymes was histochemically studied.
Normally, the processes of bone formation and resorption are balanced in adults. The ratio of these processes depends on the activity of hormones, primarily the hormone of the parathyroid glands. Recently, information has been accumulating on a certain role of thyrocalcitonin. Data were obtained on the effect of thyrocalcitonin and fluorine on the processes and formation of alveolar bone in tissue culture. The activity of acid and alkaline phosphatases is observed at a young age in the periosteum, in the channels of osteons, in the processes of osteoblasts.
On radiographs, the cortical plate of the bone looks like a clearly defined strip along the edge of the alveolus, the cancellous bone has a looped structure.
Blood supply. Periodontal tissues are supplied with arterial blood from the basin of the external carotid artery, its branch - the maxillary artery. The teeth and surrounding tissues of the upper jaw receive blood from the branches of the pterygoid (superior alveolar artery) and pterygopalatine (upper anterior alveolar arteries) parts of the maxillary artery. The teeth and surrounding tissues of the lower jaw are supplied with blood mainly from the inferior alveolar artery - a branch of the mandibular part of the maxillary artery.
From the lower alveolar artery to each interalveolar septum, one or more branches depart - the interalveolar arteries, which give branches to the periodontium and root cementum. Vertical branches penetrate through the periosteum into the gum. Branches from the dental arteries extend to the periodontium and alveoli. There are anastomoses between the branches of the dental, interalveolar arteries leading to the periosteum and the vessels of the extraaxial network. In the marginal periodontium, near the enamel-cement junction, a vascular cuff is expressed, which is connected by anastomoses with the vessels of the gums and periodontium (Fig. 9.7; 9.8). Arteriovenous anastomoses were found in periodontal tissues, which indicates the absence of end-type arteries in them.
Rice. 9.7. Blood supply to the marginal periodontium (scheme modified according to Kindlova).
1 - vessels of the gingival papilla; 2 - vascular cuff, 3 - gum vessels; 4 - enamel; 5 - dentin.
Rice. 9.8. Blood supply to the periodontium.
1 - alveolar artery. 2 - vessels going to the pulp; 3, 4 - vessels going to the periodontium; 5 - interdental artery
Structural formations of the microvasculature of periodontal tissues include arteries, arterioles, precapillaries. capillaries, postcapillaries, venules, veins and arteriovenular anastomoses. Capillaries are the thinnest-walled vessels of the microcirculatory bed, through which blood passes from the arterial to the venular link. It is through the capillaries that the most intensive flow of oxygen and other nutrients to the cells is provided. Therefore, capillaries are endowed with special structural features that make them the main ones in the reactions of hematotissue metabolism. The diameter and length of capillaries, the thickness of their walls vary greatly in different organs and depend on their functional state of the given organ. On average, the inner diameter of a normal capillary is 3-12 microns. Capillaries branch, divide into new ones and, connecting with each other, form a capillary bed. The capillary wall consists of cells (endothelium and pericytes) and special non-cellular formations (basement membrane). A fundamental difference was found in the structure of the vessels under the oral and slit epithelium (furrow epithelium). Under the slit epithelium, the vessels are located not in the form of capillary loops, but in a flat layer. The slit epithelium does not have epithelial ridges. As a result, the terminal vascular formations - arterioles, capillaries and venules - are located closer to the surface of the epithelium.
Rice. 9.9. Nerve fibers of the periodontium.
Capillaries and their surrounding connective tissue, together with lymph, provide nutrition to periodontal tissues. and also perform a protective function. The degree of wall permeability is the main physiological function of capillaries. The state of permeability and resistance of capillaries is of great importance in the development of pathological processes in the periodontium.
Innervation. The innervation of the periodontium is carried out due to the branches of the dental plexuses of the second and third branches of the trigeminal nerve. In the depths of the alveolus, the bundles of the dental nerve are divided into two parts: one goes to the pulp, the other - but the surface of the periodontium is parallel to the main nerve trunk of the pulp.
Above the place of division of the main bundles of nerve fibers in the periodontium, many thinner, parallel nerve fibers are distinguished (Fig. 9.9). Along with myelinated fibers, unmyelinated nerve fibers are also observed. At different levels of the periodontium, myelin fibers branch or thin in the vicinity of the cementum. In the periodontium and gums there are free nerve endings located between the cells. The main nerve trunk of the periodontium in the interradicular space runs parallel to the cementum and in the upper part is bent parallel to the interradicular arch. The presence of a large number of nerve receptors makes it possible to consider the periodontium as an extensive reflexogenic zone; it is possible to transfer the reflex from the periodontium to the heart, organs of the gastrointestinal tract, etc.
Lymphatic vessels. The periodontium has an extensive network of lymphatic vessels, which play an important role in ensuring the normal function of the periodontium. especially in his illnesses. In a healthy gum there are small thin-walled lymphatic vessels of irregular shape. They are located mainly in the subepithelial connective tissue basis. With inflammation, the lymphatic vessels are sharply dilated. In the lumen of the vessels, as well as around them, cells of the inflammatory infiltrate are determined. Lymphatic vessels play an important role in inflammation. They contribute to the removal of interstitial material from the lesion.
Age-related changes in periodontal tissues. Involutional changes in periodontal tissues are of practical importance not only because knowledge of them helps the doctor in diagnosing periodontal diseases, but also due to the fact that tissue aging is a complex and not fully understood general medical problem. Tissue aging is due to changes in the genetic apparatus of the cells of the periodontal tissues, a violation (decrease) in their metabolism, the intensity of physical and chemical processes. An important role in tissue aging is played by changes in blood vessels, collagen, enzyme activity, immunobiological reactivity, a decrease in the transport of nutrients and oxygen, when the processes of cell decay begin to prevail over the processes of their restoration.
Age changes gums reduced to the following: there is a tendency to hyperkeratosis, thinning of the basal layer, atrophy of epithelial cells, homogenization of the fibers of the subepithelial layer of the gums, a decrease in the number of capillaries, expansion and thickening of the vessel wall, a decrease in the amount of collagen, the disappearance of glycogen in the cells of the spinous layer, a decrease in the content of lysozyme in the gum tissues , dehydrating them.
AT bone tissue there is a decrease in the perforating fibers of the cement, an increase in hyalinosis, an increase in the activity and amount of proteolytic enzymes, an expansion of the bone marrow spaces, a thickening of the cortical plate, an expansion of the osteon channels and their filling with adipose tissue. The destruction of bone tissue with age may be due to a decrease in the anabolic action of sex hormones with a relative predominance of glucocorticoids.
Age-related changes in periodontal are characterized by the disappearance of the fibers of the intermediate plexus, the destruction of part of the collagen fibers, and a decrease in the number of cellular elements.
Clinico-radiological involutional changes in periodontal tissues are manifested by gingival atrophy, exposure of root cement in the absence of periodontal pockets and inflammatory changes in the gingiva; osteoporosis (especially postmenopausal) and osteosclerosis, narrowing of the periodontal gap, hypercementosis.
The age-related changes in the periodontium described above are accompanied by a decrease in the resistance of cellular and tissue elements to the action of local factors (trauma, infection).
From the book Normal Human Anatomy: Lecture Notes author M. V. Yakovlev6. SKELETON OF THE FREE UPPER LIMB. STRUCTURE OF THE HUMERUS AND BONES OF THE FOREARM. STRUCTURE OF THE BONES OF THE HAND The humerus (humerus) has a body (central part) and two ends. The upper end passes into the head (capet humeri), along the edge of which the anatomical neck (collum anatomykum) passes.
From the book Therapeutic Dentistry. Textbook author Evgeny Vlasovich Borovsky8. STRUCTURE OF THE SKELETON OF THE FREE PART OF THE LOWER LIMB. STRUCTURE OF THE FEMOR, PATELLET AND SHIN BONES. STRUCTURE OF THE BONES OF THE FOOT The femur (os femoris) has a body and two ends. The proximal end passes into the head (caput ossis femoris), in the middle of which is located
From the author's book2. STRUCTURE OF THE MOUTH. STRUCTURE OF THE TEETH The oral cavity (cavitas oris) with closed jaws is filled with the tongue. Its outer walls are the lingual surface of the dental arches and gums (upper and lower), the upper wall is represented by the sky, the lower wall is represented by the muscles of the upper part of the neck, which
From the author's bookChapter 3 STRUCTURE AND FUNCTIONS OF ORGANS AND TISSUES OF THE ORAL CAVITY
From the author's book3.3.2. Histological structure, chemical composition and functions of hard tissues of the tooth Enamel (enamelum). This tissue covering the crown of the tooth is the hardest in the body (250–800 Vickers units). On the chewing surface, its thickness is 1.5–1.7 mm; on the lateral surfaces, it is significantly thicker.
From the author's bookChapter 9 PERIODONTAL DISEASES 9.1. GENERAL INFORMATION Diseases of the tissues surrounding the tooth are among the diseases known since ancient times. With the progress of civilization, the prevalence of periodontal disease has increased dramatically. The importance of periodontal disease
From the author's book9.2. CLASSIFICATION OF PERIODONTAL DISEASES In modern periodontology, there are several dozen classifications of periodontal diseases. Such a large number of classification schemes is explained not only by the variety of types of periodontal pathology, but mainly
From the author's book9.4. FUNCTIONS OF THE PERIODONT The periodontium is constantly exposed to external (environmental) and internal factors. Sometimes these impacts are so strong that the periodontal tissues experience an exceptionally large overload, while at the same time they are not damaged. This is
From the author's book9.5. ETIOLOGY OF PERIODONTAL DISEASES The vast majority of periodontal diseases are inflammatory in nature, including the so-called juvenile (juvenile) periodontitis (at the age of 11–21 years); the exception is the rare special forms type of dystrophy
From the author's book9.6. MORPHOGENESIS OF PARODONTAL DISEASES Changes resulting from damage give impetus to the development inflammatory process, the successive stages of which, layering one on top of the other, determine the development of variously expressed clinically and
From the author's book9.7. METHODS OF EXAMINATION AND DIAGNOSIS OF PARODONTAL DISEASES Examination of the patient begins with a study of the anamnesis of life and disease. Identifies the patient's complaints, the reason for going to the doctor, the profession, the presence chronic diseases, diet, the presence of harmful
From the author's book9.8. CLINICAL PICTURE OF PERIODONTAL DISEASES 9.8.1. Gingivitis The group of gingivitis consists of the following independent forms of damage to the marginal periodontium: catarrhal, hypertrophic, ulcerative, atrophic. Here the first 3 forms of gingivitis will be considered as
From the author's book9.8.4. Periodontolysis (idiopathic diseases with progressive lysis of periodontal tissues) These diseases do not fit into the above nosological forms due to their peculiarities clinical manifestations and prognosis. This group includes diseases such as
From the author's book9.8.6. Pathological processes associated with periodontal diseases Periodontal diseases can contribute to the emergence of other pathological processes that occur in the dynamics of the development of the underlying disease or as a result of any intervention on the tissues
From the author's book9.9. TREATMENT OF PERIODONTAL DISEASES Treatment is based on the principle of the most individualized approach to each patient, taking into account the data of the general and dental status. Therefore, treatment is always complex, with the use of local and general therapy,
From the author's book9.10. ORGANIZATION OF THERAPEUTIC AND PREVENTIVE CARE FOR PATIENTS WITH PARODONTAL DISEASES Significant achievements in the study of local and endogenous factors in the etiology and pathogenesis of periodontal diseases, the development of new methods for their treatment and prevention have created
7.1. STRUCTURE AND FUNCTIONS OF THE PERIODONT
Periodontist is a complex of tissues surrounding the tooth. It includes: gum, periosteum, bone tissue of the socket and alveolar process, periodontium, root cement (Fig. 7.1). Periodontal tissues are a phylogenetic, biological and functional unity. They hold the teeth in the jaw bone, provide interdental communication in the dental arch, preserve the epithelial membrane of the oral cavity in the area of the erupted tooth.
Gum- mucous membrane covering the alveolar process of the jaw and the neck of the tooth, tightly adjacent to them (attached gum). The marginal or marginal part of the gum is freely located at the neck of the tooth and has no attachment to it (loose gum). The marginal gum has some mobility. Sometimes it is called a free gum. This property makes it possible to protect the mucous membrane from various external influences.
The space formed by the tooth and the loose gum is called gingival sulcus
Rice. 7.1. The structure of the periodontium:
3 - root cement
4 - periodontal
5 - bone tissue of the hole
6 - bone tissue of the alveolar
offshoot
Rice. 7.2. Gum:
1 - edge
2 - gingival groove
3 - attached
4 - gingival sulcus
Rice. 7.3. Gingival epithelium:
1 - gingival
2 - furrows
3 - attachments
doy. The indentation located at the point of transition of the free gum to the attached one is called gingival groove(Figure 7.2).
The gum is represented by stratified squamous keratinized epithelium and dense fibrous connective tissue.
Histologically, there are three types of epithelium in the gum:
1) gingival;
2) furrow epithelium;
3) junctional epithelium or attachment epithelium.
The gingival epithelium is located on the outer side of the loose and attached gums. The epithelium of the sulcus limits the gingival sulcus laterally and is devoid of a layer of keratinizing cells. The junctional epithelium lines the bottom of the gingival sulcus and is tightly bound to the enamel, which is covered by the cuticle (Fig. 7.3).
The gum is characterized by the following features: shape, color, consistency.
The shape of the gum edge, adjacent to the necks of the teeth, looks like a garland (scalloped) due to the gingival papillae (Fig. 7.4). Gingival papilla- this is the part of the gum that fills the interdental space (Fig. 7.5).
The color of the gums is normally pale pink or coral, in dark-skinned people it may be darker due to melanocyte populations (Fig. 7.6).
The surface of the gum attached to the tooth and periosteum looks bumpy. This is due to the uneven arrangement of the processes of the connective tissue under the epithelial cover of the gums. The attached gum is immobile due to the absence of a submucosal layer in it. The border of the transition of the immovable gingival mucosa to the mobile one is called the transitional fold (see Fig. 7.4).
The periosteum covering the alveolar process and the bone tissue of the alveolar process. From a functional point of view, the bone tissue of the alveolar process is divided into two parts: the alveolar bone itself and the supporting alveolar bone.
The alveolar bone itself is also called the bone tissue of the hole or a hard plate. (Lamina dura)(Fig. 7.7). This is a thin layer of bone tissue that surrounds the roots and consists of densely packed plates penetrated by collagen fibers. Sharpei fibers associated with periodontal fibers penetrate into the own alveolar bone.
Rice. 7.4. Gum:
1 - transitional fold
2 - attached gum
3 - gingival groove
4 - marginal gum
5 - gingival papilla
Rice. 7.5. Gingival papillae:
1 - vestibular
2 - oral
3 - pass
Rice. 7.6. Healthy gum
Rice. 7.7. Fragment of the bone of the body of the lower jaw
The supporting alveolar bone consists of a compact (cortical) bone located on the vestibular and oral sides of the alveolar process, and cancellous bone located between the alveolar proper and the cortical bone. The cortical bone is formed by bone plates with a system of osteons pierced by numerous channels and niches,
through which the blood passes
nasal vessels and nerves. Spongy bone contains bone marrow located between the bone trabeculae (see Figure 7.8).
Cellular components are represented by osteoblasts, osteocytes, osteoclasts.
root cement covers the surface of the root and is a link between the tooth and surrounding tissues. According to its structure, cement is divided into two types: cell-free and glue.
Rice. 7.8. Micrograph of a thin section of the interdental septum
accurate. Cellular cementum covers the apical and furcational parts, acellular cement covers the remaining parts of the root.
Periodontium is a dense connective tissue rich in cells, collagen fibers and elastic fibers. The periodontium is located between the root cementum and the bone tissue of the alveoli, contains blood, lymphatic vessels and nerve fibers. Periodontal cellular elements are represented by fibroblasts, cementoclasts, dentoclasts, osteoblasts, osteoclasts, Malasse epithelial cells, protective cells and neurovascular elements. The periodontium fills the space between the root cementum and the bone tissue of the socket.
Functions of the periodontium:
1. Support-retaining.
2. Shock-absorbing.
3. Distributing pressure.
4. Uniting teeth in the dentition.
5. Sensory (tactile, perception of pain, pressure).
6. Reflex.
7. Plastic.
8. Trophic.
9. Barrier.
10. Adaptation to functional and topographic changes.
11. Promoting physiological changes in the tooth.
12. Ability to restore tissues after traumatic injuries.
13. Participation in growth, eruption, change of teeth.
14. Renewal of periodontal tissues.
The periodontium holds the teeth in the jaw, redistributes the mechanical force exerted on the tooth to the jaw bones. The transmission of this force is due to periodontal fibers. The role of collagen fibers in the distribution of masticatory load on the tooth is so great that in modern literature the periodontium is often called the ligament of the tooth (Fig. 7.9, 7.10). The direction of the fibers in the periodontium is mainly oblique, at an angle of 45° from the top of the tooth to the side, and only at the very top of the tooth the fibers have a radial orientation. In the region of the neck of the tooth, the direction of the fibers becomes horizontal. The latter are intertwined with fibers coming from the top of the alveolar septum and gums, forming a circular ligament covering
Rice. 7.9. Periodontal fibers:
1 - dento-alveolar periodontium
2 - horizontal
4 - radial
5 - interroot
Rice. 7.10. Marginal periodontal fibers (a)
the shaping neck of the tooth in the form of a ring (Fig. 7.11). Above them are supra-alveolar fiber bundles, periodontal and interdental fibers.
The fibers are practically inextensible and, by their orientation, prevent the tooth from moving in one direction or another. Oblique fibers hold the tooth when exposed to the occlusal surface, i.e. keep the tooth suspended in the hole. At the apex of the root and in the cervical region, the fibers limit the movement of the tooth in the horizontal direction. The vertical direction of the fibers at the bottom of the alveoli prevents the tooth from moving out of the hole.
Slightly wavy course of bundles of collagen fibers and plexus of small periodontal vessels, in which the volume of the vascular bed changes under the influence of chewing load, as well as the presence of loose connective tissue, have a shock-absorbing effect. Through the contact points between adjacent teeth, pressure is transferred to adjacent teeth.
The force of masticatory pressure is regulated by mechanoreceptors located in the periodontium, which give a signal to the masticatory muscles.
The plastic function is carried out by the cellular elements of the periodontium (cementoblasts, osteoblasts).
Rice. 7.11. Circular ligament of the tooth (a)
A developed network of vessels and nerve fibers of the periodontium provides nutrition to the cement of the tooth and the walls of the alveoli.
Periodontal protection from mechanical, thermal and chemical influences is provided by a strong supra-alveolar fibrous gum apparatus and keratinized gum epithelium. Cellular and humoral immunocomponents of the gums, constant renewal of all its layers prevent the infection from penetrating into deeper tissues.
7.2. DENTAL DEPOSITS: TYPES, DIAGNOSIS,
TREATMENT
The influence of dental deposits on the occurrence of dental diseases
The deposits accumulated on the teeth are different in nature, mechanism of formation and location. Among them there are dental deposits, which are the cause of caries, periodontal diseases. Microorganisms of dental deposits can exacerbate the course of diseases of the oral mucosa.
Caries and periodontal disease - main causes of tooth loss. The waste products of some microorganisms contained in dental deposits are acids. They change the pH on the tooth surface, causing demineralization of the enamel. Other
microorganisms, accumulating under the gum, release toxins, enzymes, or invade themselves into the tissue of the marginal gum, causing inflammation.
DENTAL DEPOSITS
I. Physiological tooth formations: cuticle, pellicle
II. Dental deposits:
soft non-mineralized (pigmented and non-pigmented)
solid mineralized (pigmented and non-pigmented)
Unpigmented: food residues, soft plaque, dental plaque, tartar: supragingival (salivary). Pigmented:
smoker's plaque (brown, black), chromogenic bacteria (green, brown), food pigments (various colors), drug dyes (various colors), serum iron excess (black), bile pigments in gingival fluid (yellow), subgingival (serum ).
Cuticle- structureless organic membrane, the remnant of the outer enamel epithelium. It is closely associated with the membrane of enamel prisms. Completely covers the crown of a newly erupted tooth. Over time, it is lost in areas of the teeth that are subjected to mechanical stress.
pellicle- unstructured cell-free film (0.1 - 1.0 µm thick) on the tooth surface, consists of saliva glycoproteins. The role of the pellicle is twofold: it is a mechanical barrier on the surface of the tooth, but microorganisms and food residues easily accumulate on it. Its formation can occur from several minutes to 2 hours.
Soft white plaque is food residues and microorganisms are easily displaced from the surface of the tooth. It can be
detect on teeth without staining with special solutions. Consists of organic and inorganic substances, which were formed as a result of the decay of torn off cells of the epithelium of the oral mucosa, leukocytes, microorganisms, food debris. It does not have a permanent structure, it forms at night and is the cause of bad breath.
dental plaque- Structural, sticky and sticky plaque, consisting of bacteria and intercellular substance (matrix), components of saliva, metabolic products of bacteria, food debris, epithelial cells, leukocytes and macrophages. It is covered with a semi-permeable mucoid layer, located above the pellicle. The dental plaque is transparent, it is detected by staining with special solutions. The maximum growth of the plaque occurs with the intake of sucrose, glucose and fructose. Its formation can occur within 4 hours. The microbial landscape of dental plaque is represented by streptococci, bacilli, vibrios, actinomycetes, etc.
There are 4 stages of formation and maturation of dental plaque (Müller H.P.):
1) pellicle formation;
2) 1st day - adhesion of gram-positive cocci, production of extracellular polysaccharides, leveling of irregularities;
3) 2 - 4th day - a decrease in the proportion of streptococci, an increase in facultative and anaerobic actinomycetes, gram-negative cocci and rods;
4) a week later - the appearance of spirochetes and movable rods.
At caries there is a destruction of the hard tissues of the teeth, starting with the demineralization of the enamel. Demineralization is the result of the action of acid-forming bacteria found in soft dental deposits.
After calcification of the hard tissues of the tooth, decay of organic substances occurs with the participation of bacteria, carious cavities appear (Fig. 7.12).
As a result of the reaction of the marginal gum to the supragingival plaque, swelling and deepening of the gingival sulcus occur. There are conditions for the formation of subgingival plaque and loss of connective tissue attachment. With the appearance of deep periodontal pockets, conditions are created for the colonization of anaerobic bacteria.
Rice. 7.12. Caries
Rice. 7.13. Periodontal disease:
1 - dental deposits
2 - inflammation of the gums
3 - invasion of microorganisms
4 - cement infection
5 - bone resorption
Supragingival plaque contributes to the occurrence of caries, gingivitis, subgingival - periodontitis (Fig. 7.12, 7.13, 7.14).
Tartar- These are mineralized dental deposits formed as a result of calcification of dental plaque. There is always non-mineralized plaque on the surface of tartar. Mineralization of the plaque occurs due to the minerals of saliva and gingival fluid. Calcium salts of saliva mineralize dental plaque located above the gum (salivary stone). Supragingival calculus is deposited to a greater extent near the large salivary excretory ducts. This is the oral surface of the lower incisors and the buccal surface of the first molar of the upper jaw. Subgingival calculus is formed as a result of calcification by salts of the gingival fluid and blood serum (serum calculus). It is located on the surface of the tooth in a pathological pocket, has a dark color due to the pigments contained in the blood serum (Fig. 7.14, 7.15).
The onset and rate of plaque mineralization varies from person to person and on different teeth. It is possible to distinguish people with rapid calculus formation, with moderate, with insignificant, and people who do not form tartar.
Inflammatory conditions of the periodontium lead to quantitative and qualitative changes in the apparatus holding the tooth.
The progression of inflammatory-dystrophic processes in the periodontium is the cause of loosening and loss of teeth (Fig. 7.17, 7.18, 7.19, 7.20, 7.21).
Dental deposits can cause diseases of the oral mucosa and their complications.
In this case, it is possible:
1) dysbacteriosis of the oral cavity,
2) secondary infection in violation of the integrity of the epithelium.
Methods for determining dental deposits:
1) visual;
2) instrumental;
3) using dyes (qualitative and quantitative methods).
explorers, or probes are instruments with a pointed end, a curved working part for instrumental examination of the tooth surface for the presence of tartar, defecation
Rice. 7.14. Dental deposits:
1 - supragingival
2 - subgingival
Rice. 7.15. supragingival calculus
Rice. 7.16. Pigmented plaque on teeth
Rice. 7.17. Progression of periodontal disease: a - normal
b - gum pocket
c, d - periodontal pockets
Rice. 7.18. Recession of the gums, the formation of pathological periodontal pockets, loosening of the teeth
Rice. 7.19. Chronic generalized periodontitis
Rice. 7.20. Micrograph of a section of the interdental septum at the initial stage of periodontitis (arrows indicate the resorption of a compact plate)
Rice. 7.21. Histological structure of bone tissue at the initial stage of periodontitis: a - accumulation of osteoclasts, b - formation of lacunae
surface of the tooth and filling. There are special explorers for diagnosing tartar. By design, they can be one-sided and two-sided (Fig. 7.22).
Indices of oral hygiene
When diagnosing dental plaque, oral hygiene indices proposed by various authors are used. There are enough of them. The most common are the Fedorov-Volodkina, Green-Vermilion indices, since their methodology is simple, they do not take much time and are informative. When they are used dyes:
Fuchsin (Fig. 7.23);
Methylene blue (Fig. 7.24);
Schiller-Pisarev solution (Fig. 7.25), etc.
When staining, a qualitative and quantitative assessment of oral hygiene is given.
When conducting Fedorov-Volodkina index Schiller-Pisarev solution (crystalline iodine - 1 g, potassium iodide - 2 g, distilled water - 40 ml) stain the vestibular surfaces of the six lower frontal teeth. A quantitative assessment is carried out according to a five-point system for each stained tooth (Fig. 7.25):
Rice. 7.22. Explorers: a - double-sided b - single-sided
Rice. 7.23. The surface of the teeth stained with magenta
Rice. 7.24. Tooth surface stained with methylene blue solution
Rice. 7.25. Tooth surfaces stained with Schiller-Pisarev solution
5 points - coloring of the entire surface; 4 points - staining 3/5 of the surface; 3 points - coloring of 1/2 of the surface; 2 points - staining of 1/5 of the surface; 1 point - no staining.
where IG is the hygiene index, K is the sum of the scores for each tooth, n is the number of teeth examined.
The quality of oral hygiene is assessed according to the following criteria:
Good - 1.1 - 1.5 points,
Satisfactory - 1.6 -2.0 points,
Unsatisfactory - 2.1 -2.5 points,
Bad - 2.6 - 3.4 points,
Very bad - 3.5 - 5.0 points.
Simplified hygienic index OHI-s (Green and Vermilion, 1969). Stain 6 adjacent teeth, or 1 - 2 from different groups of teeth of the upper and lower jaws, vestibular and oral surfaces.
Evaluation is carried out on a three-point system.
When coloring:
1/3 surface - 1 point,
1/2 surface -2 points,
2/3 surfaces - 3 points,
no staining - 0 points.
If the plaque on the surfaces of the teeth is uneven, then the assessment is carried out on a larger volume or the arithmetic mean of 2 or 4 surfaces is calculated.
OHI-s = sum of indicators / 1 1 - ideal hygienic condition of the oral cavity. If the OHI-s is greater than 1, the hygiene condition is poor.
Methods for removing dental deposits:
1) individual oral hygiene;
2) professional oral hygiene.
Ways to remove dental deposits:
1) mechanical;
2) physical;
3) chemical;
4) combined.
Means used in the removal of dental deposits
Brushes, flosses, toothpicks, pastes, irrigators are used mainly for individual oral hygiene. Brushes, pastes, irrigators are also used to remove soft dental deposits in professional oral hygiene. The final professional hygiene step should include polishing the surface using rubber, silicone heads, cups, brushes and pastes.
For professional oral hygiene, you need: medicines, instruments (manual, ultrasonic, sonic scalers), curettes, excavators, devices for removing dental deposits.
Hand tools:
- scalers(with curved and straight blade, chisel, rasp, hoe),
- curettes(universal and zone-specific).
These tools can be part of a "small preventive" or "large preventive" toolbox.
Tools consist of the following elements: handle, rod, working part (Fig. 7.26).
Rice. 7.26. Tool elements:
b - rod
c - working part
When using the tool pen held by the doctor's hand. Kernel is located between the working part and the handle of the tool, has two bends and is called functional. It can be long, medium length and short. Short rods are convenient for working in the area of the anterior teeth and for removing supragingival tartar, long ones - in the area of chewing teeth and pathological pockets. Part of the rod between the working part and the first bend
Rice. 7.27. Rod and working part of the tool:
1 - functional rod
2 - end rod
3 - working part
Rice. 7.28. The working part of the tool in cross section
Rice. 7.29. Bit
is called terminal(terminal) rod and determines the contact of the working part with the surface of the tooth (Fig. 7.27).
AT working part tools are distinguished: front (F) and side (I) surfaces, cutting edge (C) and reverse side (B) (Fig. 7.28).
Chisel, rasp, hoe- tools with a specific structure of the working part (Fig. 7.29, 7.30, 7.31).
Scaler has a sharp tip of the working part and is used to remove supragingival calculus (Fig. 7.32, 7.33). curette has a rounded tip and is used for small and subgingival deposits. Universal curettes can be used on all surfaces of teeth. The working part of these tools has two cutting edges (Fig. 7.34). Zone-specific curettes work on certain surfaces and groups of teeth (curettes Gracie, Vision, furcation, etc.) and have one cutting edge (Fig. 7.35).
Tartar removal technique
Tartar removal is preceded by irrigation of the oral cavity with solutions of weak antiseptics, removal of soft dental deposits.
Rice. 7.30. Rasp
Rice. 7.31. Hoe
Rice. 7.32. Scaler
Rice. 7.33. Scaler crescent
Rice. 7.34. Curette universal
Rice. 7.35. Cureta Gracie
Rice. 7.36. Mechanical removal of supragingival calculus
If necessary, local application or injection anesthesia should be performed.
At mechanical way removal of supragingival tartar is carried out with scalers. Start with the vestibular surface of the teeth, then move on to the contact surfaces. The stage is completed on the oral surface of the teeth. The movements of the tool can be lever-like or scraping (Fig. 7.36). With lever-like movements, stable teeth located on the opposite side of the jaw can serve as a support for the lever. After the removal of the gingival stone, they proceed to the removal of the subgingival one, cleaning the surfaces of the roots of the teeth in the same sequence. In this case, curettes are used, since they have a rounded tip of the working part and do not injure the gum mucosa.
Rice. 7.37. Removal of subgingival calculus using a curette: a - vestibular surface b - proximal surface
Rice. 7.38. Air-Flow + Piezone device used for ultrafine and ultrasonic treatment
The removal of tartar is completed by polishing the surfaces of the teeth using polishing pastes, brushes, rubber, silicone heads, cups, as well as polishing discs, strips with a fine spray.
When removing dental plaque, special equipment is also used (Fig. 7.38), for example, ultrafine (powder-jet) exposure. The method consists in the directed supply of a jet stream of an aerosol containing water and an abrasive agent (sodium bicarbonate and aluminum alpha oxide).
After completion of all stages, it is necessary to carry out control
careful removal of dental deposits. In this case, visual inspection, explorers, radiography are used.
The physical method involves the removal of tartar using acoustic systems. In this case, ultrasonic, sound electromagnetic oscillations are used. The power of ultrasound in this case should be strictly regulated, since trauma to the enamel, gums, and cement is possible. Possibly also negative impact on artificial crowns and light-cured fillings. This method is often combined with mechanical. Small remnants of tartar are removed by hand and then the surfaces of the teeth are polished.
Along with the mechanical and physical, a chemical method is also used to remove tartar. The composition of the products used contains a small concentration of acid, which helps soften hard dental deposits. The negative point of this method is that acids can dissolve not only tartar, but also adversely affect the tooth and soft tissues surrounding
