Clinical determination of basic stages of development of temporal and permanent teeth

Clinical determination of basic stages of development of temporal and permanent teeth. The terms of mineralization, dentition and forming of temporal and permanent teeth at children.

Clinical and  roentgenologic determination  of features  of anatomic structure  of temporal and permanent teeth, that are found in the stage of forming .

Temporal, permanent teeth decay at children. Conformities to the law of clinical displays and motion at the children of a different age. Diagnostics, differential diagnostics.

Tooth development

 Tooth development is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. Although many diverse species have teeth, non-human tooth development is largely the same as in humans. For human teeth to have a healthy oral environment, enamel, dentin, cementum, and the periodontium must all develop during appropriate stages of fetal development. Primary (baby) teeth start to form between the sixth and eighth weeks in utero, and permanent teeth begin to form in the twentieth week in utero. If teeth do not start to develop at or near these times, they will not develop at all.

A significant amount of research has focused on determining the processes that initiate tooth development. It is widely accepted that there is a factor within the tissues of the first branchial arch that is necessary for the development of teeth.^[1]

Overview

Histologic slide showing a tooth bud.
A: enamel organ
B: dental papilla

C: dental follicle

The tooth bud (sometimes called the tooth germ) is an aggregation of cells that eventually forms a tooth. These cells are derived from the ectoderm of the first branchial arch and the ectomesenchyme of the neural crest. The tooth bud is organized into three parts: the enamel organ, the dental papilla and the dental follicle.

The enamel organ is composed of the outer enamel epithelium, inner enamel epithelium, stellate reticulum and stratum intermedium. These cells give rise to ameloblasts, which produce enamel and the reduced enamel epithelium. The location where the outer enamel epithelium and inner enamel epithelium join is called the cervical loop. The growth of cervical loop cells into the deeper tissues forms Hertwig’s Epithelial Root Sheath, which determines the root shape of the tooth.

The dental papilla contains cells that develop into odontoblasts, which are dentin-forming cells. Additionally, the junction between the dental papilla and inner enamel epithelium determines the crown shape of a tooth. Mesenchymal cells within the dental papilla are responsible for formation of tooth pulp.

The dental follicle gives rise to three important entities: cementoblasts, osteoblasts, and fibroblasts. Cementoblasts form the cementum of a tooth. Osteoblasts give rise to the alveolar bone around the roots of teeth. Fibroblasts develop the periodontal ligaments which connect teeth to the alveolar bone through cementum.

Human tooth development timeline

The following tables present the development timeline of human teeth. Times for the initial calcification of primary teeth are for weeks in utero. Abbreviations: wk = weeks; mo = months; yr = years.

 

The developing tooth bud

One of the earliest steps in the formation of a tooth that can be seen microscopically is the distinction between the vestibular lamina and the dental lamina. The dental lamina connects the developing tooth bud to the epithelial layer of the mouth for a significant time.

Tooth development is commonly divided into the following stages: the bud stage, the cap, the bell, and finally maturation. The staging of tooth development is an attempt to categorize changes that take place along a continuum; frequently it is difficult to decide what stage should be assigned to a particular developing tooth. This determination is further complicated by the varying appearance of different histologic sections of the same developing tooth, which can appear to be different stages.

Bud stage

The bud stage is characterized by the appearance of a tooth bud without a clear arrangement of cells. The stage technically begins once epithelial cells proliferate into the ectomesenchyme of the jaw. The tooth bud itself is the group of cells at the end of the dental lamina.

Cap stage

                    Histologic slide of tooth in cap stage.

The first signs of an arrangement of cells in the tooth bud occur in the cap stage. A small group of ectomesenchymal cells stops producing extracellular substances, which results in an aggregation of these cells called the dental papilla. At this point, the tooth bud grows around the ectomesenchymal aggregation, taking on the appearance of a cap, and becomes the enamel (or dental) organ. A condensation of ectomesenchymal cells called the dental follicle surrounds the enamel organ and limits the dental papilla. Eventually, the enamel organ will produce enamel, the dental papilla will produce dentin and pulp, and the dental follicle will produce all the supporting structures of a tooth.

Histologic slide of tooth in early bell stage. Note cell organization.

Bell stage

The bell stage is known for the histodifferentiation and morphodifferentiation that takes place. The dental organ is bell-shaped during this stage, and the majority of its cells are called stellate reticulum because of their star-shaped appearance.^[1] Cells on the periphery of the enamel organ separate into three important layers. Cuboidal cells on the periphery of the dental organ are known as outer enamel epithelium. The columnar cells of the enamel organ adjacent to the dental papilla are known as inner enamel epithelium. The cells between the inner enamel epithelium and the stellate reticulum form a layer known as the stratum intermedium. The rim of the dental organ where the outer and inner enamel epithelium join is called the cervical loop. In summary, the layers in order of innermost to outermost consist of dentine, enamel (formed by inner enamel epithelium, or ‘ameloblasts’, as they move outwards/upwards), inner enamel epithelium and stratum intermedium (specialised stratified cells that support the synthetic activity of the Inner Enamel Epithelium) What follows is part of the initial ‘enamel organ’, the middle of which is made up of stellate reticulum cells. This is all encased by the outer enamel epithelium layer.

Other events occur during the bell stage. The dental lamina disintegrates, leaving the developing teeth completely separated from the epithelium of the oral cavity; the two will not join again until the final eruption of the tooth into the mouth.

Histologic slide of tooth in late bell stage. Note disintegration of dental lamina at top.

The crown of the tooth, which is influenced by the shape of the internal enamel epithelium, also takes shape during this stage. Throughout the mouth, all teeth undergo this same process; it is till ncertain why teeth form various crown shapes—for instance, incisors versus canines. There are two dominant hypotheses. The “field model” proposes there are components for each type of ooth shape found in the ectomesenchyme during tooth development. The components for particular types of teeth, such as incisors, are localized in one area and dissipate rapidly in ifferent parts of the mouth. Thus, for example, the “incisor field” has factors that develop teeth into incisor shape, and this field is concentrated in the central incisor area, but decreases rapidly in the canine area. The other dominant hypothesis, the “clone model”, proposes that the  epithelium programs a group of ectomesenchymal cells to generate teeth of particular shapes. This group of cells, called a clone, coaxes the dental lamina into tooth development, causing a tooth bud to form. Growth of the dental lamina continues in an area called the “progress zone”. Once the progress zone travels a certain distance from the first tooth bud, a second tooth bud will start to develop. These two models are not necessarily mutually exclusive, nor does widely accepted dental science consider them to be so: it is postulated that both models influence tooth development at different times. Other structures that may appear in a developing tooth in this stage are enamel knots, enamel cords, and enamel niche.

Histologic slide of developing hard tissues. Ameloblasts are forming enamel, while odontoblasts are forming dentin.

Crown stage

Hard tissues, including enamel and dentin, develop during the next stage of tooth development. This stage is called the crown, or maturation, stage by some researchers. Important cellular changes occur at this time. In prior stages, all of the inner enamel epithelium cells were dividing to increase the overall size of the tooth bud, but rapid dividing, called mitosis, stops during the crown stage at the location where the cusps of the teeth form. The first mineralized hard tissues form at this location. At the same time, the inner enamel epithelial cells change in shape from cuboidal to columnar. The nuclei of these cells move closer to the stratum intermedium and away from the dental papilla.

Histologic slide of tooth. Note the tubular appearance of dentin.
A: enamel
B: dentin

The adjacent layer of cells in the dental papilla suddenly increases in size and differentiates into odontoblasts, which are the cells that form dentin. Researchers believe that the odontoblasts would not form if it were not for the changes occurring in the inner enamel epithelium. As the changes to the inner enamel epithelium and the formation of odontoblasts continue from the tips of the cusps, the odontoblasts secrete a substance, an organic matrix, into their immediate surrounding. The organic matrix contains the material needed for dentin formation. As odontoblasts deposit organic matrix, they migrate toward the center of the dental papilla. Thus, unlike enamel, dentin starts forming in the surface closest to the outside of the tooth and proceeds inward. Cytoplasmic extensions are left behind as the odontoblasts move inward. The unique, tubular microscopic appearance of dentin is a result of the formation of dentin around these extensions.

After dentin formation begins, the cells of the inner enamel epithelium secrete an organic matrix against the dentin. This matrix immediately mineralizes and becomes the tooth’s enamel. Outside the dentin are ameloblasts, which are cells that continue the process of enamel formation; therefore, enamel formation moves outwards, adding new material to the outer surface of the developing tooth.

Hard tissue formation

Sections of tooth undergoing development.

Enamel

Enamel formation is called amelogenesis and occurs in the crown stage of tooth development. “Reciprocal induction” governs the relationship between the formation of dentin and enamel; dentin formation must always occur before enamel formation. Generally, enamel formation occurs in two stages: the secretory and maturation stages. Proteins and an organic matrix form a partially mineralized enamel in the secretory stage; the maturation stage completes enamel mineralization.

In the secretory stage, ameloblasts release enamel proteins that contribute to the enamel matrix, which is then partially mineralized by the enzyme alkaline phosphatase. The appearance of this mineralized tissue, which occurs usually around the third or fourth month of pregnancy, marks the first appearance of enamel in the body. Ameloblasts deposit enamel at the location of what become cusps of teeth alongside dentin. Enamel formation then continues outward, away from the center of the tooth.

In the maturation stage, the ameloblasts transport some of the substances used in enamel formation out of the enamel. Thus, the function of ameloblasts changes from enamel production, as occurs in the secretory stage, to transportation of substances. Most of the materials transported by ameloblasts in this stage are proteins used to complete mineralization. The important proteins involved are amelogenins, ameloblastins, enamelins, and tuftelins. By the end of this stage, the enamel has completed its mineralization.

Dentin

Dentin formation, known as dentinogenesis, is the first identifiable feature in the crown stage of tooth development. The formation of dentin must always occur before the formation of enamel. The different stages of dentin formation result in different types of dentin: mantle dentin, primary dentin, secondary dentin, and tertiary dentin.

Odontoblasts, the dentin-forming cells, differentiate from cells of the dental papilla. They begin secreting an organic matrix around the area directly adjacent to the inner enamel epithelium, closest to the area of the future cusp of a tooth. The organic matrix contains collagen fibers with large diameters (0.1–0.2 μm in diameter). The odontoblasts begin to move toward the center of the tooth, forming an extension called the odontoblast process. Thus, dentin formation proceeds toward the inside of the tooth. The odontoblast process causes the secretion of hydroxyapatite crystals and mineralization of the matrix. This area of mineralization is known as mantle dentin and is a layer usually about 150 μm thick.

Whereas mantle dentin forms from the preexisting ground substance of the dental papilla, primary dentin forms through a different process. Odontoblasts increase in size, eliminating the availability of any extracellular resources to contribute to an organic matrix for mineralization. Additionally, the larger odontoblasts cause collagen to be secreted in smaller amounts, which results in more tightly arranged, heterogeneous nucleation that is used for mineralization. Other materials (such as lipids, phosphoproteins, and phospholipids) are also secreted.

Secondary dentin is formed after root formation is finished and occurs at a much slower rate. It is not formed at a uniform rate along the tooth, but instead forms faster along sections closer to the crown of a tooth. This development continues throughout life and accounts for the smaller areas of pulp found in older individuals. Tertiary dentin, also known as reparative dentin, forms in reaction to stimuli, such as attrition or dental caries.

 

Cross-section of tooth at root. Note clear, acellular appearance of cementum.
A: dentin
B: cementum

Cementum

Cementum formation is called cementogenesis and occurs late in the development of teeth. Cementoblasts are the cells responsible for cementogenesis. Two types of cementum form: cellular and acellular.

Acellular cementum forms first. The cementoblasts differentiate from follicular cells, which can only reach the surface of the tooth’s root once Hertwig’s Epithelial Root Sheath (HERS) has begun to deteriorate. The cementoblasts secrete fine collagen fibrils along the root surface at right angles before migrating away from the tooth. As the cementoblasts move, more collagen is deposited to lengthen and thicken the bundles of fibers. Noncollagenous proteins, such as bone sialoprotein and osteocalcin, are also secreted. Acellular cementum contains a secreted matrix of proteins and fibers. As mineralization takes place, the cementoblasts move away from the cementum, and the fibers left along the surface eventually join the forming periodontal ligaments.

Cellular cementum develops after most of the tooth formation is complete and after the tooth occludes (in contact) with a tooth in the opposite arch. This type of cementum forms around the fiber bundles of the periodontal ligaments. The cementoblasts forming cellular cementum become trapped in the cementum they produce.

The origin of the formative cementoblasts is believed to be different for cellular cementum and acellular cementum. One of the major current hypotheses is that cells producing cellular cementum migrate from the adjacent area of bone, while cells producing acellular cementum arise from the dental follicle. Nonetheless, it is known that cellular cementum is usually not found in teeth with one root. In premolars and molars, cellular cementum is found only in the part of the root closest to the apex and in interradicular areas between multiple roots.

Histologic slide of tooth erupting into the mouth.A: tooth B: gingiva C: bone D: periodontal ligaments

Formation of the periodontium

The periodontium, which is the supporting structure of a tooth, consists of the cementum, periodontal ligaments, gingiva, and alveolar bone. Cementum is the only one of these that is a part of a tooth. Alveolar bone surrounds the roots of teeth to provide support and creates what is commonly called a “socket“. Periodontal ligaments connect the alveolar bone to the cementum, and the gingiva is the surrounding tissue visible in the mouth.

Periodontal ligament

Cells from the dental follicle give rise to the periodontal ligament (PDL). Specific events leading to the formation of the periodontal ligament vary between deciduous (baby) and permanent teeth and among various species of animals.^[15] Nonetheless, formation of the periodontal ligament begins with ligament fibroblasts from the dental follicle. These fibroblasts secrete collagen, which interacts with fibers on the surfaces of adjacent bone and cementum.^[16] This interaction leads to an attachment that develops as the tooth erupts into the mouth. The occlusion, which is the arrangement of teeth and how teeth in opposite arches come in contact with one another, continually affects the formation of periodontal ligament. This perpetual creation of periodontal ligament leads to the formation of groups of fibers in different orientations, such as horizontal and oblique fibers. Alveolar bone

As root and cementum formation begin, bone is created in the adjacent area. Throughout the body, cells that form bone are called osteoblasts. In the case of alveolar bone, these osteoblast cells form from the dental follicle. Similar to the formation of primary cementum, collagen fibers are created on the surface nearest the tooth, and they remain there until attaching to periodontal ligaments.

Like any other bone in the human body, alveolar bone is modified throughout life. Osteoblasts create bone and osteoclasts destroy it, especially if force is placed on a tooth. As is the case when movement of teeth is attempted through orthodontics, an area of bone under compressive force from a tooth moving toward it has a high osteoclast level, resulting in bone resorption. An area of bone receiving tension from periodontal ligaments attached to a tooth moving away from it has a high number of osteoblasts, resulting in bone formation.

Gingiva

The connection between the gingiva and the tooth is called the dentogingival junction. This junction has three epithelial types: gingival, sulcular, and junctional epithelium. These three types form from a mass of epithelial cells known as the epithelial cuff between the tooth and the mouth.

Much about gingival formation is not fully understood, but it is known that hemidesmosomes form between the gingival epithelium and the tooth and are responsible for the primary epithelial attachment. Hemidesmosomes provide anchorage between cells through small filament-like structures provided by the remnants of ameloblasts. Once this occurs, junctional epithelium forms from reduced enamel epithelium, one of the products of the enamel organ, and divides rapidly. This results in the perpetually increasing size of the junctional epithelial layer and the isolation of the remnants of ameloblasts from any source of nutrition. As the ameloblasts degenerate, a gingival sulcus is created.

Nerve and vascular formation

Frequently, nerves and blood vessels run parallel to each other in the body, and the formation of both usually takes place simultaneously and in a similar fashion. However, this is not the case for nerves and blood vessels around the tooth, because of different rates of development.

Nerve formation

Nerve fibers start to near the tooth during the cap stage of tooth development and grow toward the dental follicle. Once there, the nerves develop around the tooth bud and enter the dental papilla when dentin formation has begun. Nerves never proliferate into the enamel organ.

Vascular formation

Blood vessels grow in the dental follicle and enter the dental papilla in the cap stage. Groups of blood vessels form at the entrance of the dental papilla. The number of blood vessels reaches a maximum at the beginning of the crown stage, and the dental papilla eventually forms in the pulp of a tooth. Throughout life, the amount of pulpal tissue in a tooth decreases, which means that the blood supply to the tooth decreases with age. The enamel organ is devoid of blood vessels because of its epithelial origin, and the mineralized tissues of enamel and dentin do not need nutrients from the blood.

Tooth eruption

Tooth eruption occurs when the teeth enter the mouth and become visible. Although researchers agree that tooth eruption is a complex process, there is little agreement on the identity of the mechanism that controls eruption. Some commonly held theories that have been disproven over time include:  the tooth is pushed upward into the mouth by the growth of the tooth’s root,  the tooth is pushed upward by the growth of the bone around the tooth, the tooth is pushed upward by vascular pressure, and  the tooth is pushed upward by the cushioned hammock. The cushioned hammock theory, first proposed by Harry Sicher, was taught widely from the 1930s to the 1950s. This theory postulated that a ligament below a tooth, which Sicher observed on under a microscope on a histologic slide, was responsible for eruption. Later, the “ligament” Sicher observed was determined to be merely an artifact created in the process of preparing the slide.

The most widely held current theory is that while several forces might be involved in eruption, the periodontal ligaments provide the main impetus for the process. Theorists hypothesize that the periodontal ligaments promote eruption through the shrinking and cross-linking of their collagen fibers and the contraction of their fibroblasts.

Although tooth eruption occurs at different times for different people, a general eruption timeline exists. Typically, humans have 20 primary (baby) teeth and 32 permanent teeth. Tooth eruption has three stages. The first, known as deciduous dentition stage, occurs when only primary teeth are visible. Once the first permanent tooth erupts into the mouth, the teeth are in the mixed (or transitional) dentition. After the last primary tooth falls out of the mouth—a process known as exfoliation—the teeth are in the permanent dentition.

Primary dentition starts on the arrival of the mandibular central incisors, usually at eight months, and lasts until the first permanent molars appear in the mouth, usually at six years The primary teeth typically erupt in the following order: (1) central incisor, (2) lateral incisor, (3) first molar, (4) canine, and (5) second molar. As a general rule, four teeth erupt for every six months of life, mandibular teeth erupt before maxillary teeth, and teeth erupt sooner in females than males. During primary dentition, the tooth buds of permanent teeth develop below the primary teeth, close to the palate or tongue.

Mixed dentition starts when the first permanent molar appears in the mouth, usually at six years, and lasts until the last primary tooth is lost, usually at eleven or twelve years. Permanent teeth in the maxilla erupt in a different order from permanent teeth on the mandible. Maxillary teeth erupt in the following order: (1) first molar (2) central incisor, (3) lateral incisor, (4) first premolar, (5) second premolar, (6) canine, (7) second molar, and (8) third molar. Mandibular teeth erupt in the following order: (1) first molar (2) central incisor, (3) lateral incisor, (4) canine, (5) first premolar, (6) second premolar, (7) second molar, and (8) third molar. Since there are no premolars in the primary dentition, the primary molars are replaced by permanent premolars. If any primary teeth are lost before permanent teeth are ready to replace them, some posterior teeth may drift forward and cause space to be lost in the mouth. This may cause crowding and/or misplacement once the permanent teeth erupt, which is usually referred to as malocclusion. Orthodontics may be required in such circumstances for an individual to achieve a straight set of teeth.

The permanent dentition begins when the last primary tooth is lost, usually at 11 to 12 years, and lasts for the rest of a person’s life or until all of the teeth are lost (edentulism). During this stage, third molars (also called “wisdom teeth“) are frequently extracted because of decay, pain or impactions. The main reasons for tooth loss are decay and periodontal disease.

 

The offered far of theories in relation to the mechanism dentition of the teeth. Most widespread from them there are such:

 

theory of growth of root (Hanter, 1870);

 

theory of rise of hydrostatical pressure in a periapical area

and to pulp of tooth (Yasvoin, 1929,1936);

 

theory of alteration of bone fabric (Cats, 1940);

 

theory of traction of periodont.

 

The theory of growth of root of tooth explains dentition of tooth by that root, which grows, abuts against the immobile bottom of bone alveolus and as though pushes a tooth from her. However this theory has the row of failing. She caot account for the difficult moving of rudiments of some teeth in a jaw to beginning of their dentition, and also dentition of teeth with the unformed root.

 

Theory of hydrostatical pressure. In accordance with this theory no growth of root is instrumental in dentition of teeth, and vice versa, a root develops in connection with dentition of tooth. The reason of dentition is stopped up in fabric dental papilla, which is differentiated. Thus produce fibro-blasti a plenty of basic matter, the volume of fabric on the apex of papilla is multiplied, pressure into a dental rudiment is created, that compels a tooth to move to the free edge of gums.

 

Theory of alteration of bone fabric. In accordance with this theory of dentition of teeth is conditioned by combination of processes of deposit and rezorbtion of bone fabric in the wall of alveolus. Consider that   newmade bone fabric on the day of dental alveolus is able to push a tooth toward a mouth cavity. However most researchers consider that education and rezorbtion of bone round the root of tooth is investigation, and no reason of him dentition.

 

Structure of the teeth

Tooth enamel

 

Tooth enamel is the hardest and most highly mineralized substance of the body, and with dentin, cementum, and dental pulp

 is one of the four major tissues which make up the tooth. It is the normally visible dental tissue of a tooth and must be supported by underlying dentin. Ninety-six percent of enamel consists of mineral, with water and organic material composing the rest The normal color of enamel varies from light yellow to grayish white. At the edges of teeth where there is no dentin underlying the enamel, the color sometimes has a slightly blue tone. Since enamel is semitranslucent, the color of dentin and any restorative dental material underneath the enamel strongly affects the appearance of a tooth. Enamel varies in thickness over the surface of the tooth and is often thickest at the cusp, up to 2.5 mm, and thinnest at its border, which is seen clinically as the cementoenamel junction (CEJ).

Enamel’s primary mineral is hydroxylapatite, which is a crystalline calcium phosphate. The large amount of minerals in enamel accounts not only for its strength but also for its brittleness. Tooth enamel is the hardest substance in the human body, ranking a 5 on Mohs hardness scale. Dentin, less mineralized and less brittle, 3-4 in hardness, compensates for enamel and is necessary as a support.

Unlike dentin and bone, enamel does not contain collagen. Instead, it has two unique classes of proteins called amelogenins and enamelins. While the role of these proteins is not fully understood, it is believed that they aid in the development of enamel by serving as a framework support, among other functions.

The basic unit of enamel is called an enamel rod. Measuring 4 μm – 8 μm in diameter an enamel rod, formerly called an enamel prism, is a tightly packed mass of hydroxyapatite crystals in an organized pattern. In cross section, it is best compared to a keyhole, with the top, or head, oriented toward the crown of the tooth, and the bottom, or tail, oriented toward the root of the tooth.

The arrangement of the crystals within each enamel rod is highly complex. Both ameloblasts (the cells which initiate enamel formation) and Tomes’ processes affect the crystals’ pattern. Enamel crystals in the head of the enamel rod are oriented parallel to the long axis of the rod. When found in the tail of the enamel rod, the crystals’ orientation diverges slightly from the long axis.

The arrangement of enamel rods is understood more clearly than their internal structure. Enamel rods are found in rows along the tooth, and within each row, the long axis of the enamel rod is generally perpendicular to the underlying dentin. In permanent teeth, the enamel rods near the cementoenamel junction (CEJ) tilt slightly toward the root of the tooth. Understanding enamel orientation is very important in restorative dentistry, because enamel unsupported by underlying dentin is prone to fracture.

The area around the enamel rod is known as interrod enamel. Interrod enamel has the same composition as enamel rod, however a histologic distinction is made between the two because crystal orientation is different in each. The border where the crystals of enamel rods and crystals of interrod enamel meet is called the rod sheath.

Striae of Retzius are stripes that appear on enamel when viewed microscopically in cross section. Formed from changes in diameter of Tomes’ processes, these stripes demonstrate the growth of enamel, similar to the annual rings on a tree. Perikymata are shallow furrows where the striae of Retzius end. Darker than the other stripes, the neonatal line is a stripe that separates enamel formed before and after birth.

Gnarled enamel is found at the cusps of teeth. Its twisted appearance results from the orientation of enamel rods and the rows in which they lie.

Dentin

Parts of a tooth, including dentin

Dentin (BE: dentine) is a calcified tissue of the body, and along with enamel, cementum, and pulp is one of the four major components of teeth. Usually, it is covered by enamel on the crown and cementum on the root and surronds the entire pulp. By weight, seventy percent of dentin consists of the mineral, hydroxylapatite, twenty percent is organic material, and ten percent is water. Yellow in appearance, it greatly affects the color of a tooth due to the translucency of enamel. Dentin, which is less mineralized and less brittle than enamel, is necessary for the support of enamel.

Dentin consists of microscopic channels, called dentinal tubules, which radiate outward through the dentin from the pulp to the exterior cementum or enamel border. These tubules contain fluid and cellular structures. As a result, dentin has a degree of permeability which can increase the sensation of pain and the rate of tooth decay.

The formation of dentin, known as dentinogenesis, begins prior to the formation of enamel and is initiated by the odontoblasts of the pulp. Unlike enamel, dentin continues to form throughout life and can be initiated in response to stimuli, such as tooth decay or attrition.

There are different types of dentin, differentiated by appearance and stage of development. Primary dentin forms most of the tooth. Secondary dentin develops after root formation is complete and forms much slower than primary dentin. Tertiary dentin forms as a biological response to stimuli.

Dentinal tubules are structures that span the entire thickness of dentin and form as a result of the mechanism of dentin formation. From the outer surface of the dentin to the area nearest the pulp, these tubules follow an S-shaped path. The diameter and density of the tubules are greatest near the pulp. Tapering from the inner to the outermost surface, they have a diameter of 2.5 μm near the pulp, 1.2 μm in the middle of the dentin, and 900 nm at the dentino-enamel junction. Their density is 59,000 to 76,000 per square millimeter near the pulp, whereas the density is only half as much near the enamel.

Within the tubules, there is an odontoblast process, which is an extension of an odontoblast, and dentinal fluid, which contains a mixture of albumin, transferrin, tenascin and proteoglycans. In addition, there are branching canalicular systems that connect to each other. These branches have been categorized by size, with major being 500-1000 μm in diameter, fine being 300-700 μm, and micro being less than 300 μm.^[6] The major branches are the terminal ends of the tubules. About every 1-2 μm, there are fine branches diverging from dentinal tubules at 45 degree angles. The microtubules diverge at 90 degree angles.

The porous, yellow-hued material is made up of 70% inorganic materials (mainly hydroxylapatite and some non-crystalline amorphous calcium phosphate), 20% organic materials (90% of which is collagen type 1 and the remaining 10% ground substance, which includes dentine-specific proteins), and 10% water (which is absorbed on the surface of the minerals or between the crystals). Because it is softer than enamel, it decays more rapidly and is subject to severe cavities if not properly treated, but dentin due to its elastic properties it is a good support for enamel. Its flexibility prevents the brittle enamel fracturing.

The three dimensional configuration of the dentinal tubules is under genetic control and is therefore a characteristic unique to the order, although in many mammalian species the tubules follow a gentle helical course through the solid matrix.

Types

There are three types of dentine, primary, secondary and tertiary. Primary dentine is the most prominent dentine in the tooth, it outlines the pulp chamber. The outer layer is mantle dentine, it is formed by newly differentiated odontoblasts and is approximately 150 micrometer. It is different from the rest of primary dentine in that it lacks phosphoryn, has loosely packed collagen fibrils and is less mineralized.

Newly secreted dentine is unmineralised and is called predentine. It is easily identified in haematoxylin and eosin stained section since it stains less intensely then dentine. It is usually 10-47 micrometer and lines the innermost region of the dentine. It is unmineralized and consists of collagen, glycoproteins and proteoglycans. It is similar to osteoid in bone and is thickest when dentinogenesis is occurring.

Secondary dentine is dentine that is formed after root formation is complete and the tooth is functional. It continues at a slower rate in incremental growths. It has a similar structure to primary dentine. Deposition is not always even around pulp chamber. Deposition causes a decrease in pulp chamber size, this means cavity preparation in young patients greater risk of exposing pulp.

Tertiary dentine is dentine formed as a reaction to external insult such as caries. It is of two type, either reactionary, where dentine is formed from pre-existing odontoblast or is it reparative, where newly differented odontoblast like cells are formed. Tertiary dentine is only formed by odontoblast directly affected by stimulus, the architecture and structure depends on intensity and duration of the stimuli e.g. if the stimulus is a carious lesion, there would be extensive destruction of dentine and damage to the pulp. Thus tertiary dentine would be deposited rapidly, with a sparse and irregular tubular pattern with cellular inclusion know as osteodentine. However if the stimuli is less active, it would be laid down less rapidly with a more regular tubular pattern and hardly any in any cellular inclusions.

Elephant ivory is solid dentin. The structure of the dentinal tubules contributes both to its porosity (useful for piano keys) and its elasticity (useful for billiard balls.) Elephant tusks are formed with a thin cap of enamel, which soon wears away, leaving the dentin exposed. Exposed dentin in humans causes the symptom of sensitive teeth.

Because dentin is softer than enamel, it wears away more quickly than enamel. Some mammalian teeth exploit this phenomenon, especially herbivores such as horses, deer or elephants. In many herbivores, the occlusal (biting) surface of the tooth is composed of alternating areas of dentin and enamel. Differential wearing causes sharp ridges of enamel to be formed on the surface of the tooth (typically a molar), and to remain during the working life of the tooth. Herbivores grind their molars together as they chew (masticate), and the ridges help to shred tough plant material.

Dentin may be demineralized and stained for histological study, unlike enamel. Dentin rates approximately 3 on the Mohs scale of mineral hardness.

A material similar to dentin forms the hard material that makes up dermal denticles in sharks and other cartilaginous fish.

Cementum

Cementum is the thin layer of calcified (tough calcium deposits) tissue covering the dentine of the root and is one of four tissues that support the tooth in the jaw (the periodontium). The others tissues that support the tooth are the alveolar bone, the periodontal ligament and the gingivae. Cementum is the least understood one of these four tissues.

Cementum is pale yellow with a dull surface and is softer than dentine. The permeability of cementum varies with age and the type of cementum, with the cellular variety being more permeable. In general, cementum is more permeable than dentine. The relative softness of cementum, combined with its thinness, means that it is readily removed by abrasion when the root surface is exposed to the oral environment.

Very little is known about the origin and cell dynamics of the cementum-forming cells (cementoblasts). Although restricted to the root in humans, cementum is present on the crowns of some mammals. Cementum varies in thickness at different levels of the root but is thickest at the root apex.

Cementum is adjacent with the periodontal ligament on its outer surface and is firmly fixed to dentine on its deep surface. Its primary function is to give attachment to collagen fibres of the periodontal ligament. It therefore is a highly responsive tissue, maintaining the integrity of the root, helping to maintain the tooth in its functional position in the mouth, and being involved in tooth repair and regeneration.

Cementum is slowly formed throughout life and this allows for continual reattachment of the periodontal ligament fibres. Cementum is similar in chemical composition and physical properties to bone, however cementum is avascular (not associated with or supplied by blood vessels) and is also less readily resorbed.

Cementum is volumetrically composed of 45% of inorganic material, approximately 33% of organic material and 22% water. The principal inorganic components are hydroxyapatites, which are thin and plate-like crystals similar to those in bone. They are on average 55 nm wide and 8 nm thick. The organic matrix is primarily composed of collagen. There are three main types of cementum. These are:

Acellular cementum

This is the cementum without cellular components that covers one-third to one-half of the tooth root adjacent to the cemento-enamel junction (the area where cementum and enamel meet).

Afibrillar cementum

This is a layer of cementum that sometimes extends onto the enamel of a tooth at the cemento-enamel junction.

Cellular cementum

This is the cementum covering the apical one-half to two-thirds of the tooth root.

A lack of cementum can lead to tooth loss as the tooth is held less firmly in place.

 

Deciduous teeth

A six year old girl’s deciduous teeth, which are beginning to fall out.

Deciduous teeth, otherwise known as milk teeth, baby teeth, temporary teeth, primary teeth are the first set of teeth in the growth development of humans and many other mammals. They develop during the embryonic stage of development and erupt — that is, they become visible in the mouth — during infancy. They are usually lost and replaced by permanent teeth, but in the absence of permanent replacements, they can remain functional for many years.

Deciduous teeth start to form during the embryo phase of pregnancy. The development of deciduous teeth starts at the sixth week of development as the dental lamina. This process starts at the midline and then spreads back into the posterior region. By the time the embryo is eight weeks old, there are ten areas on the upper and lower arches that will eventually become the deciduous dentition. These teeth will continue to form until they erupt in the mouth. In the deciduous dentition there are a total of twenty teeth: five per quadrant and ten per arch. The eruption of these teeth begins at the age of six months and continues until twenty-five to thirty-three months of age. The first teeth seen in the mouth are the mandibular centrals and the last are the maxillary second molars.

The deciduous dentition is made up of central incisors, lateral incisors, canines, first molars, and secondary molars; there is one in each quadrant, making a total of four of each tooth. All of these are replaced with a permanent counterpart except for the first and second molars; they are replaced by premolars. The deciduous teeth will remain until the age of six. At that time, the permanent teeth start to appear in the mouth resulting in mixed dentition. The erupting permanent teeth causes root resorption, where the permanent teeth push down on the roots of the deciduous teeth causing the roots to be dissolved and become absorbed by the forming permanent teeth. The process of shedding deciduous teeth and the replacement by permanent teeth is called exfoliation. This may last from age six to age twelve. By age twelve there usually are only permanent teeth remaining.

Teething age of deciduous teeth:

·                     Central incisors : 6-12 months

·                     Lateral incisors : 9-16 months

·                     Canines : 16-23 months

·                     First molars : 13-19 months

·                     Second molars : 22-33 months

Various cultures have customs relating to the loss of deciduous teeth; see tooth fairy.

An eight-year old’s deciduous teeth.

Deciduous teeth are considered essential in the development of the oral cavity by dental researchers and dentists. The permanent teeth replacements develop from the same tooth bud as the deciduous teeth; this provides a guide for permanent teeth eruption. Also the muscles of the jaw and the formation of the jaw bones depend on the primary teeth in order to maintain the proper space for permanent teeth. The roots of deciduous teeth provide an opening for the permanent teeth to erupt. These teeth are also needed for proper development of a child’s speaking and chewing of food.

Dental anatomy

Dental anatomy or anatomy of teeth is a field of anatomy dedicated to the study human teeth structures. The development, appearance, and classification of teeth fall within its purvue, though the function of teeth as they contact one another is referred to as dental occlusion. Tooth formation begins prior to birth and their eventual morphology is dictated during this time. Dental anatomy is also a taxonomical science; it is concerned with the naming of teeth and the structures of which they are made. This information serves a practical purpose when rendering dental treatment.

Maxilla

The maxillary central incisor is a human tooth in the front upper jaw, or maxilla, and is usually the most visible of all teeth in the mouth. It is located mesial (closer to the midline of the face) to the maxillary lateral incisor. As with all incisors, their function is for shearing or cutting food during mastication (chewing). There are no cusps on the teeth. Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge. Formation of these teeth begin at 14 weeks in utero for the deciduous (baby) set and 3–4 months of age for the permanent set.

There are some minor differences between the deciduous maxillary central incisor and that of the permanent maxillary central incisor. The deciduous tooth appears in the mouth at 10 months of age and is replaced by the permanent tooth around 7–8 years of age. The permanent tooth is larger and is longer than it is wide. The maxillary central incisors contact each other at the midline of the face. The mandibular central incisors are the only other type of teeth to do so. The position of these teeth may determine the existence of an open bite or diastema. As with all teeth, variations of size, shape, and color exist among people. Systemic disease, such as syphilis, may affect the appearance of teeth.

Maxillary lateral incisor

The maxillary lateral incisor is the tooth located distally (away from the midline of the face) from both maxillary central incisors of the mouth and mesially (toward the midline of the face) from both maxillary canines. As with all incisors, their function is for shearing or cutting food during mastication, commonly known as chewing. There are no cusps on the teeth. Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge. Though relatively the same, there are some minor differences between the deciduous (baby) maxillary lateral incisor and that of the permanent maxillary lateral incisor.

In the universal system of notation, the deciduous maxillary lateral incisors are designated by a letter written in uppercase. The right deciduous maxillary lateral incisor is known as “D”, and the left one is known as “G”. The international notation has a different system of notation. Thus, the right deciduous maxillary lateral incisor known as “52”, and the left one is known as “62”.

In the universal system of notation, the permanent maxillary lateral incisors are designated by a number. The right permanent maxillary lateral incisor is known as “7”, and the left one is known as “10”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right lateral incisors would have the same number, “2”, but the right one would have the symbol, “┘”, underneath it, while the left one would have, “└”. The international notation has a different numbering system than the previous two, and the right permanent maxillary lateral incisor is known as “12”, and the left one is known as “22”.

Maxillary canine

The maxillary canine is the tooth located laterally (away from the midline of the face) from both maxillary lateral incisors of the mouth but mesial (toward the midline of the face) from both maxillary first premolars. Both the maxillary and mandibular canines are called the “cornerstone” of the mouth because they are all located three teeth away from the midline, and separate the premolars from the incisors. The location of the canines reflect their dual function as they complement both the premolars and incisors during mastication, commonly known as chewing. Nonetheless, the most common action of the canines is tearing of food. There is a single cusp on canines, and they resemble the prehensile teeth found in carnivorous animals. Though relatively the same, there are some minor differences between the deciduous (baby) maxillary canine and that of the permanent maxillary canine.

It is the longest tooth in total length (From root to the incisal edge) in the mouth.

In the universal system of notation, the deciduous maxillary canines are designated by a letter written in uppercase. The right deciduous maxillary canine is known as “C”, and the left one is known as “H”. The international notation has a different system of notation. Thus, the right deciduous maxillary canine is known as “53”, and the left one is known as “63”.

In the universal system of notation, the permanent maxillary canines are designated by a number. The right permanent maxillary canine is known as “6”, and the left one is known as “11”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right canines would have the same number, “3”, but the right one would have the symbol, “┘”, underneath it, while the left one would have, “└”. The international notation has a different numbering system than the previous two, and the right permanent maxillary canine is known as “13”, and the left one is known as “23”.

Maxillary first premolar

The maxillary first premolar is the tooth located laterally (away from the midline of the face) from both the maxillary canines of the mouth but mesial (toward the midline of the face) from both maxillary second premolars. The function of this premolar is similar to that of canines in regard to tearing being the principal action during mastication, commonly known as chewing. There are two cusps on maxillary first premolars, and the buccal (closest to the cheek) cusp is sharp enough to resemble the prehensile teeth found in carnivorous animals. There are no deciduous (baby) maxillary premolars. Instead, the teeth that precede the permanent maxillary premolars are the deciduous maxillary molars.

In the universal system of notation, the permanent maxillary premolars are designated by a number. The right permanent maxillary first premolar is known as “5”, and the left one is known as “12”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right first premolars would have the same number, “4”, but the right one would have the symbol, “┘”, underneath it, while the left one would have, “└”. The international notation has a different numbering system than the previous two, and the right permanent maxillary first premolar is known as “14”, and the left one is known as “24”.

Maxillary second premolar

From Wikipedia, The maxillary second premolar is the tooth located laterally (away from the midline of the face) from both the maxillary first premolars of the mouth but mesial (toward the midline of the face) from both maxillary first molars. The function of this premolar is similar to that of first molars in regard to grinding being the principle action during mastication, commonly known as chewing. There are two cusps on maxillary second premolars, but both of them are less sharp then those of the maxillary first premolars. There are no deciduous (baby) maxillary premolars. Instead, the teeth that precede the permanent maxillary premolars are the deciduous maxillary molars.

In the universal system of notation, the permanent maxillary premolars are designated by a number. The right permanent maxillary second premolar is known as “4”, and the left one is known as “13”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right second premolars would have the same number, “5”, but the right one would have the symbol, “┘”, underneath it, while the left one would have, “└”. The international notation has a different numbering system than the previous two, and the right permanent maxillary second premolar is known as “15”, and the left one is known as “25”.

Maxillary first molar

The maxillary first molar is the tooth located laterally (away from the midline of the face) from both the maxillary second premolars of the mouth but mesial (toward the midline of the face) from both maxillary second molars. The function of this molar is similar to that of all molars in regard to grinding being the principle action during mastication, commonly known as chewing. There are usually four cusps on maxillary molars, two on the buccal (side nearest the cheek) and two palatal (side nearest the palate). There may also a fifth smaller cusp on the palatal side known as the Cusp of Carabelli. There are great differences between the deciduous (baby) maxillary molars and those of the permanent maxillary molars, even though their function are similar. It is important to note that the permanent maxillary molars are not considered to have any teeth that precede it. Despite being named molars, the deciduous molars are followed by permanent premolars.

In the universal system of notation, the deciduous maxillary first molars are designated by a letter written in uppercase. The right deciduous maxillary first molar is known as “B”, and the left one is known as “I”. The international notation has a different system of notation. Thus, the right deciduous maxillary first molar is known as “54”, and the left one is known as “64”.

In the universal system of notation, the permanent maxillary first molars are designated by a number. The right permanent maxillary first molar is known as “3”, and the left one is known as “14”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right first molars would have the same number, “6”, but the right one would have the symbol, “┘”, underneath it, while the left one would have, “└”. The international notation has a different numbering system than the previous two, and the right permanent maxillary first molar is known as “16”, and the left one is known as “26”.

 Maxillary second molar

The maxillary second molar is the tooth located laterally (away from the midline of the face) from both the maxillary first molars of the mouth but mesial (toward the midline of the face) from both maxillary third molars. This is true only in permanent teeth. In deciduous (baby) teeth, the maxillary second molar is the last tooth in the mouth and does not have a third molar behind it. The function of this molar is similar to that of all molars in regard to grinding being the principle action during mastication, commonly known as chewing. There are usually four cusps on maxillary molars, two on the buccal (side nearest the cheek) and two palatal (side nearest the palate). There are great differences between the deciduous (baby) maxillary molars and those of the permanent maxillary molars, even though their function are similar. It is important to note that the permanent maxillary molars are not considered to have any teeth that precede it. Despite being named molars, the deciduous molars are followed by permanent premolars.

In the universal system of notation, the deciduous maxillary second molars are designated by a letter written in uppercase. The right deciduous maxillary second molar is known as “A”, and the left one is known as “J”. The international notation has a different system of notation. Thus, the right deciduous maxillary second molar is known as “55”, and the left one is known as “65”.

In the universal system of notation, the permanent maxillary second molars are designated by a number. The right permanent maxillary second molar is known as “2”, and the left one is known as “15”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right second molars would have the same number, “7”, but the right one would have the symbol, “┘”, underneath it, while the left one would have, “└”. The international notation has a different numbering system than the previous two, and the right permanent maxillary second molar is known as “17”, and the left one is known as “27”.

Maxillary third molar

The maxillary third molar is the tooth located laterally (away from the midline of the face) from both the maxillary second molars of the mouth with no tooth posterior to it in permanent teeth. In deciduous (baby) teeth, there is no maxillary third molar. The function of this molar is similar to that of all molars in regard to grinding being the principle action during mastication, commonly known as chewing. There are usually four cusps on maxillary molars, two on the buccal (side nearest the cheek) and two palatal (side nearest the palate). Nonetheless, for this tooth, there are great variances among third molars, and a specific description of a third molar will not hold true in all cases. It is important to note that the permanent maxillary molars are not considered to have any teeth that precede it. Despite being named molars, the deciduous molars are followed by permanent premolars.

In the universal system of notation, the permanent maxillary third molars are designated by a number. The right permanent maxillary third molar is known as “1”, and the left one is known as “16”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right third molars would have the same number, “8”, but the right one would have the symbol, “┘”, underneath it, while the left one would have, “└”. The international notation has a different numbering system than the previous two, and the right permanent maxillary third molar is known as “18”, and the left one is known as “28”.

Mandibular

Mandibular central incisor

The mandibular central incisor is the tooth located on the jaw, adjacent to the midline of the face. It is mesial (toward the midline of the face) from both mandibular lateral incisors. As with all incisors, its function includes shearing or cutting food during mastication, commonly known as chewing. There are no cusps on the tooth. Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge. Though the two are similar, there are some minor differences between the deciduous (baby) mandibular central incisor and that of the permanent mandibular central incisor.

Mandibular lateral incisor

The mandibular lateral incisor is the tooth located distally (away from the midline of the face) from both mandibular central incisors of the mouth and mesially (toward the midline of the face) from both manibular canines. As with all incisors, their function is for shearing or cutting food during mastication, commonly known as chewing. There are no cusps on the teeth. Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge. Though relatively the same, there are some minor differences between the deciduous (baby) mandibular lateral incisor and that of the permanent mandibular lateral incisor.

In the universal system of notation, the deciduous mandibular lateral incisors are designated by a letter written in uppercase. The right deciduous mandibular lateral incisor is known as “Q”, and the left one is known as “N”. The international notation has a different system of notation. Thus, the right deciduous mandibular lateral incisor known as “82”, and the left one is known as “72”.

In the universal system of notation, the permanent mandibular lateral incisors are designated by a number. The right permanent mandibular lateral incisor is known as “26”, and the left one is known as “23”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right lateral incisors would have the same number, “2”, but the right one would have the symbol, “┐”, over it, while the left one would have, “┌”. The international notation has a different numbering system than the previous two, and the right permanent mandibular lateral incisor is known as “42”, and the left one is known as “32”.

Mandibular canine

The mandibular canine is the tooth located distally (away from the midline of the face) from both mandibular lateral incisors of the mouth but mesially (toward the midline of the face) from both mandibular first premolars. Both the maxillary and mandibular canines are called the “cornerstone” of the mouth because they are all located three teeth away from the midline, and separate the premolars from the incisors. The location of the canines reflect their dual function as they complement both the premolars and incisors during mastication, commonly known as chewing. Nonetheless, the most common action of the canines is tearing of food. There is a single cusp on canines, and they resemble the prehensile teeth found in carnivorous animals. Though relatively the same, there are some minor differences between the deciduous (baby) mandibular canine and that of the permanent mandibular canine.

In the universal system of notation, the deciduous mandibular canines are designated by a letter written in uppercase. The right deciduous mandibular canine is known as “R”, and the left one is known as “M”. The international notation has a different system of notation. Thus, the right deciduous mandibular canine is known as “83”, and the left one is known as “73”.

In the universal system of notation, the permanent mandibular canines are designated by a number. The right permanent mandibular canine known as “27”, and the left one is known as “22”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right canines would have the same number, “3”, but the right one would have the symbol, “┐”, over it, while the left one would have, “┌”. The international notation has a different numbering system than the previous two, and the right permanent mandibular canine is known as “43”, and the left one is known as “33”.

Mandibular first premolar

The mandibular first premolar is the tooth located laterally (away from the midline of the face) from both the mandibular canines of the mouth but mesial (toward the midline of the face) from both mandibular second premolars. The function of this premolar is similar to that of canines in regard to tearing being the principal action during mastication, commonly known as chewing. Mandibular first premolars have two cusps. The one large and sharp is located on the buccal side (closest to the cheek) of the tooth. Since the lingual cusp (located nearer the tongue) is small and nonfunctional (which refers to a cusp not active in chewing), the mandibular first premolar resembles a small canine. There are no deciduous (baby) mandibular premolars. Instead, the teeth that precede the permanent mandibular premolars are the deciduous mandibular molars.

Sometimes, premolars are referred to as bicuspids. Even though the terms are synonymous, “bicuspid” refers to having two functional cusps, and the mandibular first premolar is an example of a premolar with only one functional cusp. Thus, “biscupid” is technically not as accurate as “premolar”.

In the universal system of notation, the permanent mandibular premolars are designated by a number. The right permanent mandibular first premolar is known as “28”, and the left one is known as “21”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right first premolars would have the same number, “4”, but the right one would have the symbol, “┐”, over it, while the left one would have, “┌”. The international notation has a different numbering system than the previous two, and the right permanent mandibular first premolar is known as “44”, and the left one is known as “34”.

Mandibular second premolar

The mandibular second premolar is the tooth located distally (away from the midline of the face) from both the mandibular first premolars of the mouth but mesial (toward the midline of the face) from both mandibular first molars. The function of this premolar is assist the mandibular first molar during mastication, commonly known as chewing. Mandibular second premolars have three cusps. There is one large cusp on the buccal side (closest to the cheek) of the tooth. The lingual cusps (located nearer the tongue) are well developed and functional (which refers to cusps assisting during chewing). Therefore, whereas the mandibular first premolar resembles a small canine, the mandibular second premolar is more alike to the first molar. There are no deciduous (baby) mandibular premolars. Instead, the teeth that precede the permanent mandibular premolars are the deciduous mandibular molars.

Sometimes, premolars are referred to as bicuspids. Even though the terms are synonymous, “bicuspid” refers to having two functional cusps, and the mandibular second premolar is an example of a premolar with three functional cusps. Thus, “biscupid” is technically not as accurate as “premolar”.

In the universal system of notation, the permanent mandibular premolars are designated by a number. The right permanent mandibular second premolar is known as “29”, and the left one is known as “20”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right second premolars would have the same number, “5”, but the right one would have the symbol, “┐”, over it, while the left one would have, “┌”. The international notation has a different numbering system than the previous two, and the right permanent mandibular second premolar is known as “45”, and the left one is known as “35”.

It is a very common condition in orthodontics for a patient to have one or both mandibular second premolars congenitally absent.

Mandibular first molar

The mandibular first molar (also known as 6 yr molar) is the tooth located distally (away from the midline of the face) from both the mandibular second premolars of the mouth but mesial (toward the midline of the face) from both mandibular second molars. It is located on the mandibular (lower) arch of the mouth, and generally opposes the maxillary (upper) first molars and the maxillary 2nd premolar iormal class I occlusion. The function of this molar is similar to that of all molars in regard to grinding being the principal action during mastication, commonly known as chewing. There are usually five well-developed cusps on mandibular first molars: two on the buccal (side nearest the cheek), two palatal (side nearest the palate), and one distal. There are great differences between the deciduous (baby) mandibular molars and those of the permanent mandibular molars, even though their function are similar. It is important to note that the permanent mandibular molars are not considered to have any teeth that precede it. Despite being named molars, the deciduous molars are followed by permanent premolars.

In the universal system of notation, the deciduous mandibular first molars are designated by a letter written in uppercase. The right deciduous mandibular first molar is known as “S”, and the left one is known as “L”. The international notation has a different system of notation. Thus, the right deciduous mandibular first molar is known as “84”, and the left one is known as “74”.

In the universal system of notation, the permanent mandibular first molars are designated by a number. The right permanent mandibular first molar is known as “30”, and the left one is known as “19”. The Palmer notation uses a number in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right first molars would have the same number, “6”, but the right one would have the symbol, “┐”, over it, while the left one would have, “┌”. The international notation has a different numbering system than the previous two, and the right permanent mandibular first molar is known as “46”, and the left one is known as “36”.

Mandibular second molar

The mandibular second molar is the tooth located distally (away from the midline of the face) from both the mandibular first molars of the mouth but mesial (toward the midline of the face) from both mandibular third molars. This is true only in permanent teeth. In deciduous (baby) teeth, the mandibular second molar is the last tooth in the mouth and does not have a third molar behind it. The function of this molar is similar to that of all molars in regard to grinding being the principle action during mastication, commonly known as chewing. Though there is more variation between individuals to that of the first mandibular molar, there are usually four cusps on mandibular second molars: two on the buccal (side nearest the cheek) and two palatal (side nearest the palate). There are great differences between the deciduous (baby) mandibular molars and those of the permanent mandibular molars, even though their function are similar. It is important to note that the permanent mandibular molars are not considered to have any teeth that precede it. Despite being named molars, the deciduous molars are followed by permanent premolars.

In the universal system of notation, the deciduous mandibular second molars are designated by a letter written in uppercase. The right deciduous mandibular second molar is known as “T”, and the left one is known as “K”. The international notation has a different system of notation. Thus, the right deciduous mandibular second molar is known as “85”, and the left one is known as “75”.

In the universal system of notation, the permanent mandibular second molars are designated by a number. The right permanent mandibular second molar is known as “31”, and the left one is known as “18”. In the Palmer notation, a number is used in conjunction with a symbol deknown as “47”, and the left one is known as “37”.and Stanley J. Nelson, 2003. Wheeler’s Dental Anatomy, Physiology, and Occlusion. 8th edition.

Retrieved from “http://en.wikipedia.org/wiki/Mandibular_second_molar“

Mandibular third molar

The mandibular third molar, commonly known as a wisdom tooth, is the tooth located distally (away from the midline of the face) from both the mandibular second molars of the mouth with no tooth posterior to it in permanent teeth. In deciduous (baby) teeth, there is no mandibular third molar. The function of this molar is similar to that of all molars in regard to grinding being the principle action during mastication, commonly known as chewing. For this tooth, there are great variances among third molars, and a specific description of a third molar will not hold true in all cases. It is important to note that the permanent mandibular molars are not considered to have any teeth that precede it. Despite being named molars, the deciduous molars are followed by permanent premolars.

In the universal system of notation, the permanent mandibular third molars are designated by a number. The right permanent mandibular third molar is known as “32”, and the left one is known as “17”. In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right third molars would have the same number, “8”, but the right one would have the symbol, “┐”, over it, while the left one would have, “┌”. The international notation has a different numbering system than the previous two, and the right permanent mandibular third molar is known as “48”, and the left one is known as “38”.

Early childhood caries

Early childhood caries, also known as baby bottle caries and baby bottle tooth decay, is a syndrome characterized by severe decay in the teeth of infants or young children. Early childhood caries (ECC) is a very common bacteria infection. Its prevalence is epidemic; in the US its rate is highest in minority and rural populations, at times infecting over 70% of the children. A large body of scientific evidence indicates that ECC is an infectious and transmissible disease, with Streptococcus mutans the primary microbiological agent in the disease. The disease process begins with the transmission of the bacteria to the child, usually from the primary caretaker, the mother. Mothers with untreated dental disease present a very high risk to their children.

Causes of early childhood caries

The American Academy of Pediatric Dentistry says that frequent consumption of liquids containing fermentable carbohydrates (e.g., juice, milk, formula, soda) increases the risk of dental caries due to prolonged contact between sugars in the liquid and cariogenic bacteria on the teeth. Poor feeding practices without appropriate preventive measures can lead to a distinctive pattern of caries in susceptible infants and toddlers commonly known as baby bottle tooth decay (BBTD), a form of severe early childhood caries (ECC). Frequent bottle feeding at night, breast-feeding on demand at night, and extended and repetitive use of a no-spill training cup are associated with ECC. Children experiencing caries as infants or toddlers have a much greater probability of subsequent caries in primary and permanent teeth.

According to the American Dental Association, “As soon as a baby’s first teeth appear—usually by age six months or so—the child is susceptible to decay. This condition is often referred to as Baby Bottle Tooth Decay or Early Childhood Caries (cavities). In some unfortunate cases, infants and toddlers have experienced severe tooth decay that has resulted in dental restorations or extractions. The good news is that decay is preventable.

“Decay occurs when sweetened liquids are given and are left clinging to an infant’s teeth for long periods. Many sweet liquids cause problems, including milk, formula and fruit juice. Bacteria in the mouth use these sugars as food. They then produce acids that attack the teeth. Each time your child drinks these liquids, acids attack for 20 minutes or longer. After many attacks, the teeth can decay.”

The ADA adds, “It’s not just what you put in your child’s bottle that causes decay, but how often — and for how long a time. Giving your child a bottle of sweetened liquid many times a day isn’t a good idea. Allowing your child to fall asleep with a bottle during naps or at night can also harm the child’s teeth.”

The primary culprit for ECC is a group of bacteria called streptococcus mutans. The American Academy of Pediatric Dentistry, in their Clinical Guideline for Infant Oral Healthcare, advises that “Caries results from an overgrowth of specific organisms that are part of normally occurring human oral flora. Streptococcus mutans and Lactobacillus species are considered to be principal indicator organisms of those bacteria responsible for caries. Human oral flora is site specific, and an infant is not colonized with normal oral flora until the eruption of the primary dentition at approximately 6 to 30 months of age. The vertical colonization of S. mutans from mother to infant is well documented.”

Research on preventing or delaying maternal transmission of these bacteria to children suggest that a comprehensive program of counseling, oral hygiene instruction, fluoride treatments, and restorative care are effective. Xylitol products also are promising.

 

Pathophysiology

The progression of pit and fissure caries resembles two triangles with their bases meeting along the junction of enamel and dentin.

Enamel

Enamel is a highly mineralized acellular tissue, and caries act upon it through a chemical process brought on by the acidic environment produced by bacteria. As the bacteria consume the sugar and use it for their own energy, they produce lactic acid. The effects of this process include the demineralization of crystals in the enamel, caused by acids, over time until the bacteria physically penetrate the dentin. Enamel rods, which are the basic unit of the enamel structure, run perpendicularly from the surface of the tooth to the dentin. Since demineralization of enamel by caries generally follows the direction of the enamel rods, the different triangular patterns between pit and fissure and smooth-surface caries develop in the enamel because the orientation of enamel rods are different in the two areas of the tooth .^[58]

As the enamel loses minerals , and dental caries progress, they develop several distinct zones, visible under a light microscope. From the deepest layer of the enamel to the enamel surface, the identified areas are the: translucent zone, dark zones, body of the lesion, and surface zone.^[59] The translucent zone is the first visible sign of caries and coincides with a 1-2% loss of minerals.^[60] A slight remineralization of enamel occurs in the dark zone, which serves as an example of how the development of dental caries is an active process with alternating changes.^[61] The area of greatest demineralization and destruction is in the body of the lesion itself. The surface zone remains relatively mineralized and is present until the loss of tooth structure results in a cavitation.

Dentin

Unlike enamel, the dentin reacts to the progression of dental caries. After tooth formation, the ameloblasts, which produce enamel, are destroyed once enamel formation is complete and thus cannot later regenerate enamel after its destruction. On the other hand, dentin is produced continuously throughout life by odontoblasts, which reside at the border between the pulp and dentin. Since odontoblasts are present, a stimulus, such as caries, can trigger a biologic response. These defense mechanisms include the formation of sclerotic and tertiary dentin.^[62]

In dentin from the deepest layer to the enamel, the distinct areas affected by caries are the translucent zone, the zone of bacterial penetration, and the zone of destruction.^[58] The translucent zone represents the advancing front of the carious process and is where the initial demineralization begins. The zones of bacterial penetration and destruction are the locations of invading bacteria and ultimately the decomposition of dentin.

The faster spread of caries through dentin creates this triangular appearance in smooth surface caries.

Sclerotic dentin

The structure of dentin is an arrangement of microscopic channels, called dentinal tubules, which radiate outward from the pulp chamber to the exterior cementum or enamel border.^[63] The diameter of the dentinal tubules is largest near the pulp (about 2.5 μm) and smallest (about 900 nm) at the junction of dentin and enamel.^[64] The carious process continues through the dentinal tubules, which are responsible for the triangular patterns resulting from the progression of caries deep into the tooth. The tubules also allow caries to progress faster.

In response, the fluid inside the tubules bring immunoglobulins from the immune system to fight the bacterial infection. At the same time, there is an increase of mineralization of the surrounding tubules.^[65] This results in a constriction of the tubules, which is an attempt to slow the bacterial progression. In addition, as the acid from the bacteria demineralizes the hydroxyapatite crystals, calcium and phosphorus are released, allowing for the precipitation of more crystals which fall deeper into the dentinal tubule. These crystals form a barrier and slow the advancement of caries. After these protective responses, the dentin is considered sclerotic.

Fluids within dentinal tubules are believed to be the mechanism by which pain receptors are triggered within the pulp of the tooth. Since sclerotic dentin prevents the passage of such fluids, pain that would otherwise serve as a warning of the invading bacteria may not develop at first. Consequently, dental caries may progress for a long period of time without any sensitivity of the tooth, allowing for greater loss of tooth structure.

Tertiary dentin

In response to dental caries, there may the production of more dentin toward the direction of the pulp. This new dentin is referred to as tertiary dentin.^[ Tertiary dentin is produced to protect the pulp for as long as possible from the advancing bacteria. As more tertiary dentin is produced, the size of the pulp decreases. This type of dentin has been subdivided according to the presence or absence of the original odontoblasts. If the odontoblasts survive long enough to react to the dental caries, then the dentin produced is called “reactionary” dentin. If the odontoblasts are killed, the dentin produced is called “reparative” dentin.

In the case of reparative dentin, other cells are needed to assume the role of the destroyed odontoblasts. Growth factors, especially TGF-β,are thought to initiate the production of reparative dentin by fibroblasts and mesenchymal cells of the pulp. Reparative dentin is produced at an average of 1.5 μm/day, but can be increased to 3.5 μm/day. The resulting dentin contains irregularly-shaped dentinal tubules which may not line up with existing dentinal tubules. This dimishes the ability for dental caries to progress within the dentinal tubules.

Signs and symptoms

 

Dental explorer used for caries diagnosis.

Until caries progresses, a person may not be aware of it. The earliest sign of a new carious lesion, referred as incipient decay, is the appearance of a chalky white spot on the surface of the tooth, indicating an area of demineralization of enamel. As the lesion continues to demineralize, it can turn brown but will eventually turn into a cavitation, a “cavity”. The process before this point is reversible, but once a cavitation forms, the lost tooth structure cannot be regenerated. A lesion which appears brown and shiny suggests dental caries was once present but the demineralization process has stopped, leaving a stain. A brown spot which is dull in appearance is probably a sign of active caries.

As the enamel and dentin are destroyed further, the cavitation becomes more noticeable. The affected areas of the tooth change color and become soft to the touch. Once the decay passes through enamel, the dentinal tubules, which have passages to the nerve of the tooth, become exposed and cause the tooth to hurt. The pain can be worsened by heat, cold, or sweet foods and drinks. Dental caries can also cause bad breath and foul tastes. In highly progressed cases, infection can spread from the tooth to the surrounding soft tissues which may become life-threatening, as in the case with Ludwig’s angina.

 

Diagnosis

This preoperative photo of tooth #3, (A), reveals no clinically apparent decay other than a small spot within the central fossa. In fact, decay could not be detected with an explorer. Radiographic evaluation, (B), however, reveals an extensive region of demineralization within the dentin (arrows) of the mesial half of the tooth. When a burr was used to remove the occlusal enamel overlying the decay, (C), a large hollow was found within the crown and it was discovered that a hole in the side of the tooth large enough to allow the tip of the explorer to pass was contiguous with this hollow. After all of the decay had been removed, (D), the pulp chamber had been exposed and most of the mesial half of the crown was either missing or poorly supported.

Primary diagnosis involves inspection of all visible tooth surfaces using a good light source, dental mirror and explorer. Dental radiographs, produced when X-rays are passed through the jaw and picked up on film or digital sensor, may show dental caries before it is otherwise visible, particularly in the case of caries on interproximal (between the teeth) surfaces. Large dental caries are often apparent to the naked eye, but smaller lesions can be difficult to identify. Unextensive dental caries was formerly found by searching for soft areas of tooth structure with a dental explorer. Visual and tactile inspection along with radiographs are still employed frequently among dentists, particularly for pit and fissure caries.

Some dental researchers have cautioned against the use of dental explorers to find caries. In cases where a small area of tooth has begun demineralizing but has not yet cavitated, the pressure from the dental explorer could cause a cavitation. Since the carious process is reversible before a cavitation is present, it may be possible to arrest the caries with fluoride to remineralize the tooth surface. When a cavitation is present, a restoration will be needed to replace the lost tooth structure. A common technique used for the diagnosis of early (uncavitated) caries is the use of air blown across the suspect surface, which removes moisture, changing the optical properties of the unmineralized enamel. This produces a white ‘halo’ effect detectable to the naked eye. Fiberoptic transillumination, lasers and disclosing dyes have been recommended for use as an adjunct when diagnosing smaller carious lesions in pits and fissures of teeth.

Prevention

For most people, caries is preventable. Removal of plaque at least q 24 h, usually by brushing and flossing, helps prevent dental caries. The gingival third of the tooth is the most important area to clean but is the area most ofteeglected. Electric and electronic toothbrushes are excellent, but a manual soft toothbrush, used for an average of 3 to 4 min, suffices. Using excess toothpaste, particularly an abrasive type, may erode the teeth. Dental floss is placed between each of the teeth, curved against the side of each tooth, and moved up and down 3 times, going just beneath the gingival margin. Flosses that are very thin (dental tape) or coated with wax or polytetraethylene can be used for exceptionally tight contacts between teeth or rough filling margins.

Teeth with fluoride incorporated into their enamel are more resistant to acidic decalcification and more readily recalcify when pH increases. If drinking water is not adequately fluoridated, fluoride supplements are recommended for children from shortly after birth through age 8 yr and for pregnant women beginning at 3 mo gestation (when teeth are forming in the fetus). The dose must be selected according to the amount of fluoride present in the drinking water and the age of the child. The total dose should not be so high as to cause dental fluorosis. Fluoridated toothpaste should also be used by people of all ages.

Fluoridation offers less protection against caries in pits and fissures compared with those on smooth surfaces. Pits and fissures require use of sealants (plastic materials that adhere tightly to the surface of the enamel) to prevent nutrients from reaching bacteria, reducing their growth and acid production.

Cavities first form on permanent teeth in the early teens to late 20s. A caries-prone subset typically has a low fluoride exposure and a relatively cariogenic microflora acquired from the mother. Maintaining good oral hygiene and minimizing sugar intake are especially needed.

If these measures do not decrease cavity formation, more intensive therapy aims at changing the flora. After cavities are treated, pits and fissures, which can harbor M. streptococci are sealed. This treatment is followed by 60-sec mouth rinses using 0.12% chlorhexidine bid for 2 wk, which may reduce the cariogenic bacteria in plaque and allow repopulation with less cariogenic strains of M. streptococci. To encourage repopulation, xylitol in the form of hard candy or chewing gum is used for 5 min tid. Additionally, topical fluoride may be applied by a dentist or used at night in a custom-made fluoride carrier.

For pregnant women with a history of severe caries, the above regimen may be used before the child’s teeth erupt. If this is not feasible, the mother can use xylitol, as mentioned above, from the time of the baby’s birth to the age at which the mother no longer samples the child’s food (the hypothesized mode of transfer).

For prevention of caries in deciduous teeth (once they have erupted) in infants, bedtime bottles should contain only water.

PROPHYLAXIS OF CARIES OF TEETH

Without medical prophylaxis of caries of teeth

Rational feed.

The process of forming and mіneralіzation of teeth begins in the embryo period of life of child and proceeds after its birth that is why for forming of teeth resistance to the caries there is important the high-quality feed of expectant mother and child.

The necessity of pregnant makes: to the 1,5 g calcium, 2,5 g phosphorus, 3 mg fluorine, 2,5 mg vitamin of B 5000—10000 МО of vitamin D, on days. The necessity of consumption of these matters especially grows during the second half of pregnancy. In this period and in a period feeding of child a woman must use milk products — curd (no less as 200 g on a day), kefir, sour milk thick. Oligoelementss are contained in a beet, cabbage, nuts, oarweed, meat of rabbit, saltwater fish.

During all pregnancy the organism of woman needs the doubled amount of vitamins. The vitamin of C is especially important, vitamins of group B, A, D, E. Vitamin D takes part in formation of bone skeleton, regulating acalcium and phosphoric exchange, activity of ductless glands. At insufficiency of him a mineral exchange is violated in an organism, the amount of calcium and phosphorus diminishes in bone fabric, teeth cut throughlately, put must propensity to the caries. Day’s necessity of pregnant in the vitamin D is 500,0 МО. Vitamin A assists to correct development of bone fabric, provides normal activity of organ of sight, promotes firmness in relation to the diseases of mucus shells. Day’s dose of vitamin A — 2 mg.

For the children of 1st life milk of mother is an ideal product. It contains in optimum amounts and correlations biologically valuable albumens, fats, carbonhydratess, vitamins, mineral matters,    hormones,    immune   bodies,    enzymes    antimicrobial    and

bifidogenous factors.

A necessity in salts of calcium grows as far as growth and development of organism of child, vitamins, albumens, fluorine, which can be satisfied by the increase in the ration of milk products, green-stuffs, fruit.

 Strengthening of somatic health.

It is assumed that under act of commons diseases the terms of forming and ripening of hard fabrics of tooth change in the first turn of enamel which does them less proof in relation to influencing of cariogenic factors.

At the children of different age, burdened by the carried or concomitant diseases of internalss caries of teeth develops especially often. Thus a process is characterized by sharp motion. Practically the defeats of any organs and systems of child’s organism are extrapolated on hard fabrics of teeth. That is why it is needed with the purpose of prophylaxis of dental diseases, on possibility, to treat be – what somatic pathology.

Intensive mastication.

The large value in a prophylaxis has active   mastication,   valuable   loading on   a maxillufacial area.   It is expedient  to promote  physiology  activity  of organs  and fabrics of cavity of mouth, especially at children, by multiplying a number and varieties of natural irritants, which at the permanent use of the treated meal becomes all less. The amount of children which are characterized by untrained of masseters through protracted their underloading under act of the developed “lazinesses of mastication”. As a result putting such is renounced hard meal, is chewed languidly and slowly. Such children cost to recommend the use of products without previous culinary treatment (raw green-stuffs, fruit).

Medical prophylaxis

A medicinal prophylaxis is divided into general (endogenous) and local (exogenous). The endogenous in the turn is specific and heterospecific. At a specific prophylaxis preparations of fluorine are used and at heterospecific are vitamins, calcium containing preparations, roborants. The local consists in introduction to the cavity of mouth or directly on the surface of tooth of preparations of fluorine or remineralization solutions.  

Preparations of fluorine now are basic facilities of prophylaxis of teeth decay. The mechanism of protective action of fluorine on enamel consists in the assistance to the delay of phosphoric-calcium connections in an organism and processes of remіneralіzation of hard fabrics of tooth and also braking of activity of bacterial enzymes in the cavity of mouth and dental deposit.

Modern information show that the favourable action of fluorine is predefined by a few mechanisms:

1. Fluorine, uniting from a hydroxide apatites enamel, substituting for ОН – groups, forms a fluorapatites, doing an enamel more strong and more proof to the action of acids. This connection reduces permeability of enamel.

2. The mechanism of anticarious action of fluorides is related also to their oppressive influence on growth and exchange of matters of microflora of cavity of mouth.

3. Connections of fluorine in saliva inhibit the transport of glucose in the cages of pathogenic bacteria and formations of for cellular polysaccharidess, which form the matrix of dental deposit.

4. Fluorides violates absorption of microorganisms on-the-spot cages of tooth, absorb albumins of saliva, glycoproteins, as a result of what prevent growth of dental name-plate.

5. And finally, at internal introduction the fluorides normalize an albuminous and mineral exchange.

Fluorides present in enamel and in the dental deposit catalysis «proceeding» in the early carious defeats due to remіneralіzation of crystals of enamel, multiplies the size of crystals of hydroxide apatites.

From modern international data days’ even receipts of fluorides are distributed thus:

–    very low = 0,1-0,6 milligrams;

–   low =0,7-1,4 milligram;

–    optimum = 1,5-4,0 milligrams;

–    high (impertinent fluorosis) = 5-12 milligrams;

–    ever-higher = 20 milligrams and more (at treatment of osteoporosis of bones by fluorines preparations).

The amount of fluorine in an organism depends on his maintenance in water and food products.

ENDOGENOUS PROPHYLAXIS

A specific endogenous prophylaxis provides for:

1. Fluorination of drinking-water

2. Fluorination milk

3. Fluorination salts

4. Adopting the pills of fluorides of sodium

FLUORINATION OF WATER

One of the acknowledged methods of prophylaxis of caries there is fluorination of drinking-water   is   controlled  addition  of connections  to the fluorine  to   water of sources of water-supply with the purpose of leading to the concentration of ions of fluorine in        a drinking-water    to    the level,    which    is   sufficient    for    the effective prophylaxis of teeth decay and at the same time does not have an unfavorable influence on functional possibilities of organism of man, physical development and health of population.

First artificial enriching of tap water by fluorine it is carried out in 1945 and since got distribution more than in 35 countries in which over 150 million persons now    use    fluorination water.

For artificial fluorination to water add the followings connections to the fluorine: fluoride of sodium. This process is carried out to the step waterworks. It is rotined that for achieving maximal efficiency fluorination water, it follows to consume from birth, but some researches rotined efficiency of this method of prophylaxis and at patients which got the optimum concentrations of fluorides upon termination of odontosis.

Presently about 5% all population of earth (approximately 260 million persons) drink fluorination water. In spite of numerous objections of opponents of fluorination, the presence of undesirable effects is not well-proven, and although every objection must be explored, safety of fluorination of water can be considered set.

The optimum concentration of fluorine in a drinking-water is 1,0 mg/l. Expedience of fluorination of water in every case is set by the organs of sanitary-epidemiology service. To fluorination of water low KF” is a testimony in water and considerable staggered of population by the caries of teeth. In theory at any KF”, less than optimum, it is expedient fluorination water, but practically in the first turn it needs to be done on those plumbings in which water contains less after 0,3…0,5 mg/l to the fluorine.

Fluorination of water remains the advantageous and cheap method of prophylaxis. Most influencing of fluorination water shows up on smooth surfaces, in more small degrees on proximal, cheeks and figures. For frontal teeth, influencing of fluorinating water shows up in more small degrees that for masticatory.

Fluorination of drinking-water allows get reduction of increase of baby teeth permanent decay on 40-50% — on 50-60%.

Efficiency of fluorination is estimated by the dynamic supervision during 10—15 years after morbidity by the teeth caries of population which uses fluorinating water. It is possible also to compare findings to the indexes of morbidity by the caries of population of neighbouring settlement which uses water with small maintenance of fluorine (more small after 0,2 mg/l). For the estimation of anticarious action of fluorine use two indexes: prevalence of caries and his intensity (CSR and cs). About satisfactory efficiency it is possible to talk in that case, when in 7—8 years after the beginning of fluorination of water the index of CSR of children 7—8 years went down on 40—50%, about good — on 50—60%, about excellent — on 65—80%.

 

FLUORINATION OF MILK

The use of fluorinating milk is the alternative and effective method of prophylaxis.

Milk a long ago brings over to itself attention of researchers on a number of reasons, so as:

–    it is the necessary component of feed of child, especially in the first years of life;

–    owns valuable nourishing properties necessary for child’s organism;

–    it is the basic source of calcium and phosphorus, fabrics of bones and teeth necessary for the structure;

–    contains the high level of calcium, phosphorus and lactose which laminates carbonhydratess also.

Similar composition allows to milk to bring in the payment in the process of remіneralіzation of enamel of teeth and in its defence.

For successful introduction of method of fluorination of milk certain terms are needed:

–    high dental morbidity of population is in a region;

–    low maintenance of fluorides is in a drinking-water;

–    absence of other sources of system receipt of fluorides.

Except for it, at introduction of similar project striving to is the necessary mortgage of success collaborate from the side of regional administration and organs of health protection, as necessary refinancing for the production and organizational measures at the division and delivery of milk in the organized collectives.

For fluorination of milk more frequent fluoride of sodium is used. The table of contents of fluoride in milk concernes for help fluoride of selective electrode. Technology of fluorination of milk is simple and does not present difficulties.

The amount of fluoride, which must be added to milk, is guilty to take into account age of child and receipt of fluoride from other products and water. Yes, coming recommendations of WOHP from, for children from 3 to 7 years day’s receipt of fluoride makes 0,87-1,75 milligrams.

For the children of preschool age the concentration of fluoride in milk, even 2,5 mg/l, is optimum, as 1,0-1,15 milligrams of fluoride provide the daily total receipt in days.

At the use of fluorinating milk it is necessary to adhere to the followings recommendations:

–    effectively to use this method at children from 3 to 12 years

–    daily a child must use a 1 glass of milk from 0,5 mg of fluoride

–    during a year a child must drink milk not less 250 days.

 

ADOPTING PILLS OF FLUORIDE OF SODIUM

 

The doses of fluoride of sodium are recommended in pills

 

 

 

Pills are effective during development and ripening of teeth. Using it is needed 200-250 days in a year from 2 to 15 years. In this case effect from their use it is possible to compare to influencing of fluorinating water. It is the best to accept in the morning and chew pills. It is thus provided as general so local effect of fluorine. Adopting the pills of fluorine it is possible to be on duty with adopting the drops of Vitaftorum.

  Pills are appointed daily to 14-15-years-old age. Contra-indication to setting of pills:

– table of contents of fluorine in an environment more than 50% from optimum;

– any another ways of adopting a fluorine inward.

By major advantage of adopting the pills of fluoride of sodium inward there is «flexibility» of method at the prophylaxis of teeth caries, that allows to bring a fluorine exactly into those periods, when this more expedient in all, and also exactly to measure out a microelement taking into account age and features of organism. However much this way has failings: difficulty of organization of adopting pills, and, in addition, he appeared more dearst than other methods of bringing fluorine are into an organism.

Experience of the use of pills of fluorides of sodium rotined that only high responsibility of parents, pills constantly tracker after the regular reception by children, can provide a high enough prophylactic effect.

Vitaftorum (Vitaftorum) is the combined fluorine containing preparation. Contains in the composition of fluoride of sodium, vitamins A,D,C.

Pharmacological properties of Vitaftorum are conditioned by combination in him of vitamins A also D₂ with a fluorine which favourably influences on the maintainance and forming of fabrics of teeth. Vitamin A assists to the normal odontogeny and correct forming of skeleton. Vitamin D regulates the exchange of phosphorus and calcium in an organism, is instrumental in suction them in an intestine and timely laying in a new formed bone.A fluorine finds out the anticarious action, is well sucked in, accumulates in bones, in teeth, by a less measure — in cartilages. Vitamin C limits the deposit of fluorine in fabrics and the same prevents intoxication by fluorine.

It is used under time or after-meal during a month inward with an interval in 2-4 weeks each 3 months in locality, where maintenance of fluorine in a drinking-water is minimum. To the children from 1 year to 6 years preparation is appointed for ? of tea-spoon 1 time per a day; from 7 to 14 years — for 1 tea-spoon 1 time per a day during a month. After a 2-a week interruption a course is repeated. In a year 4-6 courses of prophylaxis are conducted with an interruption on summer months.

 

Not specific endogenous prophylaxis provides for:

1. The reception of the calcium of containing preparations

2. The reception of vitamins

3. The reception of roborants.

CALCIUM CONTAINING PREPARATIONS

Calcemin is adopted on a chart, depending on age of child. It is recommended to the use to pregnant, women in the period of lactation, to the children from 5 to 12 years of 1 pill 1 time per a day, after 12 years -1 pill on a day.

Calcium D₃ Nicomed – is accepted for 1 pill 2 times per a day in the second half of day – 10 days; 20 days – for 1 pill in a day in the evening. On the average course of treatment by preparations of calcium of makes 1month.

In a mouth liquid the use of preparation of CALCINOVA which contains a calcium and phosphates necessary for mіneralіzation of bones and teeth, and also complex of vitamins, including the vitamin of D₃, which is instrumental in absorption of these minerals in the organs of digestion and their division in the organs of digestion, is the alternative method of increase of maintenance of calcium and phosphorus. Preparation contains a calcium, phosphorus, vitamins A, D, B₆, C. In connection with that pills it is needed well to chew, in a mouth liquid the considerable increase passes the concentrations of minerals, which promote mіneralіzation and remіneralіzation of teeth.

VITAMINS PREPARATIONS

Videcholum  is preparation of vitamin of D₃. It is appointed 1 time per a year in a winter period.

Vitrum – calcium – for children after 12 years for 1 pill in a day during 1-2 months; to the adults – 1-2 pills in days 3-6 months.

ROBORANTS (ADAPTOGENS)

Adaptogens are preparations, mainly vegetable origin, what have general stimulant operating on the basic functions of the system and promote resistance of body to the unfavorable actions.

Ascorbic acid – from 7 to 13 years – for 250 milligrams, from 14 to 17 years – for 750 milligrams of ? 1 time per a day during three days, 1 time on year.

Vitamin Е- to pregnant on 7-10 and 30-32 weeks pregnancies – on a 1 capsule (0,1) or on a 1 tea-spoon 2 times per a day, during 2-3 weeks.

 EXOGENOUS PROPHYLAXIS

It follows to take to facilities of exogenous prophylaxis:

–    fluorine containing facilities for local application

–    remineralization solutions

–    encapsulants

FLUORINE CONTANING FACILITIES

 

At the use of fluorine it is needed to take into account the following:

1. The concentration of fluorides not must exceed for a local prophylaxis
1-2% (calculating on a fluorine), as with the increase of concentration efficiency does not grow.

2. Efficiency of influencing is conditioned by their concentration in the free ionized kind.

 3. It is necessary to take into account in this connection fastening possibility fluoride ions with the ions of calcium.

4. Fluorides is appointed taking into account maintenance of fluorine in a drinking-water and climatic factors.

 

Tooth-pastes

Presently became obviously, that the decline of morbidity by caries is explained to the wide uses of fluorine containing of tooth-pastes.

Pastes are given recommended to the use from 3-4 years. Cleaning is necessary 2 times per a day for 3 minutes, consistently clearing all surfaces of tooth.

Fluorine containing varnishes

One of widespread facilities of local prophylaxis there are varnishes which use for the prolonged period of influencing of fluoride on enamel. They form tape adjoining to the enamel, and which remains on teeth during a few hours and in fissures a few days and even weeks.

A fluorine – varnish shows itself composition of natural resins of vegetable origin. At the market presented: „Ftorlac” (Kharkiv), varnish „Duraphat”, „Belac” (Vladmiva).

A method is given recommended at the moderate or high level of intensity of caries of teeth, to the children and young people with the high risk of origin of caries. Frequency of causing of varnish is 2-4 times per a year, depending on activity of caries.

 

BELAK – F

 

Method: the surface of teeth is purged from the deposit and is dried out. Then by the special brush varnish is inflicted by a skim on the surface of tooth. At the same time it is possible to cover all teeth on one jaw or 3-5 teeth. For getting dry of varnish it is needed about 2-3 minutes. It is possible to dry the varnish by the compressed air. After coverage of teeth by fluorine varnish it is impossible to use the meal of 1-3 hours and in future the desired only spoon-meat. It is not recommended to clean teeth 24 hours. Varnish is contained on-the-spot tooth not less 12 hours and for this time his ions penetrate on a depth to 100 mcm of healthy enamel.

To cover teeth by varnish it follows depending on activity of cariosity: at a 1 degree — 2 times per a year, at 2 — 4 times per a year, at 3 — from 6 to 12 times per a year. Triple coverage of teeth is recommended with an interval 1-2 days.

It is set that in a year after application of fluorine containing varnish second caries of teeth goes down on the average on 50%.

Fluorine containing gels and solutions for the professional use

Gels and solutions of fluoride of sodium 1% and 2% are used for appliques and electrophoresis. A doctor-dentist conducts procedure in the conditions of policlinic. Remineralization action of gels is based on diffusion of matters from gel in saliva and from her in the enamel of tooth.

 

BELAGEL – F

 

Method: teeth preliminary clear, dry out and impose the wadding tampon well moistened by solution of fluoride of sodium on 3- 5 minutes. At first assess the masticatory surfaces of teeth, and then – labial and cheeks on both jaws. If gel is used, he is inflicted by heated by a brush and give to dry out. After procedure does not recommend eat and drink during 2 hours.

As a rule conduct 3-5 appliques by solution twice on a year and 2-6 appliques by gel on a year.

Causing of fluorides by a spoon:

1. To choose the spoon of the proper size

It must be the covered is all dental row, including the areas of retraction and it follows to provide access of gel to the contact with the structure of teeth. The ends of spoon (peripheral areas) must be closed in order that gel did not flow down in the cavity of mouth sick. Ideally spoons befit with coverage from the made foam material, as they fit snugly dental row of patient and allow to gel to achieve all surfaces

2. To place gel in a stretcher.

3. To insert a spoon in the mouth of patient.

4. To insert between the spoons of saliva ejector, making sure, that to the patient comfortably (at this method for balance of bite from opposite sides necessary wadding rollers)

5. To bring a spoon out of mouth sick.

6. To ask a patient to spit out immediately after the delete of spoon.

After procedure, at a necessity the delete of superfluous fluoride, to apply the intensive sucking

7. To warn a patient that during 30 minutes after procedure it is impossible to eat or drink

Fluorine containing solutions for the independent use

The wide use in the prophylaxis of caries was found by solutions with the low concentrations of fluoride.

The rinses begin to use, when the first second teeth cut through at children. The method of prophylaxis is given does not need considerable expenses of time and financial resources, and that time is effective enough.

Amount of rinses makes:

– by a 0,05% solution -1 once on a day

– by a 0,1% solution -1 once in a week

– by a 0,2% solution – 1 one time in two weeks

For the improvement of co-operation of fluorine with an enamel preliminary it follows well to clean teeth and rinse a mouth by alkaline water for the change of рН environment. In addition it is necessary to teach a child to rinse a mouth by ordinary water by energetic motions by cheeks.

Method: depending on age of child give to rinse the mouth of 5-10 ml solution. The rinse lasts 1-3 minutes, and for the children of junior age more expedient double rinse on 1 minute. After it a mouth is rinsed by clean water.

Application by the children of rinses by solution of fluorine sodium gives reduction to the caries 30%, upon termination of rinses an effect lasts yet in 2-3.

At casual swallowing of fluoride of sodium it is necessary to give to the child to take an a swig at the soupspoon of solution of chloride of calcium, which, linking a fluorine will not give him to be sucked in.

Application of fluorine containing disks

Fluorine containing disks (paper and paraffins) are produced in packing for 10 things. The expense of material is a 1 disk on procedure. The disk of «Ftorglicofoskal’» contains the followings ingredients:

– neurosin — 8-16 g

– fluoride of sodium — 0,5-2 g

– superficial matters — 0,5-2,0 g

– beeswax — 4,5-6,5 g

– paraffin.

A disk is fixed in an angular tip by a mandrel. A fluorine is rubbed in hard fabrics of tooth on minimum speed with the use of three types of motions: recurrently-forward, up-down, circles.

As usual, before treatment by fluorine containing disks the professional hygiene of cavity of mouth is conducted, whereupon by disks at first the vestibular surfaces of all teeth of maxilla are processed from left to right, then lower — from right to left. After it the palatal surfaces of teeth of maxilla and languages surfaces of teeth of lower jaw are processed, farther are masticatory surfaces of teeth of overhead and lower jaws with the use of only circular motions clockwise. At a variable bite process by fluorine containing disk only the second teeth. It is recommended 2-3 multiple treatment of teeth with an interval 1-2 days, in a year 2-4 courses.

In practice of therapeutic dentistry fluorine containing disks found large popularity not only at the prophylaxis of teeth decay but also at treatment of hyperesthesia of hard fabrics of teeth.

 

Remineralization solutions

At application of remineralization matters it is expedient to heat them to 40-45⁰C, taking into account that the increase of temperature of solution on 10 strengthens precipitation of ions on-the-spot enamel on 1 %.

Choosing the concentration of remineralization solution, it should be remembered that the high concentration of calcium conduces only to mіneralіzation of superficial layer of enamel, while the low concentrated solutions are instrumental in remineralization on all depth of enamel.

In behalf of the combined application of remineralization solutions and solutions of fluorine the fact of assistance of ions to the fluorine testifies to the acceleration of plugging in the net of enamel of calcium and phosphorus.

 

Borovskij’s – Leus’s method

Teeth carefully purge from the dental raid by ordinary pastes, dry out.

Consistently conduct appliques by a 10% solution of glucoside of calcium during 15 minutes(3 times for 5 minutes) and 2% by water solution of fluoride of sodium during 3 minutes. Duration of course on the average 10-15 procedures every day or in a day.

 Borovskij’s – Leus’s method

(with electrophoresis)

This chart foresees electrophoresis of a 10% solution of glucoside of calcium (3—5 minutes) and applique of a 2% soluble- fluoride of sodium (1—2 minutes) 3 times in a week.

 

Borovskij’s – Volkov’s method

Two-component solution which consists of a 10% solution of nitrate of calcium and 10% solution of hydrophosphate to the ammonium is used. Prepare teeth and consistently conduct appliques by each of these solutions for 3-5 minutes. Through 5-7 procedures on-the-spot enamel and in mіcro spaces under superficial layer the matter appear which is an ionogen phosphorus and calcium. This method is used for treatment of hyperesthesia.

 

Udovits’ka’s method

O. Udovits’ka recommends to apply at the children of 2—3 years of applique of a 10% solution of glucoside of calcium (3 minutes) and fluorine varnish 6 times per a week; course — 1 one time in a year during 3 years

 

Applique by solution „Remodent”

“Remodent”  is the preparation synthesized from natural materials consists of complex of ions macro- and micrtoelements necessary for activating of process of remіneralіzation and prophylaxis of caries. Unlike fluorine preparation is instrumental in substituting for the ions of calcium and phosphorus in the crystalline grate of enamel of teeth.

On preliminary cleared (by a tooth brush and tooth-paste) and dried up teeth inflict the wadding tampon saturated by solution of “Remodent”    on 15—20 minutes. During this time a tampon is changed twice. After an applique it is not recommended to rinse a mouth and adopt a meal during 2 hours. Next appliques conduct twice for a week after the same method. The course of treatment is 20—30 appliques.

In addition, with the purpose of prophylaxis of teeth decay it is possible to recommend the rinse of mouth by a 3% solution of “Remodent” by duration of 3—4 of minutes (1—2 times per a week) during 10 months on a year. On one rinse goes to 15—25 ml solution.

 

 Vinogradova’s method

Purge teeth by hygienical tooth-paste, appliques dry out and conduct teeth by a 10% solution of glucoside of calcium on 2-4 minutes and mouths baths (washing) by a 0,2% solution of fluoride of sodium on 2-4 minutes. This complex is conducted 3-4 times per a year.

In the over concentrations fluorides is toxic.

 

 Recommendations are on the hygienical care of cavity of mouth of children

Parents must begin the hygienical care of cavity of mouth of child from the moment of eruption of the first temporal tooth (in age 5-6 months).

This procedure needs to be executed 1 time per a day (in the evening before sleep). For the removal of dental deposit from every surface of tooth the special very soft tooth brush is recommended, what dressed on afinger. From gums to the cutting edge clear the teeth of child circular motions without application of tooth-paste.

 

To the moment of eruption for a child 8th teeth (as a rule, to one year) it is necessary to clear teeth parents already twice in a day (in the morning and in the evening) by soft child’s tooth brush (length of working part must not exceed 1,5 mm), also without application of some tooth-paste. Thus the special attentioeeds to be spared teeth which are in the stage of eruption the masticatory surfaces of which did not yet attain the level of occlusal plane.

Teeth it is recommended to purge thus:

1. To clear vestibular surfaces at serried jaws, here to set a tooth brush horizontally, athwart to the surface of teeth, carrying out only vertical motions in direction from gums to the cutting edge of teeth: on an overhead jaw – from top to bottom, on lower – from below to upwards .

To clear oral surfaces circular motions, here in the area of frontal teeth on an overhead and lower jaw to set a brush apeak.

It follows to delete a raid from the masticatory surfaces of teeth motions ahead-back.

It is recommended to use this technique in the period of eruption of all temporal teeth (to 2-2,5), when cleaning of teeth must become for a child by obligatory part of morning and evening rest room.

In 2-2,5 parents must clean teeth children by soft child’s brush twice on a day (in the morning – to breakfast and in the evening – before sleep) and to use child’s gel tooth-paste.

 

To prevent tooth decay:

·                     Brush your teeth at least twice a day with afluoride-containing toothpaste. Preferably, brush after each meal and especially before going to bed.

·                     Clean between your teeth daily with dental floss or interdental cleaners, such as the Oral-B Interdental Brush, Reach Stim-U-Dent, or Sulcabrush.

·                     Eat nutritious and balanced meals and limit snacks. Avoid carbohydrates such as candy, pretzels and chips, which can remain on the tooth surface. If sticky foods are eaten, brush your teeth soon afterwards.

·                     Check with your dentist about use of supplemental fluoride, which strengthens your teeth.

·                     Ask your dentist about dental sealants (a plastic protective coating) applied to the chewing surfaces of your back teeth (molars) to protect them from decay.

·                     Drink fluoridated water. At least a pint of fluoridated water each day is needed to protect children from tooth decay.

·                     Visit your dentist regularly for professional cleanings and oral exam.