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Cementoenamel Junction
In dental anatomy, the cementoenamel junction (CEJ) is the location where the enamel, which covers the anatomical crown of a tooth, and the cementum, which covers the anatomical root of a tooth, meet. Informally it is known as the neck of the tooth. The border created by these two dental tissues has much significance as it is usually the location where the gingiva (gums) attaches to a healthy tooth by fibers called the gingival fibers. Active recession of the gingiva reveals the cementoenamel junction in the mouth and is usually a sign of an unhealthy condition. The loss of attachment is considered a more reliable indicator of periodontal disease. The CEJ is the site of major tooth resorption. A significant proportion of tooth loss is caused by tooth resorption, which occurs in 5 to 10 percent of the population. The clinical location of CEJ which is a static landmark, serves as a crucial anatomical site for the measurement of probing pocket depth (PPD) and clinical attachment l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Anatomy
Dental anatomy is a field of anatomy dedicated to the study of Tooth (human), human tooth structures. The development, appearance, and classification of teeth fall within its purview. (The function of teeth as they contact one another falls elsewhere, under dental occlusion.) Tooth formation begins before birth, and the teeth's eventual Morphology (biology), morphology is dictated during this time. Dental anatomy is also a Taxonomy (general), taxonomical science: it is concerned with the naming of teeth and the structures of which they are made, this information serving a practical purpose in dental treatment. Usually, there are 20 primary ("baby") teeth and 32 permanent teeth, the last four being third molars or "wisdom teeth", each of which may or may not grow in. Among primary teeth, 10 usually are found in the maxilla (upper jaw) and the other 10 in the human mandible, mandible (lower jaw). Among permanent teeth, 16 are found in the maxilla and the other 16 in the mandible. Ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertwig's Epithelial Root Sheath
The Hertwig epithelial root sheath (HERS) or epithelial root sheath is a proliferation of epithelial cells located at the cervical loop of the enamel organ in a developing tooth. Hertwig epithelial root sheath initiates the formation of dentin in the root of a tooth by causing the differentiation of odontoblasts from the dental papilla. The root sheath eventually disintegrates with the periodontal ligament, but residual pieces that do not completely disappear are seen as epithelial cell rests of Malassez (ERM). These rests can become cystic, presenting future periodontal infections. Structure Hertwig epithelial root sheath is derived from the inner and outer enamel epithelium of the enamel organ.Illustrated Dental Embryology, Histology, and Anatomy, Fehrenbach and Popowics, Elsevier, 2026, p. 70-73 Function The sheath is also responsible for multiple or accessory roots (medial growth) and lateral or accessory canals in the root (break in epithelium).Ten Cate's Oral Histol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Enamel
Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The other major tissues are dentin, cementum, and Pulp (tooth), dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed on the tooth while the tooth develops wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulp (tooth)
The pulp is the connective tissue, nerves, blood vessels, and odontoblasts that comprise the innermost layer of a tooth. The pulp's activity and signalling processes regulate its behaviour. Anatomy The pulp is the neurovascular bundle central to each tooth, permanent tooth, permanent or primary tooth, primary. It is composed of a central pulp chamber, pulp horns, and radicular canals. The large mass of the pulp is contained within the pulp chamber, which is contained in and mimics the overall shape of the crown of the tooth.Fehrenbach, MJ. and Popowics, T. (2026), ''Illustrated Dental Embryology, Histology, and Anatomy'', Elsevier, page 185-86. Because of the continuous deposition of the dentine, the pulp chamber becomes smaller with the age. This is not uniform throughout the coronal pulp but progresses faster on the floor than on the roof or sidewalls. Radicular pulp canals extend down from the cervical region of the crown to the Root apex (dental), root apex. They are not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Ankylosis
Tooth ankylosis refers to a fusion between a tooth and underlying bony support tissues. In some species, this is a normal process that occurs during the formation or maintenance of the dentition. By contrast, in humans tooth ankylosis is pathological, whereby a fusion between alveolar bone and the cementum of a tooth occurs. In humans, this is a rare phenomenon in deciduous dentition and even more uncommon in permanent teeth. Ankylosis occurs when partial root resorption is followed by repair with either cementum or dentine that unites the tooth root with the alveolar bone, usually after trauma. However, root resorption does not necessarily lead to tooth ankylosis and the causes of tooth ankylosis remain uncertain to a large extent. However, it is evident that the incident rate of ankylosis in deciduous teeth is much higher than that of permanent teeth. Risk factors of tooth ankylosis can be generally classified into genetic factors and dental trauma. Diagnostic methods of tooth a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflammation
Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', ''dolor'', ''rubor'', ''tumor'', and ''functio laesa''). Inflammation is a generic response, and therefore is considered a mechanism of innate immunity, whereas adaptive immunity is specific to each pathogen. Inflammation is a protective response involving immune cells, blood vessels, and molecular mediators. The function of inflammation is to eliminate the initial cause of cell injury, clear out damaged cells and tissues, and initiate tissue repair. Too little inflammation could lead to progressive tissue destruction by the harmful stimulus (e.g. bacteria) and compromise the survival of the organism. However inflammation can also have negative effects. Too much inflammation, in the form of chronic inflammation, is associated with variou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Types Of Resorption
Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Type (Unix), a command in POSIX shells that gives information about commands. * Type safety, the extent to which a programming language discourages or prevents type errors. * Type system, defines a programming language's response to data types. Mathematics * Type (model theory) * Type theory, basis for the study of type systems * Arity or type, the number of operands a function takes * Type, any proposition or set in the intuitionistic type theory * Type, of an entire function ** Exponential type Biology * Type (biology), which fixes a scientific name to a taxon * Dog type, categorization by use or function of domestic dogs Lettering * Type is a design concept for lettering used in typography which helped bring about modern textual printi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesial
This is a list of definitions of commonly used terms of location and direction in dentistry. This set of terms provides orientation within the oral cavity, much as anatomical terms of location provide orientation throughout the body. Terms Combining of terms Most of the principal terms can be combined using their corresponding combining forms (such as ''mesio-'' for ''mesial'' and ''disto-'' for ''distal''). They provide names for directions (vectors) and axes; for example, the coronoapical axis is the long axis of a tooth. Such combining yields terms such as those in the following list. The abbreviations should be used only in restricted contexts, where they are explicitly defined and help avoid extensive repetition (for example, a journal article that uses the term "mesiodistal" dozens of times might use the abbreviation "MD"). The abbreviations are ambiguous: (1) they are not spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curvature Of CEJ
In mathematics, curvature is any of several strongly related concepts in geometry that intuitively measure the amount by which a curve deviates from being a straight line or by which a surface deviates from being a plane. If a curve or surface is contained in a larger space, curvature can be defined ''extrinsically'' relative to the ambient space. Curvature of Riemannian manifolds of dimension at least two can be defined ''intrinsically'' without reference to a larger space. For curves, the canonical example is that of a circle, which has a curvature equal to the reciprocal of its radius. Smaller circles bend more sharply, and hence have higher curvature. The curvature ''at a point'' of a differentiable curve is the curvature of its osculating circle — that is, the circle that best approximates the curve near this point. The curvature of a straight line is zero. In contrast to the tangent, which is a vector quantity, the curvature at a point is typically a scalar quantity, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cementogenesis
In animal tooth development, cementogenesis is the formation of cementum, one of the three mineralized substances of a tooth. Cementum covers the roots of teeth and serves to anchor gingival and periodontal fibers of the periodontal ligament by the fibers to the alveolar bone (some types of cementum may also form on the surface of the enamel of the crown at the cementoenamel junction (CEJ)). Process For cementogenesis to begin, Hertwig epithelial root sheath (HERS) must fragment. HERS is a collar of epithelial cells derived from the apical prolongation of the enamel organ. Once the root sheath disintegrates, the newly formed surface of root dentin comes into contact with the undifferentiated cells of the dental sac ( dental follicle). This then stimulates the activation of cementoblasts to begin cementogenesis. The external shape of each root is fully determined by the position of the surrounding Hertwig epithelial root sheath. It is believed that either 1) HERS becomes inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fragmentation (cell Biology)
Fragmentation describes the process of splitting into several pieces or fragments. In cell biology, fragmentation is useful for a cell during both DNA cloning and apoptosis. DNA cloning is important in asexual reproduction or creation of identical DNA molecules, and can be performed spontaneously by the cell or intentionally by laboratory researchers. Apoptosis is the programmed destruction of cells, and the DNA molecules within them, and is a highly regulated process. These two ways in which fragmentation is used in cellular processes describe normal cellular functions and common laboratory procedures performed with cells. However, problems within a cell can sometimes cause fragmentation that results in irregularities such as red blood cell fragmentation and sperm cell DNA fragmentation. DNA Cloning DNA cloning can be performed spontaneously by the cell for reproductive purposes. This is a form of asexual reproduction where an organism splits into fragments and then each of thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periodontal Ligament
The periodontal ligament, commonly abbreviated as the PDL, are a group of specialized connective tissue fibers that essentially attach a tooth to the alveolar bone within which they sit. It inserts into root cementum on one side and onto alveolar bone on the other. Structure The PDL consists of principal fibers, loose connective tissue, blast and clast cells, oxytalan fibers and cell rest of Malassez. Alveolodental ligament The main principal fiber group is the alveolodental ligament, which consists of five fiber subgroups: alveolar crest, horizontal, oblique, apical, and interradicular on multirooted teeth. Principal fibers other than the alveolodental ligament are the transseptal fibers. All these fibers help the tooth withstand the naturally substantial compressive forces that occur during chewing and remain embedded in the bone. The ends of the principal fibers that are within either cementum or alveolar bone proper are considered Sharpey fibers. * Alveolar cre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
