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Tertiary Dentin
Tertiary dentin (including reparative dentin or sclerotic dentin) is a form of dentin, one of the main component materials of teeth. It forms as a reaction to stimulation, including caries, wear and fractures. Tertiary dentin is therefore a mechanism for a tooth to ‘heal’, with new material formation protecting the pulp chamber and ultimately therefore protecting the tooth and individual against abscesses and infection. This form of dentin can be easily distinguished on the surface of a tooth, and is much darker in appearance compared to primary dentin. Tertiary dentin will often not be visible on the surface of a tooth, but because it is more dense it can be viewed on a Micro-CT scan of the tooth. Wear on the surface of a tooth can lead to the exposure of the underlying dentin. When wear is severe tertiary dentin may form to help protect the pulp chamber. Frequency of tertiary dentin in different species of primate suggests teeth 'heal' at different rates in different spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentin
Dentin ( ) (American English) or dentine ( or ) (British English) () is a calcified tissue (biology), tissue of the body and, along with tooth enamel, enamel, cementum, and pulp (tooth), pulp, is one of the four major components of teeth. It is usually covered by enamel on the crown and cementum on the root and surrounds the entire pulp. By volume, 45% of dentin consists of the mineral hydroxyapatite, 33% is organic material, and 22% 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 rates approximately 3 on the Mohs scale of mineral hardness. There are two main characteristics which distinguish dentin from enamel: firstly, dentin forms throughout life; secondly, dentin is sensitive and can become hypersensitive to changes in temperature due to the sensory function of odontoblasts, especially when enamel recedes an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teeth
A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tearing food, for defensive purposes, to intimidate other animals often including their own, or to carry prey or their young. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness that originate from the outermost embryonic germ layer, the ectoderm. The general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position. The teeth of mammals have deep roots, and this pattern is also found in some fish, and in crocodilians. In most teleost fish, however, the teeth are attached to the outer surface of the bone, while in lizards they are attached to the inner surface of the jaw by one side. In cartilaginous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentinogenesis
{{Refimprove, date=September 2014 In animal tooth development, dentinogenesis is the formation of dentin, a substance that forms the majority of teeth. Dentinogenesis is performed by odontoblasts, which are a special type of biological cell on the outer wall of dental pulps, and it begins at the late bell stage of a tooth development. The different stages of dentin formation after differentiation of the cell result in different types of dentin: mantle dentin, primary dentin, secondary dentin, and tertiary dentin. Odontoblast differentiation Odontoblasts differentiate from cells of the dental papilla. This is an expression of signaling molecules and growth factors of the inner enamel epithelium (IEE). Formation of mantle dentin They begin secreting an organic matrix around the area directly adjacent to the IEE, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Decay
Tooth decay, also known as caries,The word 'caries' is a mass noun, and is not a plural of 'carie'.'' is the breakdown of teeth due to acids produced by bacteria. The resulting cavities may be a number of different colors, from yellow to black. Symptoms may include pain and difficulty eating. Complications may include periodontal disease, inflammation of the tissue around the tooth, tooth loss and infection or dental abscess, abscess formation. Tooth regeneration is an ongoing Stem-cell therapy, stem cell–based field of study that aims to find methods to reverse the effects of decay; current methods are based on easing symptoms. The cause of cavities is acid from bacteria dissolving the hard tissues of the teeth (Tooth enamel, enamel, dentin and cementum). The acid is produced by the bacteria when they break down food debris or sugar on the tooth surface. Simple sugars in food are these bacteria's primary energy source and thus a diet high in simple sugar is a risk factor. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Wear
Tooth wear refers to loss of tooth substance by means other than dental caries. Tooth wear is a very common condition that occurs in approximately 97% of the population. This is a normal physiological process occurring throughout life; but with increasing lifespan of individuals and increasing retention of teeth for life, the incidence of non-carious tooth surface loss has also shown a rise. Tooth wear varies substantially between people and groups, with extreme attrition and enamel fractures common in archaeological samples, and erosion more common today. Tooth wear is predominantly the result of a combination of three processes; attrition, abrasion and erosion. These forms of tooth wear can further lead to a condition known as abfraction, where by tooth tissue is 'fractured' due to stress lesions caused by extrinsic forces on the enamel. Tooth wear is a complex, multi-factorial problem and there is often difficulty identifying a single causative factor. However, tooth wear i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enamel Fracture
An enamel fracture is when the outermost layer of the tooth is cracked, without damaging the inner layers including the dentine or Pulp (tooth), pulp. This can happen from trauma such as a fall where the teeth are impacted by a hard object causing a chip to occur. The term “craze lines” and "enamel infraction" are also used to describe minute incomplete cracks exclusive to the enamel surface. Introduction An enamel fracture occurs when the outer layer of the tooth, known as Tooth enamel, enamel, is fractured without directly impacting the underlying tooth tissues of the dentine or Pulp (tooth), pulp. This phenomenon typically arises from hard, external forces impacting the tooth to induce enamel breakage. These fractures are often characterised by irregular breaks on the biting surface of the tooth, in contrast to the smoother surfaces associated with typical tooth degradation. Enamel fractures can vary in severity, ranging from minor cosmetic issues to more significant stru ... [...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] |
Dental Abscess
A dental abscess is a localized collection of pus associated with a tooth. The most common type of dental abscess is a periapical abscess, and the second most common is a periodontal abscess. In a periapical abscess, usually the origin is a bacterial infection that has accumulated in the soft, often dead, pulp of the tooth. This can be caused by tooth decay, broken teeth or extensive periodontal disease (or combinations of these factors). A failed root canal treatment may also create a similar abscess. A dental abscess is a type of odontogenic infection, although commonly the latter term is applied to an infection which has spread outside the local region around the causative tooth. Classification The main types of dental abscess are: * Periapical abscess: The result of a chronic, localized infection located at the tip, or apex, of the root of a tooth. * Periodontal abscess: begins in a periodontal pocket (see: periodontal abscess) * Gingival abscess: involving only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micro-CT
In radiography, X-ray microtomography uses X-rays to create cross-sections of a physical object that can be used to recreate a virtual model (3D model) without destroying the original object. It is similar to tomography and X-ray computed tomography. The prefix ''micro-'' (symbol: μ) is used to indicate that the pixel sizes of the cross-sections are in the micrometre range. These pixel sizes have also resulted in creation of its synonyms high-resolution X-ray tomography, micro-computed tomography (micro-CT or μCT), and similar terms. Sometimes the terms high-resolution computed tomography (HRCT) and micro-CT are differentiated, but in other cases the term high-resolution micro-CT is used. Virtually all tomography today is computed tomography. Micro-CT has applications both in medical imaging and in industrial computed tomography. In general, there are two types of scanner setups. In one setup, the X-ray source and detector are typically stationary during the scan while the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tertiary Dentin
Tertiary dentin (including reparative dentin or sclerotic dentin) is a form of dentin, one of the main component materials of teeth. It forms as a reaction to stimulation, including caries, wear and fractures. Tertiary dentin is therefore a mechanism for a tooth to ‘heal’, with new material formation protecting the pulp chamber and ultimately therefore protecting the tooth and individual against abscesses and infection. This form of dentin can be easily distinguished on the surface of a tooth, and is much darker in appearance compared to primary dentin. Tertiary dentin will often not be visible on the surface of a tooth, but because it is more dense it can be viewed on a Micro-CT scan of the tooth. Wear on the surface of a tooth can lead to the exposure of the underlying dentin. When wear is severe tertiary dentin may form to help protect the pulp chamber. Frequency of tertiary dentin in different species of primate suggests teeth 'heal' at different rates in different spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorilla
Gorillas are primarily herbivorous, terrestrial great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or five subspecies. The DNA of gorillas is highly similar to that of humans, from 96 to 99% depending on what is included, and they are the next closest living relatives to humans after the chimpanzees. Gorillas are the largest living primates, reaching heights between , weights between , and arm spans up to , depending on species and sex. They tend to live in troops, with the leader being called a silverback. The eastern gorilla is distinguished from the western by darker fur colour and some other minor morphological differences. Gorillas tend to live 35–40 years in the wild. Gorillas' natural habitats cover tropical or subtropical forest in Sub-Saharan Africa. Although their range covers a small percentage of Sub-Saharan Africa, gorillas c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hominini
The Hominini (hominins) form a Tribe (biology), taxonomic tribe of the subfamily Homininae (hominines). They comprise two extant genera: ''Homo'' (humans) and ''Pan (genus), Pan'' (chimpanzees and bonobos), and in standard usage exclude the genus ''Gorilla (genus), Gorilla'' (gorillas), which is grouped separately within the subfamily Homininae. The term Hominini was originally introduced by Camille Arambourg (1948), who combined the categories of ''Hominina'' and ''Simiina'' pursuant to John Edward Gray, Gray's classifications (1825). Traditionally, chimpanzees, gorillas and orangutans were grouped together, excluding humans, as pongidae, pongids. Since Gray's classifications, evidence accumulating from genetic phylogeny confirmed that humans, chimpanzees, and gorillas are more closely related to each other than to the orangutan. The orangutans were reassigned to the family Hominidae (great apes), which already included humans; and the gorillas were grouped as a separate tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
