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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] |
Alveolar Bone
The alveolar process () is the portion of bone containing the tooth sockets on the jaw bones (in humans, the maxilla and the mandible). The alveolar process is covered by gums within the mouth, terminating roughly along the line of the mandibular canal. Partially comprising compact bone, it is penetrated by many small openings for blood vessels and connective fibres. The bone is of clinical, phonetic and forensic significance. Terminology The term ''alveolar'' () ('hollow') refers to the cavities of the tooth sockets, known as dental alveoli. The alveolar process is also called the ''alveolar bone'' or ''alveolar ridge''. In phonetics, the term refers more specifically to the ridges on the inside of the mouth which can be felt with the tongue, either on roof of the mouth between the upper teeth and the hard palate or on the bottom of the mouth behind the lower teeth. The curved portion of the process is referred to as the alveolar arch. The alveolar bone proper, also ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undifferentiated Cell
Cellular differentiation is the process in which a stem cell changes from one type to a differentiated one. Usually, the cell changes to a more specialized type. Differentiation happens multiple times during the development of a multicellular organism as it changes from a simple zygote to a complex system of tissues and cell types. Differentiation continues in adulthood as adult stem cells divide and create fully differentiated daughter cells during tissue repair and during normal cell turnover. Some differentiation occurs in response to antigen exposure. Differentiation dramatically changes a cell's size, shape, membrane potential, metabolic activity, and responsiveness to signals. These changes are largely due to highly controlled modifications in gene expression and are the study of epigenetics. With a few exceptions, cellular differentiation almost never involves a change in the DNA sequence itself. Metabolic composition, however, gets dramatically altered where stem cel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflex
In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs via neural pathways in the nervous system called reflex arcs. A stimulus initiates a neural signal, which is carried to a synapse. The signal is then transferred across the synapse to a motor neuron, which evokes a target response. These neural signals do not always travel to the brain, so many reflexes are an automatic response to a stimulus that does not receive or need conscious thought. Many reflexes are fine-tuned to increase organism survival and self-defense. This is observed in reflexes such as the startle reflex, which provides an automatic response to an unexpected stimulus, and the feline righting reflex, which reorients a cat's body when falling to ensure safe landing. The simplest type of reflex, a short-latency reflex, has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nociception
In physiology, nociception , also nocioception; ) is the Somatosensory system, sensory nervous system's process of encoding Noxious stimulus, noxious stimuli. It deals with a series of events and processes required for an organism to receive a painful stimulus, convert it to a molecular signal, and recognize and characterize the signal to trigger an appropriate defensive response. In nociception, intense chemical (e.g., capsaicin present in chili pepper or cayenne pepper), mechanical (e.g., cutting, crushing), or thermal (heat and cold) stimulation of sensory neurons called nociceptors produces a signal that travels along a chain of nerve fibers to the brain. Nociception triggers a variety of physiological and behavioral responses to protect the organism against an aggression, and usually results in a subjective experience, or perception, of pain in Sentience, sentient beings. Detection of noxious stimuli Potentially damaging mechanical, thermal, and chemical stimuli are detecte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanoreceptor
A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are located on sensory neurons that convert mechanical pressure into action potential, electrical signals that, in animals, are sent to the central nervous system. Vertebrate mechanoreceptors Cutaneous mechanoreceptors Cutaneous mechanoreceptors respond to mechanical stimuli that result from physical interaction, including pressure and vibration. They are located in the skin, like other cutaneous receptors. They are all innervated by Aβ fibers, except the mechanorecepting free nerve endings, which are innervated by A delta fiber, Aδ fibers. Cutaneous mechanoreceptors can be categorized by what kind of sensation they perceive, by the rate of adaptation, and by morphology. Furthermore, each has a different receptive field. By sensation * The Slowly Adapting type 1 (SA1) mechanoreceptor, with the Merkel corpuscle end-organ (also known as M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Remodeling
300 px, Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts. Both processes utilize cytokine ( Insulin-like_growth_factor.html" ;"title="TGF-β, Insulin-like growth factor">IGF) signalling. In osteology, bone remodeling or bone metabolism is a lifelong process where mature osseous tissue, bone tissue is removed from the skeleton (a process called ''bone resorption'') and new bone tissue is formed (a process called ''ossification'' or ''new bone formation''). Recent research has identified a specialised subset of blood vessels, termed Type R endothelial cells, in the bone microenvironment. These blood vessels play a crucial role in adult bone remodelling by mediating interactions between bone-resorbing osteoclasts and bone-forming osteoblasts. Type R blood vessels are characterised by their association with post-arterial capillaries and exhibit unique remodelling properties crucial for bone homeostasis. These processes also control the reshapin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Crown (tooth)
In dentistry, the crown is the visible part of the tooth above the gingival margin and is an essential component of dental anatomy. Covered by Tooth enamel, enamel, the crown plays a crucial role in cutting, tearing, and grinding food. Its shape and structure vary depending on the type and function of the tooth (incisors, Canine tooth, canines, premolars, or Molar (tooth), molars), and differ between Deciduous teeth, primary dentition and Permanent teeth, permanent dentition. The crown also contributes to facial aesthetics, speech, and oral health. Anatomical crown vs clinical crown The anatomical crown refers to the portion of the tooth covered by enamel, regardless of whether it is visible. The clinical crown is the part of the tooth that is visible in the mouth. In a healthy young adult, the gums typically follow the contour where enamel meets the root, so the clinical and anatomical crowns are similar in size. However, with age or periodontal disease, this may change. Te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Follicle
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Dental may refer to: * Dental consonant, in phonetics * Dental Records, an independent UK record label * Dentistry, oral medicine * Teeth See also * * Dental care (other) * Dentist (other) * Tooth (other) A tooth (: teeth) is a small, calcified, whitish structure found in the jaws (or mouths) of many vertebrates. Tooth or Teeth may also refer to: Music *Teeth (Filipino band), a Filipino rock band *Teeth (electronic band), UK electronic pop punk b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamina Dura
Lamina dura is compact bone that lies adjacent to the periodontal ligament, in the The lamina dura is a specialised component of the alveolar bone proper, characterized by thin, dense bone lamellae (cortical bone) that surrounds the tooth root. On an x-ray, a lamina dura will appear as a distinct radiopaque line surrounding the tooth root.Berry HM. The lore and the lure o’ the lamina dura. Radiology. 1973;109(3):525-528. Its structure contains numerous peforations that house blood vessels, lymphatics, and nerves, earning it the alternative name "cribriform plate". The lamina dura surrounds the tooth socket (at the tooth root), and provides the attachment surface with which the Sharpey's fibers (collagen fibers) of the periodontal ligament perforate and insert into, which is why it is also referred to as "bundle bone". Under the lamina dura is the less bright cancellous bone, due to its mineral composition. Trabeculae are the tiny spicules of bone crisscrossing the cancello ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiolucent
Radiodensity (or radiopacity) is opacity to the radio wave and X-ray portion of the electromagnetic spectrum: that is, the relative inability of those kinds of electromagnetic radiation to pass through a particular material. Radiolucency or hypodensity indicates greater passage (greater transradiancy) to X-ray photonsNovelline, Robert. ''Squire's Fundamentals of Radiology''. Harvard University Press. 5th edition. 1997. . and is the analogue of transparency and translucency with visible light. Materials that inhibit the passage of electromagnetic radiation are called radiodense or radiopaque, while those that allow radiation to pass more freely are referred to as radiolucent. Radiopaque volumes of material have white appearance on radiographs, compared with the relatively darker appearance of radiolucent volumes. For example, on typical radiographs, bones look white or light gray (radiopaque), whereas muscle and skin look black or dark gray, being mostly invisible (radiolucent). Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periodontium
The periodontium () is the specialized tissues that both surround and support the teeth, maintaining them in the maxillary and mandibular bones. Periodontics is the dental specialty that relates specifically to the care and maintenance of these tissues. It provides the support necessary to maintain teeth in function. It consists of four principal components, namely: * Gingiva (the gums) * Periodontal ligament (PDL) * Cementum * Alveolar bone proper Each of these components is distinct in location, architecture, and biochemical properties, which adapt during the life of the structure. For example, as teeth respond to forces or migrate medially, bone resorbs on the pressure side and is added on the tension side. Cementum similarly adapts to wear on the occlusal surfaces of the teeth by apical deposition. The periodontal ligament in itself is an area of high turnover that allows the tooth not only to be suspended in the alveolar bone but also to respond to the forces. Thus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
