Teeth
The teeth of a grown person.

Teeth (singular, tooth) are small white structures found in the jaws (or mouths) of many vertebrates that are used to tear, scrape, milk and chew food. The jaw is either of the two opposable structures forming or near the entrance to the Mouth. Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes Food is any substance usually composed primarily of Carbohydrates Fats water and/or Proteins that can be eaten or drunk by an Some animals, particularly carnivores, also use teeth for hunting or defense. A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting The roots of teeth are covered by gums. The gingiva (sing and plur: gingiva) or gums, consists of the Mucosal tissue that lies over the Alveolar bone.

Teeth are among the most distinctive (and long-lasting) features of mammal species. Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Paleontologists use teeth to identify fossil species and determine their relationships. Palaeontology redirects here For the Scientific journal, see Palaeontology (journal. FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. The shape of the animal's teeth are related to its diet. For example, plant matter is hard to digest, so herbivores have many molars for chewing. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Molars are the rearmost and most complicated kind of Tooth in most Mammals In many mammals they grind food hence the Latin name mola, " Millstone Carnivores, on the other hand, need canines to kill and tear meat. A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting "Cuspid" redirects here For the heart valves see Bicuspid valve and Tricuspid valve.

Mammals are diphyodont, meaning that they develop two sets of teeth. Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands In humans, the first set (the "baby," "milk," "primary" or "deciduous" set) normally starts to appear at about six months of age, although some babies are born with one or more visible teeth, known as Neonatal teeth. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus See also Deciduous. "Baby teeth" redirects here For the band of that name see Baby Teeth (band. Natal teeth are Teeth that are present at birth Neonatal teeth are teeth that emerge through the Gingiva during the first month of life Normal tooth eruption at about six months is known as teething and can be painful. Tooth eruption is a process in Tooth development in which the teeth enter the Mouth and become visible Teething is the process by which an Infant 's Teeth sequentially appear by breaking through the gums

Some animals develop only one set of teeth (monophyodont) while others develop many sets (polyphyodont). Sharks, for example, grow a new set of teeth every two weeks to replace worn teeth. Sharks ( Superorder Selachimorpha) are a type of Fish with a full cartilaginous Skeleton and a highly streamlined body Rodent incisors grow and wear away continually through gnawing, maintaining relatively constant length. Rodentia is an order of Mammals also known as rodents, characterised by two continuously-growing incisors in the upper and lower jaws which must Some rodent species, such as the sibling vole and the guinea pig, have continuously growing molars in addition to incisors. ^[1][2]

Anatomy

A third molar.

Main article: Dental anatomy

Dental anatomy is a field of anatomy dedicated to the study of tooth structures. Dental anatomy or anatomy of teeth is a field of Anatomy dedicated to the study human teeth structures Anatomy (from the Greek anatomia, from ana separate apart from and temnein, to cut up cut open is a branch of Biology that is the consideration The development, appearance, and classification of teeth fall within its field of study, though dental occlusion, or contact among teeth, does not. Occlusion, in a dental context means simply the contact between teeth Dental anatomy is also a taxonomical science as it is concerned with the naming of teeth and their structures. Taxonomy is the practice and science of classification The word comes from the Greek, taxis (meaning 'order' 'arrangement' and, nomos This information serves a practical purpose for dentists, enabling them to easily identify teeth and structures during treatment.

The anatomic crown of a tooth is the area covered in enamel above the cementoenamel junction (CEJ). The cementoenamel junction, frequently abbreviated as the CEJ, is an anatomical landmark identified on a Tooth. ^[3] The majority of the crown is composed of dentin with the pulp chamber in the center. ^[4] The crown is within bone before eruption. Tooth eruption is a process in Tooth development in which the teeth enter the Mouth and become visible ^[5] After eruption, it is almost always visible. The anatomic root is found below the cementoenamel junction and is covered with cementum. Cementum is a specialized calcified substance covering the root of a tooth. As with the crown, dentin composes most of the root, which normally have pulp canals. A tooth may have multiple roots or just one root. Canines and most premolars, except for maxillary (upper) first premolars, usually have one root. Maxillary first premolars and mandibular molars usually have two roots. Maxillary molars usually have three roots. Additional roots are referred to as supernumerary roots. Supernumerary roots is a condition found in Teeth there may be a larger number of roots than expected

Models of human teeth as they exist within the alveolar bone. The alveolar process is the thickened ridge of Bone that contains the Tooth sockets on bones that bear teeth.

Humans usually have 20 primary teeth (also called deciduous, baby, or milk teeth) and 32 permanent teeth. Among primary teeth, 10 are found in the (upper) maxilla and the other 10 in the (lower) mandible. This article is about the Mammal maxilla For Arthropod maxillae see Mouthparts; for Insect maxillae in particular see Insect mouthparts The mandible (from Latin mandibula, "jawbone" or inferior maxillary bone forms the lower Jaw and holds the lower teeth in place Teeth are classified as incisors, canines, and molars. In the primary set of teeth, there are two types of incisors, centrals and laterals, and two types of molars, first and second. All primary teeth are replaced with permanent counterparts except for molars, which are replaced by permanent premolars. Among permanent teeth, 16 are found in the maxilla with the other 16 in the mandible. The maxillary teeth are the maxillary central incisor, maxillary lateral incisor, maxillary canine, maxillary first premolar, maxillary second premolar, maxillary first molar, maxillary second molar, and maxillary third molar. 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 The maxillary lateral incisor is the Tooth located distally (away from the midline of the Face) from both Maxillary central incisors of the Mouth The maxillary canine is the Tooth located laterally (away from the midline of the Face) from both Maxillary lateral incisors of the Mouth The maxillary first premolar is the Tooth located laterally (away from the midline of the Face) from both the Maxillary canines of the Mouth The maxillary second premolar is the Tooth located laterally (away from the midline of the Face) from both the Maxillary first premolars of the 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 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 The maxillary third molar, commonly known as a wisdom tooth, is the Tooth located laterally (away from the midline of the Face) from both the The mandibular teeth are the mandibular central incisor, mandibular lateral incisor, mandibular canine, mandibular first premolar, mandibular second premolar, mandibular first molar, mandibular second molar, and mandibular third molar. The mandibular central incisor is the Tooth located on the jaw, adjacent to the midline of the Face. The mandibular lateral incisor is the Tooth located distally (away from the midline of the Face) from both Mandibular central incisors of the Mouth The mandibular canine is the Tooth located distally (away from the midline of the Face) from both Mandibular lateral incisors of the Mouth but The mandibular first premolar is the Tooth located laterally (away from the midline of the Face) from both the Mandibular canines of the Mouth The mandibular second premolar is the Tooth located distally (away from the midline of the Face) from both the Mandibular first premolars of the The mandibular first molar or six-year molar is the Tooth located distally (away from the midline of the Face) from both the Mandibular second 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 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 Third molars are commonly called "wisdom teeth" and may never erupt into the mouth or form at all. If any additional teeth form, for example, fourth and fifth molars, which are rare, they are referred to as supernumerary teeth. Hyperdontia is the condition of having supernumerary teeth, or teeth which appear in addition to the regular number of teeth ^[6]

Most teeth have identifiable features that distinguish them from others. There are several different notation systems to refer to a specific tooth. Dentists, in writing or speech use several different Dental notation systems for associating information to a specific tooth The three most commons systems are the FDI World Dental Federation notation, the universal numbering system, and Palmer notation method. The Universal numbering system is a dental notation system for associating information to a specific tooth and is commonly used in the United States. Palmer notation (also known as the Military Tooth Numbering System is a system used by dentists to associate information to a specific tooth The FDI system is used worldwide, and the universal is used widely in the United States.

Parts

Section of a human molar

Enamel

Main article: Tooth enamel

Enamel is the hardest and most highly mineralized substance of the body and is one of the four major tissues which make up the tooth, along with dentin, cementum, and dental pulp. 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 Dentin ( BE: dentine) is a calcified tissue of the body and along with enamel, Cementum, and pulp is one of the four Cementum is a specialized calcified substance covering the root of a tooth. The dental pulp is the part in the center of a Tooth made up of living soft tissue and cells called Odontoblasts Anatomy ^[7] It is normally visible and must be supported by underlying dentin. Ninety-six percent of enamel consists of mineral, with water and organic material composing the rest. ^[8] 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. A cusp is an occlusal or incisal eminence on a tooth Canine teeth otherwise known as cuspids, each possess a single cusp while Premolars 5 mm, and thinnest at its border, which is seen clinically as the cementoenamel junction (CEJ). The cementoenamel junction, frequently abbreviated as the CEJ, is an anatomical landmark identified on a Tooth. ^[9]

Enamel's primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Hydroxylapatite, also called hydroxyapatite, is a Mineral. It is a naturally occurring form of calcium Apatite with the formula Ca5(PO43(OH In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating Calcium phosphate is the name given to a family of Minerals containing Calcium Ions (Ca2+ together with orthophosphates (PO43- ^[10] The large amount of minerals in enamel accounts not only for its strength but also for its brittleness. ^[11] Dentin, which is less mineralized and less brittle, compensates for enamel and is necessary as a support. ^[10] Unlike dentin and bone, enamel does not contain collagen. Bones are rigid organs that form part of the Endoskeleton of Vertebrates They function to move support and protect the various organs of the body produce Collagen is the main Protein of Connective tissue in Animals and the most abundant protein in Mammals making up about 50% of the whole-body protein Instead, it has two unique classes of proteins called amelogenins and enamelins. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Amelogenin is a low-molecular-weight Protein found in developing Tooth enamel, and it belongs to a family of extracellular matrix (ECM proteins Enamelin is a protein found in developing Tooth enamel. About 30 % of developing enamel consists of protein of which enamelins comprise While the role of these proteins is not fully understood, it is believed that they aid in the development of enamel by serving as framework support among other functions. ^[12]

Dentin

Main article: Dentin

Dentin is the substance between enamel or cementum and the pulp chamber. Dentin ( BE: dentine) is a calcified tissue of the body and along with enamel, Cementum, and pulp is one of the four It is secreted by the odontoblasts of the dental pulp. ^[13] The formation of dentin is known as dentinogenesis. Dentinogenesis is the formation of Dentin, a substance that forms the majority of teeth. The porous, yellow-hued material is made up of 70% inorganic materials, 20% organic materials, and 10% water by weight. ^[14] Because it is softer than enamel, it decays more rapidly and is subject to severe cavities if not properly treated, but dentin still acts as a protective layer and supports the crown of the tooth.

Dentin is a mineralized connective tissue with an organic matrix of collagenous proteins. Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, Muscle, and Nervous tissue) Dentin has microscopic channels, called dentinal tubules, which radiate outward through the dentin from the pulp cavity to the exterior cementum or enamel border. ^[15] The diameter of these tubules range from 2. 5 μm near the pulp, to 1. 2 μm in the midportion, and 900 nm near the dentino-enamel junction. ^[16] Although they may have tiny side-branches, the tubules do not intersect with each other. Their length is dictated by the radius of the tooth. The three dimensional configuration of the dentinal tubules is genetically determined.

Cementum

Main article: Cementum

Cementum is a specialized bony substance covering the root of a tooth. Cementum is a specialized calcified substance covering the root of a tooth. ^[13] It is approximately 45% inorganic material (mainly hydroxyapatite), 33% organic material (mainly collagen) and 22% water. Hydroxylapatite, also called hydroxyapatite, is a Mineral. It is a naturally occurring form of calcium Apatite with the formula Ca5(PO43(OH Collagen is the main Protein of Connective tissue in Animals and the most abundant protein in Mammals making up about 50% of the whole-body protein Cementum is excreted by cementoblasts within the root of the tooth and is thickest at the root apex. A cementoblast is a biological cell that forms from the follicular cells around the root of a Tooth, and whose biological function is Cementogenesis, which Its coloration is yellowish and it is softer than either dentin or enamel. The principal role of cementum is to serve as a medium by which the periodontal ligaments can attach to the tooth for stability. The periodontal ligament, commonly abbreviated as the PDL is a group of specialized Connective tissue fibers that essentially attach a tooth to the Alveolar bone At the cementoenamel junction, the cementum is acellular due to its lack of cellular components, and this acellular type covers at least ⅔ of the root. ^[17] The more permeable form of cementum, cellular cementum, covers about ⅓ of the root apex. ^[18]

Pulp

Main article: Pulp (tooth)

The dental pulp is the central part of the tooth filled with soft connective tissue. The dental pulp is the part in the center of a Tooth made up of living soft tissue and cells called Odontoblasts Anatomy ^[14] This tissue contains blood vessels and nerves that enter the tooth from a hole at the apex of the root. ^[19] Along the border between the dentin and the pulp are odontoblasts, which initiate the formation of dentin. ^[14] Other cells in the pulp include fibroblasts, preodontoblasts, macrophages and T lymphocytes. Macrophages ( Greek: "big eaters" from makros "large" + phagein "eat" ( Mø) are cells within the tissues that T cells belong to a group of White blood cells known as Lymphocytes, and play a central role in Cell-mediated immunity. ^[20] The pulp is commonly called "the nerve" of the tooth.

Development

Main article: Tooth development

Radiograph of lower right third, second, and first molars in different stages of development. Tooth development is the complex process by which teeth form from Embryonic cells, grow, and erupt into the Mouth.

Tooth development is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called The term cell growth is used in two different ways in Biology. The mouth, buccal cavity, or oral cavity is the first portion of the Alimentary canal that receives food and begins digestion by mechanically breaking up Although many diverse species have teeth, non-human tooth development is largely the same as in humans. In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. For human teeth to have a healthy oral environment, enamel, dentin, cementum, and the periodontium must all develop during appropriate stages of fetal development. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus The mouth, buccal cavity, or oral cavity is the first portion of the Alimentary canal that receives food and begins digestion by mechanically breaking up 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 Dentin ( BE: dentine) is a calcified tissue of the body and along with enamel, Cementum, and pulp is one of the four Cementum is a specialized calcified substance covering the root of a tooth. Periodontium refers to the specialized tissues that both surround and support the Teeth, maintaining them in the maxillary and mandibular bones Prenatal development is the process in which an embryo or fetus (or foetus) gestates during Pregnancy, from fertilization 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. See also Deciduous. "Baby teeth" redirects here For the band of that name see Baby Teeth (band. The uterus (from the Latin word for womb) is the major Female reproductive organ of most Mammals including Humans One end the Permanent teeth are the second set of Teeth formed in humans There are thirty-two permanent teeth consisting of six Maxillary and six mandibular ^[21] 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. In the development of vertebrate animals, the pharyngeal arches (also called branchial arches or gill arches in fish develop during the fourth ^[22]

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. ^[22] 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.

The tooth bud (sometimes called the tooth germ) is an aggregation of cells that eventually forms a tooth. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called It is organized into three parts: the enamel organ, the dental papilla and the dental follicle. The enamel organ, also known as dental organ, is a cellular aggregation seen in histologic sections of a developing Tooth. The dental papilla is a condensation of Ectomesenchymal cells called Odontoblasts seen in histologic sections of a developing tooth The dental follicle is a sac containing the developing Tooth and its odontogenic organ. ^[23] The enamel organ is composed of the outer enamel epithelium, inner enamel epithelium, stellate reticulum and stratum intermedium. The outer enamel epithelium, also known as the external enamel epithelium, is a layer of cuboidal cells located on the periphery of the Enamel organ in The inner enamel epithelium, also known as the internal enamel epithelium, is a layer of cells located on the rim nearest the Dental papilla of the The stellate reticulum is a group of cells located in the center of the Enamel organ of a developing Tooth. The stratum intermedium in a developing tooth is a layer of two or three cells between the Inner enamel epithelium and the newly forming cells of the ^[23] These cells give rise to ameloblasts, which produce enamel and the reduced enamel epithelium. Ameloblasts are cells that deposit enamel, the hard outer most layer that forms the chewing surface The reduced enamel epithelium, sometimes called reduced dental epithelium, overlies a developing Tooth and is formed by two layers a layer of Ameloblast The growth of cervical loop cells into the deeper tissues forms Hertwig's Epithelial Root Sheath, which determines a tooth's root shape. The Hertwig's epithelial root sheath (frequently abbreviated as "HERS" is a proliferation of epithelial cells located at the Cervical loop The dental papilla contains cells that develop into odontoblasts, which are dentin-forming cells. An odontoblast is a biological cell of Neural crest origin that is part of the outer surface of the dental pulp, and whose biological function is Dentinogenesis ^[23] Additionally, the junction between the dental papilla and inner enamel epithelium determines the crown shape of a tooth. ^[24] The dental follicle gives rise to three important entities: cementoblasts, osteoblasts, and fibroblasts. A cementoblast is a biological cell that forms from the follicular cells around the root of a Tooth, and whose biological function is Cementogenesis, which An osteoblast (from the Greek words for " Bone " and "germ" or embryonic is a mononucleate cell that is responsible for bone formation A fibroblast is a type of cell that synthesizes and maintains the Extracellular matrix of many Animal tissues Cementoblasts form the cementum of a tooth. Osteoblasts give rise to the alveolar bone around the roots of teeth. The alveolar process is the thickened ridge of Bone that contains the Tooth sockets on bones that bear teeth. Fibroblasts develop the periodontal ligaments which connect teeth to the alveolar bone through cementum. The periodontal ligament, commonly abbreviated as the PDL is a group of specialized Connective tissue fibers that essentially attach a tooth to the Alveolar bone ^[25]

Eruption

Main article: Tooth eruption

Tooth eruption in humans is a process in tooth development in which the teeth enter the mouth and become visible. Tooth eruption is a process in Tooth development in which the teeth enter the Mouth and become visible Current research indicates that the periodontal ligaments play an important role in tooth eruption. Primary teeth erupt into the mouth from around six months until two years of age. These teeth are the only ones in the mouth until a person is about six years old. At that time, the first permanent tooth erupts. This stage, during which a person has a combination of primary and permanent teeth, is known as the mixed stage. The mixed stage lasts until the last primary tooth is lost and the remaining permanent teeth erupt into the mouth.

There have been many theories about the cause of tooth eruption. One theory proposes that the developing root of a tooth pushes it into the mouth. ^[26] Another, known as the cushioned hammock theory, resulted from microscopic study of teeth, which was thought to show a ligament around the root. In Anatomy, the term ligament is used to denote three different types of structures Fibrous tissue that connects Bones to other bones It was later discovered that the "ligament" was merely an artifact created in the process of preparing the slide. In Natural science and Signal processing, an artifact is any perceived Distortion or other Data error caused by the instrument of observation ^[27] Currently, the most widely held belief is that the periodontal ligaments provide the main impetus for the process. ^[28]

The onset of primary tooth loss has been found to correlate strongly with somatic and psychological criteria of school readiness. ^[29][30]

Supporting structures

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

The periodontium is the supporting structure of a tooth, helping to attach the tooth to surrounding tissues and to allow sensations of touch and pressure. Periodontium refers to the specialized tissues that both surround and support the Teeth, maintaining them in the maxillary and mandibular bones ^[31] It consists of the cementum, periodontal ligaments, alveolar bone, and gingiva. The alveolar process is the thickened ridge of Bone that contains the Tooth sockets on bones that bear teeth. The gingiva (sing and plur: gingiva) or gums, consists of the Mucosal tissue that lies over the Alveolar bone. Of these, cementum is the only one that is a part of a tooth. Periodontal ligaments connect the alveolar bone to the cementum. Alveolar bone surrounds the roots of teeth to provide support and creates what is commonly called an alveolus, or "socket". Dental alveolus (plural alveoli) are Sockets in the Jaws in which the roots of Teeth are held in the Alveolar process of maxilla with Lying over the bone is the gingiva or gum, which is readily visible in the mouth. The gingiva (sing and plur: gingiva) or gums, consists of the Mucosal tissue that lies over the Alveolar bone.

Periodontal ligaments

The periodontal ligament is a specialized connective tissue that attaches the cementum of a tooth to the alveolar bone. Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, Muscle, and Nervous tissue) This tissue covers the root of the tooth within the bone. Each ligament has a width of 0. 15 - 0. 38 mm, but this size decreases over time. ^[32] The functions of the periodontal ligaments include attachment of the tooth to the bone, support for the tooth, formation and resorption of bone during tooth movement, sensation, and eruption. Bone resorption is the process by which Osteoclasts break down Bone and release the Minerals resulting in a transfer of calcium from bone fluid to the blood ^[33] The cells of the periodontal ligaments include osteoblasts, osteoclasts, fibroblasts, macrophages, cementoblasts, and epithelial cell rests of Malassez. Hertwig's epithelial root sheath --> In dentistry the epithelial cell rests of Malassez or epithelial rests of Malassez (frequently abbreviated ^[34] Consisting of mostly Type I and III collagen, the fibers are grouped in bundles and named according to their location. Collagen is the main Protein of Connective tissue in Animals and the most abundant protein in Mammals making up about 50% of the whole-body protein The groups of fibers are named alveolar crest, horizontal, oblique, periapical, and interradicular fibers. ^[35] The nerve supply generally enters from the bone apical to the tooth and forms a network around the tooth toward the crest of the gingiva. ^[36] When pressure is exerted on a tooth, such as during chewing or biting, the tooth moves slightly in its socket and puts tension on the periodontal ligaments. The nerve fibers can then send the information to the central nervous system for interpretation.

Alveolar bone

The alveolar bone is the bone of the jaw which forms the alveolus around teeth. The alveolar process is the thickened ridge of Bone that contains the Tooth sockets on bones that bear teeth. ^[37] 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. An osteoblast (from the Greek words for " Bone " and "germ" or embryonic is a mononucleate cell that is responsible for bone formation An osteoclast (from the Greek words for "bone" and "broken" is a type of Bone cell that removes Bone tissue by removing its Mineralized matrix ^[31] 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. Physical compression is the result of the subjection of a material to Compressive stress, resulting in reduction of Volume. In Physics, a force is whatever can cause an object with Mass to Accelerate. Bone resorption is the process by which Osteoclasts break down Bone and release the Minerals resulting in a transfer of calcium from bone fluid to the blood 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. In Physics String Tension is the magnitude of the pulling force exerted by a string cable chain or similar object on another object

Gingiva

The gingiva ("gums") is the mucosal tissue that overlays the jaws. The gingiva (sing and plur: gingiva) or gums, consists of the Mucosal tissue that lies over the Alveolar bone. The mucous membranes (or mucosae; singular mucosa) are linings of mostly endodermal origin covered in Epithelium, which are involved in There are three different types of epithelium associated with the gingiva: gingival, junctional, and sulcular epithelium. These three types form from a mass of epithelial cells known as the epithelial cuff between the tooth and the mouth. ^[38] The gingival epithelium is not associated directly with tooth attachment and is visible in the mouth. The junctional epithelium, composed of the basal lamina and hemidesmosomes, forms an attachment to the tooth. The basal lamina is a layer of extracellular matrix on which Epithelium sits and which is secreted by the epithelial cells Hemidesmosomes (HD are very small stud- or rivet-like structures on the inner basal surface of Keratinocytes in the epidermis of skin ^[33] The sulcular epithelium is nonkeratinized stratified squamous tissue on the gingiva which touches but is not attached to the tooth. Epidermis is the outermost layer of the Skin. It forms the waterproof protective wrap over the body's surface and is made up of stratified squamous Epithelium with In Anatomy, squamous epithelium (from Latin squama, "scale" is an Epithelium characterised by its most superficial layer consisting ^[39] This leaves a small potential space between the gingiva and tooth which can collect bacteria, plaque, and calculus.

Tooth decay

Plaque

Main article: Dental plaque

Plaque is a biofilm consisting of large quantities of various bacteria that form on teeth. Dental plaque is Biofilm (usually colorless that builds up on the Teeth. A biofilm is a structured community of Microorganisms encapsulated within a self-developed polymeric matrix and adherent to a living or inert surface The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have ^[40] If not removed regularly, plaque buildup can lead to dental cavities (caries) or periodontal problems such as gingivitis. Dental caries is a disease that damages Tooth structures resulting in what is commonly called tooth decay or cavities which are holes in the teeth Periodontology, or Periodontics, is the branch of Dentistry which studies supporting structures of teeth, and diseases and conditions that affect them Gingivitis (" Inflammation of the gums quot ( Gingiva) around the Teeth is a general term for gingival diseases affecting the gingiva Given time, plaque can mineralize along the gingiva, forming tartar. In Dentistry, calculus or tartar refers to calcified deposits on the teeth, formed by the continuous presence of Dental plaque. The microorganisms that form the biofilm are almost entirely bacteria (mainly streptococcus and anaerobes), with the composition varying by location in the mouth. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Streptococcus is a Genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the An anaerobic organism is any Organism that does not require Oxygen for growth and may even die in its presence ^[41] Streptococcus mutans is the most important bacteria associated with dental caries. Streptococcus mutans is a Gram-positive, facultatively anaerobic Bacteria commonly found in the Human Oral cavity and is

Certain bacteria in the mouth live off the remains of foods, especially sugars and starches. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. In the absence of oxygen they produce lactic acid, which dissolves the calcium and phosphorus in the enamel. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Lactic acid ( IUPAC Systematic name: 2-hydroxypropanoic acid) also known as milk acid, is a Chemical compound that plays a role Solvation, commonly called dissolution, is the process of attraction and association of Molecules of a Solvent with molecules or Ions of a Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 ^[13][42] This process, known as "demineralisation", leads to tooth destruction. Saliva gradually neutralises the acids which cause the pH of the tooth surface to rise above the critical pH. For the band see Saliva (band; for the village in Azerbaijan see Səliva. In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are This causes 'remineralisation', the return of the dissolved minerals to the enamel. In Biogeochemistry, remineralisation refers to the transformation of Organic molecules to Inorganic forms typically mediated by biological activity If there is sufficient time between the intake of foods then the impact is limited and the teeth can repair themselves. Saliva is unable to penetrate through plaque, however, to neutralize the acid produced by the bacteria.

Caries (Cavities)

Tooth decay on a premolar.

Main article: Dental caries

Dental caries, also described as "tooth decay" or "dental cavities", is an infectious disease which damages the structures of teeth. Dental caries is a disease that damages Tooth structures resulting in what is commonly called tooth decay or cavities which are holes in the teeth ^[43] The disease can lead to pain, tooth loss, infection, and, in severe cases, death. Pain, in the sense of physical pain, is a typical sensory experience that may be described as the unpleasant awareness of a noxious stimulus or bodily harm Tooth loss is when one or more Teeth come loose and fall out Tooth loss is normal for deciduous teeth (baby teeth, when they are replaced by a person's adult Dental caries has a long history, with evidence showing the disease was present in the Bronze, Iron, and Middle ages but also prior to the neolithic period. The term Bronze Age refers to a period in human cultural development when the most advanced Metalworking (at least in systematic and widespread use included techniques for This article is about the archaeological period known as the Iron Age for the mythological Iron Age see Ages of Man. The Neolithic (from Greek νεολιθικός — neolithikos from νέος neos, "new" + λίθος lithos ^[44] The largest increases in the prevalence of caries have been associated with diet changes. ^[44][45] Today, caries remains one of the most common diseases throughout the world. In the United States, dental caries is the most common chronic childhood disease, being at least five times more common than asthma. In Medicine, a chronic disease is a Disease that is long-lasting or recurrent Asthma is a chronic Condition involving the Respiratory system in which the airways occasionally constrict become inflamed, and are ^[46] Countries that have experienced an overall decrease in cases of tooth decay continue to have a disparity in the distribution of the disease. ^[47] Among children in the United States and Europe, 60-80% of cases of dental caries occur in 20% of the population. ^[48]

Tooth decay is caused by certain types of acid-producing bacteria which cause the most damage in the presence of fermentable carbohydrates such as sucrose, fructose, and glucose. Fermentation in Food processing typically refers to the conversion of Sugar to Alcohol using Yeast under Anaerobic conditions Carbohydrates (from ' Hydrates of Carbon ' or saccharides ( Greek σάκχαρον meaning " Sugar " are the most Solubility of Pure SucroseTemperature(Cg Fructose (also levulose or laevulose) is a simple reducing Sugar ( Monosaccharide) found in many foods and is one of the three Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. ^[49][50] The resulting acidic levels in the mouth affect teeth because a tooth's special mineral content causes it to be sensitive to low pH. pH is the measure of the acidity or alkalinity of a Solution. Depending on the extent of tooth destruction, various treatments can be used to restore teeth to proper form, function, and aesthetics, but there is no known method to regenerate large amounts of tooth structure. A dental restoration or dental filling is a Dental restorative material used artificially to restore the function integrity and morphology of missing tooth Aesthetics or esthetics ( also spelled æsthetics) is commonly known as the study of sensory or sensori-emotional values sometimes called In Biology, an Organism is said to regenerate a lost or damaged part if the part regrows so that the original function is restored Instead, dental health organizations advocate preventative and prophylactic measures, such as regular oral hygiene and dietary modifications, to avoid dental caries. Oral hygiene is the practice of keeping the Mouth and Teeth clean in order to prevent dental problems and bad breath. ^[51]

Tooth care

Toothbrushes are commonly used to clean teeth. The toothbrush is an instrument consisting of a small Brush on a handle used to clean Teeth through Tooth brushing.

Main article: Oral hygiene

Oral hygiene is the practice of keeping the mouth clean and is a means of preventing dental caries, gingivitis, periodontal disease, bad breath, and other dental disorders. Oral hygiene is the practice of keeping the Mouth and Teeth clean in order to prevent dental problems and bad breath. Gingivitis (" Inflammation of the gums quot ( Gingiva) around the Teeth is a general term for gingival diseases affecting the gingiva Halitosis, oral malodor, breath odor mouth odor foul breath fetor oris fetor ex ore or most commonly bad breath are terms used to describe noticeably unpleasant It consists of both professional and personal care. Regular cleanings, usually done by dentists and dental hygienists, remove tartar (mineralized plaque) that may develop even with careful brushing and flossing. In Dentistry, calculus or tartar refers to calcified deposits on the teeth, formed by the continuous presence of Dental plaque. Tooth brushing is the act of cleaning Teeth with a Toothbrush. Dental floss is either a bundle of thin Nylon filaments or a plastic ( teflon or polyethylene) ribbon used to remove Food and Dental Professional cleaning includes tooth scaling, using various instruments or devices to loosen and remove deposits from teeth. The objective of scaling and root planing, otherwise known as conventional periodontal therapy or non-surgical periodontal therapy, is to remove or eliminate the etiologic

The purpose of cleaning teeth is to remove plaque, which consists mostly of bacteria. ^[52] Healthcare professionals recommend regular brushing twice a day (in the morning and in the evening, or after meals) in order to prevent formation of plaque and tartar. ^[51] A toothbrush is able to remove most plaque, excepting areas between teeth. As a result, flossing is also considered a necessity to maintain oral hygiene. When used correctly, dental floss removes plaque from between teeth and at the gum line, where periodontal disease often begins and could develop caries. The gingiva (sing and plur: gingiva) or gums, consists of the Mucosal tissue that lies over the Alveolar bone. Electric toothbrushes are not considered more effective than manual brushes for most people. An electric toothbrush is a Toothbrush that uses electric power to move the brush head normally in an Oscillating pattern though electric toothbrushes are often ^[53] The most important advantage of electric toothbrushes is their ability to aid people with dexterity difficulties, such as those associated with rheumatoid arthritis. Rheumatoid arthritis ( RA) is a chronic systemic autoimmune disorder that causes the Immune system to attack the Joints, where

In addition, fluoride therapy is often recommended to protect against dental caries. Fluoride therapy is the delivery of Fluoride to the Teeth Topically or systemically in order to prevent Tooth decay ( Dental caries Water fluoridation and fluoride supplements decrease the incidence of dental caries. Water fluoridation is the addition of a chemical to increase the concentration of Fluoride Ions in Drinking water with the purpose of reducing the Fluoride is the reduced form of Fluorine. Both organic and Inorganic compounds containing the element fluorine are considered fluorides Fluoride helps prevent dental decay by binding to the hydroxyapatite crystals in enamel. ^[54] The incorporated fluoride makes enamel more resistant to demineralization and thus more resistant to decay. ^[55] Topical fluoride, such as a fluoride toothpaste or mouthwash, is also recommended to protect teeth surfaces. Toothpaste is a Paste or Gel Dentifrice used to clean and maintain the aesthetics and health of Teeth. Mouthwash or mouth rinse is a product used for Oral hygiene. Antiseptic and anti-plaque mouth rinse claims to kill the bacterial plaque Many dentists include application of topical fluoride solutions as part of routine cleanings.

Restorations

After a tooth has been damaged or destroyed, restoration of the missing structure can be achieved with a variety of treatments. A dental restoration or dental filling is a Dental restorative material used artificially to restore the function integrity and morphology of missing tooth Restorations may be created from a variety of materials, including glass ionomer, amalgam, gold, porcelain, and composite. This page is about types of dental restorative materials For dental fillings see Dental restorations Dental restorative materials are specially fabricated materials Amalgam is a commonly used dental filling that has been used for over 150 years Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Dental porcelain (also known as dental ceramic) is a Porcelain used by a Dental technician to create Biocompatible lifelike crowns Dental composites, also called white fillings, are a group of restorative materials used in dentistry ^[56] Small restorations placed inside a tooth are referred to as "intracoronal restorations". These restorations may be formed directly in the mouth or may be cast using the lost-wax technique, such as for some inlays and onlays. Lost-wax casting, sometimes called by the French name of cire perdue, is the process by which a bronze is cast from an artist's sculpture in industrial uses the modern process In Dentistry, an inlay is a filling consisting of a solid substance (as Gold or Porcelain) fitted to a cavity in a tooth and cemented into place When larger portions of a tooth are lost, an "extracoronal restoration" may be fabricated, such as a crown or a veneer, to restore the involved tooth. Crown refers to the restoration of teeth using materials that are fabricated by indirect methods which are cemented into place In Dentistry, a veneer is a thin layer of restorative material placed over a Tooth surface either to improve the Aesthetics of a tooth or to

Picture of a restored premolar.

When a tooth is lost, dentures, bridges, or implants may be used as replacements. Dentures are prosthetic devices constructed to replace missing teeth and which are supported by surrounding soft and hard tissues of the Oral cavity. A dental bridge, otherwise known as a fixed partial denture is a Prosthesis used to replace missing Teeth and is not removable by the patient A dental implant is an Artificial tooth root replacement and is used in prosthetic Dentistry to support restorations that resemble a tooth or group of teeth ^[57] Dentures are usually the least costly whereas implants are usually the most expensive. Dentures may replace complete arches of the mouth or only a partial number of teeth. A removable partial denture (RPD is for a partially edentulous dental patient who desires to have replacement teeth for functional or esthetic reasons and who cannot have Bridges replace smaller spaces of missing teeth and use adjacent teeth to support the restoration. Dental implants may be used to replace a single tooth or a series of teeth. Though implants are the most expensive treatment option, they are often the most desirable restoration because of their esthetics and function. To improve the function of dentures, implants may be used as support. ^[58]

Abnormalities

Tooth abnormalities may be categorized according to whether they have environmental or developmental causes. ^[59] While environmental abnormalities may appear to have an obvious cause, there may not appear to be any known cause for some developmental abnormalities. Environmental forces may affect teeth during development, destroy tooth structure after development, discolor teeth at any stage of development, or alter the course of tooth eruption. Developmental abnormalities most commonly affect the number, size, shape, and structure of teeth.

Digestive

Alteration during tooth development

Tooth abnormalities caused by environmental factors during tooth development have long-lasting effects. Enamel and dentin do not regenerate after they mineralize initially. Enamel hypoplasia is a condition in which the amount of enamel formed is inadequate. ^[60] This results either in pits and grooves in areas of the tooth or in widespread absence of enamel. Diffuse opacities of enamel does not affect the amount of enamel but changes its appearance. Affected enamel has a different translucency than the rest of the tooth. Demarcated opacities of enamel have sharp boundaries where the translucency decreases and manifest a white, cream, yellow, or brown color. All these may be caused by a systemic event, such as an exanthematous fever. An exanthem (from Greek "exanthema" a breaking out) is a widespread Rash usually occurring in Children. Fever (also known as pyrexia, from the Greek pyretos meaning fire or a febrile response, from the Latin word Febris ^[61] Turner's hypoplasia is a portion of missing or diminished enamel on a permanent tooth usually from a prior infection of a nearby primary tooth. Turner's hypoplasia is an abnormality found in teeth. Its appearance is variable though usually is manifested as a portion of missing or diminished enamel on permanent Hypoplasia may also result from antineoplastic therapy. Antineoplastics (or "antitumor antibiotics" or "noncovalent DNA-binding drugs" or " Cytotoxic antibiotics" see also Neoplastics are Dental fluorosis is condition which results from ingesting excessive amounts of fluoride and leads to teeth which are spotted, yellow, brown, black or sometimes pitted. Dental fluorosis is a health condition caused by an overdose of fluoride Fluoride is the reduced form of Fluorine. Both organic and Inorganic compounds containing the element fluorine are considered fluorides Enamel hypoplasia resulting from syphilis is frequently referred to as Hutchinson's teeth, which is considered one part of Hutchinson's triad. Syphilis is a Sexually transmitted disease caused by the spirochetal Bacterium Treponema pallidum pallidum. Hutchinson's teeth (also known as Hutchinson's incisor Hutchinson's sign or Hutchinson-Boeck teeth are a sign of Congenital syphilis. Hutchinson's triad is named after Sir Jonathan Hutchinson (1828-1913 ^[62]

Destruction after development

Tooth destruction from processes other than dental caries is considered a normal physiologic process but may become severe enough to become a pathologic condition. Dental caries is a disease that damages Tooth structures resulting in what is commonly called tooth decay or cavities which are holes in the teeth Attrition is the loss of tooth structure by mechanical forces from opposing teeth. Attrition is the loss of Tooth structure by mechanical forces from opposing teeth ^[63] Attrition initially affects the enamel and, if unchecked, may proceed to the underlying dentin. Abrasion is the loss of tooth structure by mechanical forces from a foreign element. Abrasion is the loss of Tooth structure by mechanical forces from a foreign element ^[64] If this force begins at the cementoenamel junction, then progression of tooth loss can be rapid since enamel is very thin in this region of the tooth. A common source of this type of tooth wear is excessive force when using a toothbrush. Erosion is the loss of tooth structure due to chemical dissolution by acids not of bacterial origin. Erosion, otherwise known as acid erosion, is the loss of tooth structure due to chemical dissolution by acids not of bacterial origin ^[65][66] Signs of tooth destruction from erosion is a common characteristic in the mouths of people with bulimia since vomiting results in exposure of the teeth to gastric acids. Bulimia nervosa is an Eating disorder characterized by recurrent Binge eating, followed by compensatory behaviors referred to as "purging" Vomiting (also called throwing up, emesis) is the forceful expulsion of the contents of one's Stomach through the Mouth and sometimes the Another important source of erosive acids are from frequent sucking of lemon juice. The lemon ( Citrus × limon) is a hybrid in cultivated wild plants Abfraction is the loss of tooth structure from flexural forces. Abfraction is the loss of tooth structure from flexural forces As teeth flex under pressure, the arrangement of teeth touching each other, known as occlusion, causes tension on one side of the tooth and compression on the other side of the tooth. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Occlusion, in a dental context means simply the contact between teeth In Physics String Tension is the magnitude of the pulling force exerted by a string cable chain or similar object on another object Physical compression is the result of the subjection of a material to Compressive stress, resulting in reduction of Volume. This is believed to cause V-shaped depressions on the side under tension and C-shaped depressions on the side under compression. When tooth destruction occurs at the roots of teeth, the process is referred to as internal resorption, when caused by cells within the pulp, or external resorption, when caused by cells in the periodontal ligament. Internal resorption is an unusual condition of a Tooth when the dentin and pulpal walls begin to resorb centrally within the root canal External resorption is a condition of a Tooth where the root surface is lost

Discoloration

Discoloration of teeth may result from bacteria stains, tobacco, tea, coffee, foods with an abundance of chlorophyll, restorative materials, and medications. Chlorophyll is a green Pigment found in most Plants Algae and Cyanobacteria. ^[67] Stains from bacteria may cause colors varying from green to black to orange. Green stains also result from foods with chlorophyll or excessive exposure to copper or nickel. Amalgam, a common dental restorative material, may turn adjacent areas of teeth black or gray. Chlorhexidine, a mouthwash, is associated with causing yellow-brown stains near the gingiva on teeth. Chlorhexidine is a chemical Antiseptic.It kills (is bactericidal to both Gram-positive and Gram-negative Microbes although it is less effective Systemic disorders also can cause tooth discoloration. Congenital erythropoietic porphyria causes porphyrins to be deposited in teeth, causing a red-brown coloration. Porphyrias are a group of inherited or acquired disorders of certain Enzymes in the Heme biosynthetic pathway (also called Porphyrin pathway A porphyrin is a heterocyclic Macrocycle derived from four Pyrroline subunits interconnected via their α carbon atoms via Methine bridges (=CH- Blue discoloration may occur with alkaptonuria and rarely with Parkinson's disease. Alkaptonuria ( black urine disease or alcaptonuria) is a rare inherited genetic disorder of Tyrosine metabolism Parkinson's disease (also known as Parkinson disease or PD) is a degenerative disorder of the Central nervous system that often impairs the sufferer's Erythroblastosis fetalis and biliary atresia are diseases which may cause teeth to appear green from the deposition of biliverdin. Haemolytic disease of the newborn, also known as Haemolytic disease of the fetus and newborn, HDN, HDFN, or Erythroblastosis fetalis, is an Biliary atresia is a rare condition in newborn infants in which the common Bile duct between the Liver and the Small intestine is Biliverdin is a green Pigment formed as a byproduct of Heme breakdown Also, trauma may change a tooth to a pink, yellow, or dark gray color. Pink and red discolorations are also associated in patients with lepromatous leprosy. Leprosy (from the Greek lepi (λέπι meaning scales on a fish or Hansen's disease, is a chronic disease caused by the bacterium Some medications, such as tetracycline antibiotics, may become incorporated into the structure of a tooth, causing intrinsic staining of the teeth. This article deals with the specific antibiotic called tetracycline

Alteration of eruption

Tooth eruption may be altered by some environmental factors. When eruption is prematurely stopped, the tooth is said to be impacted. The most common cause of tooth impaction is lack of space in the mouth for the tooth. ^[68] Other causes may be tumors, cysts, trauma, and thickened bone or soft tissue. See also Cancer A tumor or tumour is the name for a swelling or lesion formed by an abnormal growth of cells (termed neoplastic A cyst is a closed sac having a distinct membrane and Division on the nearby tissue. Ankylosis of a tooth occurs when the tooth has already erupted into the mouth but the cementum or dentin has fused with the alveolar bone. Ankylosis, or Anchylosis (from Greek αγκυλος bent crooked is a stiffness of a Joint, the result of Injury or Disease. This may cause a person to retain their primary tooth instead of having it replaced by a permanent one.

A technique for altering the natural progression of eruption is employed by orthodontists who wish to delay or speed up the eruption of certain teeth for reasons of space maintenance or otherwise preventing crowding and/or spacing. Orthodontics is a specialty of Dentistry that is concerned with the study and treatment of Malocclusions (improper bites which may be a result of Tooth If a primary tooth is extracted prior to the root of its succeeding permanent tooth reaching ⅓ of its total growth, the eruption of the permanent tooth will be delayed. Conversely, if the roots of the permanent tooth are more than ⅔ complete, the eruption of the permanent tooth will be accelerated. Between ⅓ and ⅔, it is unknown exactly what will occur to the speed of eruption.

Developmental

Abnormality in number

Anodontia is the total lack of tooth development. In Dentistry, anodontia, also called anodontia vera, is a rare Genetic disorder characterized by the congenital absence of all primary Hyperdontia is the presence of a higher-than-normal number of teeth, where as Hypodontia is the lack of some teeth. Hyperdontia is the condition of having supernumerary teeth, or teeth which appear in addition to the regular number of teeth In Dentistry, hypodontia is the condition of naturally having fewer than the regular number of teeth. Usually, hypodontia refers to the lack of development of one or more teeth, and oligodontia may be used to describe the absence of 6 or more teeth. Some systemic disorders which may result in hyperdontia include Apert syndrome, Cleidocranial dysostosis, Crouzon syndrome, Ehlers-Danlos syndrome, Gardner syndrome, and Sturge-Weber syndrome. Cleidocranial dysostosis, also called Cleidocranial dysplasia, is a Hereditary Congenital disorder due to Haploinsufficiency caused by mutations Crouzon Syndrome is a genetic disorder known as a Branchial arch syndrome Ehlers-Danlos syndrome is a group of rare Genetic disorders affecting humans caused by a defect in Collagen synthesis Gardner's syndrome is a genetic disorder characterized by the presence of multiple polyps in the colon together with tumors outside the colon Sturge-Weber syndrome, sometimes referred to as encephalotrigeminal angiomatosis, is a rare Congenital neurological and Skin disorder ^[69] Some systemic disorders which may result in hypodontia include Crouzon syndrome, Ectodermal dysplasia, Ehlers-Danlos syndrome, and Gorlin syndrome. Ectodermal dysplasia is not a single disorder but a group of syndromes all deriving from abnormalities of the ectodermal structures The Nevoid Basal Cell Carcinoma Syndrome (NBCCS (also known as Basal Cell Nevus Syndrome, Multiple Basal Cell Carcinoma Syndrome, Gorlin syndrome ^[70]

Abnormality in size

Microdontia is a condition where teeth are smaller than the usual size, and macrodontia is where teeth are larger than the usual size. Microdontia is a condition in which Teeth appear smaller than normal Macrodontia is a condition in which the Teeth appear larger than normal Microdontia of a single tooth is more likely to occur in a 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 The second most likely tooth to have microdontia are third molars. Macrodontia of all the teeth is known to occur in pituitary gigantism and pineal hyperplasia. Gigantism or giantism, (from Greek gigas, gigantas " giant " is a condition characterized by excessive growth and height The pineal gland (also called the pineal body, epiphysis cerebri, or epiphysis) is a small endocrine gland in the vertebrate Brain Hyperplasia (or "hypergenesis" is a general term referring to the proliferation of cells within an organ or tissue beyond that which is ordinarily seen in e It may also occur on one side of the face in cases of hemifacial hyperplasia.

Abnormality in shape

The fusion of two deciduous teeth.

Gemination occurs when a developing tooth incompletely splits into the formation of two teeth. The phenomenon of gemination arises when two teeth develop from one tooth bud and as a result the patient has a larger tooth but a normal number of teeth overall in contrast to Fusion is the union of two adjacent teeth during development. The phenomenon of tooth fusion arises through union of two normally separated tooth germs and depending upon the stage of development of the teeth at the time of union it may be either Concrescence is the fusion of two separate teeth only in their cementum. Concrescence is a condition of Teeth where the Cementum overlying the roots of at least two teeth join together Accessory cusps are additional cusps on a tooth and may manifest as a Talon cusp, Cusp of Carabelli, or Dens evaginatus. A cusp is an occlusal or incisal eminence on a tooth Canine teeth otherwise known as cuspids, each possess a single cusp while Premolars A talon cusp, also known as an " eagle's talon " is an extra cusp on an anterior Tooth. The cusp of Carabelli, or Carabelli's tubercle, or tuberculus anomalus of Georg Carabelli is a small additional cusp at the mesiolingual Dens envaginatus is a condition found in Teeth where the outer surface appears to form an extra bump or cusp Dens invaginatus, also called Dens in dente, is a deep invagination in a tooth causing the appearance of a tooth within a tooth. Dens invaginatus, also known as dens in dente, is a condition found in Teeth where the outer surface folds inward Ectopic enamel is enamel found in an unusual location, such as the root of a tooth. Taurodontism is a condition where the body of the tooth and pulp chamber is enlarged, and is associated with Klinefelter syndrome, Tricho-dento-osseous syndrome, Triple X syndrome, and XYY syndrome. Taurodontism is a condition found in Teeth where the body of the tooth and pulp chamber is enlarged Klinefelter's syndrome, 47XXY or XXY syndrome is a condition caused by a Chromosome Aneuploidy. Triple X syndrome is a form of chromosomal variation characterized by the presence of an extra X chromosome in each cell of a human female XYY syndrome is an Aneuploidy of the Sex chromosomes in which a Human Male receives an extra Y chromosome, producing a 47XYY ^[71] Hypercementosis is excessive formation of cementum, which may result from trauma, inflammation, acromegaly, rheumatic fever, and Paget's disease of bone. Acromegaly (from Greek akros "extreme" or "extremities" and megalos "large" - extremities enlargement is a Syndrome Rheumatic fever is an Autoimmune inflammatory Disease which may develop two to three weeks after a Group A streptococcal infection (such as Paget's disease, otherwise known as osteitis deformans, is a chronic disorder that typically results in enlarged and deformed bones ^[71] A dilaceration is a bend in the root which may have been caused by trauma to the tooth during formation. Dilaceration is a developmental disturbance in shape of teeth Supernumerary roots is the presence of a greater number of roots on a tooth than expected. Supernumerary roots is a condition found in Teeth there may be a larger number of roots than expected

Abnormality in structure

Amelogenesis imperfecta is a condition in which enamel does not form properly or at all. Amelogenesis imperfecta presents with abnormal formation of the enamel or external layer of Teeth. ^[72] Dentinogenesis imperfecta is a condition in which dentin does not form properly and is sometimes associated with osteogenesis imperfecta. Dentinogenesis imperfecta (hereditary Opalescent Dentin is a Genetic disorder of Tooth development. Osteogenesis imperfecta ( OI and sometimes known as Brittle Bone Disease) is a genetic bone disorder ^[73] Dentin dysplasia is a disorder in which the roots and pulp of teeth may be affected. Dentin dysplasia is a genetic disorder of Teeth, commonly exhibiting an Autosomal dominant inheritance Regional odontodysplasia is a disorder affecting enamel, dentin, and pulp and causes the teeth to appear "ghostly" on radiographs. Regional odontodysplasia is a Developmental abnormality of Teeth, usually localized to a certain area and nonhereditary ^[74]

In animals

Section through the ivory tusk of a mammoth

Main article: Tooth (animal)

Teeth vary greatly among animals. Teeth in animals vary greatly Some animals such as Turtles and Tortoises are toothless Some animals, such as turtles and tortoises, are toothless. Turtles are Reptiles of the Order Testudines (all living turtles belong to the Crown group Chelonia) most of Tortoises or land Turtles are land-dwelling Reptiles of the family of Testudinidae', order Testudines. Others, such as sharks, may go through many teeth in their lifetime. Sharks ( Superorder Selachimorpha) are a type of Fish with a full cartilaginous Skeleton and a highly streamlined body Walrus tusks are canine teeth that grow continuously throughout life. The walrus ( Odobenus rosmarus) is a large flippered Marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and ^[75] Dog teeth are less likely than human teeth to form dental caries because of the very high pH of dog saliva, which prevents enamel from demineralizing. ^[76] Unlike humans whose ameloblasts die after tooth development, rodents continually produce enamel and must wear down their teeth by gnawing on various materials. ^[77] Horse teeth include twelve premolars, twelve molars, and twelve incisors. Horses' teeth are often used to estimate the animal's age hence the sayings "long in the tooth" and "Don't look a gift horse in the mouth" The structure of horse teeth is different from human teeth as the enamel and dentin layers are intertwined. ^[78]

See also

• Dentistry
• Dental tourism
• Dental auxiliary
  • Dental assistant
  • Dental hygienist
  • Dental technician
• Dental notation
• Dragon's teeth (mythology)
• Head and neck anatomy
• Language
• Tooth Fairy
• Vocal tract
• Braces
• Tooth painting

Lists

• List of oral health and dental topics
• List of basic dentistry topics

References

External links

• An overview of dental anatomy
• Tooth eruption chart
• "Broke a tooth? Grow it back", University of Alberta
• An article on the use of human tooth used as a neolithic pendant
• A teething chart showing the order in which teeth usually appear in infants