WordNet

a means of enforcement; "the treaty had no teeth in it"
one of a number of uniform projections on a gear
something resembling the tooth of an animal
toothlike structure in invertebrates found in the mouth or alimentary canal or on a shell
hard bonelike structures in the jaws of vertebrates; used for biting and chewing or for attack and defense
a minor actor in crowd scenes (同)spear carrier, extra
a person serving no apparent function; "reducing staff is difficult because our employees include no supernumeraries"
a blast of a horn
having teeth especially of a certain number or type; often used in combination; "saw-toothed"

PrepTutorEJDIC

『歯』 / 『歯状の物』,(くし・のこぎり・歯車・フォークなど)歯の働きをする物 / …に歯を付ける;…‘を'歯状(ぎざぎざ)にする
定数(員)以上の,余分な(extra);臨時の / 端役の / 定員外の人,過剰物;臨時雇い / (演劇の)端役
…もまた,その上 / 『あまりにも』,過度に,必要以上に / 『非常に』,大変,はなはだ(very, extremely) / 《話》《相手の否定の言葉に,肯定で応じて》ところがどうして
(笛・らっぱなどの)プープー鳴る音;(笛・らっぱなどを)プープー鳴らすこと / 〈笛・らっぱなど〉‘を'鳴らす / 〈笛・らっぱなどが〉鳴る
歯のある / V字型の突起がある,ぎざぎざの

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/12/30 01:14:35」(JST)

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Hyperdontia is the condition of having supernumerary teeth, or teeth that appear in addition to the regular number of teeth. They can appear in any area of the dental arch and can affect any dental organ.

Types

Dental stone model showing mesiodens and accessory tooth behind right central incisor

Supernumerary teeth can be classified by shape and by position. The shapes include the following:

Supplemental (where the tooth has a normal shape for the teeth in that series);
Tuberculate (also called barrel shaped);
Conical (also called peg shaped);
Compound odontoma (multiple small tooth-like forms);
Complex odontoma (a disorganized mass of dental tissue)^[1]

When classified by position, a supernumerary tooth may be referred to as a mesiodens, a paramolar, or a distomolar.^[1]

The most common supernumerary tooth is a mesiodens, which is a malformed, peg-like tooth that occurs between the maxillary central incisors.

Fourth and fifth molars that form behind the third molars are another kind of supernumerary teeth.^[2]

Causes

There is evidence of hereditary factors along with some evidence of environmental factors leading to this condition. While a single excess tooth is relatively common, multiple hyperdontia is rare in people with no other associated diseases or syndromes.^[3] Many supernumerary teeth never erupt, but they may delay eruption of nearby teeth or cause other dental or orthodontic problems.^[4]^[5] Molar-type extra teeth are the rarest form. Dental X-rays are often used to diagnose hyperdontia.

It is suggested that supernumerary teeth develop from a second tooth bud arising from the dental lamina near the regular tooth bud or possibly from splitting the regular tooth bud itself. Supernumerary teeth in deciduous (baby) teeth are less common than in permanent teeth.

Related conditions

A similar condition is hypodontia, in which there are fewer than the usual number of teeth.

Hyperdontia is seen in a number of disorders, including Gardner's syndrome and cleidocranial dysostosis, where multiple supernumerary teeth are seen that are usually impacted.

References

^ ^a ^b Oxford Handbook of Clinical Dentistry
^ Kokten G, Balcioglu H, Buyukertan M. Supernumerary Fourth and Fifth Molars: A Report of Two Cases. Journal of Contemporary Dental Practice, 2003 November; (4)4:067-076. Page accessed December 13, 2010.
^ M.N. Pereira, L.E. de Almeida, M.T. Martins et al. (October 2011). "Multiple hyperdontia: Report of an unusual case". American Journal of Orthodontics and Dentofacial Orthopedics 140 (4): 580–584. doi:10.1016/j.ajodo.2010.02.038. PMID 21967947. Retrieved March 25, 2014.
^ Vahid-Dastjerdi E, Borzabadi-Farahani A, Mahdian M, Amini N (2011). "Supernumerary teeth amongst Iranian orthodontic patients. A retrospective radiographic and clinical survey.". Acta Odontol Scand. 69 (2): 125–128. doi:10.3109/00016357.2010.539979. PMID 21142585.
^ Fleming PS, Xavier GM, DiBiase AT, Cobourne MT (2010). "Revisiting the supernumerary: the epidemiological and molecular basis of extra teeth.". Br Dent J. 208 (1): 25–30. doi:10.1038/sj.bdj.2009.1177. PMID 20057458.

External links

Dentistry portal

Tooth Conditions and Abnormalities at mchoralhealth.org
Supernumerary and Extra teeth
Supernumerary Teeth -An Overview of Classification, Diagnosis and Management

UpToDate Contents

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1. 歯の発達障害 developmental defects of the teeth
2. 歯の解剖学的構造および発達 anatomy and development of the teeth
3. 微細重複症候群 microduplication syndromes
4. 単一遺伝子性疾患の非メンデル遺伝のパターン non mendelian inheritance patterns of monogenic diseases
5. 歯性感染症の疫学、病因、および臨床症状 epidemiology pathogenesis and clinical manifestations of odontogenic infections

English Journal

Managing severe curvature of radix entomolaris: three-dimensional analysis with cone beam computed tomography.

Abella F, Mercade M, Duran-Sindreu F, Roig M.SourceDepartment of Endodontics, Universitat Internacional de Catalunya, Sant Cugat del Valles, Barcelona, Spain.
International endodontic journal.Int Endod J.2011 Sep;44(9):876-85. doi: 10.1111/j.1365-2591.2011.01898.x. Epub 2011 Jun 15.
Abella F, Mercade M, Duran-Sindreu F, Roig M. Managing severe curvature of radix entomolaris: three-dimensional analysis with cone beam computed tomography. International Endodontic Journal, 44, 876-885, 2011. ABSTRACT: Aim? To present a case of a mandibular first molar with an additional distoli
PMID 21671948

Reasons for extraction in a group of Libyan patients.

Byahatti SM, Ingafou MS.SourceDepartment of Oral Medicine, Diagnosis and Radiology, Faculty of Dentistry, Garyounis University, and Benghazi, Libya.
International dental journal.Int Dent J.2011 Aug;61(4):199-203. doi: 10.1111/j.1875-595X.2011.00057.x.
Aims and objectives: To investigate the pattern and causes of tooth loss in patients among eastern part of Libya. Materials and methods: This study carried out at Faculty of Dentistry, Garyounis University, Benghazi, Libya. The out patients undergoing extractions at the Oral Surgery Department were
PMID 21851351

Japanese Journal

内視鏡下副鼻腔手術により摘出した上顎洞含歯性嚢胞例

加瀬香,小野倫嗣,楠威志 [他]
耳鼻咽喉科臨床 104(8), 565-568, 2011-08
NAID 40018941036

Morphological examination of impacted tooth in maxillary lateral incisor region using computed tomography for consideration of treatment modalities

SASAKI Hidekazu,NAKANO Kazuhiko,YAMANA Aki,TANIGUCHI Naho,MICHIKAMI Ikumi,OKAWA Rena,MATSUMOTO Michiyo,OOSHIMA Takashi
Pediatric dental journal : international journal of Japanese Society of Pediatric Dentistry 20(2), 189-195, 2010-09-30
NAID 10027485989