عرض مصدر Hyperdontia

{{See also|List of dental abnormalities associated with cutaneous conditions}}
{{Refimprove|date=January 2008}}
{{Infobox medical condition |
  Name           = Hyperdontia |
  Image          = Supernumerary_teeth.jpg |
  Caption        = Supernumerary teeth in the [[Incisive bone|premaxillary]] area |
  DiseasesDB     = |
  ICD10          = {{ICD10|K|00|1|k|00}} |
  ICD9           = {{ICD9|520.1}} |
  ICDO           = |
  OMIM           = |
  MedlinePlus    = |
  eMedicineSubj  = |
  eMedicineTopic = |
  MeshID         = D014096 |
}}
'''Hyperdontia''' is the condition of having '''supernumerary teeth''', or [[tooth|teeth]] that appear [[supernumerary body part|in addition]] to the regular number of teeth. They can appear in any area of the [[dental arch]] and can affect any [[Enamel organ|dental organ]].

==Types==
[[File:Mesiodens Accessory Teeth.jpg|thumb|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)<ref name="Oxford">Oxford Handbook of Clinical Dentistry</ref>

When classified by position, a supernumerary tooth may be referred to as a ''mesiodens'', a ''paramolar'', or a ''distomolar''.<ref name="Oxford" />

The most common supernumerary tooth is a '''mesiodens''', which is a malformed, peg-like tooth that occurs between the [[maxillary central incisor]]s.

Fourth and fifth molars that form behind the third molars are another kind of supernumerary teeth.<ref>Kokten G, Balcioglu H, Buyukertan M. [http://www.exodontia.info/files/Supernumerary_4th_5th_Molars_-_A_Report_of_2_Cases.pdf 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.</ref>

==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.<ref>{{cite journal |author=M.N. Pereira |author2=L.E. de Almeida |author3=M.T. Martins |title=Multiple hyperdontia: Report of an unusual case |journal=American Journal of Orthodontics and Dentofacial Orthopedics|volume=140 |issue=4 |pages=580–584 |date=October 2011 |doi=10.1016/j.ajodo.2010.02.038|pmid=21967947|display-authors=etal}}</ref> Many supernumerary teeth never erupt, but they may delay eruption of nearby teeth or cause other dental or orthodontic problems.<ref>{{cite journal |vauthors=Vahid-Dastjerdi E, Borzabadi-Farahani A, Mahdian M, Amini N |title=Supernumerary teeth amongst Iranian orthodontic patients. A retrospective radiographic and clinical survey. |journal=Acta Odontol Scand|volume=69 |issue=2 |pages=125–128 |year=2011 |pmid=21142585 |doi=10.3109/00016357.2010.539979}}</ref><ref>{{cite journal |vauthors=Fleming PS, Xavier GM, DiBiase AT, Cobourne MT |title=Revisiting the supernumerary: the epidemiological and molecular basis of extra teeth.|journal=Br Dent J.|volume=208 |issue=1 |pages=25–30 |year=2010 |pmid=20057458 |doi=10.1038/sj.bdj.2009.1177}}</ref> [[Molar (tooth)|Molar]]-type extra teeth are the rarest form.  Dental [[X-ray]]s are often used to diagnose hyperdontia.

It is suggested that supernumerary teeth develop from a third 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 teeth|deciduous (baby) teeth]] are less common than in permanent teeth.

==Related conditions==
Another abnormal 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==
{{Reflist}}

==External links==
{{Portal|Dentistry}}
*[http://www.mchoralhealth.org/PediatricOH/mod3_5_3.htm Tooth Conditions and Abnormalities] at mchoralhealth.org
*[http://www.supernumeraryteeth.com Supernumerary and Extra teeth]
*[https://www.cda-adc.ca/jcda/vol-65/issue-11/612.html Supernumerary Teeth -An Overview of Classification, Diagnosis and Management]

{{Tooth disease}}

[[Category:Supernumerary body parts]]
[[Category:Developmental tooth pathology]]
[[Category:Teeth]]