Microdontia: Difference between revisions

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| name = Microdontia

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| image = Microdontia.jpg

| caption = Radiograph (X-ray) showing microdontia. Note also periapical lesion on the maxillary left lateral incisor.

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| field = [[Dentistry]]

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'''Microdontia''' is a condition in which one or more [[teeth]] appear smaller than normal. In the generalized form, all teeth are involved. In the localized form, only a few teeth are involved. The most common teeth affected are the upper [[lateral incisor]]s and [[third molar]]s.

Teeth affected by microdontia may also have abnormal shape, and the abnormal size may affect the whole tooth, or only a part of the tooth.<ref name=Poulsen2009 />

Males tend to have larger teeth than females,<ref name=Poulsen2009 /> and tooth size also varies by race.<ref name=Poulsen2009 /> Abnormal tooth size is defined by some as when the dimensions are more than 2 [[standard deviation]]s from the average.<ref name=Poulsen2009>{{cite book| vauthors = Poulsen S, Koch G |title=Pediatric dentistry: a clinical approach|date=2013|publisher=Wiley-Blackwell|location=Chichester, UK|isbn=9781118687192|page=191|edition=2nd|url=https://books.google.com/books?id=7Xdh8wb6zFsC&pg=PA191}}</ref> Microdontia is when the teeth are abnormally small, and [[Macrodontia (tooth)|macrodontia]] is when the teeth are abnormally large.

==Classification==

===True generalized===

All the teeth are smaller than the normal size. True generalized microdontia is very rare, and occurs in [[pituitary dwarfism]].<ref name=Ibsen2014 /><ref name=Regezi2012 /> Due to decreased levels of [[growth hormone]] the teeth fail to develop to a normal size.<ref name=Ibsen2014>{{cite book| vauthors = Ibsen OA, Phelan JA |title=Oral Pathology for the Dental Hygienist|date=2014|publisher=Elsevier Health Sciences|isbn=9780323291309|pages=164–165|edition=6th|url=https://books.google.com/books?id=nsvsAwAAQBAJ&pg=PA165}}</ref>

===Relative generalized===

All the teeth are normal size but appear smaller relative to enlarged jaws.<ref name=Regezi2012>{{cite book| vauthors = Regezi JA, Scuibba JJ, Jordan RC|title=Oral pathology : clinical pathologic correlations|date=2012|publisher=Elsevier/Saunders|location=St. Louis, Mo.|isbn=978-1-4557-0262-6|page=373|edition=6th}}</ref> Relative generalized microdontia may be the result of inheritance of a large jaw from one parent, and normal sized teeth from the other.<ref name=Ibsen2014 />

===Localized (focal)===

Localized microdontia is also termed focal, or pseudo-microdontia. A single tooth is smaller than normal.<ref name=Regezi2012 /> Localized microdontia is far more common than generalized microdontia,<ref name=Ibsen2014 /> and is often associated with [[hypodontia]] (reduced number of teeth).<ref name=Poulsen2009 /> The most commonly involved tooth in localized microdontia is the maxillary lateral incisor, which may also be shaped like an inverted cone (a "peg lateral").<ref name=Regezi2012 /> Peg laterals typically occur on both sides,<ref name=Ibsen2014 /> and have short roots.<ref name=Ibsen2014 /> Inheritance may be involved,<ref name=Ibsen2014 /> and the frequency of microdontia in the upper laterals is just under 1%.<ref name=Poulsen2009 /> The second most commonly involved tooth is the maxillary third molars,<ref name=Regezi2012 /> and after this [[hyperdontia|supernumerary teeth]].<ref name=Regezi2012 />

==Causes==

There are many potential factors involved.<ref name=Laskaris2011>{{cite book|author1=Laskaris G|title=Color Atlas of Oral Diseases in Children and Adolescents|date=2011|publisher=Thieme|isbn=9783131604712|page=2|url=https://books.google.com/books?id=dRuF_G5yRO0C&pg=PA2}}</ref>

{{columns-list|colwidth=30em|

* [[Congenital hypopituitarism]]<ref name=Poulsen2009 />

* [[Ectodermal dysplasia]]<ref name=Poulsen2009 />

* [[Down syndrome]]<ref name=Poulsen2009 />

* [[Ionizing radiation]] to the jaws during tooth development ([[Human tooth development|odontogenesis]])<ref name=Poulsen2009 />

* [[Chemotherapy]] during tooth development<ref name=Laskaris2011 />

* [[Marshall syndrome]]<ref name=Laskaris2011 />

* [[Rieger syndrome]]<ref name=Laskaris2011 />

* [[Focal dermal hypoplasia]]<ref name=Laskaris2011 />

* [[Silver-Russell syndrome]]<ref name=Laskaris2011 />

* [[Williams syndrome]]<ref name=Laskaris2011 />

* [[Gorlin-Chaudhry-Moss syndrome]]<ref name=Laskaris2011 />

* [[Coffin–Siris syndrome]]<ref name=Laskaris2011 />

* [[Salamon syndrome]]<ref name=Laskaris2011 />

* [[Cleft lip and palate]]<ref name=Laskaris2011 />

}}

Others include trichorhinopharyngeal, odontotrichomelic, neuroectodermal and dermo-odontodysplasia syndromes.<ref name=Laskaris2011 />

Unerupted microdonts may require surgical removal to prevent the formation of [[dental cyst|cyst]]s.<ref name=Ibsen2014 /> Erupted microdonts, peg laterals especially, may cause cosmetic concern. Such teeth may be restored to resemble normal sized teeth,<ref name=Ibsen2014 /> typically with [[dental composite|composite]] build ups or [[dental crown|crown]]s.<ref name=Laskaris2011 /> [[Orthodontics]] may be required in severe cases to close gaps between the teeth.<ref name=Laskaris2011 />

==Epidemiology==

Females are affected more than males,<ref name=Laskaris2011 /> and the condition occurs in permanent (adult) teeth more than deciduous (baby teeth or milk teeth).<ref name=Laskaris2011 />

== References ==

{{Reflist}}

== External links ==

{{Medical resources

| DiseasesDB = 35076

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| ICD9 = {{ICD9|520.2}}

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