Editing Incisor

{{Short description|Front teeth of most mammals}}
{{Use dmy dates|date=July 2022}}
{{Infobox anatomy
| Name        = Incisor
| Latin       = dens incisivus
| Image       = Gray997.png
| Caption     = Permanent teeth of the right half of the lower dental arch, seen from above.
| Image2      = Gray1003.png
| Caption2    = The permanent teeth of a human, viewed from the right.
}}

'''Incisors''' (from Latin ''incidere'', "to cut") are the front [[teeth]] present in most [[mammal]]s. They are located in the [[premaxilla]] above and on the [[mandible]] below. Humans have a total of eight (two on each side, top and bottom). [[Opossum]]s have 18, whereas [[armadillo]]s, [[anteater]]s and other animals in the order [[Edentata]] have none.<ref>{{cite web|url=https://www.dentalcare.com/en-us/archives|title=Archives|website=dentalcare.com|access-date=29 April 2018|url-status=live|archive-url=https://web.archive.org/web/20180429001759/https://www.dentalcare.com/en-us/archives|archive-date=29 April 2018}}</ref>

==Structure==
Adult [[human]]s normally have eight incisors, two of each type.  The types of incisors are:
* [[maxillary central incisor]] (upper jaw, closest to the center of the lips)
* [[maxillary lateral incisor]] (upper jaw, beside the maxillary central incisor)
* [[mandibular central incisor]] (lower jaw, closest to the center of the lips)
* [[mandibular lateral incisor]] (lower jaw, beside the mandibular central incisor)

Children with a full set of [[deciduous teeth]] (primary teeth) also have eight incisors, named the same way as in [[permanent teeth]]. Young children may have from zero to eight incisors depending on the stage of their [[tooth eruption]] and [[Human tooth development|tooth development]]. Typically, the mandibular central incisors erupt first, followed by the maxillary central incisors, the mandibular lateral incisors and finally the maxillary laterals. The rest of the primary dentition erupts after the incisors.<ref>{{cite book|last1=Scheid|first1=RC.|title=Woelfel's dental anatomy|date=2012|publisher=Wolters Kluwer Health/Lippincott Williams & Wilkins|location=Philadelphia|edition=8}}</ref>

Apart from the [[first molar]]s, the incisors are also the first permanent teeth to erupt, following the same order as the primary teeth, among themselves.

===Other animals===
Among other animals, the number varies from species to species. [[Opossum]]s have 18, whereas [[armadillo]]s have none. Cats, dogs, foxes, pigs, and horses have twelve. [[Rodent]]s have four. Rabbits and hares ([[lagomorph]]s) were once considered rodents, but are distinguished by having six—one small pair, called "peg teeth", is located directly behind the most anterior pair. Incisors are used to bite off tough foods, such as red meat.

[[Cattle]] (cows, bulls, etc.) have none on top but a total of six on the bottom.

==Function==
In [[cat]]s, the incisors are small; biting off meat is done with the [[canine tooth|canines]] and the [[carnassial]]s. In [[elephant]]s, the upper incisors are modified into curved [[tusk]]s (unlike with [[narwhal]]s, where it is a canine that develops into a straight and twisted tusk).<ref>{{cite journal|last=Nweeia|first=Martin|last2=Eichmiller|first2=Frederick C.|last3=Hauschka|first3=Peter V.|last4=Tyler|first4=Ethan|last5=Mead|first5=James G.|last6=Potter|first6=Charles W.|last7=Angnatsiak|first7=David P.|last8=Richard|first8=Pierre R.|last9=Orr|first9=Jack R.|last10=Black|first10=Sandie R.|title=Vestigial Tooth Anatomy and Tusk Nomenclature for Monodon Monoceros|journal=The Anatomical Record |date=30 March 2012 |volume=295|issue=6|pages=1006–1016|doi=10.1002/ar.22449|pmid=22467529|display-authors=8|doi-access=}}</ref> The incisors of [[rodent]]s grow throughout life and are worn by gnawing. In humans, the incisors serve to cut off pieces of food, as well as in the grip of other food items.

==Additional images==
<gallery>
File:3D Medical Animation Still Showing Types of Teeth.jpg|Arrangement of incisors in an adult human.
File:Illu mouth.jpg|Mouth (oral cavity)
File:Gray157.png|Left maxilla. Outer surface.
File:Gray187.png|Base of skull. Inferior surface.
</gallery>

==See also==
* [[Canine tooth]]
* [[Molar (tooth)|Molar]]
* [[Premolar]]
* [[Shovel-shaped incisors]]

== References ==
{{Reflist}}

== External links ==
* {{Commons category-inline|Incisors}}

{{Tooth anatomy}}
{{Authority control}}

[[Category:Types of teeth]]