Editing Human tooth (section)

==Structure==
{{Main|Dental anatomy}}
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| caption1          = Diagram of molar anatomy
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| image2            = 3D Medical Animation Still Showing Types of Teeth.jpg
| caption2          = 3D rendering showing the types of teeth
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Dental [[anatomy]] is dedicated to the study of tooth structure. The development, appearance, and classification of teeth fall within its field of study, though [[occlusion (dentistry)|dental occlusion]], or contact between teeth, does not. Dental anatomy is also a [[Taxonomy (general)|taxonomic]] science as it is concerned with the naming of teeth and their structures. This information serves a practical purpose for dentists, enabling them to easily identify and describe teeth and structures during treatment.

The anatomic [[crown (tooth)|crown]] of a tooth is the area covered in [[tooth enamel|enamel]] above the [[cementoenamel junction]] (CEJ) or "neck" of the tooth.<ref>{{cite book | last = Clemente | first = Carmine | title = Anatomy, a regional atlas of the human body | publisher = Urban & Schwarzenberg | location = Baltimore | year = 1987 | isbn = 978-0-8067-0323-7 | url = https://archive.org/details/anatomyregionala00clem }}</ref><ref name="ash6">{{harvnb|Ash|2003|page=6}}</ref> Most of the crown is composed of [[dentin]] ("dentine" in British English) with the pulp chamber inside.<ref name="Cate3">{{harvnb|Cate|1998|page=3}}</ref> The crown is within bone before [[tooth eruption|eruption]].<ref name="ash9">{{harvnb|Ash|2003|page=9}}</ref> After eruption, it is almost always visible. The anatomic root is found below the CEJ and is covered with [[cementum]]. As with the crown, dentin composes most of the root, which normally has [[root canal|pulp canals]]. Canines and most premolars, except for [[maxillary (disambiguation)|maxillary]] first premolars, usually have one root. Maxillary first premolars and [[mandible|mandibular]] molars usually have two roots. Maxillary molars usually have three roots. Additional roots are referred to as [[supernumerary roots]].

Humans usually have 20 primary (deciduous, "baby" or "milk") teeth and 32 permanent (adult) teeth. Teeth are classified as [[incisor]]s, [[Canine tooth|canines]], [[premolar]]s (also called ''bicuspids''), and [[Molar (tooth)|molars]]. Incisors are primarily used for cutting, canines are for tearing, and molars serve for grinding.

Most teeth have identifiable features that distinguish them from others. There are several different [[Dental notation|notation systems]] to refer to a specific tooth. The three most common systems are the [[FDI World Dental Federation notation]] (ISO 3950), the [[Universal Numbering System]], and the [[Palmer notation]]. The FDI system is used worldwide,  the Universal only in the United States, while the older Palmer notation still has some adherents only in the United Kingdom.

===Primary teeth===
Among [[Deciduous teeth|deciduous (primary) teeth]], ten are found in the maxilla (upper jaw) and ten in the mandible (lower jaw), for a total of 20. The [[Dentition#Dental formula|dental formula]] for primary teeth in humans is {{DentalFormula|upper=2.1.0.2|lower=2.1.0.2}}.

In the primary set of teeth, in addition to the canines there are two types of incisors—centrals and laterals—and two types of molars—first and second. All primary teeth are normally later replaced with their permanent counterparts.

[[File:Universal Numbering System.svg|thumb|left|upright|The [[Universal Numbering System]] for adult human teeth, used in the USA. The view is from a dental practitioner's perspective, meaning tooth 1 is the upper right rear (third) molar.  Most countries use the FDI numbering system.]]

===Permanent teeth===
Among [[permanent teeth]], 16 are found in the maxilla and 16 in the mandible, for a total of 32. The dental formula is {{DentalFormula|upper=2.1.2.3|lower=2.1.2.3}}.  Permanent human teeth are numbered in a [[boustrophedon]]ic sequence.

The maxillary teeth are the [[maxillary central incisor]]s (teeth 8 and 9 in the diagram), [[maxillary lateral incisor]]s (7 and 10), [[maxillary canine]]s (6 and 11), [[maxillary first premolar]]s (5 and 12), [[maxillary second premolar]]s (4 and 13), [[maxillary first molar]]s (3 and 14), [[maxillary second molar]]s (2 and 15), and [[maxillary third molar]]s (1 and 16). The mandibular teeth are the [[mandibular central incisor]]s (24 and 25), [[mandibular lateral incisor]]s (23 and 26), [[mandibular canine]]s (22 and 27), [[mandibular first premolar]]s (21 and 28), [[mandibular second premolar]]s (20 and 29), [[mandibular first molar]]s (19 and 30), [[mandibular second molar]]s (18 and 31), and [[mandibular third molar]]s (17 and 32). Third molars are commonly called "[[wisdom teeth]]" and usually emerge at ages 17 to 25.<ref>{{cite web|url=https://www.mayoclinic.org/diseases-conditions/wisdom-teeth/symptoms-causes/syc-20373808 |title=Impacted wisdom teeth |publisher=[[Mayo Clinic]]|access-date=5 March 2022}}</ref> These molars may never erupt into the mouth or form at all.{{Citation needed|date=March 2022}} When they do form, they often must be [[Dental extraction|removed]]. If any additional teeth form—for example, fourth and fifth molars, which are rare—they are referred to as [[hyperdontia|supernumerary teeth]] (hyperdontia). Development of fewer than the usual number of teeth is called [[hypodontia]].

There are small differences between the teeth of males and females, with male teeth along with the male jaw tending to be larger on average than female teeth and jaw. There are also differences in the internal dental tissue proportions, with male teeth consisting of proportionately more dentine while female teeth have proportionately more enamel.<ref>{{Cite journal |last1=Sorenti |first1=Mark |last2=Martinón-Torres |first2=María |last3=Martín-Francés |first3=Laura |last4=Perea-Pérez |first4=Bernardo |title=Sexual dimorphism of dental tissues in modern human mandibular molars |journal=American Journal of Physical Anthropology |language=en |volume=169 |issue=2 |pages=332–340 |doi=10.1002/ajpa.23822 |pmid=30866041 |issn=1096-8644 |year=2019|s2cid=76662620 }}</ref>
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