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mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
ian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw)
fang A fang is a long, pointed tooth. In mammals, a fang is a modified maxillary tooth, used for biting and tearing flesh. In snakes, it is a specialized tooth that is associated with a venom gland (see snake venom). Spiders also have external fa ...
s, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed
teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tea ...
. They can appear more flattened however, causing them to resemble
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. 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). Opossums have 18, wher ...
s and leading them to be called ''incisiform''. They developed and are used primarily for firmly holding food in order to tear it apart, and occasionally as weapons. They are often the largest teeth in a mammal's mouth. Individuals of most species that develop them normally have four, two in the upper jaw and two in the lower, separated within each jaw by incisors; humans and dogs are examples. In most species, canines are the anterior-most teeth in the
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
ry bone. The four canines in humans are the two
maxillary canine In human dentistry, the maxillary canine is the tooth located laterally (away from the midline of the face) from both maxillary lateral incisors of the mouth but mesial (toward the midline of the face) from both maxillary first premolars. Both the ...
s and the two
mandibular canine The mandibular canine is the tooth located distally (away from the midline of the face) from both mandibular lateral incisors of the mouth but mesially (toward the midline of the face) from both mandibular first premolars. Both the maxillary and ...
s.


Details

There are generally four canine teeth: two in the upper (maxillary) and two in the lower (mandibular) arch. A canine is placed laterally to each
lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction *Lateral cricoarytenoid muscle *Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral cons ...
incisor and mesial to the premolars. They are larger and stronger than the incisors, and their roots sink deeply into the bones, and cause well-marked prominences upon the surface. They are the only teeth in dentition with a single cusp, their crowns are roughly triangular from mesial view and trapezoidal in buccal view. The crown is large and conical, very convex on its labial surface, a little hollowed and uneven on its lingual surface, and tapering to a blunted point or cusp, which projects beyond the level of the other teeth. The root is single, but longer and thicker than that of the incisors, conical in form, compressed laterally, and marked by a slight groove on each side. The lingual surface also presents two depressions on either side of the surface separated by a ridge in between; these depressions are known as mesial and distal lingual fossae.


Eruption

In humans, the upper canine teeth (popularly called eye teeth, from their position under the eyes) are larger and longer than the lower, and usually present a distinct basal ridge. Eruption typically occurs between the ages of eleven and twelve years for upper canines and between nine and ten years for lower canines. Upper deciduous canines also known as the baby tooth, typically erupt between ages of sixteen and twenty-two months and sheds between ten and twelve years. Lower deciduous canines typically erupt between ages of seventeen and twenty-two months and sheds between nine to twelve years


Developmental defects

Transposition (positional interchange of two adjacent teeth) is a development defect that most commonly found in the permanent canine, with the maxillary being more commonly seen than mandibular. The upper canine frequently transposed with the first premolar whilst the lower canine transposed with the lateral incisor. Occasionally canines are congenitally missing.


Maxillary canine morphology

From a facial aspect, maxillary canines are approximately one millimetre narrower than the central incisor. Their mesial aspects resemble the adjacent lateral incisors, while their distal aspects anticipate the first premolars. They are slightly darker and more yellow in color than the other anterior teeth. From a lingual aspect, they have well developed mesial and distal marginal ridges and a well-developed cingulum. A prominent lingual ridge divides the lingual aspect in half and creates the mesial and distal lingual fossae between the lingual ridge and the marginal ridges. From a proximal aspect, they resemble the incisors, but are more robust, especially in the cingulum region. Incisally, they are visibly asymmetrical, as the mesial incisal edge is slightly shorter than the distal incisal edge, which places the cusp slightly mesial to the long axis of the tooth. They are also thicker labiolingually than mesiodistally. Because of the disproportionate incisal edges, the contacts are also asymmetrical. Mesially, the contact sits at the junction of the incisal and middle third of the crown, while distally, the contact as more cervical, in the middle of the middle third of the crown.The root of the maxillary canines are the longest root of any tooth and conical in shape.Oral Anatomy, Histology and Embryology Barry K. B. Berkovitz, G. R. Holland, and Bernard J. Moxham Chapter 2.


Mandibular canine morphology

The lower canine teeth are placed nearer the middle line than the upper, so that their summits correspond to the intervals between the upper canines and the lateral incisors. From a facial aspect, the mandibular canine is notably narrower mesiodistally than the maxillary one, the root is compressed mesiodistally with well-marked grooves on both sides and may be just as long as the maxillary (and at times bifurcated). A distinctive feature is the nearly straight outline this tooth has compared to the maxillary canine which is slightly more bowed. As in the maxillary canine, the mesial incisal edge (or cusp ridge) is shorter than the distal side, however, the cusp is displaced slightly lingual relative to the cusp of the maxillary canine. Lingually, the surface of the tooth is much smoother compared to the very pronounced surface of the maxillary canine, and the cingulum is noted as less developed. The cusp may be lost with attrition over time and may resemble an upper second permanent incisor.


Sexual dimorphism

With many species, the canine teeth in the upper or lower jaw, or in both, are much larger in the males than in the females, or are absent in females, except sometimes a hidden rudiment. Certain antelopes, the
musk-deer Musk deer can refer to any one, or all seven, of the species that make up ''Moschus'', the only extant genus of the family Moschidae. Despite being commonly called deer, they are not true deer belonging to the family Cervidae, but rather their fa ...
,
camel A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. C ...
,
horse The horse (''Equus ferus caballus'') is a Domestication, domesticated, odd-toed ungulate, one-toed, ungulate, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two Extant taxon, extant subspecies of wild horse, ''Equus fer ...
,
boar The wild boar (''Sus scrofa''), also known as the wild swine, common wild pig, Eurasian wild pig, or simply wild pig, is a suid native to much of Eurasia and North Africa, and has been introduced to the Americas and Oceania. The species is n ...
, various apes, seals, and the
walrus The walrus (''Odobenus rosmarus'') is a large flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the fami ...
, offer instances. Humans have the proportionately smallest male canine teeth among all anthropoids and exhibit relatively little sexual dimorphism in canine tooth size. It has been proposed that the receding canine teeth in human males was likely to be a result of sexual selection for less aggressive partners by female humans. The dimorphism is also similarly less pronounced in
chimpanzee The chimpanzee (''Pan troglodytes''), also known as simply the chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. When its close relative the ...
s.


Non-synapsids

In non-
synapsid Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes repti ...
s, such as reptiles and crocodiles, teeth similar to canines may be termed "caniniform" ("canine-shaped") teeth.


Additional images

File:3D Medical Animation Still Showing Types of Teeth.jpg, Medical animation showing Canine teeth and their arrangement in the mouth of an adult human being. File:Illu mouth.jpg, Mouth (oral cavity) File:Gray157.png, Left maxilla. Outer surface. File:Gray187.png, Base of skull. Inferior surface. File:Gray1001.png, Unerupted permanent teeth underlie the
deciduous teeth Deciduous teeth or primary teeth, also informally known as baby teeth, milk teeth, or temporary teeth,Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 255 are the first set of teeth in the ...
.


See also

*
Carnassial Carnassials are paired upper and lower teeth modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. This adaptation is found in carnivorans, where the carnassials are the modified ...
*
Incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. 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). Opossums have 18, wher ...
*
Premolar The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mou ...
* Molar


References


External links

* {{Authority control Teeth Mammal anatomy Types of teeth