Canine tooth

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Canine tooth
Azawakh K9.jpg
This dog's longer pointed cuspids or "fangs" show why they are particularly associated with canines.
Details
Identifiers
Latin dentes canini
MeSH D003481
TA98 A05.1.03.005
TA2 907
FMA 55636
Anatomical terminology

In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, eye teeth, vampire teeth, or fangs, are the relatively long, pointed teeth. In the context of the upper jaw, they are also known as fangs . They can appear more flattened, however, causing them to resemble incisors 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 maxillary bone. The four canines in humans are the two upper maxillary canines and the two lower mandibular canines. They are specially prominent in dogs (Canidae), hence the name.

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There are generally four canine teeth: two in the upper (maxillary) and two in the lower (mandibular) arch. A canine is placed laterally to (outside of) each lateral incisor and mesial to (inwards of) the premolars. They are larger and stronger than the incisors, and their roots sink deeply into the bones, causing well-marked prominences upon the surface. They are the only teeth in dentition with a single cusp, their crowns are roughly triangular from a mesial viewpoint and trapezoidal from a buccal viewpoint .

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 [1] ) 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 the ages of sixteen and twenty-two months and shed between ten and twelve years. Lower deciduous canines typically erupt between the ages of seventeen and twenty-two months and shed between nine and twelve years. [2]

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. [3] Occasionally canines are congenitally missing. [4]

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. [5]

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). [5] 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. [5]

Sexual dimorphism

The sabre-tooth water deer of China is often called the vampire deer due to the exceptionally long canine teeth in the males. Hydropotes inermis male - cropped image.png
The sabre-tooth water deer of China is often called the vampire deer due to the exceptionally long canine teeth in the males.

In many species the canine teeth in the upper or lower jaw, or in both jaws, are much larger in males than in females, where they are sometimes hidden or completely absent. Animals where this occurs include antelopes, musk-deer, camels, horses, wild boar, some apes, seals, narwhal, and walrus. [6] Male dogs have larger canines with different contour than do females. [7]

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. [8] The dimorphism is also similarly less pronounced in bonobos and chimpanzees. [9]

Non-synapsids

In non-synapsids, such as reptiles and crocodiles, teeth similar to canines may be termed "caniniform" ("canine-shaped") teeth. Teeth or appendages with similar appearances found in many snakes and invertebrates, such as spiders, are referred to as fangs, but are usually modified to inject venom. [10]

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Related Research Articles

<span class="mw-page-title-main">Incisor</span> Front teeth of most mammals

Incisors 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. Opossums have 18, whereas armadillos have none.

<span class="mw-page-title-main">Premolar</span> Transitional teeth located between the canine and molar teeth

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 mouth. They have at least two cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars.

<span class="mw-page-title-main">Maxillary central incisor</span> Tooth

The maxillary central incisor is a human tooth in the front upper jaw, or maxilla, and is usually the most visible of all teeth in the mouth. It is located mesial to the maxillary lateral incisor. As with all incisors, their function is for shearing or cutting food during mastication (chewing). There is typically a single cusp on each tooth, called an incisal ridge or incisal edge. Formation of these teeth begins at 14 weeks in utero for the deciduous (baby) set and 3–4 months of age for the permanent set.

<span class="mw-page-title-main">Maxillary lateral incisor</span> Tooth (one of a pair) in upper jaw adjacent to the maxillary central incisor

The maxillary lateral incisors are a pair of upper (maxillary) teeth that are located laterally from both maxillary central incisors of the mouth and medially from both maxillary canines. As with all incisors, their function is for shearing or cutting food during mastication, commonly known as chewing. There are generally no cusps on the teeth, but the rare condition known as talon cusps are most prevalent on the maxillary lateral incisors. The surface area of the tooth used in eating is called an incisal ridge or incisal edge. Though relatively the same, there are some minor differences between the deciduous (baby) maxillary lateral incisor and that of the permanent maxillary lateral incisor. The maxillary lateral incisors occlude in opposition to the mandibular lateral incisors.

<span class="mw-page-title-main">Maxillary canine</span>

In human dentistry, the maxillary canine is the tooth located laterally from both maxillary lateral incisors of the mouth but mesial from both maxillary first premolars. Both the maxillary and mandibular canines are called the "cornerstone" of the mouth because they are all located three teeth away from the midline, and separate the premolars from the incisors. The location of the canines reflects their dual function as they complement both the premolars and incisors during mastication, commonly known as chewing. Nonetheless, the most common action of the canines is tearing of food. The canines often erupt in the upper gums several millimeters above the gum line. The canine teeth are able to withstand the tremendous lateral pressure caused by chewing. There is a single cusp on canines, and they resemble the prehensile teeth found in carnivorous animals such as the extinct saber-toothed cat. Though relatively the same, there are some minor differences between the deciduous (baby) maxillary canine and that of the permanent maxillary canine.

<span class="mw-page-title-main">Maxillary first molar</span> Human tooth

The maxillary first molar is the human tooth located laterally from both the maxillary second premolars of the mouth but mesial from both maxillary second molars.

<span class="mw-page-title-main">Mandibular central incisor</span> Human tooth

The mandibular central incisor is the tooth located on the jaw, adjacent to the midline of the face. It is mesial from both mandibular lateral incisors. As with all incisors, its function includes shearing or cutting food during mastication, commonly known as chewing. There are no cusps on the tooth. Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge. Though the two are similar, there are some minor differences between the deciduous (baby) mandibular central incisor and that of the permanent mandibular central incisor. The mandibular central incisors are usually the first teeth to appear in the mouth, typically around the age of 6–8 months.

<span class="mw-page-title-main">Mandibular lateral incisor</span>

The mandibular lateral incisor is the tooth located distally from both mandibular central incisors of the mouth and mesially from both mandibular canines. As with all incisors, their function is for shearing or cutting food during mastication, commonly known as chewing. There are no cusps on the teeth. Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge. Though relatively the same, there are some minor differences between the deciduous (baby) mandibular lateral incisor and that of the permanent mandibular lateral incisor.

<span class="mw-page-title-main">Mandibular canine</span>

The mandibular canine is the tooth located distally from both mandibular lateral incisors of the mouth but mesially from both mandibular first premolars. Both the maxillary and mandibular canines are called the "cornerstone" of the mouth because they are all located three teeth away from the midline, and separate the premolars from the incisors. The location of the canines reflect their dual function as they complement both the premolars and incisors during mastication, commonly known as chewing. Nonetheless, the most common action of the canines is tearing of food. The canine teeth are able to withstand the tremendous lateral pressures from chewing. There is a single cusp on canines, and they resemble the prehensile teeth found in carnivorous animals. Though relatively the same, there are some minor differences between the deciduous (baby) mandibular canine and that of the permanent mandibular canine.

<span class="mw-page-title-main">Mandibular second premolar</span> Human tooth

The mandibular second premolar is the tooth located distally from both the mandibular first premolars of the mouth but mesial from both mandibular first molars. The function of this premolar is assist the mandibular first molar during mastication, commonly known as chewing. Mandibular second premolars have three cusps. There is one large cusp on the buccal side of the tooth. The lingual cusps are well developed and functional. Therefore, whereas the mandibular first premolar resembles a small canine, the mandibular second premolar is more alike to the first molar. There are no deciduous (baby) mandibular premolars. Instead, the teeth that precede the permanent mandibular premolars are the deciduous mandibular molars.

<span class="mw-page-title-main">Mandibular first molar</span> Human tooth

The mandibular first molar or six-year molar is the tooth located distally from both the mandibular second premolars of the mouth but mesial from both mandibular second molars. It is located on the mandibular (lower) arch of the mouth, and generally opposes the maxillary (upper) first molars and the maxillary 2nd premolar in normal class I occlusion. The function of this molar is similar to that of all molars in regard to grinding being the principal action during mastication, commonly known as chewing. There are usually five well-developed cusps on mandibular first molars: two on the buccal, two lingual, and one distal. The shape of the developmental and supplementary grooves, on the occlusal surface, are described as being M-shaped. There are great differences between the deciduous (baby) mandibular molars and those of the permanent mandibular molars, even though their function are similar. The permanent mandibular molars are not considered to have any teeth that precede it. Despite being named molars, the deciduous molars are followed by permanent premolars.

<span class="mw-page-title-main">FDI World Dental Federation notation</span> Worlds most commonly used dental notation

FDI World Dental Federation notation is the world's most commonly used dental notation. It is designated by the International Organization for Standardization as standard ISO 3950 "Dentistry — Designation system for teeth and areas of the oral cavity".

<span class="mw-page-title-main">Talon cusp</span> Rare dental anomaly resulting in teeth having more than one cusp

Talon cusp is a rare dental anomaly resulting in an extra cusp or cusp-like projection on an anterior tooth, located on the inside surface of the affected tooth. Sometimes it can also be found on the facial surface of the anterior tooth.

<span class="mw-page-title-main">Dental anatomy</span> Field of anatomy dedicated to human teeth

Dental anatomy is a field of anatomy dedicated to the study of human tooth structures. The development, appearance, and classification of teeth fall within its purview. Tooth formation begins before birth, and the teeth's eventual morphology is dictated during this time. Dental anatomy is also a taxonomical science: it is concerned with the naming of teeth and the structures of which they are made, this information serving a practical purpose in dental treatment.

Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest.

<span class="mw-page-title-main">Cusp (anatomy)</span> Pointed, projecting, or elevated anatomical feature

A cusp is a pointed, projecting, or elevated feature. In animals, it is usually used to refer to raised points on the crowns of teeth. The concept is also used with regard to the leaflets of the four heart valves. The mitral valve, which has two cusps, is also known as the bicuspid valve, and the tricuspid valve has three cusps.

This is a list of definitions of commonly used terms of location and direction in dentistry. This set of terms provides orientation within the oral cavity, much as anatomical terms of location provide orientation throughout the body.

Serial extraction is the planned extraction of certain deciduous teeth and specific permanent teeth in an orderly sequence and predetermined pattern to guide the erupting permanent teeth into a more favorable position.

Orthodontic indices are one of the tools that are available for orthodontists to grade and assess malocclusion. Orthodontic indices can be useful for an epidemiologist to analyse prevalence and severity of malocclusion in any population.

Occlusion according to The Glossary of Prosthodontic Terms Ninth Edition is defined as "the static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues".

References

PD-icon.svgThis article incorporates text in the public domain from page 1116 of the 20th edition of Gray's Anatomy (1918)

  1. ↑ "eye-tooth". Oxford English Dictionary Online. Oxford University Press. 1989.
  2. ↑ Oral Anatomy, Histology and Embryology Barry K. B. Berkovitz, G. R. Holland, and Bernard J. Moxham., Chapter 26 pg 424,425, 438 and 439
  3. ↑ Oral Anatomy, Histology and Embryology Barry K. B. Berkovitz, G. R. Holland, and Bernard J. Moxham chp 2 pg 62 and 64
  4. ↑ Borzabadi-Farahani, A. (2015). "Bilateral agenesis of maxillary permanent canines: Review of the literature". J Orthod Sci. 4 (1): 26–9. doi: 10.4103/2278-0203.149614 . PMC   4314837 . PMID   25657989.
  5. 1 2 3 Oral Anatomy, Histology and Embryology Barry K. B. Berkovitz, G. R. Holland, and Bernard J. Moxham Chapter 2.
  6. ↑ The Descent of Man. Charles Darwin. s:Descent of Man/Chapter XVII
  7. ↑ Lorber, M.; Alvo, G.; Zontine, W. J. (1979-01-01). "Sexual dimorphism of canine teeth of small dogs". Archives of Oral Biology. 24 (8): 585–589. doi:10.1016/0003-9969(79)90017-7. ISSN   0003-9969.
  8. ↑ Suwa, Gen; Sasaki, Tomohiko; Semaw, Sileshi; Rogers, Michael J.; Simpson, Scott W.; Kunimatsu, Yutaka; Nakatsukasa, Masato; Kono, Reiko T.; Zhang, Yingqi; Beyene, Yonas; Asfaw, Berhane (2021-12-07). "Canine sexual dimorphism in Ardipithecus ramidus was nearly human-like". Proceedings of the National Academy of Sciences. 118 (49). Bibcode:2021PNAS..11816630S. doi: 10.1073/pnas.2116630118 . ISSN   0027-8424. PMC   8670482 . PMID   34853174.
  9. ↑ Weston, Eleanor M.; Friday, Adrian E.; Johnstone, Rufus A.; Schrenk, Friedemann (2004-12-07). "Wide faces or large canines? The attractive versus the aggressive primate". Proceedings of the Royal Society of London. Series B: Biological Sciences. 271 (suppl_6): S416–S419. doi:10.1098/rsbl.2004.0203. PMC   1810116 . PMID   15801591.
  10. ↑ The Teeth of Non-Mammalian Vertebrates: Form, Function, Development and Growth by Barry Berkovitz, Peter Shellis -- Academic Press 2023 Page 335--355
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