incisor

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Detailed anatomical diagram of an open human mouth showing teeth, gums, and the roof of the mouth, with labels identifying features such as incisors, canines, premolars, molars, hard and soft palate, uvula, and various oral structures.

incisor

Also known as: front tooth

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June 29, 2026

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Detailed anatomical diagram of an open human mouth showing teeth, gums, and the roof of the mouth, with labels identifying features such as incisors, canines, premolars, molars, hard and soft palate, uvula, and various oral structures. — Human mouth Anterior view of the oral cavity.

Incisors are the front teeth in mammals, typically adapted for cutting food. They are located between the canine teeth when canines are present. In humans, there are four incisors in each jaw, making a total of eight. These teeth have a wide, thin biting surface that forms a chisel-shaped cutting edge. The upper incisors also possess a tactile sense, allowing them to help identify objects in the mouth through nibbling.12

While canines are often the largest teeth and are used for tearing, incisors are specialized for plucking, cutting, and holding. In some animals, like rodents, incisors grow continuously throughout life and are used for gnawing. Elephant tusks, for example, are actually enlarged upper incisors.324

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tooth
Tooth form and function
…thus made up of four incisors, two canines, four premolars, and six molars in each jaw.
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…thus made up of four incisors, two canines, four premolars, and six molars in each jaw.
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human evolution
Reduction in tooth size
…canines are unique in being incisorlike, and the front lower premolar tooth is bicuspid. In apes and in many monkeys, however, the lower premolar is unicuspid and hones the upper canine tooth to razor sharpness.
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…canines are unique in being incisorlike, and the front lower premolar tooth is bicuspid. In apes and in many monkeys, however, the lower premolar is unicuspid and hones the upper canine tooth to razor sharpness.
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primate
Teeth
…has retained more than two incisors in the upper jaw. The incisors are subject to considerable variation in strepsirrhines. Characteristically, the upper incisors are peglike, one or the other pair often being absent; in the lower jaw, the incisors show a peculiar conformation that has been likened structurally and functionally…
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…has retained more than two incisors in the upper jaw. The incisors are subject to considerable variation in strepsirrhines. Characteristically, the upper incisors are peglike, one or the other pair often being absent; in the lower jaw, the incisors show a peculiar conformation that has been likened structurally and functionally…
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rodent
…lower pairs of ever-growing rootless incisor teeth. Rodents are the largest group of mammals, constituting almost half the class Mammalia’s approximately 4,660 species. They are indigenous to every land area except Antarctica, New Zealand, and a few Arctic and other oceanic islands, although some species have been introduced even to…
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…lower pairs of ever-growing rootless incisor teeth. Rodents are the largest group of mammals, constituting almost half the class Mammalia’s approximately 4,660 species. They are indigenous to every land area except Antarctica, New Zealand, and a few Arctic and other oceanic islands, although some species have been introduced even to…
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