Canines and their anatomical and functional features

Canines are a special group of teeth. It is located in an important position, helping to support the lips, and at the same time determine the contours of the face. Morphologically, the canines seem to have a transition between the incisors and premolars. Its position on the jaw also changes more or less, it may be outside or inside, or even change position with other teeth. We often call the deviated canines with the cute name "snobs". For many people, "skewed teeth" are a special charm.

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• 1. General introduction to canines
• 2. Upper canines (top 3 teeth)

1. General introduction to canines

1.1 Why is it called a canine?

The canine is named for its resemblance to a dog's similar tooth. However, human teeth are not as long, pointed or sharp as equivalent teeth in a dog's mouth. But they are all in the same position and are often longer and more pointed than the other teeth.

1.2 Quantity 

These teeth are single teeth, with only one tooth in each quadrant, two in the upper and two in the lower arch. Thus, each of us has 4 canines, including in the baby teeth and permanent teeth. They are designated in the set of teeth as 3 teeth. Each is placed next to a lateral incisor. They are larger and stronger than the front teeth. Their legs sink deep into the bone, creating a distinctly prominent protrusion on the surface.

1.3 Time to grow

The first baby teeth appear between the ages of 16 and 20 months. The upper teeth come in first, followed by the lower teeth. Adult permanent teeth appear in the opposite way. First, the lower molars erupt around the age of 9. Then the upper molars appear at the age of 11 or 12.

1.4 Body shape

• With its position between the incisors and premolars, the canine exhibits morphology and function as a transitional tooth. The canine has a biting edge that is a pointed apex.
• The size is larger than the incisors and has a conical shape. The raised, tapered surface at the crown of the tooth forms the apex of the cusp. They have only one root, but they are longer and thicker than the front teeth. Roots are conical, with longitudinal grooves on the lateral surfaces of the roots.  
• Viewed from the outside, the canines are about a millimeter narrower than the central incisors. Their mesial edges resemble the lateral incisors, while their distal aspects closely follow the premolar profile. The teeth are slightly yellow and darker than the other anterior teeth.

1.5 Functions

On many mammals, canines are integral to their existence. Because these teeth are used as a tool to hunt, capture prey, tear food. It is also a weapon for attack and self-defense. In humans, that "life" function of the canines is gone, but they are still considered one of the most "strategic" teeth in the mouth.

Canines have a high tolerance for strong forces during chewing. It acts as a shock absorber. Thereby this tooth tends to alleviate potential damage, excessive conditions caused by lateral forces during eccentric movements of the mandible against the posterior teeth.

The fangs are used to tear food

• It is also the most stable tooth on the arch. With the longest and strongest roots compared to other teeth, they are firmly held in the alveolar bone and are therefore less likely to be lost prematurely. The protrusion of the canine crown in the lateral direction makes this tooth well protected by a self-cleaning mechanism.
• The canines are located at the four "corners" of the two dental arches. Considered to be the foundation of the dental arch, helping to support the facial muscles. When this tooth is lost, the face becomes flat and difficult to restore as before.
• It also has a great effect in guiding the contact movement of the lower jaw to the side and anteriorly.

Therefore, the canines are considered as "guide piles" for occlusion. It is the only tooth that guides lateral movement in people with a "canine guide" mechanism (which is considered the ideal mechanism).

Summary of canine group characteristics:

• They are single teeth.
• The biting margin is shown as a zone.
• There is only one root and is the largest root in the set of teeth.
• It is a single-cushion tooth, but the functional aspect of the upper canine lingual surface is more important than that of the occlusal margin.
• The arch characteristic of the canines is also unique because there is only one canine in each half of the jaw.

2. Upper canines (top 3 teeth)

The upper 3 molars grow quite late in the mouth. Usually around 10-11 years old. That is, approximately the eruption age of the 2nd premolars and before the 2nd and 3rd molars. In terms of size, the upper 3 teeth are larger than the lower 3 teeth.

Size of teeth

Features of maxillary canines

1. The crown is larger than the lower 3 teeth on the same set of teeth.
2. The mesial and distal contours, seen from the outside, converge a lot towards the neck of the tooth.
3. The crown edge occupies at least one-third of the crown height and can be as much as half the mesio-distal dimension
4. The mesial and distal lateral margins, medial margins, and cingulum are more pronounced than those of the lower third teeth, making the lingual recesses deeper.
5. On the medial surface, lingual pits and grooves are often seen.
6. The lateral-internal dimension of the crown (including the neck) is larger than that of the lower canine.
7. The mesial and distal halves of the crown are asymmetrical when viewed from the occlusal side.

3/ Mandibular canines (lower 3 teeth)

The lower 3rd teeth are the first in the group of canines to appear in the oral cavity. Compared with the upper 3rd teeth, this tooth is narrower in the mesio-distal direction and therefore longer in the incisal margin - cervical direction. Furthermore, the lower 3rd teeth are narrower than the upper canines in the lateral lateral direction.

The lower 3rd teeth are usually the teeth that last the longest in the mouth.

Size and age of teething :

The lower 3rd teeth are placed closer to the midline than the maxillary teeth, so that their apex corresponds to the spaces between the upper 3rd teeth and the lateral incisors.

Features of the lower canine arch:

1. The crown is smaller than the upper 3 teeth in the same set of teeth.
2. The mesial and distal contours seen from the outside tend to be parallel or only slightly converging towards the neck.
3. The bite margin occupies about a quarter or a fifth of the root height, making the tooth appear longer and narrower than the upper canine.
4. The medial surface is flatter than the upper 3rd tooth because the lingual, lateral, and cingulum ridges are less protruding. Usually without tongue tubers, tongue pits and grooves.
5. The outer-inside size near the neck of the tooth is smaller than that of the upper 3 teeth.
6. The mesial and distal halves of the crown look more symmetrical when viewed from the biting side

4/ Canines and receding gums

The gum tissue around the canines is prone to receding due to their position in the mouth. According to the Journal of Orthodontics, incisors and canines are the most common sites of receding To reduce the risk of gum tissue degeneration around the canines, brush gently with a soft toothbrush. Limit rough brushing. Maintain good oral hygiene to avoid receding gums. However, receding gums can also occur because of the anatomical features of the bone tissue and gingival mucosa in that canine area. For treatment, we can also perform restorative gum graft surgery.

The shape and position of the canines make them particularly important in the structure and function of the dentition. Canines also play an important role in functional activities such as chewing, biting and tearing food. If you know how to take good care of your canines, they will serve you well for a lifetime.

>> See more: Incisors: The area of ​​​​the teeth determines the aesthetic

Doctor Truong My Linh