Incisor teeth: what functions do they perform, how they differ, anatomy

Incisors are teeth located in the middle of the front of the jaw. There are eight of them. Four at the top and four at the bottom. Numbered 1 and 2.

The incisors are so named because of their functional purpose: they are involved in the first phase of chewing and play an important role in the smile aesthetics as they are the most conspicuous.

Functions and structure of incisors

As already mentioned, the name of this type of teeth comes from the functions they perform:

1. Grabbing food: serve for nibbling.
2. Cutting: perform the function of crumbling and cutting of pieces, as well as primary grinding in the first phase of chewing.

All teeth are located in the dental alveoli of the jaws. Consist of the same fabrics and differ only in structure, location and their number.

The incisor consists of three parts: the root (hidden part), the neck (covered by the gum) and the crown - the part visible to the eye.

The crown has several surfaces:

• lingual (facing the language);
• vestibular or facial (facing the vestibule of the oral cavity);
• contact (facing the adjacent tooth);
• chewing (the surfaces of the lower and upper teeth are facing each other).

Now let's look at the inside of the root and crown.

The skeleton of the tooth is hard dentin, which is yellow in color. From above, the dentin is covered with enamel, and near the root - with cement (represents bone tissue), near the neck - with thinned cement, which does not contain cells.

Inside the dentin there is a cavity in which the pulp is located. It consists of connective tissue and has many vessels and nerves.

The supplying vessels enter from the main artery into the apex of the root. Through the root hole, an artery and a nerve enter the cavity, and a vein exits.

The cavity of the crown is filled with a root canal and a root hole.

The pulp performs the function of protection and, in case of any violations, signals this through the nerve endings located in it. The soft pulp is located along the entire tooth, starting from the root, further to the root canal, and fills the space of the crown cavity.

Enamel is the most durable tissue in the human body and is composed of inorganic substances. Its strength is comparable to that of diamond. It is the enamel that makes our smile sparkling white.

Each individual tooth is held in the jawbone by the so-called periodontal ligament. It looks like a layer between the root and the jawbone and has an elastic structure that allows the tooth to move when chewing. The periodontium communicates with the jaw bone marrow.

Not to be confused with the word periodontium. The periodontium is the gums, periodontium, cement, alveolar processes.

Peculiarities

There are several characteristics that distinguish these teeth from the rest:

1. One root.
2. They resemble a chisel in shape.
3. The side ones are more curved than the central ones.
4. There are grooves along the root surface.
5. The lateral incisors have a quadrangular vestibular surface and a triangular lingual surface.

Views and anatomy

A person has two central and two lateral incisors on the upper and lower jaw.

In size, the central incisors of the upper jaw are larger than the lateral ones. And on the bottom - on the contrary, the central ones are less than the side ones. There are several cutter surfaces:

• vestibular or labial;
• oral or palatal, lingual;
• contact or median, lateral;
• occlusal or incisal edge.

Let's consider each cutter separately:

• upper medial;
• upper lateral;
• lower medial;
• lower lateral.

Upper medial

The upper medial incisors are located in the middle of the jaw, next to each other. They consist of a single root and a chisel-shaped crown. They look like a quadrangle, elongated and tapered towards the top.

The vestibular surface is convex, and therefore the crown has a characteristic shine. Two grooves are located vertically along the tooth, which, as it were, divide it into three parts. Each part is shaped like a roller. If you look at the incisal edge, you can see three tubercles. This is the type of rollers, but on the other hand. Over time, the surface of the tooth becomes flat due to the abrasion of the rollers.

The lingual surface is triangular, has narrower dimensions than that of the front. Concave shape. Along the edges, along the entire crown, there are two protruding ridges, they are called medial and lateral ridges. The rollers may or may not be very prominent. Sometimes this side is a kind of gutter. There is a tubercle near the neck of the tooth. If the degree of its severity is high, then it can be divided into several teeth, from two to five.

Thus, there are one-tubercle, two-tubercle, three-tuberous forms, etc. There are usually two prongs. They are called medial and distal.

If these combs have a strong protrusion, then they, as a rule, form a ridge at the neck of the tooth and repeat the outline of the neck itself. This roller is called the cervical girdle.

If you look at the contact surface, you can see a triangular shape. There is also a bulge here.

The root of the central incisor is cone-shaped, slightly flattened, and rounded at the top. The root is deflected towards the adjacent lateral incisor.

The cavity is similar to the shape of a tooth. Near the incisal edge, it is slit-like; in the vestibolingual direction, it is flatter. The cavity of the crown is narrowed in the shape of the root.

Upper lateral

The lateral or lateral incisors are very similar to the previous view and are located on either side of the central ones. They are chisel-shaped and smaller than the central ones.

The labial surface is trapezoidal. The angle between the incisor and distal is more rounded than that of the medial incisor.

The incisal tubercles are practically invisible. The grooves along the tooth are also practically invisible and poorly developed.

The side surfaces have a slightly convex triangular shape.

The palatal surface has the same ridges along the edges. Most often, the upper lateral has a protruding tubercle, under which a blind fossa is well formed. Typically, the lateral incisor does not have multiple teeth.

The root is flattened in the form of a cone, and on its front surface you can see a groove located vertically. Sometimes its apex is inclined towards the sky.

Lower medial

The medial (central) lower incisor is the smallest among the fellows. The crown is narrow and widens towards the incisal edge.

The lip surface is in the form of an elongated quadrangle, has a slightly convex shape. Grooves and three ridges are clearly visible along the entire tooth vertically, as well as three tubercles on the incisal edge. In the middle third, the ridges are already invisible. With age, they disappear as well as on the upper incisors.

If there are no ridges, then the labial surface is smooth and slightly flattened.

The palatal side can be convex, flat, or concave. The crown is shaped like a shovel. Sometimes marginal ridges are visible, which may also be absent. A bump can sometimes be seen near the crown of the crown. A roller can extend from the tubercle to the cutting edge. There is no multi-pronged tubercle.

Wedge-shaped side surfaces. Occlusal - in the form of an arc. The root is short, slightly compressed and sometimes deviated towards the labial side. Has grooves along the vertical.

Lower lateral

The lower lateral incisor has a chisel crown that is convex towards the obverse. This species is larger in size than the medial one. Has a wider cutting edge than the central lower tooth.

The root is larger than that of the central one, flattened, and has a deviation in the distal direction.

The vestibular surface contains ridges, which end in scallops at the cutting edge.

The lingual surface resembles the previous description. Concave triangle shape with dental tubercle. Wedge-shaped side surfaces.

The absence of lateral lower incisors is very rare. Sometimes there are diastemas, as well as crowding (crowding of incisors).

Probable diseases

Let's list the problems that are inherent in this particular type of teeth:

1. The most common disease is caries. It occurs under the influence of harmful factors: plaque, pathogenic bacteria and poor oral care can provoke the development of the disease.
2. First, caries affects the enamel, then develops, it deepens and affects the next layer - dentin. Then the development of caries reaches the nerve and pain occurs. If no treatment measures are taken at this stage, the bacteria will reach the pulp. Is developing pulpitis Is an inflammation of the nerve. It is dangerous because it can further provoke inflammation of the gum bone.
3. Periodontitis Is an inflammation that affects the apex of the tooth root. It manifests itself as swelling of the gums. It occurs due to untreated pulpitis or improper root canal filling.
4. Periostitis or in other words, flux is an inflammation of the periosteum due to untreated periodontitis. Looks like a bump on the gum in the root area. It can also be caused by common caries and pathogenic bacteria, staphylococci, streptococci, etc. More often affects the lower jaw.
5. Granuloma - This is the proliferation of inflammatory tissues of the dental root. It occurs due to untreated pulpitis, periodontitis, due to trauma, in the presence of caries. If you do not start treatment at the time, the disease develops into severe forms, for example, a flux.
6. Cysttooth - a capsule with pus at the apex of the root, appearing due to infection in the root canals. It occurs due to pulpitis, periodontitis or caries.
7. Injuryincisors can occur due to mechanical damage to the crown. It can be a bruise, crack, root fracture, dislocation, etc. With such problems they turn to traumatology. Depending on the degree of damage, treatment is prescribed: therapy aimed at maximum preservation of the dentition, endodotic treatment, restoration of the crown with special materials, restoration. If treatment is not possible, then they resort to removal and subsequent implantation or prosthetics.
8. Hypersensitivity. Sensitivity manifests itself from exposure to cold, hot, spicy, sour, sweet foods. Pain can also occur when brushing your teeth, when going out into the cold air.

Despite their size, the incisors are quite fragile. They reach up to 9 mm in length and up to 6 mm in width. Not only the appearance of a person depends on their condition, but also the entire chewing process.

Beautiful front teeth create a beautiful smile. Take care of your teeth, because this is the only organ in the human body that does not heal itself.