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The structure of the tooth - what you need to know?

The human chewing apparatus is a well-coordinated system ideally suited for food processing. Teeth are an important component of it, which has a complex structure. It has anatomical and histological nuances, depending on the localization.

Teeth – structural features and functions

The considered elements of the oral cavity consist mainly of hard tissue, covered with special enamel on the outside. They have their own blood and lymph vessels, an extensive nervous network. There are different types of teeth, the structure and function depend on the type of bone structure. By age, there are temporary (milk) and permanent bites. By location – the teeth of the upper and lower jaws. Depending on the form and purpose, the classification is as follows:

  1. Molars. The most massive and remote teeth are located in the depths of the oral cavity. They serve for chewing, thorough grinding of food.
  2. Premolars. Large teeth, precede the molars, similar in structure to them. These elements are responsible for grinding pieces of food.
  3. Fangs. Pointed teeth, localized on the sides, are necessary for holding food, tearing it.
  4. Incisors. Chisel-shaped front elements. They are designed to bite off pieces of food.

Teeth structural features and functions

In addition to individual tasks, the main among which is the mechanical preparation of food for ingestion, teeth also have common functions:

  1. Holding food inside the mouth during consumption.
  2. Formation of speech sounds. The external structure of the teeth ensures the correct pronunciation of hissing letters.
  3. Maintaining the external aesthetic image, youthfulness and elasticity of the skin, visual beauty of the face.

Anatomical structure of teeth

All described elements of the jaws in medicine are considered identical in terms of components. Studying the structure of the tooth, anatomy offers the following division:

  1. Crown. The upper part, visible from the outside. It is covered with thin and strong enamel, under which the tooth cavity and pulp are located.
  2. Neck. Towards the bottom, closer to the entrance to the gum, the crown narrows. At this point, the enamel layer turns into root cementum. If the structure of the tooth is normal, the neck is under the outer edge of the gum.
  3. Root. Depending on the functionality of the bone element, the number of these parts ranges from 1 to 3. For example, the structure of a tooth incisor does not provide for several roots. This element has a small size, so it is monolithic. The roots are localized in special jaw pits – alveoli. They serve to fix the teeth by means of ligamentous fibers. The root has the shape of a sharp cone, ending in a narrowed tip. The diagram of the structure of the tooth is presented below. Crown shape and number of roots may differ for incisors, canines and molars.

Anatomical structure of teeth

Anatomical structure of the teeth of the upper jaw

The above scheme is valid for all bone elements of the oral cavity. The anatomical structure of the tooth of the upper arch is similar to that of the lower jaw. In this case, the difference concerns only the ligamentous apparatus. The upper jaw is motionless, is part of the bones of the skull. The ligaments in it are less elastic, more “stable”. The location of bone structures in the alveoli of the upper arch is shown in the figure.

Anatomical structure of the teeth of the upper jaw

Anatomical structure of the teeth of the lower jaw

The only movable bone of the skull is equipped with an identical set of bone elements. The structure of a human tooth in the lower jaw is similar to the upper arch. Visually, the incisors are very different. The anterior central teeth are the smallest of the entire set and have a slight concavity from the side adjacent to the tongue. The numbers and localization of all parts of the lower jaw are shown in the diagram below.

Anatomical structure of the teeth of the lower jaw

Histological structure of teeth

The tissue features of the presented structures should be considered separately. The histological structure of the tooth includes both hard elements that perform mainly protective functions, and soft formations that provide blood and lymph flow, and nerve communication with the brain. There are the following parts:

  • enamel;
  • dentine;
  • pulp;
  • root zone.

Histological structure of teeth

The structure of tooth enamel

This layer has exceptional hardness. Enamel reliably protects the internal structure of the tooth from chips and damage. The characteristics of this structure are due to its chemical composition, which is dominated by minerals (about 96%). The structure of the tooth in the enamel layer includes mainly calcium, which ensures hardness and resistance to stress. The thickness of this area varies depending on the localization. On the sides it is about 1-1.2 mm, closer to the top of the crown it reaches 2.5-3.5 mm.

The structure of dentin

The underlying tissue that forms the base mass of the tooth. It is a cell-free, avascular material that is 5 times softer than enamel, but harder than bones in the body and cement. The structure of the dentin of the tooth includes almost 70% inorganic substances and less than 15% water. It is a porous intercellular tissue permeated with channels. Organic substances make up slightly less than 20% of dentin, they are close in structure to the bone matrix.

The structure of the pulp

The softest and most sensitive area, causing high soreness. The structure of the dental pulp is specialized connective fibers. They fill the root canals and a small area in the depth of the crown. The structure of the tooth in the pulp area includes numerous cells, blood and lymphatic vessels, which ensure the correct metabolism, formation and nutrition of dentin. Here are located the nerves necessary for protection and transmission of signals to the brain.

Root structure

The described parts of the teeth are covered with special cement. Outside, it is surrounded by periodontium. It is a connective tissue composed of collagen that binds the cementum to the alveolar matrix. The structure of the tooth root allows it to be securely held in the sockets of the jaws even with excessive pressure. Additional functions – providing access to nutrients to tissues, innervation. The arteries and nerves that make up the internal structure of the root are responsible for them. They pass to the pulp and dentin through special hollow channels.

The difference between temporary and permanent teeth

In the period from 5 to 13 years, there is a gradual replacement of both rows of bone structures. The most obvious difference between milk and permanent teeth is their number – 20 and 28-32 pieces. Other features:

  1. The shade of the “children’s” enamel is bluish-white, and the adult one is exceptionally yellowish if it is normally mineralized.
  2. Roots, significantly shifted to the side, have only a milk tooth, a structure of this type provides a comfortable formation of permanent bone elements.
  3. There are no premolars in the primary bite, they grow already in adolescence.
  4. The structure of temporary teeth suggests a more convex and wider crown, especially in the neck area.
  5. The mineralization of milk enamel is less, so it is thinner.
  6. The cavities and root canals of temporary teeth are much wider.
  7. “Baby” roots have a rounded tip, which makes them easier to remove.
  8. Dental rows in children are characterized by pronounced gaps. In the “adult” normal bite there are no three and diastema.
  9. Milk teeth are mobile because their roots are slowly resorbed.
  10. The cutting edges and tubercles of temporary structures wear out quickly.

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