The evolution law of teeth is that the shape of teeth evolves from a single isomorphic tooth to a complex irregular tooth; The number of teeth varies from small to large; The number of teeth changed from multi-dentition to double dentition; The distribution of teeth is from extensive to gradually concentrated in the upper and lower jaws; From scratch, the root is attached to the jaw, and the way of tooth attachment is from the end tooth to the lateral tooth, and finally to the alveolar tooth.

First, the origin of teeth

The origin of teeth can be traced back to the appearance of vertebrates about 500 million years ago, but not all vertebrates have teeth. It was not until the appearance of vertebrate jaw fish that teeth appeared in the real sense. Then amphibians, reptiles, ancient birds and mammals all inherited teeth as an organ.

Second, the type of teeth.

Teeth are divided into three types: end teeth, side teeth and slot teeth.

1, end tooth

Final teeth are a type of teeth, especially those protruding from one end of the crown and facing the oral side. This kind of tooth is characterized by short root, so the overall position of the tooth is more prominent.

2. Side teeth

Lateral tooth is a kind of tooth, especially the tooth is attached to the inner edge of the jaw, and the opposite to the lateral tooth is the final tooth. The root of the lateral tooth is fixed on the inside of the jaw, which makes the root stronger and can better fix and grind food.

3. Grooved teeth

Alveolar tooth is a special kind of tooth. Through orthodontic treatment or other technical means, the original missing teeth grow back in the alveolar bone and have normal physiological functions. The realization of alveolar bone depends on the regeneration of alveolar bone and the application of transplantation surgery technology, which is the result of medical and scientific development.

Third, the growth of teeth

Tooth growth goes through two processes: deciduous dentition and permanent dentition.

1, deciduous dentition

Primary teeth refer to the first group of teeth that begin to erupt 6- 10 months after a child is born. Generally, all the teeth erupt before the child is 3 years old, with a total of 20 teeth.

2. Permanent dentition

Permanent dentition is the second group of teeth that gradually erupt when children are 6 years old, and it lasts until 18 years old. The erupted permanent teeth include the first permanent molar, the second permanent molar and the third permanent molar (wisdom tooth). In the stage of permanent dentition, the number of children's teeth can reach up to 32.

How to prevent oral problems

1, strengthen oral care

Usually pay attention to brushing your teeth in the morning and evening, rinse your mouth in time before and after meals, remove the food residue left in your mouth, and avoid the invasion of pathogenic bacteria.

2. Adjust the diet structure

Eat more fresh vegetables and fruits rich in vitamins and trace elements, help the body to supplement adequate nutrition, maintain the balance of oral microenvironment, and avoid eating spicy and irritating food.

3. Develop good living habits

Usually, we should quit smoking and drinking, try not to drink strong tea, reduce the bad stimulation to the oral cavity, keep a regular schedule and maintain healthy living habits.