Morphology And Structure Of Oral Care Teeth

1. The shape of the tooth The tooth is divided into three parts: crown, neck and root. The crown of tooth exposed in the mouth is white and shiny; the root of tooth embedded in the alveolar; the part between the crown and the root is surrounded by the gums and is called the neck ( dental neck).

The internal cavity of the tooth is called the dental cavity, and the root canal (root canal of tooth) located in the root of the tooth is connected to the alveolar. There is dental pulp in the tooth cavity, which is rich in blood vessels and nerves. When the dental pulp becomes inflamed, it can cause severe pain.

2. The structure of the tooth The tooth is mainly composed of light yellow dentine. The crown surface is covered with a layer of white glossy enamel, and the root and neck surface are covered with a layer of adhesive. Gum, periodontal ligament and alveolar bone together constitute periodontal tissue, which has protective, support and fixation effects on teeth.

3. The name of the tooth and the time of eruption. Two sets of teeth occur in a person's life. After a person is born, deciduous teeth usually begin to erupt at about 6 months, and there are 20 in total at about 3 years old. Deciduous teeth are divided into incisors, canines and molars. The deciduous teeth begin to fall out around the age of 6 and are replaced with permanent teeth, which will appear at the age of 12 to 14. Permanent teeth are divided into incisors, canines, premolars and molars. The third molars erupt late. Some people do not erupt until they reach adulthood. They are called late teeth, or even do not erupt for life. There are 28-32 adult permanent teeth.

4. The arrangement of teeth is symmetrical to the tooth type. Clinically, in order to record the position of the teeth, based on the orientation of the examinee, the "+" sign is used to record the arrangement of teeth, which is called the tooth type, and the Roman numerals I to V are used to indicate the deciduous teeth, and the Arabic numerals 1 to 8 are used to indicate the permanent teeth.