The external image of the gum is arched, which is also called dental arch. The upper teeth are called upper dental arch and the lower teeth are called lower dental arch. The shape of dental arch and facial shape are in harmony with each other, and what kind of facial shape there is, there is a corresponding dental arch shape. And people's facial shape is influenced by heredity. Naturally, the corresponding dental arch and the arrangement of teeth are also affected by heredity. Dental arch can be divided into three types: oval, pointed and square. For those with a wide face, his dental arch is mostly square, while for those with a narrow face, his dental arch is mostly pointed. Most people have oval faces and dental arches.

The function of teeth in dental arch is not exactly the same because of different positions and different beginnings. The incisors, also called incisors, are located in front of the dental arch, and the wedge-shaped cutting edge is conducive to cutting food; The fangs located at the corner of the mouth, also called canine teeth, are mostly used to tear food; Behind the fangs are bicuspids, which are good for mashing food; Located at the back of the gums are molars, and many multi-pointed molars are used to grind and crush food.

There are three dentition periods in a person's life, from 6 months of birth to about 6 years old, and the deciduous teeth are completely out of line. This period is called deciduous dentition period, and one ***2 teeth are arranged neatly and symmetrically on the gums. The period of 6-13 years old is the replacement period of primary and permanent teeth. At this time, the teeth are often irregularly arranged, and even double-layer teeth appear, that is, new teeth grow and the primary teeth are not removed. After the age of 13, all the deciduous teeth are replaced, which is called the permanent dentition period. As the child's face grows up, the jaw will also change from small to large, and the original crowded teeth will be partially adjusted. If you can't adjust yourself, it belongs to uneven tooth arrangement, also known as malocclusion.

malocclusion can be corrected by using the plasticity of the jaw before the facial development is fully finalized, so that the teeth that are naturally out of alignment can be artificially aligned. Generally speaking, the correction effect is more obvious at the age of 13 to 16. If you lose the opportunity of orthodontics and leave a pair of teeth that are twisted and twisted, it will bring regret to your child's life.