More than 75% of patients who need orthodontic treatment today require tooth extraction. Because orthodontics requires tooth extraction, the first reaction of most patients or parents when they hear this is great resistance, and may even give up treatment because of it. Teeth are valuable, and many people will be willing to spend tens of thousands of dollars on dental implants, and as dentists, we do not know this, so why orthodontics instead requires tooth extraction? Intuitively speaking, there is a limit to the number of teeth that can be accommodated in each person’s mouth. We call the volume of the mouth the bone volume and the sum of the width of all the teeth the tooth volume. According to the size of the relationship between bone volume and tooth volume, the following three situations occur: 1, bone volume and tooth volume are the same, which is the most ideal, because the two match, most do not need orthodontics, or only need a simple alignment can be; 2, bone volume is less than tooth volume, which is the most common situation, that is, the mouth can not accommodate the total number of existing teeth, manifested as uneven teeth, tilt shift, etc.. Generally speaking, the crowding below 4 mm can not be extracted, more than 4 mm crowding will need to be extracted to correct, the specific extraction of the site and the number of teeth need to be measured and analyzed to determine; 3, the amount of bone is greater than the amount of teeth is manifested as a gap in the teeth, this situation also does not need to be extracted, the gap can be used to internalize the protruding teeth, or move the back teeth to close the gap. Why are there so many children who need orthodontic treatment? Before the age of 12 is a critical period of growth and development for children, as well as a critical period of jawbone growth. The bone, like the muscles, needs constant stimulation and exercise from chewing movements to become strong and grow to sufficient length and width to accommodate all the teeth. However, many families tend to neglect this, such as not giving their children chewy foods, eating only fluffy foods, and eating apples in small pieces or squeezed into juice, which appear to be caring for their children, but are actually extremely detrimental to their jaw development, which is the main reason why malocclusion remains high. Therefore, parents must pay attention to eat more chewy food from the age of three to twelve to promote the growth of the jawbone and reduce the incidence of malocclusion. The advantages of tooth extraction If crowded teeth are not extracted, the only way to align the teeth is to expand the arch, and the stability of the arch is not good, so it is necessary to wear retainers for a long time. After extraction, all the gaps are closed and the teeth are more stable, and the teeth can be receded internally to improve facial aesthetics. Parents and friends also do not have to worry about the impact on eating, the alignment is neat and chewing efficiency is greatly improved than before orthodontics, and will not be affected by the reduction in the number of teeth.