The transfer rate during orthodontic treatment mainly depends on the rate of alveolar bone reconstruction. When you are young, your metabolism is vigorous, the alveolar bone is not shaped, the transfer rate is fast, and the speed of orthodontics will also be accelerated. Studies have shown that the tooth movement of about 1mm per month is safe.
In addition, the time of orthodontic treatment is closely related to the severity of tooth deformity. The more serious the condition, the slower the tooth movement and the longer the treatment time. Conventionally, the time for orthodontics is generally two to three years, but the time for orthodontics for adults is relatively longer than that for children. Of course, everyone's physiological condition is different, the moving speed of the teeth will be different, and the correction time will be different. In some complex cases, the process of alveolar bone reconstruction is more difficult, and the correction time usually exceeds three years or even longer.
In the oral cavity, the part of the tooth that we can see is called the crown, and the root of the tooth stands upright in the alveolar bone, just like the root of a tree. Normally, it is invisible to the naked eye. There are a lot of elastic fiber tissue around the tooth root, which suspends the tooth root in the alveolar socket. These fibrous tissues, we call periodontal ligament. You can understand it as "periodontal ligament = many small rubber bands".
As the saying goes, "It's harder to start a business, but it's even harder to maintain the business." This saying is also very suitable for orthodontics. During the orthodontic process, the movement of the teeth is carried out at the same time as osteoclasts and osteogenesis. New bone is formed on the moving side, and the opposite direction is the bone breaking process.
When the tooth moves to a new position, the "business" is started, but the tooth is not stable at this time. Because the cell reaction in the bone continues to proceed, the elastic effect of the periodontal ligament also makes the tooth tend to relapse, and the neuromuscular has not yet fully adapted to the new position. So, after orthodontics, we need to insisit our efforts and wear orthodontic aligners for a period of time to maintain the hard-won "business".