Three months after extraction, dental implants are generally available, and immediate implantation is also possible. 1. The alveolar bone will be absorbed to a certain extent after tooth extraction, and it will be absorbed faster in the early stage of tooth extraction, and the absorption of the alveolar bone will be gradually stabilized in about three months. Moreover, the alveolar fossa will have different degrees of damage at the early stage of tooth extraction, sometimes accompanied by postoperative inflammatory reaction, so, we can only perform dental implantation when the alveolar bone is fully recovered. 2. With the development of technology, immediate implantation is also gradually developed. In the case of better alveolar bone condition after tooth extraction, immediate implantation can be carried out, but it should be noted that after implantation, do not immediately load, eat some soft food, so as not to accelerate the alveolar bone resorption. Therefore, dental implants can be done three months after tooth extraction, and those with good alveolar bone conditions can be implanted immediately.