Dental implants were discovered by a Swedish scientist who found that a titanium metal and bone tissue have good biocompatibility, i.e. titanium metal and bone tissue bond better, and further developed dental implants based on this feature. There are several reasons why dental implants are not rejected by bone tissue: 1. The biocompatibility of the implant material is better, and the amount of bone cut during the implant surgery can be grasped at the right level to ensure that the vitality of bone cells is not reduced, and the implant is closely bonded to the bone tissue after implantation, which can form a good osseointegration interface; 2. In the restoration process, attention is paid to keeping the force on the implant in an appropriate direction, so that the osseointegration interface 3. When the implant crosses the cancellous bone area, the fibroblasts, osteoblast cytoplasm and bone trabeculae in the cancellous bone penetrate deeply into the implant surface for effective organic bonding. From the above three aspects, there is no rejection of dental implants by human body.