When the posterior maxillary teeth are missing, the bottom wall of the maxillary sinus will drop to the position of the original roots of the missing teeth, and there is a risk of penetrating the wall of the maxillary sinus once the implant is placed, so in order to place the implant, it is often necessary to transplant some synthetic bone substitute to elevate it to its original position, which will ensure that the implant is in the maxillary bone. The procedure is called maxillary sinus lift. 1. Lateral maxillary sinus lift: A window is opened in the lateral wall of the maxillary sinus, the mucosa of the maxillary sinus floor is peeled off and pushed inward under direct vision, and bone graft material is implanted or not (with a smaller lift height) between the mucosa of the maxillary sinus floor and the maxillary sinus floor to increase the amount of bone from the maxillary sinus floor to the top of the alveolar ridge. The decision of whether or not a one-stage implant restoration is possible can be based on whether the original bone height of the maxillary sinus floor can guarantee the initial stability of the implant, or if the bone volume is less, a two-stage implant surgery is also feasible. 2. Transalveolar crest elevation: During the implantation process, the distance from the alveolar crest to the maxillary sinus floor is precisely determined by means of a curved tomographic image restoration ratio or CT examination of the maxilla, and the implant socket is prepared with a circular drill. The endosseous lift instrumentation, with its concave or convex tip and the use of a stopper, provides effective protection against rupture and perforation of the mucosa of the maxillary sinus floor. Then the artificial bone substitute material is placed, the mucosa of the maxillary sinus floor is pushed upward from the implant socket and separated from the bone of the sinus floor, the bone graft material delivered through the implant socket is used to elevate the sinus floor, or the remaining bone is abraded by an ultrasonic bone knife, which has the advantage of only abrading the bone tissue without damaging the mucosal tissue, and then the mucosa of the maxillary sinus is elevated, avoiding the discomfort and fear of bone chisel striking, and the bone augmentation is completed with the implantation of the The implant is placed while the bone augmentation is completed. However, if the bone is thin enough to provide the initial stability of the implant, a second-stage implant restoration can be chosen.