Sinus lift is a surgical intervention in the upper jaw, in which the bottom of the maxillary sinus is raised artificially by filling it with bone material. Sinus lift is recommended to patients who want to have dental implants in the upper jaw, but their bone height in the lateral part of the maxilla is inadequate. Being a foreign body, an implant requires special favorable conditions in the oral cavity. And the most important condition at the moment is a sufficient amount of bone tissue in the implant area. Simply put, the bone should be sufficient for a doctor to insert an implant of a proper length and diameter. The anatomical structure of the upper jaw (maxillary sinus availability) does not always allow for an immediate implantation. This condition can be treated with an internal augmentation of the maxillary sinus floor. The essence of the operation is to create the necessary "depot" of bone material by raising the maxillary sinus floor, and if necessary by fitting a special membrane.