Sinus lift

Maxillary sinus floor augmentation (also termed sinus lift, sinus graft, sinus augmentation or sinus procedure) is a surgical procedure which aims to increase the amount of bone in the posterior maxilla (upper jaw bone), in the area of the premolar and molar teeth, by lifting the lower Schneiderian membrane (sinus membrane) and placing a bone graft.

When a tooth is lost the alveolar process begins to remodel. The vacant tooth socket collapses as it heals leaving an edentulous (toothless) area, termed a ridge. This collapse causes a loss in both height and width of the surrounding bone. In addition, when a maxillary molar or premolar is lost, the floor of the maxillary sinus expands, which further diminishes the thickness of the underlying bone. Overall, this leads to a loss in volume of bone that is available for implantation of dental implants, which rely on osseointegration (bone integration), to replace missing teeth. The goal of the sinus lift is to graft extra bone into the maxillary sinus, so more bone is available to support a dental implant.

While there may be a number of reasons for wanting a greater volume of bone in the posterior maxilla, the most common reason in contemporary dental treatment planning is to prepare the site for the future placement of dental implants.

Sinus augmentation (sinus lift) is performed when the floor of the sinus is too close to an area where dental implants are to be placed. This procedure is performed to ensure a secure place for the implants while protecting the sinus. Lowering of the sinus can be caused by: Long-term tooth loss without the required treatment, periodontal disease, trauma.

Patients who have the following may be good candidates for sinus augmentation.

Prior to undergoing sinus augmentation, diagnostics are run to determine the health of the patient’s sinuses. Panoramic radiographs are taken to map out the patient's upper jaw and sinuses. In special instances, a computed tomography or CT scan is taken to measure the sinus’s height and width, and to rule out any sinus disease or pathology.

...
Wikipedia