Maxillary sinus floor augmentation also termed sinus lift, sinus graft, sinus augmentation or sinus procedure is a planned surgical procedure aimed at increasing the amount of bone in the posterior maxilla (upper jaw bone), in the area of the premolar and molar teeth, by lifting the lower sinus membrane (Schneiderian membrane) and placing a bone graft to prepare the site for the future placement of dental implants It 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 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 maxillary sinus pneumatizes in this region 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.