A sinus lift is a type of dental surgery used to increase the amount of bone available for dental implants in the upper jaw. It is done when there is not enough bone for an implant to be securely placed. The surgery involves lifting up or moving the sinus membrane, and adding bone beneath it. The bone can come from another part of your body, or from a donor. The new bone is used to create a solid base for a dental implant, so the implant will be strong and stable. The sinus lift helps make sure that the implant is securely placed and can last for many years.