A sinus graft is a surgery that adds bone to your upper jaw in the premolar and molar areas of your mouth. To add bone, an incision is made where the premolar and molar teeth were previously located. Once the bone is exposed, a small circular shape is made in the bone to access the sinus. Once the sinus is accessed, the sinus membrane is gently pushed up and away from the upper jaw. Once this is done, bone graft material is placed into the sinus space to change the shape and provide support. Once the bone is in place, the incision is closed and the healing process begins.