A sinus lift is done when there is not enough bone height in the upper jaw, or the sinuses are too close to the jaw, for dental implants to be placed. There are several reasons for this:
Many people who have lost teeth in their upper jaw — particularly the back teeth, or molars — do not have enough bone for implants to be placed. Because of the anatomy of the skull, the back of the upper jaw has less bone than the lower jaw.
Bone may have been lost because of periodontal (gum) disease. Tooth loss may have led to a loss of bone as well. Once teeth are gone, bone begins to be resorbed (absorbed back into the body). If teeth have been missing for a long time, there often is not enough bone left to place implants.
The maxillary sinus may be too close to the upper jaw for implants to be placed. The shape and the size of this sinus varies from person to person. The sinus also can get larger as you age.
Sinus lifts have become common during the last 15 years as more people get dental implants to replace missing teeth.
Your surgeon will cut the gum tissue where your back teeth used to be. The tissue is raised, exposing the bone. A small, oval window is opened in the bone. The membrane lining the sinus on the other side of the window separates your sinus from your jaw. This membrane is gently pushed up and away from your jaw.
Granules of bone-graft material are then packed into the space where the sinus was. The amount of bone used will vary, but usually several millimeters of bone is added above the jaw.
Once the bone is in place, the tissue is closed with stitches. Your implants will be placed four to nine months later. This allows time for the grafted material to mesh with your bone. The amount of time depends on the amount of bone needed.