A sinus lift (a sinus augmentation) is surgery that adds bone to your upper jaw in the area of your molars and premolars to make it taller. The bone is added between your jaw and the maxillary sinuses, which are on either side of your nose. To make room for the bone, the sinus membrane has to be moved upward, or "lifted." A sinus lift usually is done by an oral and maxillofacial surgeon or a periodontist.

A sinus lift is done when there is not enough bone 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 molars teeth - 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.
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 among individuals. In addition, the sinus can get larger as you age.
Bone may have been lost because of periodontal (gum) disease.