The maxillary sinuses are in the upper jaw behind the cheeks. They are empty air-filled spaces above the upper teeth and sometimes the roots of the upper teeth extend up into the floor of the sinus.  When these teeth are removed, there may be just a thin wall of bone separating the maxillary sinus and the mouth.

 

Dental implants need bone to hold them in place, so if bone loss has occurred due to injury, periodontal disease or resorption as a consequence of prolonged absence of the teeth, a sinus augmentation can be completed to raise the sinus floor and allow for new bone formation. The sinus graft procedure makes it possible for many patients to have dental implants when years ago, the only other option was dentures.