The maxillary sinuses are hollow, air-filled cavities located behind the cheeks and above the roots of upper molar and premolar teeth. Occasionally, some of the roots of the upper teeth will extend up into the maxillary sinuses. When these upper teeth are removed, there often remains just a thin wall of supportive bone separating the maxillary sinus and the mouth. Often, the remaining bone height is not sufficient for placement of dental implants.
A sinus lift is a procedure that serves to increase the height of the bone so that dental implants can be placed in an ideal position. Most commonly, a small incision is made in the premolar or molar region to expose the bony ridge. A small opening (window) is made in the bone, and the membrane lining the sinus is gently pushed upward. The underlying space is filled with bone graft material and the incision is closed.
After several months of healing, implants can be safely and predictably placed in the newly regenerated bone. In cases with less advanced bone loss, dental implants can sometimes be placed at the same time as sinus grafting.