The maxillary sinuses are behind your cheeks and on top if the upper teeth. Sinuses are empty with nothing in them. Some of the roots from your upper teeth extend into the maxillary sinuses. When you get your upper teeth removed there is often a thin wall of bone separating the maxillary sinus and the mouth. After removal of teeth and placing dental implants keep in mind that dental implants needs bone to hold them in place. When you have a very thing sinus wall it makes it impossible to place dental implants. The solution to this problem is sinus lift graft (sinus graft).
The oral surgeon enters the sinus from where the upper teeth used to be to lift the sinus membrane and insert bone onto the floor of the sinus. The floor of the sinus is the roof of the upper jaw.
Sinus lift graft makes it possible for patients to have dental implants whereas years ago you had no other options except wearing loose dentures. If there is enough bone between the upper jaw ridge and the bottom of the sinus to stabilize the implant then sinus augmentations and implant placement can sometimes be done in one visit. If there isn’t enough bone available then the sinus augmentation will be preformed first. You will have to wait several months for the graft to mature. Once the graft has matured the implants can be placed.