A dental implant is essentially an artificial tooth root, which fuses to the jaw bone. Eventually, a replacement tooth or bridge will be firmly fixed to this root, restoring complete function to the tooth. The key to a successful and long-lasting implant is the quality and quantity of jawbone to which the implant will be attached. If bone has been lost due to injury or periodontal disease in the posterior upper jaw where the maxillary sinus is located and the bone density is loose, a sinus augmentation can raise the sinus floor to allow for new bone formation. This increase in bone volume and height will allow for implant placement.
In the most common sinus augmentation technique, a tiny incision is made near the upper premolar or molar region to expose the jawbone. A small opening or window is cut into the bony wall of the sinus and the membrane lining the sinus on the other side of the opening is gently pushed upward. The underlying space is filled with a bone graft material and the incision is closed. The bone, which is used for this procedure may be from your own body, from a cow or from a cadaver. This bone graft will act as a matrix for new bone formation. The implants are placed after healing and additional bone has formed; this will depend on the individual case. This procedure is called an External Sinus Augmentation and has been shown to increase the success of dental implant procedures.
There is also a less invasive procedure called an Internal Sinus Lift, where if there is a narrow border of bone below the maxillary sinus, the floor of the sinus can be lifted with special instruments called osteotomes and bone added to increase the height of bone for implant placement.