The upper back jaw (molar and premolar area) has traditionally been one of the most difficult areas in which to successfully place dental implants. This is due to the poor quality of the bone located in this area and the close proximity of the maxillary sinus, an airfilled space within the upper (maxillary) jawbone. The maxillary sinuses are cavities in the skull located behind the cheekbones, directly above the upper teeth. The floor, or base, of the maxillary sinus is generally located near the ends of the roots of the upper molars and premolars. If you’ve lost bone in that area due to periodontal disease or tooth loss, you may be left without enough bone in which to place implants and may require a secondary bone grafting procedure referred to as a sinus elevation or sinus lift.
During a sinus lift procedure, the bone in the upper back jaw is augmented by elevating the skin-like tissue that lines the sinus floor and placing a bone graft under the elevated tissue. Several techniques can be used to raise the sinus and allow for new bone to form.
When at least 5 mm of jawbone is present below the base of the sinus cavity, Dr. Ramirez can often perform what is called a crestal (or internal) sinus elevation. First, the implant site is prepared to a level just below the floor of the sinus. Next, a special drill attachment is used to cut the bone at the base of the sinus while preserving the skin-like sinus membrane. Once the sinus membrane has been exposed, it can be further elevated hydraulically through the introduction of the bone graft. Once sufficient bone height has been established, the implant can be placed during the same surgery.
When more than a few millimeters of bone height is necessary, Dr. Ramirez utilizes a procedure know as a lateral wall sinus elevation to augment the bone. Following an incision, a small window is cut into the bone on the side or lateral wall of the sinus. Care is taken to preserve the skin-like membrane that lines the sinus by utilizing a small ultrasonic vibrating instrument. This bony "window" and the attached membrane are pushed inwards towards the hollow sinus much like a trap door. As the window and the membrane are pushed inwards, the doctor carefully separates the membrane from the bony floor of the sinus so that it can be elevated upwards. The space underneath the elevated membrane is filled with bone graft material. Finally, the incision is closed, and healing is allowed to take place. The bone usually will be allowed to develop for about six months before implants can be placed. In some cases, the implant can be placed at the time of sinus elevation.