The maxillary sinus is a hollow, tissue lined (membrane) cavity in the posterior of the top jawbone. It has several proposed functions, including: vocal resonance, olfaction, humidification of air, and “crumple” zone (head trauma).
Following extraction of the maxillary posterior teeth, the ridge begins to atrophy. The maxillary sinus membrane also has bone resorbing properties, and the sinus begins to come down (pneumatize). Bone grafting at the time of extraction modulates this process. If no bone grafting was performed, there may be inadequate height for implant placement.
Sinus augmentation procedures allow us to create vertical bone height for implant placement. Performed under local anesthesia, the sinus membrane is gently lifted from the bony walls and bone graft is introduced. Following a healing period of approximately 6 months, implants are placed.
There are two types of sinus augmentation procedures:
- Lateral Window – also referred to as a modified Caldwell-Luc procedure. A small incision is made near the upper premolar or molar region to expose the jawbone. A small opening (“window”) is cut into the bone and the membrane lining the sinus on the other side of the opening is gently pushed upward utilizing special instruments. The underlying space is filled with bone graft material and the “window” is covered with a membrane. The incision is sutured. The graft is allowed to mature for a minimum of 6 months prior to implant placement.
- Internal (Osteotome) Lift – when there is adequate remaining vertical height (minimum of 3mm) of bone, the patient may be a candidate for a transalveolar sinus lift. The sinus lift is performed through the crest of bone utilizing specialized bone tapping instruments called osteotomes. Bone graft is introduced through the osteotomy (hole), which serves to push/elevate the sinus membrane. The implant may be placed at the same time, thereby reducing the number of required surgeries and healing time.