A sinus-lift procedure is a surgical procedure, performed by an appropriately trained dentist or dental specialist, to augment bone mass in the top jaw (maxilla), which increases the likelihood of successful placement of dental implants. Bone from another part of the body, such as the iliac crest, or artificial bone grafting material is grafted into the bone (endosseous) below the floor of the maxillary sinus. In the upper jaw the amount of bone is reduced by the presence of the sinus. A number of techniques are used to increase the bone height:
- Onlay grafts
- Interpositional (Lefort I) grafts
- Inlay grafts for nasal floor
- Sinus-lift and grafting
Lateral Window approach (opening a window in the buccal bone) A crestal incision is made with vertical extensions and the lateral aspect of the maxilla is exposed. Then the osteotomy aka. anthrostomy is completed. The sinus membrane, aka Schneiderian Membrane, is then detached from the bony walls of the internal aspects of the sinus, utilizing various curettes. Once properly detached, the lateral wall window with the sinus membrane is rotated medially into the sinus. The sinus membrane can fold on itself when reflected medially. Implant sites can be prepared and implants placed at this stage. The medial part of the sinus is grafted first. The graft material used can be either and autograft, an allograft, a xenograft, an alloplast a growth-factor infused collagen matrix, or combinations thereof. After the implants have been placed, the remaining lateral part of the sinus defect is grafted. The flaps are relieved and closed primarily. The graft is left for 6–9 months. Implant placements should be delayed if they cannot be properly stabilised, to prevent complications.
The Osteotome approach (cracking the crestal bone) A crestal incision is made, and the crestal ridge is exposed. A sharp osteotome is used to "chisel" a rectangle in the crestal ridge of the maxilla, then a sinus-lift osteotome is used like a mallet to fracture the bone, and punch a hole through where the rectangle was created into the sinus floor. The sinus is then raised with bone grafting material and implants are placed.
Hydraulic Sinus Condensing (drilling a hole into crestal bone) A crestal incision is made, exposing the crestal ridge of the maxilla. An osteotomy is initiated on the crestal ridge, and water pressure is used to gently raise the sinus membrane from the sinus floor. Then the sinus membrane is raised with bone grafting material, and implants are placed.