A maxillary sinus floor augmentation procedure[1] (sometimes known informally as a sinus-lift or sinus 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, a human or animal donor (from an accredited tissue bank), or artificial bone grafting material is grafted into the bone (endosseous) above 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:
1.Onlay grafts
2.Interpositional (Lefort I) grafts
3.Inlay grafts for nasal floor
4.Sinus-lift and grafting
Surgical techniques
Straumann implant placed in site of maxillary left permanent first molar. Sinus floor provided approximately 6.8 mm of apico-coronal height whereas placement of a 10 mm implant was desirable. The sinus floor was thus lifted using the osteotome approach and packing bone into the osteotomy to lift the floor of the sinus. The dome of bone graft can be seen apical to the implant. Today, there are several variations of sinus graft procedure, these are the most common:
Lateral Window approach (opening a window in the anterolateral sinus wall) – done by Tatum in February, 1975.- 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. Tatum does not recommend implant placement into the grafts at the time of sinus grafting. For most patients, he recommends a uniform lining elevation off all axial walls to a height necessary to result in a healed height of 18-20 mm bone. The Osteotome approach – First done by Tatum in 1974 and published by Summer in 1994 – 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. Though this was the technique used by Tatum in 1974, he currently prefers a closed (floor elevation without sinus entry) technique.
Hydraulic Sinus Condensing – Invented by Chen in 2005 – A crestal incision is made, exposing the crestal ridge of the maxilla. An osteotomy is initiated with a sinus drill, 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.
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