Sinus lifting

the preferred technique for tooth replacement, dental implants offer a number of advantages to patients. They look good, they’re long-lasting, and over the long-term, they’re more cost-effective than other alternatives.

In a sinus graft, the soft sinus floor is essentially raised, encouraging additional bone growth in the area.  An incision is made in the gums in the area below the sinus and then cut through the bone to create a “window” into the sinus cavity.  Bone graft material, which ultimately encourages thicker bone growth, is then placed in the area, and the incision is then sutured.  A sinus graft can take place under local anesthesia.

Sinus-lift procedure

  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, a human or animal donor (from an accredited tissue bank), 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:

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 the site of maxillary left permanent first molar. Sinus floor provided approximately 6.8mm of apico-coronal height whereas placement of a 10mm 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 the bone graft can be seen apical to the implant.

Today, there are several variations of sinus lift procedure, these are the most common:

• Lateral Window approach (opening a window in the anterolateral sinus wall) - Invented by Tatum in 1986 - A crestal incision is made with vertical extensions and the lateral aspect of the maxilla is exposed. Then the osteotomy aka. antrostomy 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 alloplastic 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 stabilized, to prevent complications.

• The Osteotome approach - Invented 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 as 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 - 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.

Complications

• Graft failure

• Infection

• Oral antral fistula

• Sinusitis

• Tilting or loosening of implants

How It's Done

Your surgeon will cut the gum tissue near your premolars and molars. The tissue is raised, exposing the bone. A small, oval window is opened in the bone. The membrane lining the sinus on the other side of the window separates your sinus from your jaw. This membrane is gently pushed up and away from your jaw. Granules of bone-graft material are then packed into space where the sinus was. The amount of bone used will vary, but usually, several millimeters of bone is added above the jaw.

Once the bone is in place, the tissue is stitched closed. Your implants will be placed four to nine months later, depending on the graft material that was used. This allows time for the grafted material to mesh with your bone.

Follow-Up

After the procedure, you may have some swelling of the area and may bleed from your mouth or nose. You should not blow your nose or sneeze, because these activities can cause the bone-graft material to move, and can cause the stitches to loosen.

Your dentist may give you saline sprays to keep the inner lining of your nose wet and prescribe medication to prevent sneezing. If you have seasonal allergies, you should schedule the procedure when they are not active. You also will be given pain medication, an antibiotic and an antimicrobial mouthwash to help prevent infection. Most patients have only a little discomfort after a sinus-lift procedure.

You will see the specialist after 7 to 10 days to have the sutures removed, and for the specialist to see how you are healing. You probably will be asked to return a few more times to make sure the area is healing properly.

After a sinus lift, you need to wait several months for the bony material to harden and integrate with your jaw. Once this happens, the implants will be placed.

If your own bone is used in the procedure, you may wait as few as six months. If cadaverous or synthetic bone is used, you will need to wait longer, usually nine to 12 months.

Some specialists have started using proteins called growth factors to help the new bone harden faster. Platelet-rich plasma, which contains the growth factors, is taken from your blood before surgery and mixed with the graft that is placed into your sinus.