Sinus Lift Procedure

A sinus lift is a bone grafting procedure that is sometimes performed as a part of preparing a site for a dental implant. A sinus lift is required in those instances where the amount of bone found in a patient's upper jaw (in the region originally occupied by their bicuspid or molar teeth) is inadequate to accommodate the planned implant.

Situations that might necessitate that a sinus lift be performed before a tooth implant can be placed.

There can be several reasons why the amount of bone found in the patient's upper jawbone might be insufficient to accommodate a dental implant. Some of them include:

• The patient's normal jaw anatomy presents complications.  The relative size and shape of an individual's upper jaw as well as the current size and shape of their maxillary sinus (the size of the sinus can change with age) varies among people. While over simplified, any one person may have a combination of a relatively small upper jaw and relatively large sinus which together create a situation where there is an insufficient amount of bone for the placement of a tooth implant.
  
• The patient has experienced bone loss due to gum disease.  In situations where advance periodontal disease (gum disease) is present, the bone that surrounds and supports the person's teeth is damaged. In the most severe cases, significant amounts of bone can be lost from around the person's teeth, to the point where there is no longer an adequate amount of bone in which to place a tooth implant.
  
• Bone resorption associated with previous tooth extractions.  When teeth are extracted the bone that originally held the teeth in place will undergo a process called resorption. The net effect of this process is that much of the bone in the region originally occupied by the tooth is lost, possibly to the point where there is an insufficient amount of bone in which to place a dental implant. 
  
  The magnitude of post tooth extraction bone loss can be as much as 40 to 60 percent within the first three years after teeth have been removed. Beyond that point, the rate of bone loss typically subsides substantially. The cause of post extraction bone resorption is typically attributed to disuse atrophy, decreased blood supply, localized inflammation and/or unfavorable pressure from a dental appliance (denture or partial denture).
  
• Bone loss due to other factors.  In some cases a bone deficiency may be associated with a previous surgical procedure such as a difficult tooth extraction or the removal of a cyst or tumor.

How is the sinus lift procedure performed?

The sinus lift is a surgical procedure. The specific technique that the oral surgeon utilizes can vary depending upon their training and experiences but traditionally the procedure has been performed as follows:

1. The oral surgeon will make an incision in the patient's gum tissue on the cheek side of their upper jaw in the area where the placement of the dental implant is planned (in the region originally occupied by the patient's bicuspid or molar teeth). This incision allows the oral surgeon to flap back the patient's gum tissue and expose the jawbone that lies underneath.
   
2. The exposed bone is cut in a fashion where a "trap door" of bone, hinged at the top, is created. This movable section of bone is then pushed gently inward and upward into the sinus cavity. This bone movement caries the sinus membrane attached to it with it, thus "lifting" the membrane (and hence the sinus floor) to a new, higher level. The empty space underneath the lifted sinus membrane is then packed with bone-graft material thus providing the new bone into which the tooth implant will be placed.
   
3. Once the bone-graft material has been positioned the gum tissue is stitched closed.

In some instances it can be possible that the oral surgeon will place the dental implant at the same time that the sinus lift is performed. In most cases, however, an oral surgeon will allow a healing period of six to nine months before the dental implant is placed. The specific time frame allowed for healing is dependent upon the type of bone-graft material that has been utilized.

What types of bone-graft materials are used with the sinus lift procedure?

Several different types of bone-graft materials can be utilized with the sinus lift procedure. In some instances the patient's own bone will be used, such as bone harvested from another location in the patient's mouth or else from other bones (including the hip (iliac crest) or shin bone (tibia)). In other instances prepared bone (frozen bone, freeze-dried bone, demineralized freeze-dried bone), either human or from another species (i.e. bovine), can be purchased from a tissue bank for use. Another alternative involves the use of synthetically derived graft material such as hydroxyapatite.