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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:
- 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.
- 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.
- 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.
