Sinus Lifting: Dental
Implants (2/2)
A
sinus lift, sometimes called a sinus augmentation, is surgery that adds
bone to your upper jaw in the area of your molars and premolars to make
it taller. The bone is added between your jaw and the maxillary
sinuses, which are on either side of your nose. To make room for the
bone, the sinus membrane has to be moved upward, or "lifted."
A
sinus lift is done when there is not enough bone in the upper jaw, or
the sinuses are too close to the jaw, for dental implants to be placed.
There are several reasons for this:
° Many people who have lost
teeth in their upper jaw particularly the back teeth, or molars do not
have enough bone for implants to be placed; ° Because of the anatomy of the skull, the back of the upper jaw has less bone than the lower jaw;
° Bone may have been lost because of periodontal (gum) disease;
° Once
teeth are gone, bone begins to be resorbed (absorbed back into the
body). If teeth have been missing for a long time, there often is not
enough bone left to place implants;
° The
maxillary sinus may be too close to the upper jaw for implants to be
placed. The shape and the size of this sinus varies among individuals.
In addition, the sinus can get larger as we age.
Sinus lifts have become common over the past 15 years as more people are getting dental implants to replace missing teeth.
Preparation
The bone used in a sinus lift may
come from your own body (autogenous bone) or from a cadaver (allogeneic
bone). Synthetic materials, which can stimulate bone formation, also
are used sometimes. If your own bone will be used in the sinus lift, it
will be taken from other areas of your mouth or body. In some cases,
the surgeon removes bone from your hip or your tibia (the bone beneath
the knee).
You may need X-rays taken before your sinus lift so the
dentist can study the anatomy of your jaw and sinus. You also may need
a special type of computed tomography (CT) scan to accurately measure
the height and width of your existing bone and to evaluate the health
of your sinus.
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 the
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.