Bone
grafting
What does your dentist mean when
he says a Bone Graft is necessary to place your dental
implant?
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The success of a dental implant, it's ability to support
a dental restoration, is very much dependent upon how
much bone is available in the site where the implant
is placed. There are lots of things that affect the
bone volume including things like periodontal disease,
trauma and infections and it is not unusual to open
up a site in the mouth for implant placement and find
out that some of the critical supporting bone is missing.
No problem.... We have great techniques available to
us to replace missing bone. We can increase the height
of bone and the width of bone. We can fill in anatomical
voids in bone thereby creating new bone and we can fill
in all sorts of defects that develop when teeth are
lost. We can even use grafting techniques to prevent
the loss of bone in circumstances where bone would normally
be lost like the extraction of a tooth.
Replacing missing bone or adding to existing bone is
very often essential to the success of a dental implant
and the ensuing restoration. The techniques to do this
are well documented and should be used when indicated
by any dentist who places dental implants. We have a
good idea when additional bone or bone repair will be
necessary before actually starting the placement of
a dental implant and you should be informed of this
possibility.
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Types of Bone Grafting:
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There
are many ways in which bone grafting can be done. Very often,
we can use "bone in a bottle" to do bone grafting
for dental implants. This bone is specially prepared from
cadavers or other sources and used to get your own bone to
grow into the repair site. It is very effective and very safe.
Sometimes synthetic materials can be used to stimulate bone
formation and sometimes we even use factors from your own
blood to accelerate and promote bone formation in graft areas.
Sometimes it is as simple as collecting bone when preparing
an implant site and then reusing the bone for grafting purposes.
Whenever we can use your own bone for repairs or additions,
we will get the best results. In extreme cases, bone can be
harvested from areas outside the mouth. The most common area
is the hip. Needless to say, when this type of bone graft
is done, everyone has to be fully prepared and you would usually
find yourself in a hospital setting with a physician actually
removing the bone from your hip.
Very often, bone grafting is done in combination with what
dentistry refers to as a "Barrier Membrane Technique".
Membranes made out of special materials are placed over bone
graft sites to keep out the types of soft tissue cells we
do not want and promote the growth and migration of cells
which will turn into normal, healthy bone. These membranes
are very successful and are used quite a bit these days to
promote sound bone formation. The membranes are usually removed
at a later date, but sometimes they can be resorbed by the
body and disappear all on their own.
In addition, it is not uncommon to use "screws"
and "tacks" to secure membranes and bone grafts
at an implant site. Sometimes these pieces will also have
to be removed at a later date, but rest assured that all of
these components and grafting materials are safe and effective
and their use has gone a long way in increasing the success
rates of dental implants.
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The
Sinus Lift:
The
human skull has several cavities or air spaces which are called
"sinuses". They are part of the overall design of
human beings to make the head lighter so that it can be supported
on our neck. Sometimes the sinus are enlarged and intrude
on areas where we want to place dental implants. We cannot
place a dental implant into the sinus because we would just
be placing it into an air cavity and nothing would hold it
into place (although, very often, implants that are placed
securely into solid bone will protrude a small way into the
sinus) so when we encounter this problem, we place bone or
bone growth stimulating material into the sinus.
This procedure really only affects the maxillary sinuses which
are located just over the molar teeth in the upper jaw. There
are no sinuses in the lower jaw. When the maxillary sinus
prevents the placement of an implant, we merely open up the
side of the sinus and raise the bottom portion of the sinus
so it will fill in with bone. We can then go back several
months later and place our dental implants in solid bone.
Sometimes, there is enough bone to place the implants at the
same time that you raise the floor of the sinus. This will
save time.
There are some more conservative ways to grow bone in the
sinus. We can do what is called an "Osteotome Lift"
and just raise the floor of the sinus right over where we
are placing an implant. This can be done without actually
opening the sinus and healing and implant integration will
then proceed as if the sinus was not in the way. Sinus lifts
of all types have a high success rate and are commonly used
today for promoting dental implant procedures.
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