Bone Grafting
Over a period of time, the jawbone associated with
missing teeth atrophies or is reabsorbed. This often leaves a condition
in which there is poor quality and quantity of bone suitable for
placement of dental implants. In these situations, patients may not be
candidates for placement of dental implants without a bone graft.
Today, we have the ability to place bone where needed.
This not only gives us the opportunity to place implants of proper
length and width, it also gives us a chance to restore functionality and
esthetic appearance.
Bone grafting can repair implant sites with inadequate
bone structure due to previous extractions, gum disease or injuries.
The bone is either obtained from a tissue bank, animal sources or your
own bone is taken from the jaw, hip or tibia (below the knee.) Sinus
bone grafts are also performed to replace bone in the posterior upper
jaw. In addition, special membranes may be utilized that dissolve under
the gum and protect the bone graft and encourage bone regeneration.
This is called guided bone regeneration or guided tissue regeneration.
Large defects are repaired using the patient’s own bone.
This bone is harvested from a number of different sites depending on
the size of the defect. The hip (iliac crest), and lateral knee
(tibia), are common donor sites. These procedures are routinely
performed in an operating room and require a hospital stay.
Sinus lift procedure
The maxillary sinuses are behind your cheeks and on top
of the upper teeth. Sinuses are like empty rooms that have nothing in
them. Some of the roots of the natural upper teeth extend up into the
maxillary sinuses. When these upper teeth are removed, there is often
just a thin wall of bone separating the maxillary sinus and the mouth.
Dental implants need bone to hold them in place. When the sinus wall is
very thin, it is impossible to place dental implants in this bone.
There is a solution: it’s called a sinus graft or sinus
lift. The dental implant surgeon enters the sinus from where the upper
teeth used to be. The sinus membrane is then lifted upward and donor
bone is inserted into the floor of the sinus. Keep in mind that the
floor of the sinus is the roof of the upper jaw. After several months
of healing, the bone becomes part of the patient’s jaw and dental
implants can be inserted and stabilized in this new sinus bone.
The sinus graft makes it possible for many patients to
have dental implants when years ago there was no other option other than
wearing loose dentures.
If enough bone between the upper jaw ridge and the
bottom of the sinus is available to stabilize the implant well, sinus
augmentations and implant placement can sometimes be performed as a
single procedure. If not enough bone is available, the Sinus
Augmentation will have to be performed first, then the graft will have
to mature for several months, depending upon the type of graft material
used. Once the graft has matured, the implants can be placed.
Nerve- repositioning
The inferior alveolar nerve, which gives feeling to the
lower lip and chin, may need to be moved in order to make room for
placement of dental implants to the lower jaw. This procedure is
limited to the lower jaw and indicated when teeth are missing in the
area of the two back molars and/or and 2nd premolar, with the
above-mentioned secondary condition. Since this procedure is considered
a very aggressive approach (there is almost always some postoperative
numbness of the lower lip and jaw area, which dissipates only very
slowly, if ever), usually other, less aggressive options are considered
first, i.e. keeping implants toward the front of the jaw.
Typically, we remove an outer section of the cheek side
of the lower jawbone in order to expose the nerve and vessel canal.
Then we isolate the nerve and vessel bundle in that area, and slightly
pull it out to the side. At the same time we place the implants we’ll
be tracking the neurovascular bundle. Then the bundle is released and
placed back over the implants. The surgical access is refilled with
bone graft material of the surgeon’s choice and the area is closed.
These procedures may be performed separately or
together, depending upon the individual's condition. As stated earlier,
there are several areas of the body that are suitable for attaining bone
grafts. In the maxillofacial region, bone grafts can be taken from
inside the mouth, in the area of the chin or third molar region or in
the upper jaw behind the last tooth. In more extensive situations, a
greater quantity of bone can be attained from the hip or the outer
aspect of the tibia at the knee. When we use the patient’s own bone
for repairs or addition, we generally get the best results.
In many cases, we can use allograft or xenograft
material to implement bone grafting for dental implants. This bone is
prepared from cadavers or animals and used to get the patients own bone
to grow into the repair site. It is quite effective and very safe.
Synthetic materials can also be sued to stimulate bone formation. We
even use factors from your own blood to accelerate and promote bone
formation in graft areas.
These surgeries are performed in the out-office surgical suite under IV sedation/ general anesthesia.
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