Bone Augmentation
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Transcript of Bone Augmentation
Bone Augmentation
Bone Augmentation
• For dental implants to be successful, the
jawbone must have enough bone to support
them. You may not have enough bone because
of tooth loss from periodontal (gum) disease,
injury or trauma, or a developmental defect. If
your jaw is too short (up and down), too narrow
(side to side), or both, you will need a procedure
to add bone to your jaw before implants can be
placed.
•Bone augmentation is a term that is used to
describe a variety of procedures that are used
to "build" bone so that dental implants can be
placed. These procedures typically involve
grafting (adding) bone or bonelike materials
to the jaw, and waiting for the grafted
material to fuse with the existing bone over
several months.
•There are several different procedures that
can be used for bone augmentation. The
dentist will select a procedure depending on
the type, location and number of implants to
be used. If it needs a bone graft, it is
important that the patient and the dentist
discuss all of the options available.
•After a bone-augmentation procedure, the
dentists usually wait 6 to 12 months
before placing implants, although some
dentists may place them sooner.
Where Does the Bone Come From?• Most bone-augmentation procedures involve the use of
bone grafts. The best material for a bone graft is our
own bone, which most likely will come from our chin or
ramus (the back part of the lower jaw). If the oral
surgeon cannot get enough bone from these areas, he
may need to get bone from the hip or shin bone (tibia)
instead. The hip is considered to be a better source
because the hip bone has a lot of marrow (soft tissue
within the bone), which contains bone-forming cells.
• If the patient don't like the idea of having bone removed
from their body to be placed in their jaw, there are other
options available. The dentist can use materials made
from the bone of human cadavers or cows. There are also
synthetic materials that can be used for bone grafting.
While most dentists prefer using a person's own bone,
possibly in combination with other materials. The dentist
and the patient should discuss their options and their
risks and benefits before any procedures are done.
A Typical Bone-Augmentation Procedure
•Local anesthesia will be used to numb the
area where the bone augmentation is needed
(recipient site) as well as the area from where
bone will be removed (donor site). The
specialist first will make an incision in the
gum where the implant will be placed to
determine how much and what type of bone is
needed.
• Then will make an incision in the gum below the
lower front teeth to expose the chin bone. A block
of bone will be removed from the chin along with
any bone marrow. The specialist will fill the spot
where the bone was removed with another type of
bone-graft material, and will cover this with a
membrane to keep soft tissue from filling the
space as it heals. The incision then will be
stitched closed.
• To place the removed bone in the recipient site, the
specialist first will drill little holes in the existing
bone to cause bleeding. This is done because blood
provides cells that help the bone heal. The block of
bone that was removed from the chin will be
anchored in place with titanium screws. A mixture of
the patient's bone marrow and some other bone-graft
material will then be placed around the edges of bone
block. Finally, the specialist will place a membrane
over the area and will stitch the incision closed.
• After a bone-augmentation procedure, the patient
will be given antibiotics, pain medication and an
antibacterial mouthwash. He will be asked to avoid
certain foods, and will be told how to avoid putting
pressure on the area while it heals. If the patient
wear a denture, he may not be able to wear it for a
month or longer while the area heals. If you have
natural teeth near the bone graft, your dentist may
make a temporary removable bridge or denture to
help protect the area.
•The bone graft will take about 6 to 12
months to heal before dental implants can
be placed. At that time, the titanium
screws used to anchor the bone block in
place will be removed before the implant
is placed.
Success of Bone Grafting
• The success rate for bone grafts in the jaws for
the purpose of placing dental implants is very
high. However, there is always a chance that
the bone graft will fail, even if your own bone
was used. Bone grafts are not rejected like
organ transplants. When they fail, it is usually
because of an infection or because the grafted
bone wasn't stabilized and has come loose from
your jaw.
•Dentists don't know why some bone grafts fail,
but they do know that certain people — such
as those who smoke and those with certain
medical conditions — have a higher risk of
graft failure than others.
•A failed graft will be removed. Once the area
has healed, your dentist can place a second
graft.
Other Types of Bone-Augmentation Procedures
Sinus Lift
•One type of bone-augmentation procedure,
called a sinus lift (or elevation), increases the
height of your upper jaw by filling part of your
maxillary sinus (the area above your jaw on
either side of your nose) with bone. This is done
when there is not enough bone to allow
implants to be placed in the back part of the
upper jaw.
Ridge Expansion
• A ridge expansion is a type of bone graft that can be
done when the jaw is not wide enough to support
implants. Your oral surgeon uses a special saw to
split the top of thejaw ridge, and then packs graft
material into the newly created space. Some dentists
will place implants directly after this procedure.
Others will wait several months for the ridge to heal.
This procedure can be done in the dental office under
local anesthesia.
Distraction Osteogenesis• One of the newest procedures for augmenting areas of bone is called
distraction osteogenesis. This procedure originally was used for lengthening
the bones of patients with abnormally short legs. It now has been adapted for
use in the mouth. A surgeon makes cuts in your jawbone to separate a piece of
bone from the rest of the jaw. A titanium device inserted into the jaw with pins
or screws holds the piece of bone apart from the rest of the jawbone. Over time,
the space between the piece of bone and the jawbone is widened slightly by
unscrewing the device, and the area between the pieces gradually fills in with
bone. "Distraction" refers to the process of separating the two pieces of bone,
and "osteogenesis" refers to the forming of new bone. Distraction osteogenesis
is used more often to make the jawbone taller, but it can be used to increase
the bone in any direction. The procedure is becoming more common.
Nerve Repositioning
• A nerve called the inferior alveolar nerve runs through
the lower jaw. This nerve gives feeling to the lower lip
and chin. In patients who have lost significant amounts
of lower jawbone, it may not be possible to place
implants without damaging this nerve. To address this
problem, an oral surgeon can drill a small window in
the bone and move the nerve to one side. The implants
then can be placed through the bony canal previously
filled by the nerve. This technique is not used very
often because it is possible to damage the nerve just
by moving it.
Case Report
•A 53-year-old female patient came to the
Clinic of Oral and Maxillofacial Surgery of
the Ribeirão Preto Dental School, University
of São Paulo, Brazil, complaining of
impairment of her masticatory function
associated with the instability of the
mandibular complete denture.
• The clinical exam revealed edentulism in both
arches, while the mandibular arch presented
severe reabsorption resulting in denture
instability and chronic trauma to the oral
mucosa. The radiographic exam showed a
mandibular atrophy class VI, according Cawood
and Howell (12), that made unpredictable any
rehabilitation based on osseointegrated
implants.
•Figure 1. Panoramic radiograph exhibiting a class VI Cawood and Howell (18) mandibular resorption.
The treatment plan proposed consisted of 3 steps:
• 1) to apply the modified visor osteotomy technique
together with autogenous bone graft harvested
from the iliac crest;
• 2) the placement of at least 5 osseointegrated
implants with a minimum length of 13 mm; and
• 3) to construct a fixed Brånemark’s protocol
prosthesis.
•The first surgical procedure was applied
under general anesthesia at the Hospital
of Clinics at the Medical School,
University of São Paulo, Brazil.
•Figure 2. Visor shape of mandibular distal segment after the mobilizing the segments.
•Figure 3. Autogenous corticocancellous bone grafts placed in an intepositional fashion, fixed with 2.0 titanium screws. Only particulated bone was placed in the posterior aspect of the mandible.
•
• After 6 months, 6 osseointegrated implants with dimension of 3.75 x 15
mm were implanted according to a previous prosthetic treatment plan.
Four months later, these implants were exposed to the oral cav-ity using
abutment healings preserving the keratinized gingiva, and 3 weeks after
that the patient was referred to the prosthesist. Twelve months after the
installation of the final Brånemark protocol prosthesis, the evaluation of
the osseointegrated implants revealed suc-cess according to the
previously established criteria (15).
•Figure 4. Different views of modified visor osteotomy in a dry mandible.
Figure 5. Uniform augmentation both in anterior and posterior region of the mandible, as demonstrated in a panoramic radiograph.
Figure 6. Placement of long implants for rehabilitation of the edentulous mandible.
•Figure 7. Good oral health after 12 months of follow up.
•The modified visor osteotomy technique,
applied together with autogenous bone
graft harvested from the iliac crest, offers
predictable results for reconstruction of
the severely resorbed edentulous mandible
and posterior rehabilitation with
osseointegrated implants.
Video Presentation:
Box Technique - Vertical
Ridge Augmentation
Procedure in Severe
Mandibular Atrophy.
Box Technique
•Box technique was invented in November
2008 by Dr. Andrea Menoni. It is the first
prosthetically guided by bone
regeneration technique aimed at fully
restoring the lost bone volume by using
only Polylactic acid absorbable materials.
•The technique allows bone regenration in
3 dimension of space without the need for
bone grafts to the patients, thus
minimizing the trauma of surgery.
•The aim of box technique is to fully
restore the bone to approximately its
original condition so that it is not only
functional but also aesthetically pleasing.
•The use af absorbable material is
beneficial for the following reasons:
•1. a second operation for their removal is
not required.
•2. the surgical intervention is far less
traumatic for the patient
•3. in cases of osseointegrated implants, the
rehabilitation period is significantly
reduced.
• The poly DL lactic acid is an absorbable material
which is completely amorphous as both
components are present in equal proportions. As
a result, the biodegration process is completely
predictable and safe. This new material is fully
tolerated by human tissue and does not result in
inflammation after contact with the PDLLA after
application sonic weld methodology.
• The degredation of PDLLA and its componentsis
through the metabolic process of hydrolysis,
where upon the final product is water and
carbondioxide, both of which are physiologically
eliminated from the body. This innovative
material presents the prime advantage of being
reabsorbed while simultaneously maintaining its
structural strength for the time necessary to
ensure the stability of the dot, the graft, and the
load resistance. All of which is important in GBR
(guided bone regeneration).
• The box technique is a new technique which
prosthetically used a guided bone regeneration
and only uses absorbable materials which are
processed naturally by the body. This
revolutionary method does not require the use
of the patient’s bone in the regeneration
process. Instead it uses a choice of either
XENOGRAFT or ALLOGRAFT creating
discomfort to the patient.