10 September 2009
Osseointegrated Implants For Craniofacial Prostheses
Over the last decade, there has been a very rapid development in
technical possibilities to provide patients with facial prostheses
retained by skin penetrating implants after ablative tumor surgery.
This chapter will present some background information on the surgical
technique of osseointegration, and the technical procedure for
preparing a facial prosthesis. The use of osseointegrated implants in
the patient who has undergone radiotherapy will also be reviewed.
HISTORICAL BACKGROUND
The
literature indicates that facial prostheses were used in China as early
as 2300B.C. In ancient Egypt, prostheses were used to cover facial
disfigurement. One of the most well-known people to wear a nasal
prosthesis was the Danish astronomist Tycho Brahe, who died in 1601.
Brahe lost his nose in a duel and wore a prosthesis made of silver, the
most commonly used prosthetic material at that time. In the mid-19th
century, prostheses were made from leather, enamel, and porcelain.
After the Great War in Europe, a large number of soldiers came back
with facial defects, and the first organized services to provide these
soldiers with prostheses were established in Germany and the United
Kingdom. Papier-mache and gutta-percha were introduced to make the
prosthesis more natural looking and also to reduce the weight.
Subsequently, the same technique was used to help patients who had
defects secondary to infectious diseases such as leprosy and also tumor
patients. Bulbulian, a dentist based at the Mayo clinic in Rochester,
Minnesota, was the first to advocate the use of a latex compound. After
World War II, acrylic was introduced as a reliable material but had the
disadvantage of being very hard.
Silicone rubber was a
new material introduced in the late 1970s that could be made soft to
follow the defect perfectly. For the first time, the edges could also
be made thin. However, when such a silicon prosthesis was kept in place
with glue, the edges soon became discolored and lost their softness.
There
are two very important properties that a prosthesis must possess. It
must approximate the defect area both in shape and color, and the
retention must be good enough to keep the prosthesis safely in place
during daily activities. Glue is frequently used for retention but also
has disadvantages. The skin and the prosthesis have to be cleaned
following removal, and exact positioning when placing the prosthesis is
not very easy. Sweating will impair the adhesive properties of the
glue. When the prosthesis is attached to glasses, the cosmetic result
is poor due to the weight of the prosthesis, which causes a gap between
the surgical defect and orbit.
One of the few reports on
the use of craniofacial prostheses was published in 1978 by
investigators from Rose-well Park. In this study, patients who had
undergone craniofacial surgery were rehabilitated with acrylic
prostheses secured with adhesive. Less than 50% of the patients used
their prostheses long term, and fewer could tolerate wearing their
prostheses for the entire day. Compliance was decreased because of skin
irritation and poor cosmesis with the prosthesis in place.
Since
1979, we have used silicone rubber prostheses retained by
osseointegrated, skin penetrating implants made from commercially pure
titanium for the rehabilitation of patients with post-tumor surgery
defects. Since that time, more than 300 patients with defects of the
external ear, orbit, nose, and midface have undergone implant surgery
in our Implants Unit.
OSSEOINTEGRATION
The
term osseointegration was coined by professor P.I.Branemark in the
1970s to describe a direct contact between living haversian bone and a
loaded implant surface. Branemark and associates have identified a
number of prerequisites necessary for osseointegration of titanium
implants. The technique of implantation must be carried our with ahigh
degree of precision to achieve initial implant stability. The implant
itself must have properties that are compatible with the host tissue to
prevent rejection. Several factors important to osseointegration have
been identified: the type of implant material, structure of the
implant, implant surface, implant site, bone quality, surgical
technique, and loading conditions. A reference for a more comprehensive
review can be found in the text entitled Advanced Osseointegration
Surgery.
INDICATIONS
To
achieve success with an implant retained craniofacial prosthesis, the
surgeon must be familiar with the indications and surgical technique
which, although not technically demanding, require close attention to
detail. The surgical procedure can often be performed under local
anesthesia on an outpatient basis. Implantation can often be performed
during the same operation as the ablative procedure. When placed in the
mastoid process at the time of auriculectomy, the patient can be fitted
with a prosthesis 5 to 6 week after surgery. Implants may also be
placed at the time of orbital exenteration but should be left
undisturbed for 6 months.
CONCLUSION
Today, the use of titanium implants for retention of craniofacial prostheses is an
established
treatment modality. Plastic surgery procedures should of course
contemplated, and implant retained prostheses should be regarded as an
option. We feel that this option should be available at major cancer
centers. One of the advantages is that the surgical procedure from the
patient’s point of view is minor and can often be performed under local
anesthesia. Another advantage is that the result is predictable.
According to our experience, one of the most important advantages of
this technique is the short time between tumor surgery and the time
that the patient can return to his/her everyday social activities. This
is important for elderly patients who often do not like an extended
time schedule that involves multiple surgeries. We also feel that the
cosmetic result often is superior compared with plastic surgery. This
is especially true when an external ear or an eye, with or without
maxillectomy, has been sacrificed.
Before this type of
rehabilitation protocol is introduced, there are some factors we feel
are of great importance. Close cooperation and understanding must exit
between the surgical team and the team working with the
anaplastologist. The patient only benefits if both teams co-operate.
The teams must be aware that they are assuming a commitment for the
rest of the patient’s life. The patient and his/her family must
understand the concept of “prosthesis” and be willing to take part in a
follow-up protocol. The selection of and information given to the
patient is thus extremely important. Informing the patient that the
prosthesis has to be remade at intervals should also be stressed during
the preoperative information session. After fitting of the prosthesis,
the patient has to make outpatient visits twice or three times a year.
These visits are of course coordinated with the tumor control visits.
The
longevity of a prosthesis varies. If the patients is a heavy smoker or
has a work environment where he/she is exposed to dirty oil, asphalt,
fumes, and so on, the prosthesis may get discolored within a year. On
the other hand, if the patient is not exposed to such contaminants and
is careful with hygiene, the prosthesis may keep its freshness for 3 to
4 years, and sometimes even longer.
There are very few
contraindications for this type of rehabilitation. Drug and alcohol
abuse, psychiatric disease, immature personality, and lack of patient
compliance are almost always considered to be contraindications. Among
our patients, we have individuals with diabetes, psoriasis,
scleroderma, and other skin diseases, but they do not have any
increased frequency of adverse skin reactions.
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29 June 2009
FUTURE DENTAL MEDICINE
TISSUE ENGINEERING AND LIFE LONG ORAL HEALTH ARE THE TRENDS OF THE FUTURE
VISION 1 – Restoration to Regeneration
The
current trend is moving from replacing tissue to healing it, that is,
from restorative to regenerative dentistry. Synthetic osteo -
conductive bone replacement materials, which are already used today,
will be optimized the future. Furthermore they will be given additional
osteoinductive properties by incorporating biological growth factors...
For this purpose, suitable signaling molecules and matrices will be
combined and a newly formed tissue implanted in the patient. Throughout
the world, interdisciplinary research groups are using biotechnology
methods to improve the treatment of exposed pulp, regenerating the
dental supporting tissue and to develop natural biological fillings and
even to re - grow entire teeth from bodies own cells.
VISION II – Lifelong oral health
In
future, microbiological test carried out in practice will be used to
detect harmful bio film that causes carries and gum infections within
few minutes. The type and extent of infection will be discussed with
the patient immediately. Further more the dental team will have the
possibility to heal the patient by selectively combating the
pathogenesis that is causing the diseases. This prebiotic treatment
approaches based on specific bioactive agents, which are dispensed in
the form of dental varnishes or mouth washes. These active agents will
eliminate the pathogens in plaque that causes decay of the teeth or gum
infection. And convert the plaque into a tooth friendly biofilm.
If
the infection should recur, that is, if the tooth friendly bio film
should become invaded by harmful bacteria, this could be detected
during a routine dental check up and probiotictreatment could be
resumed. This is a tremendous step towards maintain life long oral
health
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25 June 2009
The first patient
Gosta
Larsson was born in 1931 with severe chin and jaw deformities.At the
time, there was no treatment available. He grew up without being able
to chew properly, his speech was severely affected and his teeth were,
as he expressed it, "not in the place they were supposed to be".
It
was Larsson's doctor who suggested a closer look at the new method he
had heard of - titanium implants. Gosta larsson met with professor
Branemark and it was then decided that tha first titanium implant
surgery should take place in Gothenburg.
"During
my childhood and youth I learned to accept the fact that very little
could be done to reduce the effects of my handicap. My life was far
from normal, I was unable to eat or talk properly, I couldn't even chew
a slice of white bread.
When Professor Branemark told me
he could nelp me, I'm not sure I knew what to expect.K knew nothing but
the current state, and I was to be the first person ever to try this
new, bery advanced treatment. I was hardly the ideal patient as my
jawbone was not the strongest.
But as we
talked and it was all explained to me, I felt that mutual trust and
respect was building up.To cut a long story short, the surgery gave me
a fixed set of new teeth, anchored by a bridge held by four titanium
implants, and on the day of the surgery I realized my life would change
for the better.
I need only close
my eyes to recall that incredible feeling of being able to eat just
like every body else. And when I talked I could articulate and make
myself understood so much better. For a long time afterwards I
constanly had to look twice in the mirror to remind myself that this
really was the way I now looked.
After
forty years I still have my original implants.It's more than true to
say my life has changed - and it has changed in so many ways. The
physical and functional benefits alone are more than anyone can
imagine,at least with regard to the situation I was in at the time.The
greatest change, however,came in my everyday life, as I noticed how my
personality and self-confidence developed,all thanks to professor
Branemark and his method. My gratitude and my respect for him is
limitlesss."
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Titanium - the secret behind dental implants
The
main benefit provided by implant technology is that the new teeth last
a life-time. There are few substances that are biocompatible with the
human body - and titanium is one of them. Titanium is very strong at a
low weight, and is also extremely resistant to corrosion.
While
these features are ideal in serving the mechanical needs, the most
unique feature of titanium is that the bone tissuegrows on, and bonds
to, the surface of the titanium.
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