Implant supported maxillofacial prosthesis./ lingual orthodontics courses

GOOD MORNING
www.indiandentalacademy.com

OSSIOINTEGRATED IMPLANTS
IN
MAXILLOFACIAL
PROSTHODONTICS
INDIAN DENTAL ACADEMY
Leader in continuing dental education

CONTENTS
Introduction to Maxillofacial Prosthodontics.
Etiology of Maxillofacial defects.
Introduction to Maxillofacial osseointegration.
History of Maxillofacial osseointegration.
Differences between oral and Maxillofacial
osseointegration.
Advantages of Maxillofacial implants over
conventional adhesives.
Cost effectiveness of Maxillofacial implants.
Criteria of success of Maxillofacial osseointegration
Success rates of Maxillofacial osseointegration.
Patient assessment and selection.www.indiandentalacademy.com

Treatment planning.
Surgical technique for placement of Maxillofacial implants.
Auricular prosthesis.
Ocular prosthesis.
Nasal prosthesis.
Midfacial prosthesis.
Oral prosthesis.
Skin response at abutment sites.
Osseointegration in irradiated patients.
Complications around percutaneous implants.
Fallow up and management.
Review of literature.
References.

INTRODUCTION TO MAXILLOFACIAL
PROSTHODONTICS
Def : The branch of Prosthodontics concerned with the
restoration and/or replacement of the stomatognathic
and Maxillofacial structures with prostheses that may or
may not be removed on a regular or elective basis.

It can be expected that a facial deformity may have a
significant impact on a patient's self image and ability to
function and interact socially. The emotional insult and
consequent interference with quality of life may be far
greater than that might be suggested by either the quantity
or nature of the tissue defect. The rehabilitation of these
patients with a prosthesis that replaces the missing tissue
functionally and esthetically can bring back not just their
appearance but also the confidence which is needed to live
in a civilized society.www.indiandentalacademy.com

ETIOLOGY OF MAXILLOFACIAL DEFECTS
The etiology of Maxillofacial defects falls into two categories.
1. congenital defects:
The microtia and agenesis of ear are associated with several
congenital syndromes. Treacher collins, crouzon’s, and
Pierre robins are some of the syndromes that are associated
with facial deformities, palatal cleft and significant
malformation external ear. congenital abnormalities are
unlikely to result in complete absence of the eyes or nose.

2.Acquired defects :
Traumatic loss such as vehicle accidents, explosive
injuries and gun shot wounds can result in loss of
facial structures. The ear and nose are also frequently
lost in bite attacks.
Surgical removal as a result of oral and facial
carcinomas.

Introduction To Maxillofacial
Osseointegration
For a facial prosthesis to be successful, it must meet criteria
of aesthetic acceptability, functional performance,
biocompatibility, and longevity. As a result of the problems
encountered with adhesive systems, advocacy of the use of
mechanical retention has been made. In the past, mechanical
retention has involved the engagement of divergent
undercuts within the defect or the use of external retention by
headbands, elasticized retention, spectacle frames, or other
methods.

Frequently, inherent retention within the defect is absent or
external forms of retention are unacceptable to the patient.
With these historically crude approaches to facial prosthesis
retention, it is not surprising that methods of retention
continued as a source of debate with little resolution and
remained the primary limiting factor to success with
prosthetic reconstruction. With the introduction of
osseointegrated implants to facial prosthetics, there is an
opportunity to provide secure retention of prostheses without
jeopardizing the integrity of the skin and underlying tissues
or the prosthesis.

History of Maxillofacial Osseointegration
• In 1975, Branemark postulated that a skin-penetrating
implant should be possible based on the principles of
dental Implants.
• Following the pioneering work by Branemark and his co-
workers, the first clinical trial on skin-penetrating
osseointegrated implants was conducted in 1977 at
Sahlgren's Hospital in Goteborg, Sweden, where
specifically designed implants were placed in the
mastoid region to support a bone conduction hearing aid.

• In 1979, the first implants were placed in the mastoid
region to retain an auricular prosthesis.
• In February 1988, the Bone Anchored Hearing Aid
(BAHA) was approved for use within the Swedish health
system by the Swedish National Social Welfare Board.

• A conference was held in Goteborg, Sweden, on
September 1,1988, to consider bone anchored implants in
the head and neck region. A report on this landmark
conference was compiled by the Swedish Council on
Technology Assessment in Health Care.
• This report was the founding document on the
introduction of Maxillofacial osseointegration in head and
neck reconstruction.

• On January 13, 1995, the food and drug administration
provided clearance to Nobel Biocare USA, to market the
branemark Maxillofacial implant system.
• Since 1986, international conferences on Maxillofacial
osseointegration have been convened and reports
published from that time have confirmed the efficacy and
predictability of Maxillofacial osseointegration.

Historical development of Maxillofacial osseointegration in relation
to the development of intraoral osseointegrated implants.

Differences Between Oral and
Maxillofacial Rehabilitation
Oral cavity Extraoral environment
Saliva Air exposure
Oral Microflora Skin Microflora
Mucosal covering Skin covering
plaque Keratin, sebum, sweat,
More standardized anatomy Highly variable local anatomy
Longer implant lengths Shorter implant lengths
Higher loading forces Lesser loading forces
Lesser incidence of radiation
therapy
Higher incidence of radiation
therapy
Varying aesthetic demands of
prosthesis With main emphasis on
function
Highly dependent on Aesthetics.

Maxillofacial implant fixtures
are fabricated from pure
titanium. They are available in
either 3 mm or 4 mm lengths
and with a 5-6 mm diameter
flange. The flange facilitates
initial stabilization of the
implant and prevents undue
penetration into interior
compartments.

Advantage of Maxillofacial implants over
conventional adhesives
• Improved retention and stability of prosthesis.
• Elimination of occasional skin reactions to adhesives.
• Ease and enhanced accuracy of prosthesis placement.
• Improved skin hygiene and patient comfort.
• Decreased daily maintenance associated with removal and
reapplication of adhesives.
• Increased longevity of prosthesis.
• Enhanced esthetics at the lines of junction between the
prosthesis and skin.www.indiandentalacademy.com

Cost effectiveness of Maxillofacial
implants
Time interval, (yrs) Adhesive
retained
Maxillofacial
osseointegrated
implant retained
1
5
10
20
Maintenance cost
Total Cost
3,056
8,418
15,278
28,518
2,910
31,428
6,419
7,946
12,748
19,077
2,565
21,642

Criteria of success of Maxillofacial implants
The Swedish Council on
Technology assessment in
Health Care
Jacobson et al.
1) The implants should be
immobile, as verified by clinical
examination.
1) Individual unattached
implants should be immobile
when tested clinically.
2) No prolonged symptoms,
such as pain, infection, tactile
disorders, or nerve damage,
should be present in
connection with the implants.
2) Individual implant
performance should be
characterized by the absence
of persistent or irreversible
signs and Symptoms such as
pain, infections, neuropathies,
or paresthesia.

3) Penetrated soft tissue
should be free from irritation in
at least 85% of the regular
outpatient postoperative check
ups.
3) Soft tissue reactions around
skin-penetrating abutments
should be of types 0 (reaction
free) or 1 (slight redness, not
demanding treatment) in more
than 95% of all observations.
4) At least 95% of the temporal
bone implants and at least
75% of other extra oral
implants should be functional
after 5 years.
4) A success rate of 95% in the
mastoid process and 90% in
the orbital region, in non-
irradiated bone tissue, at the
end of a 5-year observation
period should be a minimum
criterion for success.

Success rates of Maxillofacial implants
(Non-irradiated)
Patients
treated,
no.
Implants
Inserted,
no.
Implants
Integrated,
no.
Success
rate, %
Sweden 435 767 755 98.4
USA 84 268 253 94.4
Canada 84 186 182 97.8
Total 603 1,221 1,190 97.5

Success rates of Maxillofacial implants
(Irradiated)
Patients
treated,
no,
Implants
Inserted,
no.
Implants
Integrated,
no.
Success
rate, %
Sweden 16 57 33 57.9
USA 11 51 33 64.7
Canada 7 36 34 94.4
Total 34 144 100 69.4

Patient assessment and selection
Maxillofacial reconstruction based on the principles of
osseointegration is always an elective procedure.
Because of this, it must be done only under optimum
conditions on carefully selected patients for whom the
potential benefits have been weighed carefully against
the known possible complications and risks. Additionally,
patients should be kept fully informed about all aspects
of the nature of treatment and be given a realistic view of
the likely outcome.

In selecting a patient for a particular reconstructive
procedure, attention should be focused whether it
represents the optimum form of treatment for an
individual's physical, psychological, and personal
circumstances and perceived quality of life.
Many factors and variables need to be considered
carefully, including age, the presence of any disease
process, the significance of any previous therapy,
alternative available treatments and the patient's own
wishes.

Special care should be exercised in evaluating children.
In many situations all information regarding the effects of
the condition will be gained from the parents, with little or
no input from the child. Although the parents concerns
are of most important and indeed their whole hearted
support for all phases of the rehabilitation is essential, it
is vital in all cases to understand the problem from the
patient's viewpoint.

Uncontrolled Diabetes Mellitus:
Diabetes patients are predisposed to tissue degeneration and
compromised healing with increased risk of infection and
vascular complications.
Hyperthyroidism:
Patients are sensitive to epinephrine used in local
anesthetics. When exposed to such catecholamine
coupled with stress and tissue damage (implant surgery), an
exacerbation of the symptoms of hyperthyroidism may occur
(thyrotoxicosis). This is a life threatening condition. The
treatment is deferred until a medical and laboratory
evaluation confirms control of the disorder.
EVALUATION OF SYSTEMIC DISEASES.

Adrenal disorders:
Patients with a history of adrenal gland disease, whether
hyper functioning or hypo functioning, face similar problems
related to dentistry and stress. The body is unable to
produce increased levels of steroids during stressful
situations and cardiovascular collapse may occur. Therefore
for patients with known adrenal disorders the physician
should be consulted before any implant related treatment.
Recent Myocardial Infarction (MI):
If surgery is done within 3 months of MI, the risk of another
MI is 30%.If within 3 – 6 months, it is 15%. After 12 months
the incidence of recurrent MI stabilizes at about 5%.

Hypertension:
Essential hypertension is treated with medications, many of
which have an impact on implant therapy because of their
numerous side effects. These include hypotension,
dehydration, sedation, and xerostomia, gingival hyperplasia
around teeth and implants and depression. Anxiety greatly
affects the blood pressure.
Pregnancy:
Implant surgery procedures are contraindicated for the
pregnant patient. The radiographs or medications that may
be needed for implant therapy and the increased stress are
being reasons. The elective implant surgical procedure
should be postponed till childbirth.www.indiandentalacademy.com

Osteoporosis:
The most common disease of bone metabolism the implant
dentist will encounter is osteoporosis, an age related disorder
characterized by a decrease in bone mass, increased micro
architectural deterioration and susceptibility to fractures. This
condition is common in post menopausal women. The bone
density affects the treatment plan, surgical approach, length
of healing and the nature of loading.
Hyperparathyroidism:
It has been noted that when skeletal depletion occurs as a
result of stimulation by the parathyroid gland, alveolar bone
may be affected before that of the rib.www.indiandentalacademy.com

Fibrous Dysplasia:
A disorder in which fibrous connective tissue replaces areas
of normal bone. It is found twice more commonly in women
than men and may affect a single bone or multiple bones,
twice more commonly in the maxilla than mandible. Implant
dentistry is contraindicated in the regions of this disorder.
Paget’s disease:
A slowly progressive chronic bone disorder where both
osteoblasts and osteoclasts are involved, but osteoblastic
activity is more predominant. The maxilla is more often
involved than the mandible. Oral implants are
contraindicated in the regions affected by this disorder.

Multiple myeloma:
Plasma cell neoplasm originating in the bone marrow.
Usually seen in patients between 40 – 70 years of age.
Pathologic fractures usually occur. Paresthesia, swelling,
tooth mobility and gingival enlargements are also seen.
Implants are contraindicated in these patients.
Smoking Habits:
Tobacco smoke decreases neutrophil count leading to
reduced phagocytic activity. Smoking is also associated
with decreased calcium absorption and delayed
secondary healing. It also contaminate a bone graft and
contribute to early bone loss during initial healing.

Radiation therapy:
Disruption of defense mechanisms, compromised
Endoosseous vascular system, and localized loss of
osseous vitality are the main insults to the tissues while
the patient undergoes radiation therapy. With regard to
bone, the osteogenic potential of the periosteum is most
severely affected. All these conditions can severely limit
the prognosis for reconstructive procedures. Such patients
may be subjected to osteoradionecrosis and should be
treated with caution only after the dentist consults the
radiotherapist.

TREATMENT PLANNINGTREATMENT PLANNING
Each case must be evaluated on the basis of its own
individual requirements; however, a number of fundamental
considerations are relevant to all cases.
On occasion, bone morphology will not permit ideal
configuration of fixtures, and as a result the retentive system
may take on a variation of geometric form.

The auricular prosthesis :
In congenital cases, developmental remnants in the line of
the prosthesis, or anterior to it, must be considered for
removal if they are counterproductive to the final result. If
practical, they can be reshaped to simulate a tragus to help
mask the anterior border of the prosthesis.

• Two flange fixtures are more than adequate to retain the
average size prosthetic ear.
• Implants are ideally positioned in a semilunar fashion
beneath the thickest parts of the ear to provide maximum
room for restorative materials with minimal over contouring
of the part.
• Ventilation slits can be positioned conveniently around the
distal periphery of the ear base.

The orbital prosthesis:
Preliminary data have indicated a higher failure rate of
fixtures in the orbital rim than elsewhere in the cranial
skeleton.
It is important that fixtures be placed 15 mm or more
apart because of the radial geometry of the orbital cavity.
Ventilation slits can be placed conveniently at the eyelid
conjunctival line angle to minimize condensation and
irritation within the defect.

The nasal prosthesis:
The state of the maxillary dentition and presence or
absence of anterior teeth can be important diagnostic
factors in selecting fixture type, length, and location.
Ventilation requirements for nasal prostheses are
facilitated via perforations within the artificial nares.
Fixture sites for large midfacial defects are dictated by the
residual anatomy. The residual zygomatic arches can also
be used for the horizontal placement of long fixtures which
offer excellent anchorage points.

The combination intraoral extraoral prosthesis:
Defects requiring this combination type prosthesis involve
loss of facial continuity combined with partial or total
maxillectomy. They are of surgical or traumatic origin.

Surgical technique for placement of
Maxillofacial implants
The first patient treated with a Maxillofacial prosthesis
retained on skin-penetrating osseointegrated implants was
operated on in 1979. This was a patient who was missing
his right external ear as a result of tumor surgery. The
surgical technique was based on the intraoral procedure
developed by Branemark. Four implants were placed in the
mastoid process and allowed to integrate without any load
for 3 months. The second stage procedure was performed
and skin-penetrating abutments were connected to the
implants, and a silicone rubber prosthesis made.

When the technique was Introduced in 1979, four implants
were used for the retention of an auricular prosthesis. In
some cases there was not room for four, and only three and
in some cases only two implants were used for the
retention.
The two-stage procedure was used until 1988, and one
stage procedure started in 1989.

“We noted no higher rate of implant losses in these cases.
We also noted some important advantages with the use
of only two implants. It was much easier for the patient to
clean the implant area, which is important to avoid
adverse skin reactions. The skin bridges between the
implants were, in cases with four implants, often too
narrow and more vulnerable, resulting in a risk of adverse
skin reactions”.

One-Stage Surgical Technique for
Auricular Implant Placement
Implant Site Selection: This must be done before the
patient is taken to surgery. The external ear canal is a good
landmark. The ideal placement is 18 to 22 mm from the
center of the external auditory meatus, and on the left-hand
side it is between the 1-0’ and 2-0'clock positions for the
upper cranial implant and between the 3:30 and 4:30
positions for the caudal implant. The reason for this is that
the implants and the bar construction will then be located
underneath the antihelix ridge. This is important to be able to
achieve an adequate depth and contour of the prosthesis.

Marks are made with surgical ink where the implants
should be placed, and the area is cleaned and patient is
draped in the usual way. The incision line, usually 7 to
10 mm behind the intended implant sites is marked.
10ml of 2 % lidocaine with epinephrine is injected, and
the incision is made down to the periosteum. That flap is
folded anterior and kept in place with two self-retaining
retractors.

Implant Placement:
The positions of the implant sites are checked and marked
in the periosteum. In the mastoid tip area the air cells are
larger and the cortical shell sometimes is fairly thin. A
6 mm wide incision is made in the periosteum and the
drilling with a guide drill is started. During all drilling
procedures, generous cooling with saline solution is
important.

When the lower implant is in place, the position of the
upper implant is selected. The distance between the two
implants should be at least 15 to 20 mm. The position of
the cranial implant often will be in the temporal bone where
the bone in most cases is dense and thicker. The drilling in
the cranial site is started with a 3 mm guide drill. If bone is
still found in the bottom, a drill that will provide space for a
4mm implant is used.

It is important to make sure that the whole length of the
guide drill has gone down. The reason is that the next
drill, which is the spiral drill with a countersink edge,
does not cut at the tip. The drills are made of stainless
steel and 1,500 to 3,000 rpm is used. The next steps are
made at slow speed, 8 to 15 rpm, and with titanium tap.

The titanium tap is
picked up, with the
connector placed in
the low speed hand
piece. The tap is kept
over the entrance and
the direction is
checked carefully.
Adequate cooling is
used when the tap is
removed.www.indiandentalacademy.com

The implant mount is picked up with the fork shaped
instrument and the screwdriver. The implant mount is
screwed on top of the implant. The implant site is
cleaned of soft tissue and bone fragments by flushing
with saline and using a blunt dissecting instrument. The
implant mount with the implant is picked up with the
adapter on the hand piece of the drill and kept over the
hole. The direction is checked. With the drill at low
speed, the implant is allowed to find its way into the
threaded hole using slight pressure.

When the implant is all the way down, the hand piece is
turned slightly counterclockwise to release the implant
mount from the connector. It is Important not to tilt the
implant mount when disconnecting it from the hand
piece. The implant mount is then removed from the
implant. It is then covered with the thin skin and sutured
in place.

Soft Tissue Management :
1) The immobility of the skin close to the implants relative
to the underlying bone and the abutment is very important.
This is achieved by making a subcutaneous tissue
reduction at the implant site.
2) There should be no hair follicles present in the skin at
the Implant site.
These two goals can be achieved by reducing the
thickness of the flap or by using a split-thickness skin graft.

Abutment Connection :
With a 4mm disposable skin punch, a hole is made
immediately over the implant and the abutment is secured to
the implant with an internal screw. When the fit is
established, the abutment screw is tightened firmly. Healing
caps are then attached to the abutments to keep ointment
soaked gauze down toward the skin to avoid postoperative
hematoma and swelling. The surgical procedure is finished
by applying a firm mastoid dressing for 1 day. After this, only
a light dressing is needed.

Postoperative Care :
After 5 to 7 days, the packing and the healing caps are
removed and the surgical field is left open. A mild
antibiotic ointment is prescribed and the patient is told to
use that for a week or two and then just occasionally.
Three weeks after operation the patient may start to
clean the area with soap and water. The implants are left
without any load for 3 months.

Orbital prosthesis
Historically, different retentive methods have been used to
retain Orbital prostheses. Skin adhesives or double sided
tape is capable of adequate retention but may lead to the
complications of skin irritation, loss of prosthetic margin
integrity, discoloration, and misalignment. Mechanical
devices such as eyeglasses are useful, but they have
limitations such as having to wear the glasses, and
movement of the facial muscles independent of the
eyeglass frames. The success rate in orbital bone has
ranged from 92% to 100% in nonirradiated patients and
45% to 79% in irradiated ones.

Patient Selection :
The majority of patients who have undergone
exenteration were been treated for life threatening
neoplasms or aggressive infections involving fungus.
The exenteration procedure consists of removal of the
entire soft tissue contents of the orbit, extra ocular
muscles, fat, and periorbita. The remaining orbital
volume or depth of the socket, influences the options to
offer the patient.

Total exenteration allows adequate spacing for proper
positioning of a prosthesis. A subtotal exenteration or a
partially filled orbit restricts the facial prosthesis to being
thin, with a less natural appearance.
Because the orbital walls are thin, only the superior,
lateral, and inferior orbital rims are suitable for
osseointegration of titanium implants.

Surgical Procedure :
The osseointegration procedure is performed in two
stages. In the first stage the titanium implants are placed
into the orbital rim and the implants are allowed to bond
to bone through osseointegration. The second stage is
performed 3 to 4 months later when tissue penetrating
abutments are attached to the initial implants.

Stage 1
It can be performed under general or local anesthesia. A
skin incision is marked with gentian violet or a marking
pen along the orbital rim at the designated locations. The
skin incision is made just anterior to the rim, and a flap of
skin, muscle, and periosteum is elevated to expose the
bony rim. Typically, three to four sites are chosen for
implantation, with the superolateral and the inferolateral
rim the more frequent sites.

The initial drilling is done with an exploring cutting bur, which
produces a small hole. The orientation of this hole should be
directed toward the center of the orbit. This allows space for
any bridging apparatus used and the future prosthesis. If the
bone is adequate, a 3 - 4 mm spiral drill with a countersink
is used to form the final hole diameter. Next, the threading
of the hole is done with the threading tap. This step is
accomplished at the slow speed of 8 to15 rpm that allows
the precise cutting of bone needed for proper implant
setting.

• The titanium implant is selected for the hole depth (3 or 4
mm) and screwed into the threaded hole with an implant
mount on the drill.
• The implant has a cover screw placed that is screwed into
the internal threads of the implant.
• A topical antibiotic is applied with a pressure dressing. This
dressing is removed in 1 week.
• If the continuity of the orbital rim is disrupted, several
options are available for bony reconstruction to create a
bed for implant placement. Common sites for autogenous
bone grafts are the calvarial bone, iliac crest, and fibula.www.indiandentalacademy.com

Stage 2 :
This is done after 3 to 4 months. The second stage
involves the placement of Titanium abutments and the
proper thinning of the skin around them to prevent the
movement of skin adjacent to it. This step prevents skin
irritation and infection and allows integration of the skin
with the abutment. It is usually done under local
anesthesia.

A trephine is used to cut an opening over the implant. An
abutment is placed through the opening and attached to
the implant with an internal screw. The abutment can be
3 or 4 mm in height. The abutment is covered with a
healing cap. Antibiotic soaked gauze is wrapped around
the abutment to immobilize the skin.
Four to five weeks after stage 2, the patient is ready for
prosthesis fitting.

Nasal prosthesisNasal prosthesis
• Throughout the history the nose has been described as
the object of beauty and symbol of strength. The
amputation of nose has been the bitter price of social
dishonor and even the reason for military conflict in the
history.
• The nasal reconstruction has been credited to Indians.
Sushruta in his book “Sushruta Samhita” (600 BC)
described the use of a cheek flap for the reconstruction
of nasal tip.

In the total nasal defect, there is usually sufficient amount
maxillary bone that creates the inferior border of the piriform
aperture.
If the nasal defect involves only the lower portion of the
nose, only two osseointegrated implants inferiorly in the
maxilla are enough or further resection of the remaining
nose in the upper area is done to expose the nasal bones.
For aesthetic reasons, glabella and lateral maxillary sites are
poor choices for implants, because framework will interfere
with the aesthetic formation of the nose.

Stage I
An incision is made and the periosteum and skin are
elevated together. The location of the implants is
marked, and a 4 mm implant is usually placed in the
lower piriform aperture and 4 mm or 3 mm implants in
the nasoethmoidal area. It is extremely important to use
minimally traumatic technique, low speed drilling, and
copious irrigation.

Stage II
Approximately 3 months after the first stage, It is preferred to
open the old incision and the flaps are thinned and the
wound is approximated with a few sutures. The holes for the
penetration of the abutments are created with a punch or a
scalpel. The cover screws are removed, abutments are
placed such that the abutment extends approximately 3 mm
above the skin. Healing caps are applied, and a moderately
compressive dressing is used to facilitate adherence of the
flaps and to limit edema formation. The wound is allowed for
2 weeks to heal before the prosthetic work is started.www.indiandentalacademy.com

Attachments :
The decision is made about using a metal bar to connect
the abutments for a clip on attachment or using
individual magnets. In general, metal bars work better in
the area of the nose. The bar has the additional
advantage that it limits rotational forces on the implants.
once the metal bars or magnets have been placed, the
work of attaching the prosthesis can be started.

Framework Design
Framework design must consider:
• Space available, including space allowance for
retention clip plate or magnet plate;
• Length of framework extension from abutments and
need for location of cross-bracing stabilization;
• Establishment of sufficient airway;
• Access for cleaning periabutment tissues and nasal
cavity;

• Amount of projection of the framework from the face in
the coronal plane;
• Facial tissue movement that might affect the fit or
retention of the nasal prosthesis;
• Ease of prosthesis application and patient capabilities;
and
• Anticipation of nasal prosthesis mold design.

For nasal prostheses, a midline clip and framework retention
is best in most cases. The framework is designed to be cast
in metal and is an inverted Y shape that has a cross brace
between the widest part of the Y near the abutments.
The advantages of this design are that it:
1) Allows maximum bilateral air flow.
2) Provides for vertical and horizontal clip orientation,
preventing the misapplication of the facial prosthesis; and
3) Provides adequate access to the nasal cavity and
periabutment tissues for hygiene maintenance.

As part of the wax framework model, plastic sprues 2 mm in
diameter are cut and positioned as the vertical stem and
transverse brace of the inverted Y. There should be enough
space below the cross brace, so that the periabutment
tissues can be accessed for hygiene maintenance.
Triangular segments of the Y should be as far away from the
walls of the nasal cavity as possible, so cleaning of septal
surfaces of the internal nose can be accomplished. The stem
on the inverted Y should be as short as possible but still
allow the attachment of a vertically oriented clip.

Disadvantages of adhesive retained
prosthesis.
• Adhesive tapes will not stick to the silicone and require
daily trimming. They may cause inadvertent margin loss
and subsequent unaesthetic thick edges.
• The pastes and liquid aromatic cements require daily
removal which can cause frictional damage the extrinsic
colour of facial surface.
• Some patients will also develop allergic reactions to
these substances.www.indiandentalacademy.com

• The silicone base adhesives are extremely adhesive on
silicone prosthesis but they tend to damage fine margins
with daily prosthesis use.
• Adhesives may also limit the patients sense of security.
• Patients with altered skin sensation may be unaware of
loosening or fallen prosthesis.
• Some adhesives tend to loose the adhesive bond in
regions where perspiration can affect the interface.

MIDFACIAL PROSTHESIS.
A 63 year old man, was exposed to repeated surgical
procedures over several years, because of a basal cell
carcinoma of his face. After 10 years, tumor histology
changed into a squamous cell carcinoma.
A decision was made to provide him with not only a facial
prosthesis but also an implant supported fixed bridge in the
maxilla using osseointegrated fixtures.
Preoperative examination revealed that the quantity of
maxillary bone was not sufficient for a standard procedure,
so a bone graft had to be used.www.indiandentalacademy.com

Framework:
• The purpose of a fixed framework or substructure is to
retain the facial prosthesis.
• For retention in this particular case, a bar splint with clips
is one alternative to a bar splint with magnets.
• Two conventional bar constructions were made, one on
the three upper and the other on the three lower
maxillary abutments.

A third part of the framework connects the two bar
constructions. This part of the construction has an
exceptionally long span. Therefore, a Custom made
three dimensional framework was prepared. The goal
was to achieve stiffness with low weight. These fittings
were then soldered to the bar splints and enabled to
connect the three parts of the construction. The entire
framework was made out of a premachined gold alloy
clasp wire 2 mm in diameter, which was bent and
soldered to conventional 3 mm gold cylinders.

ORAL PROSTHESIS.
Hemimaxillectomy:
In most defects with surgical resection of a minor or
major portion of the maxilla, adjacent bone tissue still
allows integration of anchoring fixtures. Careful
presurgical prosthetic planning is required, particularly in
major defects, in order to evaluate the correct positioning
of fixtures and adequate design of the retention
framework in relation to expected mechanical load.

Patient presentation 1
A 74 year old woman with a Hemimaxillectomy on left
side; there was enough remaining alveolar and basal
maxillary bone on the right side to accommodate
integrated fixtures. With a connecting bar extending into
the defect side, an overdenture obturator could be
adequately supported.

If the defect involves both sides, it is quite often difficult
to achieve anchorage in the anterior region. It is then
important to use not only any remaining posterior
portions of the maxilla in combination with bone grafts,
but also to install fixtures in the base of the zygomatic
bone. A carefully designed metallic framework can then
stabilize and retain a denture obturator prosthesis.

If, in addition to the bone defect, the upper lip has also
been removed, the soft tissue prosthesis can be retained
onto the denture obturator with magnets, as in this case
of a 72 year old woman. Bone grafts in both sinuses
were used to improve fixture anchorage.

This case shows the rehabilitation of a 20 year old man
presented with a major anterior maxillary defect with
inadequate bone anchorage of the teeth close to the
defect. These were removed, and after an adequate
healing time an autologous iliac bone graft was used to
substitute for the anterior maxillary segment. Special
long fixtures were used to anchor the graft. A long time
was allowed for incorporation and fixture integration. A
fixed bridge was then connected.www.indiandentalacademy.com

HEMIMANDIBULECTOMY
The Hemimandibulectomy is most commonly performed
as part of a tumor resection, for the treatment of
osteoradionecrosis or occasionally for osteomyelitis. It
leaves the patient with multiple problems, as regards to
esthetics and function. Because of the loss of bone and
teeth the patient cannot chew efficiently, speech is
adversely affected, and there is distortion of the facial
contours.

These problems are intensified by the displacement of
the mandibular fragments that remain, drifting under the
unopposed action of those muscles which are still
attached to the residual fragments. Shifting of the
remaining mandible toward the operated side and
malocclusion results.

Diagram showing restoration of
facial contour by bone graft but
persistent dental deficiency.
Diagram showing displacement of
mandibular fragments after partial
mandibulectomy.

The following are the advantages of reconstruction using
osseointegrated implants:
• They provide stability and retention for the prosthesis.
• They allow the use of a fixed or removable prosthesis.
• It avoids the preparation of remaining teeth as abutments.
• It avoids the problems of the tissue borne prosthesis.
• It compensates for a diminished denture bearing area.
• It provides the stimulus needed for preservation and
maintenance of the bone graft.
The principal disadvantages are only two. These are the
additional cost and the additional surgery.www.indiandentalacademy.com

The abutments need to rise 3 to 4 mm above the
surrounding soft tissue to allow for ease of hygiene
maintenance. The special problem of salivary
incontinence is most likely to appear when, in addition to
the resection of the mandible, there has been significant
disturbance of the associated soft tissues with loss of
sensation and loss of proper muscle control.
osseointegrated implants can provide predictable
rehabilitation for the hemimandibulectomy patient with
both cosmetic and functional success.

THE CLEFTPALATE
• Edentulous patients with persistent unilateral or bilateral
cleft palate defects may be provided with a bone
anchored prosthesis, which not only substitutes for the
teeth but also obturates the oronasal communication.
• In most cases the available alveolar and basal maxillary
bone tissue is adequate in volume and mechanical
capacity for fixture anchorage.

A 52 year old man had a cleft palate. When the final
remaining tooth was removed he had insufficient retention
for his denture obturator. Because of inadequate soft tissue
availability, no bone grafting was performed, but each
section of the maxilla was provided with three fixtures in the
alveolar and basal maxillary bone. After integration, a
metallic bar was used to connect the abutments on each
side, and a mechanical clip connection was used to anchor
the overdenture obturator.

This patient, who was the first cleft patient reconstructed
according to the osseointegration procedure, was treated
at the Mayo Clinic, Rochester, Minnesota, in
collaboration with D. Tolman, E. Keller, and W. Laney.
A 69 year old woman with a unilateral cleft which was
closed with an iliac bone graft. A bar connects the
anchoring elements and provides mechanical retention
of the overdenture.

SKIN RESPONSE AT ABUTMENT SITE
Skin response to Percutaneus abutments has also been
considered as an indicator of success, by rating it on a
five point scale.
This five point scale is a result of the work of Holgers et al
in 1987 and has been adopted widely.

Class Description
0 No irritation: epithelial debris removed if present.
1 Slight redness: temporary local treatment.
2 Red and slightly moist tissue; no granuloma formation:
local treatment; extra controls.
3 Reddish and moist; sometimes granulation tissue:
revision surgery is indicated.
4 Removal of skin-penetrating implant necessary
as a result of infection.
R Removal of implant for reasons not related to skin
problems. www.indiandentalacademy.com

Grade I – slight redness Grade II - red and slightly moist
Grade III - Red and moist Grade IV - INFECTION

The following conditions at skin penetration sites are
advocated.
1) Subcutaneous skin reduction;
2) Fixed, Nonmobile skin; and
3) Absence of hair.
Brown et al stated: "Fastidious adherence to these
principles, will almost always guarantee a favorable skin
reaction, but contravention of them will almost as surely
result in an unfavorable reaction."

Osseointegration in irradiated patients
when the irradiated patients are to be rehabilitated with use
of the osseointegration concept, it is necessary to be aware
of different factors influencing osseointegration, healing of
the soft tissues, and the risk of severe side effects in the
compromised tissues.
Such side effects include decreased healing rate of the soft
tissue over the implants, fistulation, skin or mucosa
infections, loss of implants, denuded bone around the
implants, and even osteoradionecrosis.

Among the non-irradiated patients, most implants are found
non-integrated at the second stage surgery or are lost during
the first year. After this time, the remaining implants seem to
be relatively well integrated and remain in the bone.
The irradiated group of patients has a different course.
Most of the implants are lost during the first 3 years, but
implants are lost throughout the follow up period; even up to
10 years or more after placement, osseointegration is lost.

Complication Patients, %
Loss of implant 35
Slow wound healing 18
Fistula 15
Wound dehiscence 12
Soft-tissue infection 10
Osteoradionecrosis 2
Rupture of major vessel 0
Flap necrosis 0
Complications In Irradiated Patients

In a study investigating the possible effects of different
irradiation procedures, it was found that radiation dose had a
negative effect on the osseointegration process in two ways.
First, in the high dose region above 120 Gy a high proportion
of implants were lost. Second, in the low dose region,
proportionally more implants were lost, whereas
osseointegration in the medium dose region showed minor
effects.
The high frequency of implant losses in the high radiation
dose region could be related to the irradiation effect per se,
whereas the high losses in the low radiation dose region are
more difficult to explain.www.indiandentalacademy.com

The irradiation process induces a progressive endarteritis that
becomes more evident with elapsing time. The very low dose
irradiation protocols (15-25 Gy) that produced higher implant
failures with time are not used in modern radiotherapy. The
extremely high dose radiotherapy is only attained in patients
with recurrent cancer or new tumor development;

The patients rehabilitated earliest after the radiotherapy
course show the highest implant survivals. This has
stimulated to perform implant related surgery as soon as
possible after tumor removal, and today actually most of the
implants are inserted at the time of tumor removal. This has
the advantages that the patient is rehabilitated early and
implant survival is higher. The negative aspects could be
that tumor recurrences might appear during the following
years, necessitating more radiotherapy and the removal of
the implants at a time of extended tumor removal and other
side effect could be the risk of inducing osteoradionecrosis
or other complications due to too early surgery in an
irradiation field.

Radiotherapy with a metal object in the radiation field induces
scattering effects from a radiation beam "bouncing" on the
metal framework. These scatter effects depend on the
energy and source of irradiation, the distance from the metal
to the tissue, and the atomic number of the metal.
Possible effects of the increased radiation dose in the delicate
interface zone between an implant and the bone or between
the abutment and the skin are not completely understood. In
certain patients it could be the cause of implant loss and skin
reactions, but in other patients it also could stimulate cell
turnover. www.indiandentalacademy.com

HYPERBARIC OXYGEN THERAPY
The protocol: 20 sessions at 2.5 atmospheric pressure
preoperatively and 10 postoperative sessions.
The biologic effects that can be measured in an irradiated
tissue that has undergone HBO treatment are improved
vascularisation, improved bone turnover, and improved metal
to bone contact. The target cells influenced by oxygen seem
to be undifferentiated mesenchymal cells in the callus or
granulation tissue that has the ability to differentiate into
osteoblasts.
In a healing soft tissue wound, the granulation tissue
exposed to hyperoxia will form angioblasts, leading to
improved angiogenesis. Both of these factors are important
for the osseointegration process, especially in compromised
tissue.

COMPLICATIONS AROUND PERCUTANEUS
IMPLANTS
A Percutaneus implant is a foreign body penetrating the skin
through a defect created during surgery. Because the skin
barrier is broken, exogenous agents more easily penetrate
into the tissue. The following may be important for the
function of epithelial penetrations:
• A tight contact between the epithelium and the penetrating
implant;.
No relative Motion in the interface area.
• The surface architecture of the implant material; and
• The status of the connective tissue.

Marsupialization:
The epithelium has a tendency to grow down along the
skin penetrating implant to a varying extent, and such an
epithelial down growth is a common finding. A total
epithelial down growth is one of the failure modes forming
a sinus tract along the implant and is due to the free edge
effect of the epithelial cells.

Avulsion:
The skin around a Percutaneus implant is subjected to
forces that lead to mechanical disruption of the interface,
with microhematomas and subsequent microfoci of
acute inflammation. This is considered to be a
mechanically induced failure mode.

Permigration:
The health and the maturity of the connective tissue are of
great importance for the epidermis. Immature connective
tissue cannot nourish the epidermis, which will permigrate
deeper down around the skin penetrating implant. This
failure mode is related to implants with a porous surface.
The soft connective tissue and the epidermis migrate into
the implant and continue throughout the entire porous
extent of the implant.

Infection:
When an infection is established around an implant, it
may have serious effects and usually leads to failure of
the implant. The major pathogen in infections around
metal implants is considered to be Staphylococcus
aureus. Coagulase negative staphylococci, in particular
Staphylococcus epidermidis, seem to be the most
common agent in infections related to implants of
polymers.

Delayed Hypersensitivity:
Another important reaction, especially for metal implants,
is delayed hypersensitivity or contact allergy. This is well
known for non skin penetrating implants of nickel,
chromium, and cobalt. Reports indicating hypersensitivity
to titanium are rare.

Implant Failure:
Failure of an implant is the most severe complication.
Depending on the number of implants remaining and the
design of the retentive mechanism, the prosthesis may need
to be modified. If two or more implants remain and the
retention design is not compromised, the prosthesis can be
stable and retentive.
If a bar clip system is used and implant loss means that
there is no inadequate support for the bar, then individual
magnets or ball or stud attachments need to be used.

FALLOW UP AND MANAGEMENT
Once a patient is treated, the osseointegration team has
to undertake a lifelong responsibility for the maintenance
of the bone anchored prosthesis. Much time and effort are
spent in the fabrication of a bone anchored prosthesis that
will provide a lifelike facial restoration.
For all of its advantages, the bone anchored facial
prosthesis does require more care on the patient's part
and closer professional follow up than one retained with
adhesive.

Follow up management actually begins once the abutments
have been placed. After the initial healing period and once a
surgical dressing is no longer needed, the patient should be
instructed to clean this area on a daily basis. The purpose is
to remove cellular material on the skin or abutment, which
can come from the interface of the epithelium and abutment.
This is performed with a soft end nylon bristle toothbrush, an
interproximal dental brush, or a cotton swab. To facilitate
cleaning, the area should be moistened first with an even
mixture of hydrogen peroxide and water to soften any dried
debris. www.indiandentalacademy.com

End tuft tooth brush Interproximal tooth brush Cotton swab

The prosthodontist should monitor the stability of the
abutment and the health of the soft tissue during the regularly
scheduled visits for prosthesis fabrication. abutment tightness
can be checked using a abutment clamp. If the abutment
loosens, complete seating should be verified before
retightening. This is done with an abutment holder.
On the day that the prosthesis is given to the patient,
adequate time should be allotted for instructions on placing
and removing the prosthesis as well as proper maintenance
of the prosthesis, abutments, and surrounding skin areas.

Abutment clamp provides
counter torque for checking
abutment tightness.
Abutment holder ensures
complete seating of loose
abutment.www.indiandentalacademy.com

When placing the prosthesis, the patient should be
certain that the retentive elements are engaged
completely to ensure that the prosthesis is seated fully.
The retention elements (clips, magnets, or balls or studs)
within the acrylic resin plate ensure security of the
prosthesis.

The patient should be careful when removing the prosthesis
so that the thin margins do not tear and the silicone rubber
does not separate from the resin plate.
For an auricular or nasal prosthesis, proper removal by
grasping a thick portion of the prosthesis and slowly
disengaging the retentive elements should be demonstrated
and performed several times by the patient.
For an orbital prosthesis, an outer margin should be lifted
carefully until a thicker portion can be grasped to lift the
prosthesis.

Review of literature
George E. Anastassov and Eric S. Asher (JPD 2000;84:215-
16) stated that the soft tissues overlying the percutaneous
implants are usually thick and mobile, which requires longer
transcutaneous attachments. However these attachments
may compromise the stability of the implants and lead to the
implant loss. To avoid these complications skin and
subcutaneous debulking and split thickness skin grafts
should be performed.

Stephen M. Parel. P I Branemark et al states that the
application of osseointegrated fixtures to the cranial
skeleton for facial prostheses retention marks
revolutionary step in search for the perfect soft tissue
replacement. They along present Eastover technology to
be used to its greatest potential by protecting surface
color and allowing long term retention of fine but weak
peripheral margins.

Albertson et al conducted 951 clinical observations of
skin response around 389 abutments for BAHA(243
observations) and auricular prostheses (708
observations). Of these observations 92.1% showed no
skin response and 3.9% showed slight redness,
potentially serious skin responses occurred in only 2.8%
of observations.

Rubinstein reported that orbital prostheses were
fabricated with wider variety of attachments than any
other type bone anchored facial prostheses: bar clips,
magnets, ball studs, or a combination of these types.

In review of treatment centers Rubenstein found that
magnetic retention represented nearly half of the
attachments in united states and Canada compared with
only one third of those used in Sweden. Clips were used
only 20% of the time in united states, 33% of the time in
Canada and nearly 50% of the time in Sweden.
Approximately 20% of the orbital prostheses in the
united states and Sweden used a combination of
magnets and clips.

References
• Osseointegration in Maxillofacial reconstruction :
Per-ingvar branemark, Dan E. Tolman.
• Advanced Osseointegration Surgery – application in
maxillofacial region:
Philip Worthington, Per-ingvar Branemark.
• Maxillofacial rehabilitation:
Keith F. Thomas.

1. Craniofacial osseointegration .The canadian experience
– Int J Oral maxillofac Implants 1993;8:197-204.
2. Microflora associated with percutaneous craniofacial
implants used for the retention of facial prosthesis
-Int J Oral maxillofac Implants 1995;10:578-82
3. Console abutment loading in Craniofacial osseointegration
-Int J Oral maxillofac Implants 1998;13:245-52.
4. Craniofacial osseointegrated implant induced strain
distribution -Int J Oral maxillofac Implants 1997;12;200-10

5. Biomechanical considerations for implant supported orbital
prosthesis –J facial somato prosthet 1995;1:43-53
6. Rehabilitation of irradiated cancer patients with tissue
integrated prosthesis: Adjunctive use of hyperbaric oxygen
to improve osseointegration- J facial somato prosthet
1996;2:1-11.
7. Use of surgical positioner for bone anchored facial
prosthesis –Int .J oralmaxillofac implants 1997;12:376-79.

8. Use of frontal process of the maxillary bone for implant
placement to retain a nasal prosthesis .A clinical report.
Int J oral maxillofac implants 2004;19:901-05.
9. Osseointegration in maxillofacial prosthesis part II
Extraoral applications Prosthet dent 1986;55:600-06.
10. Bone anchored maxillofacial prosthesis.
Quintessence 1989;235
11. Surgical considerations for endoosseous implants in the
craniofacial region report.
Int J oral maxillofac surg 1993;22:272-77

12. Diminishing dependence on adhesives for retention of
facial prosthesis. J Prosthet dent 1980;43:552
13. The use of magnets in maxillofacial prosthesis.
J Prosthet dent 1971;25:334
14. Osseointegrated implants for replacement of absent or
defective ear. Clin plast surg.1990;17:355-366.
15. Bone anchored craniofacial prosthesis study.
Int J oral maxillofac implants 1996;11:159-68.

THANQ
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