Preprosthetic surgery.ppt

INTRODUCTION
A thorough examination of the mouth prior
to the construction of complete denture prosthesis is
necessary to identify potential problem areas.
A determination of whether surgery is necessary is
an essential part of that examination and plays an
important role in successful patient management.

 The vast majority of patients for whom
complete denture therapy is prescribed have
already been wearing dentures.
 There is a risk in wearing dentures for
prolonged periods.
 This risk, or biologic price, manifests
itself in a number of adverse changes in
the denture foundations.

Several conditions in the edentulous mouth
should be corrected or treated before the
construction of complete denture prosthesis.
Often patients are not aware that tissues
in the mouth have been damaged or
deformed by the presence of old prosthesis.
Other oral conditions may have developed
that must be altered to increase the
chances for the success of the new
dentures.

 The patient must be cognizant of these
problems, and a logical explanation by the
dentist, supplemented by radiographs and
where required, diagnostic casts, usually
will convince the patient of the necessity
for the suggested treatment.

Either non-surgical or surgical in nature, or a
combination of both methods.
 A treatment plan calling for surgical
correction should be made only after
alternate non-surgical approaches have been
considered and evaluated.
The methods of treatment to improve the
patient’s denture foundation

It is always hoped that the results of the
preprosthetic surgery are acceptable both
surgically and prosthodontically.

 In this vein, the services of an oral and
maxillofacial surgeon may be required,
especially as the surgical preparation
becomes more complicated AND a team
approach is needed with the surgeon and
the prosthodontist serving as equal
members of the team.

Since the support, retention, and stability of a
denture base depend on the quantity and quality
of the denture bearing area and border seal,
every effort is to be made to preserve the
alveolar bone. The goal of pre-prosthetic surgery is
to modify the denture bearing areas to render it
free of disease and to make its form (and possibly its
function) more compatible with the requirements of
complete denture wearing.

Some of the characteristics of this ideal form which
provide for maximum support and stability and
minimum interference with function are:
1. Adequate bone support for dentures.
2. Bone covered by adequate soft tissue.
3. No undercuts or overhanging protuberances.
4. No sharp ridges.
5. Adequate buccal and lingual sulcus.

6. No scar bands to prevent normal seating of
denture.
7. No muscle fibers or frenula to interfere
with the periphery of the prostheses.
8. Satisfactory ridge relationship between the
maxilla and the mandible.
9. No soft tissue folds or hypertrophies on
the ridge or sulci.
10. A ridge free of neoplastic disease.

PREOPERATIVE
EXAMINATION
It must first be determined that no mental or
physical condition exists which would
contraindicate the wearing and use of the
denture itself. The next goal of the
preoperative examination then becomes one
of determining realistic treatment goal based
on the age of the patient, his physical and
mental status and his individual need.

•What the patient expects from the dentures
should be discussed.
If he expects performance like his natural
teeth, education is indicated. A complete
understanding and acceptance of the
limitations of denture performance must be
accomplished before treatment is begun.

 The patient’s past medical history and current
medical status must be reviewed with
particular attention to allergies, drug
idiosyncrasies, medications, hemorrhagic
tendencies or systemic disorders which would
require hospitalization, complicate anesthetic
procedures, increase surgical risk, or possibly
even contraindicate a contemplated surgical
procedure.

Additional radiographic studies may be required.
Routine pantographic and periapical radiographs
used for screening may be supplemented with lateral
jaw and occlusal radiographs if a pathologic
disorder is suspected. Cephalometric radiographs
may be required in cases which involve orthognathic
surgery or oral implant placement.
Nutritional deficiencies and needs should be
assessed, especially in the geriatric individual.
Recommendations should be made early so that full
benefits of proper nutrition can be achieved during
the healing phase.

NON-SURGICAL METHODS
Non-surgical methods of edentulous mouth
preparation include:
1. Rest for denture supported tissues.
2. Occlusal and vertical dimension correction
of old prostheses.
3. Good nutrition.
4. Conditioning of the patient’s musculature

SURGICAL METHODS
Frequently, certain conditions of the denture
bearing tissues require edentulous patients to be
treated surgically.
These conditions are the result of unfavorable
morphologic variations of the denture bearing
area, or more commonly may follow long term
wear of ill-fitting dentures.

According to the Glossary of Prosthodontic
Terms (7), preprosthetic surgery is defined as
surgical procedures designed to facilitate
fabrication or to improve the prognosis of
prosthodontic care.
According to Brucc Donoff, preprosthetic surgery
is that part of the oral and maxillofacial surgery
designed to establish the best hard and soft
tissue bases for prosthetic appliances.

Initial hard tissue procedures
 These are the surgical procedures
which involve teeth and bone and
which are often done by the
general practitioner in the private
office.

Teeth/Retained dentition
 The extraction of erupted or partially erupted
teeth should preserve as much bone and soft tissue
as needed to result in a suitable contoured ridge
for denture support.
 Bony alveolar margins should be firmly palpated
through their soft tissue covering to discover
sharp bony alveolar projections which would be
potential fulcrum points for denture movement
and soreness.

Root tips
They must be evaluated individually.
Those with radiographic evidence of pathologic
change should be removed.
Root tips that are covered by sound bone and show
no radiographic evidence of pathologic change,
especially if they have been covered by a denture in
the past, can usually be justifiably left in place.
 During removal, instrumentation should provide for
the preservation of as much bone and soft tissue as
possible.

Unerupted teeth
Unerupted teeth in the edentulous arch or in a
condemned dentition should be evaluated from
several aspects:
(1) Evidence of associated pathologic activity,
(2) The location of the unerupted tooth in the arch,
(3) The age of the patient,
(4) The history of symptomatology,
(5) The past prosthodontic history.

•The majority of embedded or impacted teeth
usually should be removed at the time the other
teeth are being removed and the mouth is being
prepared for dentures. An attempt should be made
to remove all impacted or embedded teeth without
surgically creating a large bony defect.
There are reasons for the removal of unerupted
teeth before denture construction. A relatively high
percentage shows pathologic transformation in their
early stages of development.

The canine eminences, maxillary tuberosities, and
mandibular retromolar pads are bony areas of
vital importance to denture function.
Lack of eruption of a maxillary third molar
usually retards or prevents the development of
the maxillary tuberosity.
This lack of development plus the necessary
removal of bone to deliver the tooth could
result in maxillary notch area which is
anatomically deficient.

Non-pathologic Bony Conditions

Alveoloplasty
The surgical reshaping of the alveolar ridge, is
indicated where uneven interseptal spines or bilateral
bony undercuts exist.
Bone removal should always be done with prudence
because it is accompanied by varying degrees of bone
resorption.
The use of ridge augmentation implant materials
should be considered when removal of bony undercuts
will result in a deficient ridge. The use of these
materials can both preserve bone and correct the
anatomic defect.

Removal of interseptal bone and gentle compression
of the expanded socket is often all that is required to
achieve the goal of a well-contoured ridge with the
conservation of bone. Excessive removal of bone
during multiple extractions should be avoided as a
ridge with an inverted “V” shape may result.

In the mandibular arch, an area which often
requires alveoloplasty but is frequently overlooked is
the lingual aspect at the posterior termination of the
mylohyoid ridge.
The mylohyoid ridge lies inferior to the internal
oblique ridge and represents the attachment of
the mylohyoid muscle to the mandible.
The denture flange should extend below this area.
The internal oblique ridge extends inferiorly
from the temporal crest of the coronoid process
to the lingual alveolar margin of molar teeth.
Both of these ridges becomes prominent and
progressively higher on the mandible as
resorption occurs.

•The superficial position of these ridges can
interfere with border extensions and retention in
critical alveolo lingual sulcus area.
The removal of these bony projections should be
bilateral. This may be achieved with a bone file if
the projection is small.
If the projection is large an osteotome must be used,
followed by smoothing with a bone file.
Care should be exercised during these procedures
not to displace bony fragments in an inferior and
posterior direction.
Such fragments could cause undesirable
postoperative complications.

In general, internal oblique ridge and mylohyoid
ridges should be reduced when one of the three
conditions occur:
1.The mucoperiosteum becomes repeatedly
traumatized and relief is necessary to permit soft
tissue closure.
2.In grossly resorbed mandible in which
improved border seal is critical to retention.
3.To permit greater flange extension for
increased stability and retention of the denture.

In the atrophic mandible the alveolar process,
because of lateral resorption, frequently presents a
thin bony ridge called a “knife-edge-ridge”.
The overlying soft tissue is often rolled with a mobile
fibrous base. Denture tooth contact may cause pain
and require extensive modification of the denture
base in this area.
Previously, surgical procedures to remove or
stabilize the mobile soft tissue and recontour the
sharp bony ridge left the patient with less vertical
tissue height and continued bone resorption
frequently leading to a recurrence of the “knife-
edge-ridge”. Today, ridge augmentation with
synthetic implant materials shows great promise to
correct this inadequacy.

•In the maxillary arch, an area which often requires an alveoloplasty
is the alveolar tuberosity.
The tuberosity often present opposing bilateral buccal undercuts
that become a problem in impression making and, if reproduced,
with the insertion and removal of the denture.
Removal of these undercuts by grinding from the tissue surface of
the denture can lead to retention and food accumulation problems.
If no undercuts are present in the anterior section of the arch, it is
not always necessary to remove the undercuts from both
tuberosities.
Before an undercut is allowed to remain one should be sure to check
that adequate form exists in a horizontal direction to allow free
passage of the coronoid process without crushing or trapping
sensitive cheek tissues between it and the denture base.

In a vertical direction, the alveolar tuberosities frequently
approximate the retromolar papilla and pad area to the
extent that adequate denture base coverage and correct
placement of the occlusal plane is not possible.
Both bony and soft tissue removal should be accomplished
where possible to allow adequate vertical height for the
denture bases. Care should be exerted to avoid damaging the
greater palatine artery or entering the maxillary sinus.
Careful presurgical examination to determine the location of
the sinus floor is necessary.
Gentle repositioning of the sinus floor superiorly and
medially can also be accomplished when an enlarged tubercle
with a thin sinus wall is evident.

One time when bone conservation may be overlooked
is in the situation of the radical alveoloplasty
following multiple tooth extraction and prior to
radiation therapy for the neoplasm of the head and
neck area.
The desire is to achieve primary closure of the wound
and complete uneventful healing. Failure of these may
result in infection and osteomyelitis.

The surgical technique of alveoloplasty requires an
adequate mucoperiosteal flap to allow removal of
bone with a minimum of soft tissue trauma. The
alveolar process should be reapproximated and
carefully sutured. A surgical splint can be
constructed which will protect the area from trauma
until it is healed. If used, such a splint should not be
opposed by a functional denture and should avoid
placing undue pressure on the surgical site to avoid
possible impingement on the vascular supply of the
newly repositioned flap.

Pressure on mental foramen
If resorption in the mandible has been extreme,
the mental foramen may open near or directly
at the crest of the residual bony process. The
bony margins of the mental foramen usually are
more dense and resistant to resorption than the
rest. This causes the margins of the mental
foramen to extend and have very sharp edges 2-
3mm higher than the surrounding alveolar bone.

Pressure from the denture against the mental
nerve and pinching of the oral mucosa between
the sharp bony margin of the mental foramen
and the denture will cause pain.
Treatment is altering the denture or by trimming
the bone so that pressure does not exist. The
opening of the mental foramen is increased
downward to permit the mental nerve to exit at a
point lower than it had previously.

Exostoses
Exostoses are bony nodules located on the
alveolar process of the mandible and the
maxillae. The buccal aspect in the molar
region of the mandible and the buccal aspect
from the premolars posteriorly to the alveolar
tubercle in the maxillae are the most frequent
locations. These exostoses usually present
undercuts to the path of insertion and
removal of the denture and should be
removed by alveoloplasty techniques.

Tori
Tori are bony hyperostoses common to both maxilla and
mandible. The torus palatinus is located at the junction of
the palatine process of the maxillary bones in the midline
of the palate. The torus may be smooth or pedunculated
and covered with a mucosa that varies in quality and
quantity.
Small tori that do not act as fulcrum points under a
denture may not require removal. The torus, however,
even when small, may act as a fulcrum under a denture if
the mucosal covering of the crest and slopes of the ridges
are displaceable to a greater extent than the mucosal
covering of the torus. In these instances, the denture base
over the area must be relieved to compensate for
difference or the torus should be surgically removed.

When a torus is large, grossly undercut, or located
posteriorly where the post palatal seal is to be
placed, it should be surgically removed. The
surgical technique requires careful radiographic
examination to rule out the possibility of
pneumatization. A midline incision with lateral
reflection of laterally based mucoperiosteal flaps is
necessary because this mucosa is often very thin,
tears readily, and has poor blood supply. The poor
healing qualities of this tissue and the possibility of
hematoma formation usually necessitate the
mechanical support and protection of a surgical
splint.

The torus mandibularis is found on the lingual
cortical surface of the mandible; it is usually
bilateral and is located in the premolar area. These
tori vary in size and shape. Their mucosal covering
is usually thin. Most mandibular tori should be
removed prior to denture construction as relief in
the denture base rarely suffices for comfort. As a
rule the patient will not tolerate the denture well.
The reflection of the mucoperiosteal flap should be
adequate in size and should avoid the use of vertical
releasing incisions which would delay healing and
which present the potential for injury to structures
in the floor of the mouth. Care should be exercised
not to traumatize the flap.

The torus is removed with a bur and an osteotome
and smoothed with a bone file to provide a smooth
bony base devoid of undercuts. It should be noted
that, due to the shape of the mandible in this area,
complete elimination of undercuts is frequently
impossible. This bony reduction also should be
limited to a level above the attachment of the
mylohyoid muscle. A surgical splint is not usually
necessary because the mucoperiosteal covering can
be readapted, it is vascular, and heals rapidly. With
a careful suturing technique and digital pressure
approximately 15 or 20 minutes after the procedure,
the mucoperiosteal flap repositions itself quickly.
The normal position and weight of the tongue help to
maintain the tissue in its correct position.

Genial tubercle
Genial tubercles are neither exostoses nor tori but
are often prominent following advanced alveolar
ridge resorption in the anterior area of the
mandible. They are covered by thin tissue which
will not bear the pressure of a denture flange located
in this area. The superior portion of these
prominences may be removed in a fashion similar to
the mandibular torus. That portion of the
genioglossus muscle which is attached in the area is
usually left free. If necessary it may be reattached
by suturing it to the muscle layers located below.

Complete removal of the genial tubercles should be
avoided as lack of attachment of the genioglossus
and geniohyoid could lead to impaired tongue
function. Care must be taken during this procedure
not to interfere with the salivary gland orifices
located in the area.

Pathologic bony conditions
The traumatic bone cyst is often seen in the body of
the mandible in the premolar and molar area. It is
painless and usually discovered by radiograph. A
surgical approach to the area should be made so
that the surgical defect is minimal. On opening into
the area one usually find a void in the portion of the
bone with no epithelial lining. In these instances the
wound should be debrided, closed, and the
prosthodontic treatment continued.

Larger cystic lesions are usually
marsupialized to allow shrinkage and bone
fill-in, and to prevent surgical fracture or
damage to adjacent structures. In several
months, as shrinkage allows, enucleation
should be performed. Large infected cysts
must be packed open and allowed to heal by
secondary intent. As granulation progresses,
the dressings are reduced in size. All of these
cysts may grow at the expense of the denture
foundation. Therefore, the earlier they are
surgically controlled the better the denture
foundation will be.

Tumors
Tumors may be classified as benign or malignant.
They may be classified by their origin: ectodermal,
mesodermal and mixed. They may be considered
odontogenic or non-odontogenic and may include
both hard and soft tissue. All these lesions require
medical management before denture construction.
In all instances histologic diagnosis is required as
radiographic findings are not conclusive. The biopsy
may be done by the dentist or the oral and
maxillofacial surgeon.

Proper examination and diagnosis will then be
facilitated by a tumor site undistorted or discolored
by the previous biopsy procedure. The surgical care
for a tumor is dictated by the nature and extent of
the tumor. When possible, attempts should be made
to preserve as much residual ridge as possible for
best denture support.

Initial Soft Tissue Procedures
Alveolar tuberosity
Frequently the alveolar tuberosity area approximates
the retromolar papilla and pad. This tuberosity may
be composed of hard or soft tissue but is most
frequently pendulous and consists mainly of fibrous
connective tissue. Besides obliterating the vertical
space required for the denture bases, this pendulous
tissue does not offer a stable foundation for the
denture. The tissue should be removed by a series of
wedge shaped incisions. Suturing is usually adequate
to hold the tissue in close approximation for healing.
The goal of this procedure is a firm well defined
tubercle which will provide denture support.

Frenae
Enlarged or prominent frenae represent probably
the most common abnormality which is encountered
when considering pre-prosthetic surgical
preparation. The maxillary and mandibular labial
and buccal frenae can resent undesirable situations
when, due to resorption, they become attached too
near the crest of the residual alveolar ridge. If the
labial frenum has been irritated by a pre-existing
denture and has become hyperplastic it often
interferes with the border extension
and exerts a dislodging influence on the denture.

A frenectomy accomplishes two important things (1)
the procedure allows increased border extension:
and, (2) it releases a mobile band of tissue that is in
contact with the denture. Simple incisions are used
for narrow attachments, incisions with mucosal
undermining for larger attachments and "Z" or
"V-Y" plasties for broad based attachments. A
surgical splint is not needed following the
frenectomy unless a sulcus extension is also
performed. The frenectomy should be anticipated
prior to denture construction and the denture flange
should be contoured to occupy the space that is
created.

The lingual frenum should be evaluated carefully.
In some individuals with excessive alveolar
resorption, the genioglossus muscle could be
mistaken for a high frenum attachment. If the
attachment results in a partial ankyloglosia, a simple
release is sufficient. However, a wide band
attachment that is strong and resistant to
displacement when the tongue is elevated will
necessitate an alveolar detachment as an additional
dissection.

Scar contracture
Scar contracture may be present in the vestibule.
These are handled much like frenal attachments.
Unlike frenae, however, they will tend to recur
unless some facility is made to provide a surgical
splint immediately following surgery for a period of
10 to 14 days.

Benign soft tissue lesions
The lips of denture patients should be devoid of
fissures, ulceration, or masses before beginning
denture construction procedures. Any unhealed soft
tissue ulceration that remains two week after a
mechanical etiology has been corrected should be
biopsied. The most common pathological disorder of
the lips includes papilloma, mucocele, scar tissue
hyperkeratosis, lichen planus, epidermoid
carcinoma, hemangioma, irritation fibroma,
recurrent aphthous ulcer, and recurrent herpes
labialis.

The epulis fissuratum is a benign lesion that presents
clinically as excessive or redundant tissue that
frequently is associated with overextension of the
denture border or an ill-fitting denture. Palatal
papillary hyperplasia is secondary to chronic
denture irritation, usually under a poorly fitting
prosthesis and often involves some degree of
candidial infection. Epulis fissuratum and palatal
papillary hyperplasia are also seen in the anterior
vestibule when the patient has natural mandibular
anterior teeth opposing a complete maxillary
denture. It is also seen in this same area when
patients have received an immediate complete
maxillary denture and have used it until the
resorption results in labial flange irritation.

These two hyperplastic reactions are often painless
and well advanced before professional treatment is
sought. The treatment consists of: (1) the removal of
the irritant and placement of a soft lining material in
the denture to reduce inflammatory and bleeding
during surgery and, (2) surgical removal of the
tissue by excision or cautery, being careful to avoid
and preserve the periosteum and other underlying
structures. Guernsey described supraperiosteal
removal of this tissue with an electrosurgery loop.
When using this care should be taken not to
cauterize the periosteum or bone because this causes
bone necrosis and significantly delays healing.

The use of patient’s old denture with a soft liner or
an accurate fitting non-functioning surgical splint
with a soft lining is indicated when excision is
carried out. The splint seems to stabilize and protect
the tissues during healing and to mold the vestibular
fornix preventing shortening due to scar
contracture. The splint is not necessary after
cauterization.

Alveolar ridge resorption frequently results in a
narrow, knife edge bony ridge which is covered with
soft, mobile, unsupported soft tissue. These tissues
present as unstable and undesirable denture base
foundation and should be treated with the goal of
establishing a firm, immobile, denture foundation.
Excision and removal of excess tissue from the ridge
crest is frequently performed. This often results in
total loss of any vertical height under the denture or
a sharp bony ridge protruding from under a firm
but thin soft tissue covering. Both of these results are
undesirable.

A procedure which is currently drawing much
interest is the preservation of this mobile tissue and
augmentation of the underlying ridge with a ridge
augmentation type of implant material. Such a
procedure can also be used to broaden ridges and fill
undercuts, thus preserving bone.

The only true means to differentiate between
hyperkeratosis and dyskeratosis is by surgical biopsy and
histologic examination. It is frequently recommended that
areas of hyperkeratosis in the area of the denture base or
its peripheral extensions be removed by stripping with low
intensity electrocautery. While this may be practical for
small areas it is not practical in areas that are diffuse and
widespread. In these instances the existing denture should
be removed for a period of 1 to 2 weeks and then small
biopsies of the suspect areas should be made and sent for
examination. Those areas not surgically treated should be
noted and monitored by the dentist. Any clinical change in
the appearance of the lesion would indicate a repeat biopsy
of the region.

Lichen planus is a white plaque-like lesion closely
resembling oral hyperplasia. The buccal mucosa is
the most common site in the mouth, and it is thought
to be caused by debilitating disorders and anxiety.
Dentures are not contraindicated for these patients,
but patients affected with the erosive form of this
disease may have difficulty with dentures due to the
continued soreness of the erosive lesions.

Mucoceles and retention cysts are the results
of chronic mucous retention in tissues, usually
due to some form of trauma such as cheek or
lip biting. They can occur in the lips, cheeks
or floor of the mouth. Mucoceles are
described as diffuse or well-circumscribed
mucous pools in the connective tissue stroma
without an epithelial lining. Retention cysts
are mucous pools that are lined by epithelium.
Surgical excision is indicated for removal of
these cysts, with the exception of large
retention cysts, called ranulas.

These are located in the floor of the mouth and are
associated with the ducts of the submandibular
glands. Because of the size and depth of a ranula,
complete removal by excision is often impossible .In
these patients marsupialization is indicated. The
chance of recurrence of these lesions following
surgical removal is high due to unavoidable trauma
to adjacent glandular structures during surgery.

The so called “dermoid cyst” is due to cystic
degeneration of developmentally trapped epithelial
structures. It is also located in the floor of the mouth.
It usually presents as a midline swelling which
elevates the tongue if the lesion is superficial.
Excision is the treatment of choice. Recurrence is
seldom following excision.
Papillomas and fibromas are rather common benign
neoplasms of the oral mucosa. The papilloma is
usually pedunculated with a cauliflower-like surface.
A fibroma is also usually pedunculated but with a
smooth surface. The papilloma is of surface
epithelial origin. The fibroma is comprised of
connective tissue. Both of these tumors should be
excised before denture construction.

Secondary hard tissue procedures
Certain surgical procedures, which are required
when preparing the hard tissues of the mouth for
complete dentures, which involve ridge
augmentation and ridge relationship alternations
may require hospitalization of the patient and
special pre and post-surgical care.

Ridge augmentation procedures
The goal of these procedures is to recreate an
edentulous ridge with characteristics which are
compatible with the requirements of denture
wearing. Many variables combine to affect the
success of these techniques. Among these are : the
materials used for the augmentation, the
augmentation site, surgical design, prosthodontic
design, patient interest, prosthodontic follow up and
the skill of the surgeon and the prosthodontist.

Careful preoperative evaluation by both the dentist
and the surgeon is vital. Complete radiographic
evaluation using cephalometrics as well as lateral
and anteroposterior head films may be required.
Frontal and profile photographs are invaluable in
evaluating and discussing potential facial changes.
Of greatest importance is the use of properly
mounted diagnostic models.
The amount of bone selected and used for the
augmentation should, to some degree, compensate
for the expected loss due to resorption but should
not impinge on the inter-arch distance. A minimum
of 16 to 18 mm of interarch space is required to
construct complete dentures following this
procedure.

Maxillary ridge augmentation
Severe ridge loss is seen more often in the mandible
than in the maxilla; however the demands of
esthetics, phonetics, retention and comfort
frequently demand a maxillary ridge augmentation
procedure.

One procedure which has shown some success in the
past takes advantage of the osteogenic potential of
hematopoietic bone marrow through the use of
particulate bone chips contained within a metal crib
(mesh). The mesh is left in place over the graft and
acts to protect and contain the bone graft (which is
usually of iliac crest origin) for a period of 10 to 14
weeks. Following removal of the mesh, soft tissue
procedures are instituted to reconstruct the vestibules
which where obliterated to supply adequate soft tissue
to cover the graft. Complications include a high rate of
dehiscences over the metal crib and a high resorption
rate of the graft under the prosthesis.

Other procedures currently used for maxillary ridge
augmentation are the classic LeFort I Maxillary
osteotomy with down fracture of the maxillae and the total
alveolar maxillary osteotomy, which leaves the plate in
place but allows downward movement of the alveolar
ridge segments. Interpositional or inlay bone grafting
with iliac crest bone used as blocks along with
particulate bone and marrow is frequently used in
both of these procedures to fill voids. These two
techniques may be called composite or combination
procedures because they combine the separate techniques
of osteotomy and bone grafting. Such procedures will alter
the spatial relationship of the ridges as well as augment the
ridge height and must be used with caution only after
careful preoperative evaluation.

Vestibuloplasties are often required following this
procedure. A maxillary splint constructed on
mounted diagnostic casts following cast surgery may
be used to keep the graft and soft tissue adapted
during healing, to prevent hematoma formation, and
for fixation of maxillae during the healing period.
This splint will help to engage the proper spatial
repositioning after the maxillae are disarticulated
from the cranial base. In the edentulous patient, an
opposing mandibular splint is required to interface
with the maxillary splint. The splints are usually
worn for a period of 6-8 weeks. Denture is not
constructed before the graft has been allowed to heal
and mature for approximately 3-4 months.

Mandibular ridge augmentation
Mandibular ridge augmentation is performed more
frequently than maxillary augmentation. In addition
to restoring ridge shape, these procedures may also
be used in an attempt to strengthen the severely
atrophic mandible which is in danger of spontaneous
pathologic fracture. Mandibular augmentations via
onlay or inlay grafting with autogenous bone may
involve rib, iliac crest, cancellous bone and marrow
or combinations of these.

The use of rib for mandibular augmentation as
suggested by Davis has fallen into disfavor due to
high initial resorption rate of 50% or more in
the first two years after placement. In this
procedure, two ribs or one rib and bone
particles from the iliac crest are used. The rib is
onlayed over the ridge and the remaining spaces
are filled with bone particles from the second
rib or the iliac crest. A minimum of 4 months
is required for graft maturity before
vestibuloplasties are used to recreate the
vestibules. This long post-operative healing
period is necessary as the functional shape of
the alveolar ridge must remodel before dentures
can be reconstructed.

Sanders and Cox have suggested inferior bone
grafting as a possible solution for this problem.
When used on the inferior border, the graft
does not to bear the weight of the denture, the
vestibules are preserved, no splint is needed and
the healing period before a denture can be worn
is reduced. Disadvantages include sensory or
motor nerve deficiencies which lead to lip biting
and changes in facial appearances.

The use of iliac crest for onlay or inlay bone
grafting, as suggested by MacIntosh and Obwegeser
either through an extraoral or intraoral approach,
was once procedure of choice. This procedure
involves osteotomy with interpositional grafting.
Donor blocks of iliac crest provides the cortical
bone framework and cancellous marrow is used to
fill the spaces between the segments of cut cortical
bone. The pieces are wired into place. Resorption of
30-50% will be seen in first 5 years, with most in the
first year. Prolonged donor site tenderness is an
additional problem with this technique.

A healing period of 4-6 months must be observed
before Vestibuloplasties are performed.
Prosthodontic follow-up with this technique, as
with any bone graft technique, involves careful
observation and adjustment of occlusion, denture
base extension and adaptation.

The procedure involving the use of particulate
bone and marrow is analogous to maxillary
augmentation. This procedure is less successful in
mandible, however due to rapid resorption following
prosthetic loading. Exposure of the mesh is a
common occurrence as is infection of the graft
material.

The procedures of choice for mandibular ridge
augmentation include the combination of osteotomy
techniques (horizontal or vertical) with
interpositional bone grafting. These procedures
involve the movement of a pedicle of bone (not
technically a graft) along with its blood supply.
Theoretically, the viability of the bone will be greater
and the resorption decreased because the blood
supply to the bone is maintained.

In the horizontal osteotomy technique, an
adequate vertical height must exist so that the
mandible can be cut horizontally. This cut is
placed below the level of the mandibular canal
and below the mental foramen to avoid injury
to the mandibular nerve. The superior part of
the ridge is elevated and iliac bone blocks,
particulate bone, and marrow are sandwiched in
between. Model surgery is critical to determine the
amount of augmentation, the amount of autogenous
bone needed and the postoperative spatial
relationship of the arches. Transosteal wires hold the
components in place.

Advantages are increased bone height which is
relatively stable and a shortened post-operative
period (3 months). Disadvantages include nerve
trauma, parasthesia, mandibular fracture and flap
dehiscence. This procedure cannot be performed
if other surgical procedures such as previous
bone grafting have been done.

The vertical or visor osteotomy was originated
by Harle and modified by Peterson and Slade. It
is used where insufficient vertical mandibular
bone height is present for the horizontal
osteotomy technique but adequate bone width
(approximately 10mm) is present. The mandible
is split vertically and the lingual section is
elevated to increase the mandibular height.
Cancellous bone or particulate bone and marrow
is placed to correct the contours and fill in the
gaps on the facial side of the elevated segment.
Transosteal wires hold the segments in place for
a period of 3-4 months before vestibuloplasties
are performed. The disadvantage is unavoidable
nerve trauma and the resultant parasthesia.

The most recent and exciting advances in the area of
the ridge augmentation, both maxillary and
mandibular, involves the use of alloplastic materials
either alone or in combination with autogenous
bone.
Hydroxyapatite, a bone substitute, is similar to the
mineral structure of both bone and tooth. It has
proven to be biocompatible, nonresorbable and
nonosteogenic. The graft material produces a bond
with the bone due sometimes to a deposition of new
bone mineral on the supporting matrix of
hydroxyapatite and other times to a fibrous
ingrowth. In some patients, lack of bond to the ridge
and fibrous encapsulation leads to the production of
a mobile or firm and rigid body beneath the tissue.

This mass also remains somewhat compressible,
necessitating refitting of the prosthesis over time. For
ridge augmentation, this material is placed by
tunneling beneath the mucosa and periosteum. The
graft is deposited directly on the bone surface to be
augmented. Though it seems that a splint should be used
to contain, control and protect the material, the use of
splint has proven troublesome. The trouble arises when the
actual area of material deposition, which is controlled by
anatomic and surgical limitations, differs from the ideal
area as determined on presurgical casts. A splint
fabricated using a predicted location which differs
from the actual location would tend to displace the
material into the tissue where it acts as an irritant
beneath the denture. Vestibuloplasties are often required
about 10 weeks after graft placement.

A defined subperiosteal tunnel can be created
using silicone implants which are later removed.
The hydroxyapatite is then injected into the defined
space. Another technique using a resorbable
material (plaster or collagen cylinders) to confine
the hydroxyapatite is tried to minimize the
problem of control of the material following
placement.

Tricalcium phosphate is another alloplastic material
which may be used as a bone substitute. This
material is resorbable and shows osteogenic
potential when it is located adjacent to the
periosteum. It has been used in periodontal and
endodontic bone defects as well as in the
augmentation of deficient alveolar ridges.

Ridge relationship procedures
These procedures involve the correction of
discrepancies of both arch size and arch relationship
to each other in space. Malrelated jaws should be
analyzed early in the diagnostic procedures, and
surgical corrections should be performed prior to
removal of all teeth. The teeth act as landmarks
during the orientations of the jaws and also act as
stabilizers while the jaws are healing. It is possible to
correct the malrelations surgically in the absence of
teeth, but the construction of splints and
immobilization of these splints may prolong the
treatment plan.

Complete diagnostic work out is vital. Radiographs
must include periapicals, the panograph, and
cephalometric films made with the jaws supported in
the proper centric relation and vertical dimension by
correctly shaped record bases and wax rims. The
location of the actual jaw deformity is even less
obvious in the edentulous patient than it is in the
dentulous, making cephalometric prediction of the
final surgical outcome more difficult. Frontal and
lateral profile photographs and the services of a
medical illustrator skilled in portraiture and
knowledgeable in the area of expected surgical
changes may be valuable to evaluate and discuss
possible facial appearance changes.

Psychologic evaluation of the patient's ability to
adapt to stress and change along with possible self-
image problems is certainly in order if large changes
are expected. Secondary plastic surgical procedures
are sometimes required to shorten sagging muscles
left following the repositioning of their bony
attachments.
Mounted diagnostic casts and properly performed
cast surgery are critical to success with these
complicated and exacting procedures. The
relationship of the ridges or the segments of ridges in
all three planes of space must be considered. A
Gunning-type splint made on these preoperatively
altered casts will accurately reposition the segments
and provide for proper fixation.

Relapse tendencies in both the vertical and
horizontal directions are common as a result of
muscle pull. This may be decreased with the use of
skeletal fixation but can never be completely and
predictably eliminated. The final results, even after
careful planning and execution, often include minor
errors that need to be corrected prosthetically. In
some instances, orthognathic surgery may seem like
a radical form of treatment for the edentulous
patient. In truth, this procedure is rarely performed
on edentulous patients as a result of advanced age,
poor health, cost or lack of cooperation. Mounted
diagnostic casts and properly performed cast
surgery are critical to success with these complicated
and exacting procedures.

Maxillary advancement procedures are used to
correct problems of maxillary retrusion. In the
complete denture patient these problems may
involve a combination of true skeletal maxillary
retrusion and pseudo-retrusion due to resorption of
the small maxilla. Lateral relationships must be
considered as well as anteroposterior and vertical
relationships of the arches. The procedure of choice
for the correction of this problem seems to be the
LeFort I osteotomy with or without interpositional
grafting. This procedure will produce a relationship
that is both stable and reliable.

Procedures producing maxillary retrusion
(retropositioning) are less commonly performed
because the problem of true skeletal maxillary
protrusion is less common than retrusion. In the
past, a radical alveolectomy was used to correct the
problem of maxillary protrusion. The result was a
more correct bony relationship with a severe and
prosthetically uncorrectable denture base deformity.
The Lefort I osteotomy is once again the procedure
of choice. The maxilla is positioned superiorly and
posteriorly. The use of an interpositional bone graft
may or may not be necessary, as an excess of bone
exists at the surgical site. In 1991, Massad et al.
recommended this procedure for poor denture
esthetics that is due to vertical excess in the anterior
maxillary skeleton.

Mandibular advancement procedures which involve
the retrognathic mandible are not commonly
performed because there is less bone and soft tissue
for the surgeon to work with. The retrognathic
mandible, however, does produce a great
prosthodontic problem and sometimes demands this
procedure. The problems of a smaller bony
mandible with a smaller denture bearing area make
control of the mechanics of complete denture
prosthodontics and occlusion problematic. For
mandibular advancement the sagittal osteotomy or
several of its variants performed from an intra-oral
approach seems to be the procedure of choice.

A thin ramus or severe mandibular atrophy in the
posterior region of the mandible contraindicates this
procedure. If a movement greater than
approximately 8 mm is required, the use of bone
grafts and one of the variant techniques is
necessitated. Skeletal fixation for 6 to 8 weeks is
required. Following this, prosthodontic procedures
may be performed.

Mandibular prognathism may be acquired as a
result of ridge resorption, or may be a true skeletal
abnormality, which requires a mandibular retrusion
procedure to correct. Although prognathism is a
common finding that can, in many instances be
aided prosthetically by careful tooth placement and
control of the occlusion, the control of esthetics is a
definite and often uncontrollable problem in the
severe situation. The currently accepted technique
involves an osteotomy procedure in the subcondylar
region or an osteotomy in the ramus. The body of
the mandible is most often avoided in osteotomy
procedures of this nature.

The subcondylar (oblique) osteotomy involves cither
an extraoral or an intraoral approach. The intraoral
approach maybe used when less than 10mm of
movement is required. With this approach, access is
limited, making greater modification of the segments
difficult. An extraoral approach that allows good
access for bone and muscle surgery can be used
when movement of 10 to 12 mm is required.

The sagittal or ramus osteotomy is similar to that
discussed for mandibular advancement procedures
but is usually performed by an intraoral approach.
It may be performed and is preferred when extreme
movement (more than 10 mm) is required and when
symmetry of the segments to he moved is present.
Rarely, an additional procedure performed in the
body of the mandible may be required when
symmetry is lacking or a greater amount of
movement is required in one segment. Skeletally
based intermaxillary fixation of at least 4-6 weeks is
required. Surgical splint is a necessity and should be
worn until definitive complete dentures are inserted.

Relapse tendencies due to muscle imbalances are a
real prosthodontic problem. Even slight relapse
changes may produce great changes in the occlusion
and may lead to uncontrollable forces on the
dentures bearing foundation. Close follow-up is
necessary and consideration must be given to
delaying definitive prosthodontic treatment when
relapse is anticipated.

Secondary soft tissue procedures
These procedures are often made necessary by years
of denture wearing and neglect which injure and
modify the denture basal seat area and make
successful denture wearing difficult or impossible.
These techniques are useful and are preferred over
the hard tissue procedures when adequate bone
exists beneath the soft tissue and muscle covering.
This bone must somehow be uncovered by modifying
the relationships of hard and soft tissues. Thus,
existing bone is made available for use in support
and retention of the denture.

The presurgical evaluation is once again
accomplished with a team approach.
Contraindications include medical or psychological
problems, insufficient bone and the availability of a
more conservative procedure. The diagnostics work
up includes panoramic and cephalometric
radiographs. These are valuable in order to observe
structures which could limit the extent and success
of the extension procedure. In the maxilla these
structures are the anterior nasal spine and the malar
buttresses. In the mandible they are the mental
foramina, the genial tubercles and the inferior
border of the mandible.

In some instances the surgeon will require a splint to
be placed immediately following the surgery. The
splint may be made on an overextended impression
of the involved ridge and modified with the
placement of a soft lining material at the time of the
surgery. Such splints may be maintained by relining
during the healing period and worn until definitive
dentures are ready for insertion. Sometimes the
existing dentures may be used for this purpose.

Maxillary ridge extension procedure
The procedures currently used to uncover
existing maxillary bone and make it available
for denture retention and support involve one
of the various techniques for vestibuloplasty.
These include the submucous resection
vestibuloplasty, the secondary
epithelialization vestibuloplasty and the soft
tissue graft vestibuloplasty with oral mucosal
tissue or skin. A cut off point of 10mm of
available maxillary bone has been set as a
necessity for the success of these procedures.

Submucosal vestibuloplasty
The submucosal vestibuloplasty procedure, designed by
Obwegeser, is used more frequently and enjoys greater
success in the maxilla than the mandible when
adequate bone exists under an essentially healthy
mucosa. The advantage of the procedure is that it
preserves the vestibular mucosal fold without scarring.
The presence of extensive fibrous or hyperplastic
tissue complicates the procedure and indicates a graft
type of procedure where poor mucosa is replaced with
new tissue. The adequacy of the existing bone may be
assessed by distending the labial or buccal vestibular tissue
with a finger or mouth mirror upward along the bony
surface. If this can be done to the desired depth without
distorting the lip, it may be concluded that adequate bone
exists for the procedure.

A midline incision is made and the submucous
layer is dissected free of the overlying mucosa
and underlying periosteum by blunt and sharp
dissection. A second vertical incision may be
required in the posterior region if further
extension is required. The middle layer of
submucous tissue is resected. A surgical splint
with soft liner is inserted and fixed in place
with wires, pins, staples or a mid-palatine screw.
The splint will compress the submucosal tunnel
and prevent hematoma formation. The splint is
removed and relined in 7-10 days and is worn
until replaced with definitive dentures. Relapse
rate of 50% can be expected within three years.

Submucous resection
Submucous resection via an open technique was
first described by Wallenius. Further
modifications were proposed by Gongloff, Keagle
and others. With these techniques, hypermobile
soft tissue is removed or firmed up while the
keratinized epithelium is preserved without
shortening of the vestibule.

In the technique described by Keagle, a facial incision
is made at the mucogingival junction. The hypermobile
soft tissue is dissected supra-periosteally and bisected
supra-crestally stopping 2-2.5mm short of the soft
tissue crest. The superfluous spongy connective tissue
is removed from the inner side of the flap and from
the palatal aspect of the ridge, making sure hat a
uniform 2-2.5mm of mucosa remains. The mobilized
mucosa is held firmly against the alveolar crest and
an incision made at its border into the alveolar
mucosa. This mucosa is then sharply dissected from
the alveolar ridge periosteum in a coronal direction.
The mobilized ridge mucosa is then sutured snugly to
the periosteum with interrupted mattress sutures. A
soft liner is needed for 4-6 weeks.

Secondary epithelialization vestibuloplasty
Secondary epithelialization vestibuloplasty may be used
when inadequate ridge is combined with a poor
mucosal covering. In this technique, a subperiosteal
flap is dissected and repositioned, leaving the exposed
periosteum to cover by secondary growth of epithelial
tissue from the wound margins. This technique is
especially good when only small areas are involved.
The use of surgical splint is controversial. A splint may be
indicated when the procedure is limited to maxillary
posterior region. Another advantage of this technique is
its easy application on an outpatient basis. Relapse
with secondary epithelialization procedure has been a
large problem. It may occur early, before denture is
placed. For this reason this procedure has been
replaced by soft tissue grafting procedures.

Soft tissue graft vestibuloplasties
Soft tissue graft alveoloplasties include those done
using free mucosal grafts and those done using split
thickness skin grafts. The use of a graft procedure has
a wide range of applications and few limitations.
Among the indications are the expected presence of
adequate bone for denture success after the procedure
is performed and the expected 20-30% relapse has
occurred. The presence of a poor mucosal covering
which would be best removed and replaced is a
second indication. Some authors believe that the
planned use of bone graft material for ridge
augmentation is another indication for soft tissue graft
vestibuloplasty.

Mandible ridge extension procedures
Procedures used for mandibular ridge extension are
similar to those used for the maxilla. Additional
considerations must be made concerning the area
which is to be extended. The labial, buccal, lingual,
and distolingual areas may sometimes require
different procedures for best results. A figure of 15
mm is used as a diagnostic cut-off point. With less
bone than this available, the success of a mandibular
ridge extension is questionable.

Submucosal vestibuloplasty
The procedure is similar to that performed in the
maxilla. Both open and closed procedures may be
used with great care so that the mental nerve or
neurovascular bundle is not traumatized.
Secondary epithelialization vestibuloplasty
(sulcus slide)
A supra-periosteal flap is raised from an incision
on the lip side or ridge side of the sulcus. The
flap is repositioned and sutured at the depth of
the new sulcus. Relapse is severe problem. The use
of splint is controversial.

Transpositional flap vestibuloplasty
It is also called as lip switch. The procedure was
originally designed by Kethley and Gamble and is
especially indicated in people who require
mandibular ridge extension procedure but are
medically unable to tolerate more extensive
procedures. A split thickness mucosal flap is
dissected from a periosteal flap. The periosteal
flap is used to cover the raw soft tissue surface
and the mucosal flap to cover the raw bony
surface.

The advantages are:
It is applicable in almost any patient.
No lengthy healing period.
Bony contouring or ridge augmentation can be
performed at the same time.
There is very little regression.

Soft tissue graft vestibuloplasty
The surgical procedure is the same for the
secondary epithelialization procedure, with the
soft tissue graft placed over the de-epithelialized
site. The is accomplished by securing the graft,
bleeding surface upwards, to a newly relined
splint with tincture of benzoin or dermatome
glue. Following trimming of the excess graft
material the splint is placed over the ridge and
wired in place. The wires are removed in 7-10
days. The redundant graft material is excised
and the splint relined with a soft liner material.
This splint is worn till the final prosthesis is
inserted.

The prosthesis should not be begun before the graft
has been allowed to mature for a minimum of 3-5
weeks. Antibiotic coverage and the use of drugs
such as dexamethasone are recommended to
decrease morbidity. Frequent recall to avoid
pressure spots is necessary but will not totally
prevent local areas of pressure necrosis that must be
allowed to epithelialize. A second splint used to cover
the intraoral donor site in the case of the free
mucosal graft is sometimes also recommended when
the palate is used. This splint will protect the donor
site and increase patient comfort. This second splint
is also removed in 7 to 10 days and will reveal a
white surface covered with cellular debris.

Wiping will reveal a granular bleeding surface,
which will heal in approximately 2 weeks. Anti-
biotic coverage and the use of drugs such as
dexamethasone are recommended to decrease
morbidity. This is especially true when the
mandibular lingual is included in the surgery.
Possible complications include mental nerve
involvement, painful swallowing, and swelling
causing difficulty in breathing. Hospitalization
therefore is desired. Oral feedings are usually
discontinued until the swelling is decreased and
swallowing can be accomplished comfortably. An
oral liquid diet for 24 hours followed by a full liquid
diet with supplementation is often ordered.

The free mucosal graft may be taken from any area
of the oral cavity. The cheek and palate are the most
frequent choices. The amount of donor tissue is
obviously limited by these sites, but the donor graft
may be enlarged by fenestration or meshing.
Specially designed instruments are available for this
purpose. Some operators feel that the use of like
tissue, and especially well-keratinized palatal
mucosa, will produce a superior denture-bearing
area which is capable of providing better support
and retention and which contracts less on healing.
These grafts are usually obtained and defatted by
hand. Air-driven dermatomes, which make graft
harvesting quicker, easier, and more controlled, are
available.

If a large amount of donor graft tissue is required,
this procedure is usually performed in the operating
room under general anesthesia. With these patients,
a good consideration is the use of skin rather than
mucosa. The mucosal graft may be secured to the
graft receptor site, as indicated previously, or it may
be sutured to the site after fenestrating the graft to
allow for the escape of blood and fluids. Some
surgeons prefer to use a soft-lined surgical splint.
Others feel that careful suturing followed by
controlled pressure to prevent hematoma formation
without the use of the splint avoids the problems of
pressure necrosis and the time-consuming
complications of splint fabrication and adjustment.

If no splint is used following surgery, one is usually
placed in 7 to 10 days. This splint is soft lined and
used until a new denture is inserted. Great care
must be exerted not to overextend this splint. It
should terminate just at or slightly short of the
vestibular reflection to avoid pressure on the suture
line.

About 20 to 30% shrinkage and relapse may be expected
from the procedure during healing. This amount may be
compensated for during surgical planning. Other
disadvantages include obvious donor site problems
including hemorrhage and scarring, the sharp nature of
the vestibule generated by this procedure, the loss of the
graft in large or small areas, and the production of tunnels
and webbing that are due to local complications at the
graft site. The free mucosal graft is easily performed on an
outpatient basis. Other advantages include the absence of
extraoral scar and of skin graft donor site problems. The
presence of like tissue (especially if keratinized palatal
mucosa rather than nonkeratinized cheek mucosa is used)
and the simplicity of the procedure make it the choice for
small sites in the mandible.

The split-thickness skin graft vestibuloplasty uses
hairless donor skin from the buttocks, inner thigh,
or abdomen. A thin graft of uniform thickness of
0.0125 to 0.015 inches is obtained with an electric
dermatome. Although thicker grafts may be
preferred because they tend to ulcerate and contract
less during healing, the presence of hair follicles and
other adnexal structures in thicker skin sections is a
long-term problem for the patient and
prosthodontist. Careful coverage of the donor site is
important to provide patient comfort
postoperatively.

The site should be left undisturbed for a period of 10
to 14 days. Healing will be essentially complete in 2
to 3 weeks, but the area may not attain normal
coloration for 4 to 6 months. A soft-lined splint is
often required to protect the graft and prevent
hematoma formation. The graft is usually
fenestrated in a manner similar to that one for the
free mucosal graft to facilitate the escape of fluids,
prevent formation of dead space, and allow for
better graft adaptation to the tissue.

Implant procedures
There is no area of preprosthetic surgery which
presents as much excitement and as much potential
for future growth and development as the area of
oral implantology.
Maxillary oral implants
The bone of the maxilla, being more spongy in nature
and the presence of anatomical limitations, makes
maxillary implantation risky. The success rate of
maxillary sub-periosteal implants is poor. So, endosseous
implants are positioned in the remaining bone of the
alveolar ridge. The size and location of the maxillary
sinus and floor of the nose place definite limitations
on the implant placement.

The mucosal insert, while not truly an implant,
may serve to provide valuable retention. They
are mushroom shaped. They are attached to the
tissue surface of the maxillary denture using
autopolymerizing resin and a special preparation
bur which is supplied by the manufacturer.
After this the denture is placed into the patient's
mouth and the sites located on the mucosa. The
mucosal sites are prepared with a special tissue
receptor site bur. The denture is then inserted
and held in place with a palatal bone screw for
a period of 1-3 weeks.

Mandibular oral implants
Subperiosteal implants
Indications are severe mandibular atrophy
with dehiscence of mental nerve and intolerance
to a conventional lower denture due to lack of
adequate bony support. Contraindications include
impacted teeth, bony pathology, recent extractions
and spiny alveolar ridges requiring alveoloplasty.

It involves two surgical episodes. The first surgery
exposes the area of the mandible on which sub-
structure will rest. An impression is made of
this bony support area before it is carefully
closed. The resulting cast is used to design the
subperiosteal framework. Surgical Vitallium is the
material of choice for the framework.
During the second surgery, the framework is
inserted beneath the mucoperiosteum being
careful not to trap mucosa or periosteum. New
complete dentures are usually inserted and
adjusted following the completion of second
surgery.

Endosteal implants
Vent blade implants have holes or vents through
which the bone can grow. They are made of
stainless steel, Vitallium or titanium. These are
placed in channels in the alveolar bone.
The current emphasis is to prepare a receptor
site which is more specific to the shape of the
implant than cutting a channel in the alveolar
bone with a bur. Two examples of this type of
implant are the osseointegrated implant system
by Branemark and Core-Vent system by Niznick.
These two systems use titanium, as pure or
alloyed, as the implant material.

The ramus frame mandibular implant was
designed by Harold and Ralph Roberts. The
implant is a stainless steel tripod designed after
examining a large number of mandibles. The
tripod gains support from the symphysis in the
anterior and the rami posteriorly. They are
available in sizes 4 through 7. These implants can
be adapted by bending the side rails and the
implant foot. The foot is 30mm long and is
intended to be inserted into the most available
bone in the area of the symphysis between the
mental foramens. The foot is 2mm wide and
should be inserted 3mm below the crest of the
alveolar ridge.

A channel, approximately 12mm long and directed
upward and laterally to avoid nerve and vessel
involvement, is used to locate the posterior ends of
the frame. The rails should be placed 5mm above the
mucosa of the remaining ridge.
This type of implant is indicated in a patient with
severe bone resorption in the posterior area but an
adequate symphysis height (8-12mm) to allow
placement of anterior foot. It requires a rapid, simple
and inexpensive one step surgical procedure for
insertion.
Other advantage is the possibility of immediate
function using an all acrylic duplicate denture over
the implant following surgery and the fact that the
failing implant can be easily removed leaving little
surgical defect.

Transosteal implants
Mandibular staple bone plate is made up of
titanium alloy and an extraoral, submandibular
approach of implant insertion. It provides
prosthetic retention only. The minimal bone height
in anterior region is 9mm. A clear acrylic drill
guide will allow the surgeon to locate the exit
points of the transosseous pins. A rigid cast bar
is placed following healing to connect the oral
screw posts and create a rigid box like form,
which will minimize stress placed on the bone.
The final prosthesis is totally supported by the
ridge with slight allowance for setting of the
base.

Congenital deformities
Congenital deformities that affect the construction of
complete dentures are usually of the cleft lip and
cleft palate type. Careful dental follow up should be
maintained for these patients through life to assure
the retention of the natural teeth. These patients
usually present with multiple problems due to years
of neglect. When dentures are indicated extractions
and other additional oral surgery is often necessary
to prepare the oral cavity. The use of special
materials in impression making, denture
construction and speech aid fabrication must be
considered. These patients can best be helped by
utilizing the team approach.

CONCLUSION
A thorough examination of the mouth prior to
construction of complete dentures is necessary to
identify potential problem areas. To determine
whether surgery is necessary or not is an
essential part of examination and plays an
important role in successful patient management.
Many conditions should be corrected prior to
denture construction to improve the treatment
prognosis and reduce the number of post-
insertion adjustments. In general, bony
abnormalities should be managed first. Associated
soft tissue corrections can be delayed if required.

Final prosthesis design and goal of long term
function, esthetic quality and tissue maintenance
must be considered during all phases of
treatment. Since the support, retention and
stability of a denture base depends on quantity
and quality of denture bearing area and border
seal, every effort is made to preserve the
alveolar bone. Conservation is a philosophy in
surgical patient management.

If resorption or atrophy is far advanced the jaw
bone has to be reconstructed, so that an absolute
increase in the ridge height is the aim. This is
secured by onlay grafting, preferably of autologous
bone, or inlay grafting (sandwich technique:
horizontal osteotomy with bone interposition). In the
lower jaw there is also the possibility of
'displacement grafting' (visor osteotomy: vertical
osteotomy and visor-like displacement) and grafting
to the lower border in cases of extreme mandibular
atrophy. In the long term onlay grafts show a high
degree of resorption; in appropriate circumstances,
the results of the other methods are encouraging. A
feature common to all procedures is a greater or
lesser functional disturbance of the mental nerve.

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