Pre prosthetic surgery/ dental crown & bridge courses

IMPROVING THE PATIENTS DENTURE
BEARING AREAS AND RIDGE
RELATIONS
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

INTRODUCTION
A thorough examination of the mouth prior to the
construction of complete dentures 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. Consequently, several conditions in
the edentulous mouth should be corrected or treated
before the construction of complete dentures. 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.

The methods of treatment to improve the
patient’s denture foundation and ridge relations
are usually 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.
A patient who presents with deformed, abused
pathologic tissues from an existing denture
should first undergo non-surgical approach.

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. In these
instances, 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:
• Adequate bone support for dentures.
• Bone covered by adequate soft tissue.
• No undercuts or overhanging protuberances.
• No sharp ridges.
• Adequate buccal and lingual sulcus.
• No scar bands to prevent normal seating of denture.
• No muscle fibers or frenula to interfere with the
periphery of the prostheses.
• Satisfactory ridge relationship between the maxilla and
the mandible.
• No soft tissue folds or hypertrophies on the ridge or
sulci.
• A ridge free of neoplastic disease.www.indiandentalacademy.com

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

Rest for denture supporting tissues:
Rest for the denture supporting tissues can be
achieved by the removal of the dentures from
the mouth for an extended period or the use
of temporary soft liners inside the old
dentures. Regular finger or toothbrush massage
of denture bearing mucosa, especially of those
areas that appear edematous and enlarged is
also beneficial.

Tissue abuse caused by improper occlusion can
be made to disappear by,
• Withholding the faulty denture from the patient.
• Adjusting/correcting the occlusion and/or refitting
the denture by means of a tissue conditioner.
• Substituting properly made dentures.

In these cases, it is necessary to allow the soft
tissues to recover by removing the dentures for
24-48 hours before the impressions are made for
the construction of new dentures. However, it
generally is not feasible to withhold the patient's
denture for an extended period while the tissues
are recovering. Therefore, temporary soft liners
have been developed as tissue treatment or
conditioning materials. These soft liners maintain
their softness for several days while the tissues
recover.

Occlusal correction of old prostheses:
An attempt should first be made to restore an
optimum vertical dimension of occlusion to the
dentures presently worn by the patient by using an
interim resilient lining material. This step enables the
dentist to prognosticate the amount of vertical facial
support that the patient can tolerate, and it allows the
presumably deformed tissues to recover. The decision
to create room inside the denture depends on its fit
and the condition of the tissues. The tissue treatment
material also permits some movement of the denture
base so its position becomes compatible with the
existing occlusion, apart from allowing the displaced
tissue to recover their original form.

Consequently, ridge relations are improved and
this improvement facilitates the dentist's eventual
relation registration procedures. It also facilitates
the occlusal adjustments intraorally and
extraorally, i.e., on an articulator.
It may also be necessary to correct the extent
of tissue coverage by the old denture base so
all usable supporting tissue is included in the
treatment. This correction can easily be achieved
by use of one of the resin border-molding
materials combined with a tissue conditioner.

Good nutrition:
A good nutritional program must be
emphasized for each edentulous patient. This
program is especially important for the
geriatric patient whose metabolic and
masticatory efficiency have decreased.

Conditioning the patient's musculature:
The use of jaw exercises can permit relaxation
of the muscles of mastication and strengthen
their coordination as well as help prepare the
patient psychologically for the prosthetic
service. If at the initial appointment the dentist
observes that the patient responds with
difficulty to instructions of relaxation and
coordinated mandibular movements, a program
of mandibular exercises may be prescribed.
Such a program may be beneficial and the
subsequent clinical appointment stages of
registration of jaw relations facilitated.www.indiandentalacademy.com

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 den-ture
bearing area, or more commonly may follow long
term wear of ill-fitting dentures.

Correcting conditions that preclude optimal prosthetic
function
( Hyperplastic ridge, Epulis fissuratum, Papillomatosis.)
The premise underscoring surgical intervention is that
mobile tissues (e.g., a hyperplastic ridge), tissue that
interfere with optimal seating of the denture (eg epulis), or
tissues that readily harbor microorganisms (a papillomatosis
are not conducive to firm healthy foundations for complete
dentures. Whenever possible, these tissues should be rested,
massaged, and / or treated with an antifungal agent prior to
their surgical ex-cision. If the patient's health precludes
surgical in-tervention, the impression technique and design
of the denture base have to be modified.

Frenular attachments and pendulous maxillary
tuberosities. Frena, or fibrous bands of tis-sue
attached to the bone of the mandible and maxillae,
are frequently superficial to muscle at-tachments. If
the frenum is close to the crest of the bony ridge, it
may be difficult to ob-tain the ideal extension and
border of the flange of the denture.This tissue can be
removed surgically. Frena often become prominent
as a re-sult of reduction of the residual ridges. If
muscle fibers are attached close to the crest of the
ridge when the frenum is removed, they usually are
de-tached and elevated or depressed to expose the
amount of desired ridge height.www.indiandentalacademy.com

The frenectomy can be carried out before prosthetic
treatment is begun, or it can be done at the time of
denture insertion when the new denture can act as a
surgical template.
Pendulous fibrous maxillary tuberosities are
frequently encountered. They occur unilaterally or
bilaterally and may interfere with denture
construction by excessive encroachment on or
obliteration of the interarch space. Surgical excision
is the treatment of choice, but occasionally
maxillary bone must be removed. Care must be used
to avoid opening into the maxillary sinus.

Bony prominences, undercuts, spiny ridges, and
nonparallel bony ridges.
Mandibular tori are usually removed to avoid
undercuts and to make possible a border seal beyond
them against the floor of the mouth. They generally
occur so close to the floor of the mouth that a border
seal cannot be made. On the other hand, maxillary
tori are infrequently removed. Satisfactory dentures
can be made over most of them.

The indications for the removal of maxillary tori
are as follows:
• An extremely large torus that fills the palatal vault
and prevents the formation of an adequately
extended and stable maxillary denture.
• An under cut torus that traps food debris, causing a
chronic inflammatory condition; surgical excision
is necessary to create optimal oral hygiene.
• A torus that extends past the junction of the ard
and soft palates and prevents the development of
an adequate posterior palatal seal.
• One that causes the patient concern (because of a
cancerphobia)

Bony exostoses may occur on both jaws but are
more frequent on the buccal sides of the posterior
maxillary segments. They may create discomfort if
covered by a denture and usually are excised. It
must be emphasized that routine excision of
mandibular exostoses is not recommended
because all alveolar ridge surgery is accompanied
by varied, but often dramatic residual ridge
reduction. Frequently the denture can be relieved to
accommodate the exostosis, or a permanent soft
liner can be employed.

Sometimes, the genial tubercles are extremely
prominent as a result of advanced ridge reduction in
the anterior part of the body of the mandible. If the
activity of the genioglossus muscle has a tendency
to displace the lower denture or if the tubercle
cannot tolerate the pressure or contact of the denture
flange in this area, the genuial tubercle is removed
and the genioglossus muscle detached. If it is
clinically necessary to deepen the alveololingual
sulcus in this area, the genioglossus muscle is
sutured to the geniohyoid muscle below it.

Residual alveolar ridge undercuts are rarely excised
as a routine part of improving a patient's denture
foundations. Usually, a path of insertion and
withdrawal of the prosthesis can be determined
together with careful adjustment of a denture
flange, which enable the dentist o use the undercuts
for extra stability.

Discrepancies in jaw size. Impressive advances in surgical
techniques of mandibular and maxillary osteotomy have
enabled the oral surgeon to create optimal jaw relations for
prosthetic patients who have discrepancies in jaw size. The
prognathic patient frequently places considerable stress and
unfavorable leverages on the maxillary basal seat. This may
cause excessive reduction of the maxillary residual ridge.
Such a condition is even more conspicuous when some
mandible teeth are still present. A mandibular osteotomy in
these cases can create a more favorable arch alignment and
improve cosmetics as well. However, changes in the soft
tissues of the face tend to be accentuated by such a
procedure.
Usually an adjunctive facelifting procedure in this type of
patient produces impressive results.www.indiandentalacademy.com

Pressure on the mental foramen. If bone resorption in the
mandible has been extreme, the mental foramen may open
near or directly at the crest of the residual bony process.
When this happens, the bony margins of the mental foramen
usually are more dense and resistant to resorption than the
bone anterior or posterior to the foramen is. This causes the
margins of the mental foramen to extend and have very
sharp edges 2 to 3 mm higher than the surrounding
mandibular bone. Pressure from the denture against the
mental nerve exiting the foramen and over this sharp bony
edge will cause pain. Also pressure against the sharp bone
will cause pain because the oral mucosa is pinched between
the sharp bony margin of the mental foramen and the
denture.

The most suitable way of managing this is to alter the
denture so pressure does not exist. However, in rare
instances it may be necessary to trim the bone to relieve the
mental nerve of pressure. Pressure on the mental nerve is
reduced by increasing the opening of the mental foramen
downward toward the inferior border of the body of the
mandible. Such a change permits the mental nerve to exit
the bone at a point lower than it had previouslv, thereby
taking pressure off the nerve.
A lack of parallelism between the maxillary and mandibular
ridges can be encountered and, on occasion, may require
surgical repair. This lack of parallelism may be caused by a
lack of trimming of the tuberosity and ridge behind the last
maxillary tooth when it is removed or may be the result of
defects, unequal ridge reduction, or abnormalities of growth
and development. Most clinicians favor parallel ridges for
their denture foundations, because the resultant forces
generated are directed in a way that tends to seat the denture
rather than dislodge it.www.indiandentalacademy.com

Virtually all the surgical procedures described
necessitate the use of a surgical template. The
patients old dentures can usually be modified with a
soft treatment resin to function as such. The use of a
lined template protects the operated area from
trauma and enables the patient to continue wearing
the dentures. It must be understood that extensive
surgical preparation of the edentulous mouth is
rarely necessary, infact clinical experience indicates
that careful prosthetic technique and design will
frequently preclude a surgical intervention. When
essential, any required surgical procedure should be
as conservative as possible.www.indiandentalacademy.com

ENLARGEMENT OF DENTURE BEARING AREAS
(VESTIBULOPLASTY) The reduction of alveolar ridges
is frequently accompanied by an apparent encroachement of
muscle attachments on the crest of the ridge. These so called
high (mandibular) or low (maxillary) attachments serve to
reduce the available denture bearing areas and to undermine
denture stability. The anterior part of the body of the
mandible is the sight most frequently involved: the labial
sulcus is virtually obliterated and the mentalis muscle
attachment appear to migrate to the crest of the residual
ridge. This usually results in the dentist arranging the teeth
more
Lingually than the position of the former anterior teeth.
Such lingual crowding may not be tolerated by the patient;
and when the absent sulcus is accompanied by little or no
attached alveolar mucosa in this area, it is virtually
impossible for a lower denture to be retained.www.indiandentalacademy.com

Myoplasty accompanied by sulcus deepening has been
carried out in an attempt to improve denture retention. This
enables the prosthodontist to increase the vertical
extensions of the denture flanges. When horizontal bony
shelving is present in the mentalis muscle region, the
surgical procedure is less successful and its relative efficacy
is attributable to the modification of the powerful mentalis
muscles activity. A wide and deep sulcus is not essential for
success and the vestibuloplasty can be restricted to the
premolar region because the buccinator muscles are not a
major cause of the problem. Although a lingual
vestibuloplasty can provide for a major denture dimensional
increase, the procedure is traumatic, particularly in frail and
elderly patients and therefore not frequently recommended.

The use of acrylic resins template or the modified
previous dentures to support vestibuloplasty in the
mandible is essential. These templates must be
fastened to the mandible with circum mandibular
wires for atleast one week. Carefully designed
splints will reduce inflammation, reduce post
operative scarring and maintain muscles in the
desired positions thereby improving the result.

One other result of excessive alveolar bone loss or
reduction is obliteration of the hamular notch.This
anatomical culdesac, with its potential for
displacement, makes it an important part of the
posterior palatal seal of the maxillary denture. Its
absence can severely undermine retention of the
• denture, and a small localized deepening of the
sulcus in this area may be indicated. The patient's
old denture or a surgical template is employed after
the surgery to help retain the patencv of the newly
formed sulcus, or notch.

Ridge augmentation. For many years surgeons
have attempted to restore mandibular bulk by plac
ing onlay bone grafts from an iliac or rib source
above or below the mandible. Unfortunately, fol
lowup reports suggest that the result generally
leaves much to be desired with respect to ridge
height and minimal morbidity as a treatment out
come. Other methods of dimensional increase of the
mandible also have been proposed. However, it is a
formidable undertaking for elderly patients.

REPLACING TOOTH ROOTS BY
OSSEOINTEGRATED DENTAL IMPLANTS.
Complete dentures are not the only method available
for treating edentulous patients. Recent research has
provided irrefutable evidence of the desirability and
feasibility of osseointegrating tooth replicas or
analogues in edentulous jaws. This scientific
advance has ushered in a new era in the treatment of
edentulism by virtue of the fundamental change in
its applied concept of pre prosthetic surgery. In this
technique, a number of cylindrically shaped screws,
made of specific materials and confirming to
specific designs are buried inside the selected host
bone sites.

They are left to heal in situ for 4 to 6 months while
osseointegration occurs. The screws or tooth root
analogues are uncovered at a second surgical
procedure, when an elective removable fixed bridge
is attached to the implants. The technique also
improves the scope for use of supporting over
dentures and is widely regarded as having
completely eclipsed the previously mentioned pre
prosthetic surgical methods.

Pre prosthetic surgery/ dental crown & bridge courses

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