Aside from studies of chewing efficiency using analysis of masticated test foods, the use of strain gauges attached to indication of denture teeth and electromyography has been applied to this problem Hickey and Asso demonstrated that there was less activity from the closing muscles when using anatomic (33 degree) teeth than when using 5cm – Anatomic (20 degree) or non anatomic (0 degree) teeth in tests of chewing efficiency.
Resorbed ridge seminar koto
DR. MANESH LAHORI
PROFF & HEAD
DEPT. OF PROSTHODONTICS
DR. PRATEEK AGRAWAL
M.D.S. IIIrd YEAR
• ETIOLOGY OF RIDGE RESORPTION
• CLASSIFICATION OF RESIDUAL RIDGE
• PREVENTION AND TREATMENT
Residual ridge is a term used to describe the shape of
the clinical alveolar ridge after healing of bone and soft
tissues after tooth extractions.
After tooth extraction, a cascade of inflammatory
reactions is immediately activated, and the extraction
socket is temporarily closed by the blood clot. Epithelial
tissue begins its proliferation and migration within the first
week and the disrupted tissue integrity is quickly restored.
The most striking feature of the extraction
wound healing is that even after the healing of
wounds, the residual alveolar ridge bone undergoes a
life-long catabolic remodeling. The size of the residual
ridge is reduced most rapidly in the first 6 months,
but the bone resorption activity continues throughout
life at a slower rate, resulting in removal of a large
amount of jaw structure.
This unique phenomena has been described as
Residual Ridge Resorption (RRR).
Residual ridge resorption after loss of
teeth is a multifactorial oral problem.
According to Atwood, the degree of mandibular
loss of its alveolar portion is 3-4 times higher
than alveolar resorption in the maxilla. The
rate of RRR is different among persons and
even at different sites in the same person.
Residual bone is considered to be the base
which provides support for dentures and is an
area where forces created while biting and
chewing foods are transmitted.
Loss of alveolar bone from the edentulous
jaws is a serious and common clinical problem,
especially among the elderly.
In particular, “flat lower ridge” is associated
with difficulties in providing successful dentures.
Stability of lower denture in such cases is usually
the distinguishing factor between success and
ETIOLOGY OF RIDGE
It is postulated that residual ridge resorption
is a multifactorial, biomechanical disease that
results from a combination of:
• Anatomic factors
• Metabolic factors
• Mechanical factors
• Prosthodontic factors
A. Anatomic factors:-
Ridge resorption varies with-
Quantity and Quality of the bone.
Shape& Form of the ridges (Large, well-rounded ridges
and broad palates would seem to be favorable anatomic
Density of the ridge (density at any given moment does
not signify the current, metabolic activity of the bone and
bone can be resorbed by osteoclastic activity regardless of its
degree of calcification)
B. Metabolic factors:-
• Generally, body metabolism is the net sum of all the building
up (anabolism) and the tearing down (catabolism) going on it
RRR α bone resorption factors
bone formation factors
• In equilibrium the two antagonistic actions (of osteoblasts
and osteoclasts) are in balance.
• In growth, although resorption is constantly taking place in
the remodeling of bones as they grow, increased osteoblastic
activity more than makes up for the bone destruction.
• Whereas in osteoporosis, osteoblasts are hypoactive,
and, in the resorption related to
hyperparathyroidism, increased osteoblastic activity
is unable to keep up with the increased osteoclastic
• The normal equilibrium may be upset and
pathologic bone loss may occur if either bone
resorption is increased or bone formation is
decreased, or if both occur.
• Ridge resorption varies directly with some systemic
or localized bone resorptive factors and inversely
with some bone formation factors.
• Some local biochemical factors in relation to
periodontal disease which affects the ridge
Endotoxins from dental plaque on unclear
Osteoclast activating factor (OAF).
Human gingival bone resorption stimulating
Heparin acts as a cofactor in bone resorption
which is produced from mast cells
• Systemic factors influence the balance between the
normal bone formation and bone resorption. These
factors create a natural resistance to unfavorable
local factors. They are-
C. Mechanical factors:-
When force within physiologic limits is applied to
bone that force brings about the remodeling of bone
through a combination of bone resorption and formation
• RRR directly proportional to Force:-
– Amount, frequency, duration, direction, area over which force
is distributed (force/unit area) and damping effect of the
– Some postulate that it is because of disuse atrophy and others as
abuse of bone.
– There is increased tendency for mandibular ridge to undergo
resorption compared to maxilla.
Damping Effect/ Energy Absorption-
Resorbing residual ridge is indirectly
proportional to damping effect. Dampening
effect takes place in the mucoperiosteum, which
is a viscoelastic material. Maxillary bone (RR) is
frequently broader, flatter and more cancellous
than its mandibular counterpart.
So it is ideally constructed for the absorption
and dissipation of energy. Frost pointed out that
the trabaculae in cancellous bone are arranged
parallel to direction of compression
D. Prosthodontic factors:-
Clinical observations indicate that excessive
alveolar bone resorption can be caused by
physiologically intolerable forces produced by
functioning complete dentures.
The inherent denture factors which may affect the
supporting structures include:
– The occlusal forms of the teeth.
– The alignment of the denture teeth / occlusal pattern.
– Deformation of the denture bases.
– Materials with which denture teeth are made and
– The effects of the loss of proper occlusal vertical
dimension (over closure).
The occlusal forms-
• The form of the occlusal surfaces of artificial teeth,
wether of the Anatomic, Non anatomic or 0 degree
configuration, must have some effect on chewing
efficiency and on forces tending to distort the
• One of the earliest opponents of the anatomic tooth
form was French who coined the term “cusp trauma”
as one of the most serious defects that had to be
guarded against in complete denture construction.
Soon after, Sear’s developed his non anatomic tooth
form which initiated the introduction of many new
designs to denture teeth throughout the years.
• Results of early studies on chewing efficiency with
various occlusal forms were contradictory.
Thompson, Trapozzon and Lazzari found anatomic
teeth to be more efficient than non anatomic teeth,
whereas Soboik, Manly and Vinton found no
statistical difference between the efficiency of the
anatomic and non-anatomic teeth.
• More recent studies have shown that there is no
statistical difference in the chewing performance in
denture teeth with cuspal ranging from 0 to 30
Denture base deformation –
• Studies done by Askew and Hoyer showed that
when the mandible with denture was pulled
into lateral and protrusive more deformation
was caused under the denture with anatomic
tooth form than with non anatomic tooth form
and same was with acrylic resin denture bases
which resorbed the ridge more than the metal
base when used with anatomic teeth than with
non anatomic teeth.
Tooth material –
• The material from which the denture teeth are made
may have some effect on the forces transmitted
through the denture base material to the supporting
• It is said that porcelain tooth when placed causes
more resorption of ridge than acrylic tooth.
Loss of occlusal vertical dimension (over
• The loss of proper occlusal vertical dimension after
the insertion of complete dentures results in the
triggering of a cyclic series of event detrimental to the
health of the residual alveolar ridges.
CLASSIFICATION OF RESIDUAL
• The basic structural change in RRR is a
reduction in the size of the bony ridge under
the mucoperiosteum. It is primarily a
localized loss of bone structure. In some
situations, this loss of bone may leave the
overlying mucoperiosteum excessive and
• In order to provide a simplified method for
categorizing the most common residual ridge
configurations, Atwood (1963) described a system of
six orders of residual ridge-
Order I – Pre extraction.
Order II – Post extraction.
Order III – High well rounded.
Order IV – Knife edge.
Order V – Low, well rounded.
Order VII – Depressed.
• Several authors have affirmed the relationship of the
foramen to the inferior border of the mandible remains
relatively constant in spite of increasing age or resorption
of the alveolar process above the foramen. (JPD; 32 (1);
– CLASS I: Up to one third of the original vertical height lost.
– CLASS II: From one third to two thirds of the vertical height
– CLASS III : Two thirds or more of the mandibular height lost.
DR. MANESH LAHORI
PROFF & HEAD
DEPT. OF PROSTHODONTICS
DR. PRATEEK AGRAWAL
M.D.S. IIIrd YEAR
• ETIOLOGY OF RIDGE RESORPTION
• CLASSIFICATION OF RESIDUAL RIDGE
• PREVENTION AND TREATMENT
TREATMENT AND PREVENTION
• SWENSON stated, “ The ideal ridge is one that is broad
in its bearing surface and has practically parallel
• But in the degenerative denture ridges- undercut
ridges, V- shaped ridges, thin knife edge ridges, and
flat or non- existent denture ridges may be seen.
• Prosthodontists must correct dentures on all of these
degenerated ridges and should aim not only to replace
the lost structures and lost function but also to
preserve the remaining ridge.
• The cause of the degenerative denture ridge
will determine the type of treatment.
• So a detailed examination must be performed.
• Complete mouth and panographic
radiographs are essential.
• A comprehensive dental history including-
Previous prosthetic treatment
Number of old dentures made
Frequency of denture rebasing should be
appreciated in order to estimate both the
apparent rate of progression of RRR and the
capability of the individual to cope up with
• Intra-oral examination should determine the
ridge form and extent of resorption. Mucosal
form on and surrounding the ridge should be
checked along with palpation to locate any
tender areas of mucosa.
• The assessment of quantity, quality, viscosity
of the saliva should be made. This may affect
physical retention of the denture associated
with the cohesive and adhesive properties of
saliva between the denture and mucosa.
• The tongue size and tongue movements
should be assessed.
• Radiographs should also be taken which aids
in assessing ridge resorption, inadequate bone
thickness (risk of spontaneous fracture). The
position of the mental nerve and mandibular
canal can also be established.
• Diagnostic models may also be taken to allow
case evaluation in the absence of the patient.
• A dietary analysis can be obtained through
• Their ability to chew will frequently dictate
their selection of food, and this will usually
generate a diet high in refined carbohydrates
and low in proteins, vitamins and minerals-
just the opposite of what is needed to help
stop the onslaught of bone destruction.
– Best of all is to prevent the loss of teeth.
– Prevention and/or the correct diagnosis and
management of all of the etiologic factors of the
– Any systemic illness that is contributing to the
degenerated bone condition must be corrected or
stabilized. Any dental treatment should follow
only after the condition is under control and the
patient is fit for treatment. In cases where limited
help can be given, the patient should be counseled
about its effect on dental health.
– Diet is one of the most neglected facets of
treatment in degenerate denture ridge patients.
These patients need a diet high in protein,
vitamin, and mineral content. So the dietary
problems should be corrected.
– Correcting deficiency of various hormone,
vitamin, mineral etc.
– Tissue treatment therapy to rejuvenate the tissue
bearing area by the use of soft conditioning
– Muscle strengthening exercises.
II. Prosthetic management:
A. IMPRESSION MAKING-
• In patients with severely resorbed ridges, lack of ideal
amount of supporting structures decreases support
and the encroachment of the surrounding mobile
tissues onto the denture border reduces both stability
• Thus the main aim of the impression procedure is to
gain maximum area of coverage. A broad area
coverage with maximal denture base extension
decreases the force experienced per unit area of the
mucosa beneath the denture and the likelihood of its
• However, in resorbed ridge the extension of
the base is critical to avoid interferences with
the movement of border structure.
• There are different impression techniques to
follow. The principles employed in
impression making should be maximal
support, retention and stability.
• Special techniques, to determine accurately
the denture border extension have been
Fish recommended a technique where,
sublingual fold space, extending from
premolar to premolar region on each side was
recorded. This horizontal flange acted as
‘tongue rest’ thereby increasing the stability
Bernard Levin: Suggests making primary
impression with alginate (25% less water).
Special tray should be wider and heavier in
the buccal shelf area. While border molding
tongue should be allowed to extend fully.
Patient should make only moderate
movements. Final impression should be
completed with Elastomeric impression
material. Exaggerated tongue movements
should be made.
Winkler technique involves the use of the tissue
• A preliminary impression is made to obtain a
generally overextended registration.
• Using the resulting cast, a resin tray is made, and
an occlusal wax rim is added to simulate the
height and position of the anterior and posterior
teeth and then tried in the mouth.
• The borders are adjusted so that the lingual
flange and sublingual crescent area are in
harmony with the resting and active phases of
the floor of the mouth.
• The buccal and labial extension of the acrylic
tray is adjusted to be deliberately short of the
reflections of the cheek and lip.
• A stable, nonretentive tray should now be
• From this point on, an open- or closed mouth
technique may be employed.
• In general, three applications of conditioning material
• Two applications of the more viscous material are
made, each application being allowed to remain in the
mouth for eight to ten minutes, removed, rinsed, and
• Pressure areas are corrected at the time of the first
• The third and final wash is made with the relatively
• This results in an impression that has a tissue-placing
effect, very thick and conforming buccal borders, and
a relatively thick lingual and sublingual crescent area.
• The overall denture is bulkier, with more surface
contact area, than is found in the conventional
• It can be thought of as a mandibular denture
with minimal bony contact in the alveolar
ridge area, suspended in a compatible soft
• This method results in improved retention of
the mandibular denture, even with its built-in
instability, because of the conformity of the
residual alveolar ridge.
Dynamic Impression Method:
• Its significance:
– Avoids the dislocating effect of the muscles on improperly
formed denture border.
– Complete utilization of the possibilities of active and
passive tissue fixation of the denture.
– Dynamic impressions in contrast to non dynamic
impression records the tissues in an immobile condition,
– Semi dynamic impressions in which the denture borders
are determined by partly passive and partly active
movements was described by Fournet and Tull.
Fabrication of the special tray is done.
A ridge of self curing resin is built up in the premolar molar region on each side
to support the thermoplastic material.
While the thermoplastic material is soft the tray is placed in position on the
lower ridge in the mouth and the patient is asked to close the jaws slowly.
The upper residual ridge will form an impression in the soft thermoplastic
material at a height corresponding to the rest mandible. Tray is removed from
mouth and cooled.
Lingually the mandibular rests should be concave to provide space for the
Sufficient amount of an irreversible hydrocolloid is mixed with 50%
extra water material and is placed directly into the mouth to cover all
The tray is pressed through alginate by digital force until the stops
are firmly seated on the residual ridge.
Then, the patient is asked to close his mouth slowly until the
mandibular rests have obtained firm contact with the maxillae.
The patient should swallow three to four times at 10 seconds interval
while the final impression material is still in a moldable condition.
The action of the muscles that function in deglutition is accentuated
because the mandibular rests prevent the mandible from reaching the
vertical, relation of occlusion and force it to remain in its rest position.
This procedure develops a registration of the denture space which
ordinarily results in a proper extension of the lingual flanges of the
Forceful protrusion of the lips brings the mentalis and orbicularis oris
muscles into action and is responsible for forming the labial part of the
In another method, an old denture can be used for a
dynamic impression when opposing natural or
artificial teeth are present. Often the vertical
dimension at occlusion is decreased hence steps are
placed at re-established height. The mandibular rests
are built up include the inter-occlusal distance.
In still another method, denture is processed in a
conventional manner. Then a correcting dynamic
impression is made in the denture base to reshape
and complete the final design and the denture is
relined. This procedure was originally indicated by
Momme in 1872.
Klein in 1957, suggested three distinct types
of impression techniques for mandibular
dentures depending on the type of foundation.
(J. Pros. Dent. September, 1957)
– First Condition-
•When the mandibular ridge is almost
completely resorbed with just a rib of soft
fibrous tissue along the crest. This rib of
tissue is easily displaced and can be a
constant source of irritation, if the
impression is not recorded correctly.
After a routine modeling compound wax
mandibular impression is made in the usual
manner, approximately 3mm of compound is
relieved over the crest of the ridge and a cast is
The clear acrylic resin tray processed on the
preliminary cast will not contact the ridge crest.
Three holes are drilled in the tray on each side
in the areas of the ridge crest to prevent a
building up of undesired pressure.
The final impression is made inside the tray
and the free flowing paste will allow the soft
tissue along the crest of the ridge to place itself.
– Second Condition-
•In cases with almost complete resorption
and with a spiny ridge of dense bony tissue
along the crest of the residual ridge.
Compound impression is made as above. In
addition to the crest of ridge, compound is scraped
away along the crest of mylohyoid ridge and
posterior lingual flange to a depth of 2mm.
Physiologic wax is added and primary
impression completed. The cast is poured and the
area of the mylohyoid ridge is relieved with 0.001
inch tin foil.
The clear acrylic resin tray is made and final
wash impression made. Master cast is poured.
The knife edged ridge crest is again relieved with
0.001 inch tin foil. Thus forces of mastication will
be exerted along the sides of the ridge rather than
on the crest.
• In cases where ridge is flat or concave.
The impression of lingual border is recorded
accurately with the impression wax.
This type of foundation should not require any
alteration or modification in the impression
technique, except where the mylohyoid ridge
becomes a disturbing factor. This situation is
handled as described previously. The coverage of
the denture-bearing area will be the same as for
an average foundation. The supporting structures
have changed, but the muscles of the border
regions still function normally and will mold the
borders of the impression.
The technique is same as stated above.
B. SELECTION OF DENTURE BASE-
• For degenerative ridge patients there are
three types of denture bases:
– Methyl methacrylate resin denture bases
– Cast metal bases
– Processed resilient , lined denture bases
Methyl methacrylate resin denture bases:
• These are the standard bases normally used.
• These bases are quickly and easily
• Dimensionally stable.
• But in a short time the base appears to
soften and change color, and is not strong.
Cast metal bases:
• Main advantage is the great accuracy of fit to the
tissues by surface tension, than acrylic denture
• They maybe of gold, chromium cobalt or
Prevention of acrylic warpage,
Less tissue change under the base,
Less porosity and therefore easier to clean and
Less deformation in function.
Processed, Resilient, Lined Denture Bases
• Its greatest advantages are its cushioning
effect upon the mucosa and its ability to
distort and spring back.
• It is indicated in the cases of
– Severely undercut ridges where surgery is
– Patients with no ridge
– Patients with a flat ridge and delicate tissues.
– Spinous ridge, tori, the mental foramen, and the
• The lining is best when there is a 2 mm
thickness. So, it cannot be used in the cases
of small inter-ridge distance.
• The biggest disadvantage is deterioration of
the resilient liner in few months.
C. JAW RELATION-
• Correct recording of vertical and horizontal
relations are equally important for the
preservation of residual bone resorption.
• The difficulty in obtaining good jaw-relation
records is complicated by the frequently
impaired masticatory apparatus.
• Perhaps the most important factor in
articulation is that centric occlusion be
harmonious with the centric relation.
• In horizontal relations unless centric relation is
established properly, the mandibular teeth will not
occlude properly with those on the maxillary arch,
thus proper occlusion is essential to the health of
• Otherwise during eccentric movement it causes
pressure on bone due to failure of the stability factor.
Hence cause resorption of bone.
D. SELECTION OF TEETH AND OCCLUSION-
• The neutrocentric concept was developed by
• DeVan has suggested embodying the two key
objectives of his occlusal scheme
– Neutralization of inclines,
– Centralization of forces.
• The neutralization of inclines and centralization of
occlusal forces aids in stability without interfering
with speech, appearance and chewing capacity.
• The five elements of this scheme are:
• Position: the position of posterior teeth should be
centralized over the residual ridge so that the forces are
perpendicular to the support areas. This avoids tensile and
• Proportion: DeVan reduced the teeth width by 40%. This
reduced the vertical stress on the ridge. Horizontal forces
are reduced because friction between opposing surfaces is
decreased. The forces are thus centralized without
encroaching on the tongue.
• Pitch: This is the inclination or tilt of the occlusal plane. It
is oriented parallel to the underlying ridge and midway
between them. This directs the forces perpendicular to the
mean osseous foundation plane.
• Form: Flat teeth with no deflective inclines were
used so that there is no interference with
• Number: The number of posterior teeth was
reduced from eight to six. This reduced the
magnitude of occlusal force and centralized it to
second premolar and first molar.
• William H. Goddard introduced the concept
of linear occlusion.
• Frush described occlusion in geometric terms
as one dimensional (linear), two dimensional
(flat) and three dimensional (cusped).
• Groans and Stout explained how anatomic
and non anatomic occlusal schemes transmit
lateral forces to the denture and reduce
stability and suggested that the linear occlusal
scheme has the potential for creating the
smallest lateral force component.
• Linear occlusion consists of the following basic
– Zero degree teeth (flat teeth) are opposed by bladed
(line contact) teeth in which the blade is a straight
line over the crest of the ridge.
– The arch which requires the greatest stability receives
the bladed teeth (the mandible most often requires
greater stability and receives bladed teeth).
– There is no anterior interference to protrusive or
– This non-interceptive occlusion provides a consistent
vertical seating force in both centric and eccentric;
hence transverse vectors are eliminated.
• Overdentures are designed to distribute the
masticatory load between the edentulous ridge and
• The overdenture transfers occlusal forces to the
alveolar bone through the periodontal ligament of
the retained tooth roots.
• Proprioceptive feedback, from the periodontal
ligament to the muscles of mastication, may act to
prevent occlusal overload and thereby prevent bone
resorption because of excessive forces.
• The short term and long-term preservation of
alveolar bone has been documented not only
adjacent to the overdenture abutments but also
adjacent to the edentulous ridges.
• A comparison of immediate conventional
dentures and immediate overdentures found
half as much bone loss (0.9mm compared with
1.8 mm) in the anterior mandible over the first
year in the overdenture group, surprisingly, the
bone loss was also slowed in the posterior
• The increased stability that resulted from the
use of overdentures may limit lateral forces
placed on residual bone.
F. SUBMERGENCE OF ROOTS (VITAL OR
• Studies have shown that the roots that were
submerged remained asymptomatic and
help to preserve residual ridge and it may
be an alternate method to conventional over
III. SURGICAL MANAGEMENT:
• The various problems associated with RRR
and stability of removable soft tissue borne
dentures have aroused interest in dental
implantology to provide stable mechanical
support to the dental prosthesis. This is
because of the following advantages
offered by implant supported prosthesis.
Maintenance of alveolar bone
Restoration & maintenance of occlusal vertical
Maintain facial esthetics.
Improved psychological health.
Increased stability, retention
Improved masticatory performance.
Immune to caries.
Increased trabeculation and density of bone.
Overall volume of bone is maintained.
Efficiency to take up stress and strain.
There is 20 fold decrease in the loss of structure
with implants when compared with resorption that
occurs with removable prosthesis.
B. VESTIBULAR EXTENSION PROCEDURE-
• Indicated when there is high muscular and
• The reduction of alveolar ridge size is frequently
accompanied by an apparent encroachment of
muscle attachments on the crest of the ridge.
These serve to reduce the available denture
bearing area and undermine denture stability.
• Soft tissue vestibuloplasties including localized
mucosal flap to a full-skin graft vestibuloplasty
may be performed to increases the relative
height and extent of the denture foundation.
C. RIDGE AUGMENTATION-
These are the procedures designed to
enlarge or increase the size, extent, or quality
of deformed residual ridge.
– Restoration of optimum/near optimum ridge
height & width, ridge form, vestibular depth and
optimum denture bearing area
– Protection of neurovascular bundle
– Establishment of proper inter arch relationship
– Improvement of retention and stability of
– Improve the patient comfort for wearing the
• Superior border augmentation
– Bone grafts
– Cartilage grafts
– Alloplastic grafts.
• Inferior border augmentation
– Bone grafts (autogenous or allogenic freeze dried
– Cartilage grafts.
• Interpositional or Sandwitch bone grafts
– Bone grafts
– Cartilage grafts
– Hydroxyapatite blocks.
• Onlay bone grafting - autogenous /
• Onlay grafting by alloplastic material.
• Interpositional or Sandwich grafts.
• Sinus lift procedure.
Residual ridge resorption is a chronic,
progressive, irreversible, and disabling disease ,
of multifactorial origin. Much is known about
its pathology and pathophysiology, but a lot
remains to know about its pathogenesis,
epidemiology and etiology.
Resorbed ridge requires a multiple
approach for diagnosis and treatment planning.
The cause must be detected, by the aid of a
physician, and then eliminated or stabilized
before dentures are constructed.
Although challenging, the severely
resorbed ridges can be resorted to a certain
level of mastication with the help of
improved impression techniques, proper
selection of occlusion schemes, the use of
specialized dentures techniques and a
regular follow up.
More recently, implant supported
overdentures are playing tremendous role in
the treatment of the severely resorbed ridges.
As prosthodontists, we need to perform
the most meticulous and intelligent
prosthodontic care of the patient within our
capabilities for the restoration of the physical
and mental vitality of the patient.
…and then , it would not seem a nebulous
hope that some day there will be control over
residual ridge resorption.
• Essentials of Complete Denture Prosthodontics, 2nd Edition, By Sheldon
• Prosthodontic Treatment for Edentulous patients, 11th Edition, By Boucher.
• Impression for Complete Denture, by Bernard Levin
• Misch implant dentistry
• The management of gross alveolar resorption : (JPD 1973, vol. 29, Pg.
• The degenerative denture ridge-Care and treatment. (JPD 1974, vol. 32,
• Reduction of residual ridges: A maior oral disease entity (JPD 1971, vol.
• Lamie G.A. : The reduction of the edentulous ridge. J. Prosthet. Dent. 10 :
• Conservative prosthodontic procedures to improve mandibular denture
stability in an atrophic mandibular ridge. JIPS December 2008, Vol 8,