Rrr final/cosmetic dentistry courses

RESIDUALRESIDUAL
RIDGERIDGE
RESORPTIONRESORPTION
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.comwww.indiandentalacademy.com

CONTENTS
•Introduction.
•Basic concept of bone.
•Mechanism of bone resorption
•Pathology of RRR
•Pathophysiology of RRR
•Pathogenesis of RRR
•Changes in maxilla and mandible

•Epidemiology of RRR
•Etiology of RRR
•Calcium homeostasis and RRR
•Osteoporosis and RRR
•Management of RRR
•Summary
•Conclusion
•References

Introduction
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.
It consists of the denture-bearing mucosa,
submucosa and periosteum, and the underlying
residual alveolar bone.

•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).
•The rate of RRR is different among persons and even at
different sites in the same person.

The mechanical aspect of bone remodeling is usually
associated with Wolff’s law of bone transformation (1892)
which states that “EVERY CHANGE IN THE FORM AND
FUNCTION OF BONE , OR OF THEIR FUNCTION
ALONE,IS FOLLOWED BY CERTAIN DEFINITE
CHANGES IN THEIR INTERNAL ARCHITECTURE,
AND EQUALLY DEFINITE ALTERATION IN THEIR
EXTERNAL CONFORMATION, IN ACCORDANCE
WITH MATHEMATICAL LAWS.”, which simply means
that bone remodels in response to the forces applied.
However, the mere reference to ‘Wolff’s law’ in relation to
bone resorption is an inadequate explanation of this
complex physiologic process.

Consequences of RRR
•Apparent loss of sulcus width and depth.
•Displacement of the muscle attachment closer to the
crest of the residual ridge.
•Loss of vertical dimension of occlusion.
•Reduction of lower face height.
•An anterior rotation of the mandible.
•Increase in relative prognathia.

•Changes in inter-alveolar ridge relationship.
•Morphological changes such as sharp, spiny, uneven
residual ridges.
•Resorption of the mandibular canal wall and exposure of
the mandibular nerve.
•Location of the mental foramina close to the top of the
mandibular residual ridge.
This provides serious problems to the clinician on how
to provide adequate support, stability and retention of the
denture.

Basic concept of bone:
A basic concept of bone structure and its functional
elements must be clear before bone resorption can be
understood. The structural elements of bone are:
a)Osteocytes found in bone lacunae.
b)The intercellular substance or bone matrix consisting of
fibrils and calcified cementing substance.
c) Osteoblasts.
d)Osteoclasts

(a) Osteocytes:
These are small, flattened and rounded cells
embedded in the bone lacunae.
They are the main cells, of the developed bone and
are derived from the matured osteoblasts.
Function:
• Help to maintain bone as a living tissue because of
their metabolic activity.
• Play an important role in maintaining the exchange
of calcium between bone and extra cellular fluid.
(b) Calcified cementing substance:
Consists of mainly polymerized glycoproteins and
mineral salts namely CaCo3 and phosphate which
are bound to these protein substances.www.indiandentalacademy.comwww.indiandentalacademy.com

(c) Osteoblasts:
Concerned with bone formation and are situated on the
outer surface of bone in a continuous layer.
Functions:
• Responsible for synthesis of bone matrix.
• Role in calcification.
(d) Osteoclasts:
They are the giant multinucleated cells found in the
lacunae of bone matrix.
Functions:
• Responsible for bone resorption during bone
remodeling. Bone resorption always requires the
simultaneous elimination of organic and inorganic
components of the intercellular substance.www.indiandentalacademy.comwww.indiandentalacademy.com

Mechanism of bone resorption
•The organic components of the intercellular substance
are removed by proteolytic action of the osteoclasts.
•Then, the Ca salts (inorganic) are dissolved by a
chelating action of the osteoclasts.
•As resorption takes place, the osteocytes released may
revert to osteoblasts or become osteoclasts, depending
on the physiologic and pathologic demands.
• Histologically, bone apposition and resorption take
place in close approximation, making possible the bone
balance of shape and size.

Pathology of RRRPathology of RRR

Gross pathology:
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 redundant. In order to
provide a simplified method for categorizing the most
common residual ridge configurations, a system of six
orders of RR form has been described.
Order 1 - Pre extraction
Order 2 - Post extraction
Order 3 - High, well-rounded
Order 4 - Knife edge
Order 5 - Low, well-rounded
Order 6 - Depressedwww.indiandentalacademy.comwww.indiandentalacademy.com

•It is clear that RRR does not stop with the residual
ridge , but may well go below where the apices of the
teeth were, sometimes leaving only a thin cortical plate
on the inferior border of the mandible or virtually no
maxillary alveolar process on the upper jaw.
•Sometimes a knife edge ridge maybe masked by a
redundant or inflamed soft tissue, which can be detected
by palpation or by Lateral cephalometric radiographs.

Microscopic pathology:
• Studies have revealed evidence of osteoclastic activity
on the external surface of the crest of the residual ridges.
The scalloped margins of Howship’s Lacunae sometimes
contain visible osteoclasts .
•Studies have shown total absence of periosteal lamellar
bone on the crest of the residual ridge, and a presence of
cortical layer consisting of an endosteal type of bone, or no
cortical layer but simply a medullary type of trabecular
bone.
•Varying degrees of inflammatory cells ,including
lymphocytes and plasma cells, have also been seen.www.indiandentalacademy.comwww.indiandentalacademy.com

PATHOPHYSIOLOGY OF RRRPATHOPHYSIOLOGY OF RRR

•It is a normal function of bone to undergo constant
remodeling throughout life through the process of bone
resorption and bone formation.
•Growth : ↑ Bone formation.
•Osteoporosis/localized periodontal disease: ↑ Bone
resorption.

•RRR is a localized pathologic loss of bone that is not
built back by simply removing the causative factors.
•Yet, the physiologic process of internal bone
remodeling goes on even in the presence of this
pathologic external osteoclastic activity that is
responsible for the loss of so much of bone substance.
•It has been shown that remodeling takes place in 3
dimensions such that certain portions of bone become
narrower to the extent that all existing cortical bone in
that area is removed by external osteoclastic activity
and is replaced by a new cortical layer that is formed
by simultaneous endosteal bone formation.

•Even if a great deal of RR is removed in total, there is
often a cortical layer of bone over the crest of the ridge.
This means that new bone has been laid down inside the
RR in advance of the external osteoclastic removal of
bone.
•The mechanism of the reduction of the mandibular
residual ridge actually represents a modified version of
the Enlow’s “V” principle, showing external resorption
accompanied by endosteal deposition.

Based on the clinical fact that :
•RRR is not inevitable
• Its rate varies
• The rate of resorption is greater that the rate of
formation in some patients ,
….RRR should be considered a pathologic
process.

Pathogenesis of RRRPathogenesis of RRR

Order I: pre-extraction: The tooth is in its socket with thin
labial and lingual cortical plates merged with the lamina
dura.
Order II: postextraction: The healing period includes clot
formation and organisation, filling of the socket with the
trabecular bone and epithelisation over the socket site. The
edges of the residual ridge are still sharp.
Order III: High , well rounded residual ridge: The cortical
plates are rounded off by external osteoclastic resorption,
narrowing of the crest of the ridge begins and remodelling
of the internal trabecular structure takes place.www.indiandentalacademy.comwww.indiandentalacademy.com

Order IV: Knife edge RR : Sharp narrowing of the labio-
lingual diameter of the crest of the ridge with a
compensatory internal remodelling leading to a sharp
crest of the ridge.
Order V: Low well rounded RR : Progressive labio lingual
narrowing of knife edge ridge leads to a widely rounded
and lower residual ridge.
Order VI: Depressed RR: Eventually further progression of
the resorption leads to a flat, depressed ridge.

•RRR is chronic, progressive, irreversible and
cumulative. Usually, RRR proceeds slowly over a
long period of time flowing from one stage
imperceptibly to the next. Autonomous regrowth
has not been reported. Annual increaments of
bone loss have a cumulative effect leaving less and
less residual ridge.

Changes In TheChanges In The
Maxilla And TheMaxilla And The
MandibleMandible

•Maxillary teeth are generally directed downward
and outward, so bone reduction generally is upward
and inward. Since the outer cortical plate is thinner
than the inner cortical plate, resorption from the
outer cortex tends to be greater and more rapid. As
the maxilla becomes smaller in all dimensions, the
denture bearing area (basal seat) decreases.
•The bone of the maxillae resorbs primarily from the
occlusal surface and from the buccal and labial
surfaces.
•Thus the maxillary residual ridge looses height and
maxillary arch becomes narrower from side to side
and shorter anteroposteriorly.

•The anterior Mandibular teeth generally incline
upward and forward to the occlusal plane, whereas the
posterior teeth are either vertical or incline slightly
lingually.
•The mandibular ridge resorbs primarily from the
occlusal surface.
•Because the mandible is wider at its inferior border
than at the residual alveolar ridge in the posterior part
of the mouth, resorption, in effect, moves the left and
right ridges progressively farther apart.

•The mandibular arch appears to become wider, while
the maxillary arch becomes narrower.
•Thus, RRR is centripetal in maxilla and centrifugal
in mandible.
•The cross section shrinkage in the molar region, is
downward and outward. In the anterior region it is
first downward and backward ,and then moves
forward.
•The surface of the arches maybe resorbed out of
parallelism which can result in diminished stability of
dentures.
•Severe ridge resorption can also result in increased
inter arch space.

Epidemiology of RRR:Epidemiology of RRR:
•To date, it would appear that RRR is world-wide,
occurs in males and females, young and old, sickness
and in health, with and without dentures and is
unrelated to the primary reason for the extraction of
the teeth (Caries / periodontal disease).
•Rate of RRR is variable
-between persons.
-within the same person at diff. times.
-within the same person at diff. sites.

Etiology of RRREtiology of RRR

It is postulated that RRR is a multifactorial,
biomechanical disease that results from a
combination of:
• Anatomic.
• Metabolic.
• Functional.
• Prosthetic factors.

ANATOMIC FACTORS:
It is postulated that RRR varies with the quantity
and quality of the bone of the residual ridges:
RRR α anatomic factors
The amount of bone:
• It is not a good prognostic factor for the rate of RRR,
because it has been seen that some large ridges resorb
rapidly and some knife edge ridges may remain with little
changes for long periods of time.
•Although the broad ridge may have a greater potential for
bone loss, the rate of vertical bone loss may actually be
slower than that of a small ridge because there is more
bone to be resorbed per unit of time and because the rate
of resorption also depends on the density of bone.www.indiandentalacademy.comwww.indiandentalacademy.com

Quality of bone:
On theoretic grounds, the denser the bone, the
slower the rate of resorption because there is more bone to
be resorbed per unit of time.
METABOLIC FACTORS.
Generally, body metabolism is the net sum of all the
building up (anabolism) and the tearing down (catabolism)
going on it the body.
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 activity. 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.www.indiandentalacademy.comwww.indiandentalacademy.com

•Since bone metabolism is dependent on cell metabolism,
anything that influences cell metabolism of osteoblasts
and osteoclasts is important.
•The thyroid hormone affects the rate of metabolism of
cells in general and hence the activity of both, the
osteoblasts and osteoclasts.
•Parathyroid hormone influences the excretion of
phosphorous in the kidney and also directly influences
osteoclasts.
•The degree of absorption of Ca, P and proteins
determines the amount of building blocks available for
the growth and maintenance of bone.
•Vit C aids in bone matrix formation.
•Vit D acts through its influence on the rate of
absorption of calcium in the intestines and on the citric
acid content of bone.
•Various members of Vit B complex are necessary for
bone cell metabolism.

•According to Reifenstein, in the young person,
there is a relative predominance of anabolic
hormones (estrogen and testosterone) over the anti
anabolic hormones( cortisone and hydrocortisone)
resulting in continued growth of skeleton.
•He further states that, as people get older, the
anabolic hormones are so reduced that the
antianabolic hormones are in relative excess with
the result that bone resorption may take place
faster than bone formation and that bone mass
may be reduced.

FUNCTIONAL FACTORS
•Forces within the physiological limits are beneficial
in their massaging effect. On the other hand,
increased or sustained pressure produces bone
resorption.
•Bone that is used as by regular physical activity
will tend to strengthen within certain limits , while
bone that is in disuse will tend to atrophy.

Disuse atrophy
•It is directly proportional to the extent of disuse.
•It does not result from the direct loss of non
functional bone, but the lack of replacement of bone
not needed for function.
•After the loss of natural teeth, bone cannot be
stimulated by a denture base as the teeth did
internally. The lack of internal stimuli contributes
to the disuse atrophy.

•The amount and frequency of stress and its
distribution and duration are important factors.
•The reaction of bone to pressure can cause both
apposition and resorption.
•Whenever pressure interferes with the blood or nerve
supply of the bone, resorption occurs.
•The interference maybe due to pressure directly from
the bone or inflammatory in origin.

PROSTHETIC FACTORS
 Excessive stress resulting from artificial
environment:
• Human tissues have not evolved in nature to
accept ranges of artificial things and the denture
acts as an artificial entity.
 Abuse of tissues from lack of rest:
• Abused tissues are always manifested with a
slung, glistering surface. Bone is moldable. It can
tolerate masticatory forces within the limits of
physiologic tolerance but exceeding that it causes
damaging forces which will result in resorption of
the alveolar bone and alteration in tissue form .

 Long continued use of ill fitting dentures:
• In ill fitting dentures, there is an improper relation of
the denture base to the supporting tissue. Ill fitting
dentures may be due to :
• Long use
• Loss of bone
• Incorrect occlusion
• Incorrect jaw relation
 UNDER EXTENDED DENTURES:
• Lead to less retentive dentures and increase load
per unit area. Common sites are:
• Lingual flange
• Buccal shelf area
• Retromylohyoid area
• Retromolar padwww.indiandentalacademy.comwww.indiandentalacademy.com

 Faulty improper procedures employing
compression forces:
• Before impression procedures, care has to be
taken on selection of trays. If the tray selected is
too large, it will distort the tissues around the
borders of the impression, away from the tissues.
If it is too small, the border tissues will collapse
inward onto the residual ridge. This will reduce
the support of the lips by the denture flange.
• The use of minimal and selective pressure
impression techniques should be implicated in
order to avoid distortion of the mucosa and ridge
area which may be under considerable pressure
otherwise. www.indiandentalacademy.comwww.indiandentalacademy.com

 Error in relating maxilla to the cranial landmarks
(orientation relation):
The plane of the maxilla should be oriented to the facial
reference line (Camper’s plane or ala tragus line). If not,
may cause instability of denture leading to resorption.
 Lack of freeway space due to increased vertical
dimension of occlusion:
Freeway space is present in the teeth in the physiologic
rest position. It is normally 2-8mm but in complete
dentures it is around 2mm. At times, due to lack of
freeway space the bone resorbs because of increased
vertical height in an attempt to create the space.

 Incorrect Centric relation record:
If the Centric relation is not recorded properly, the
mandibular teeth will not occlude properly with those on
the maxillary arch. This proper occlusion is essential to
the health of bony support. Otherwise, during eccentric
movement, it causes pressure on bone due to failure of
denture stability. Hence resorption of base occurs.

Faults in selection and placement of posterior teeth:
The selection of proper tooth size is based on :
•Capacity of ridges to receive and resist the
forces of mastication.
•Space available for the teeth.
•When the ridge is weak, resorbed and covered
by only lining mucosa, then the use of the
posterior teeth should be smaller. This will limit
the occlusal surface, which in turn will minimize
the forces directed to such a ridge.

 If occlusal corrections are not done:
• These errors which may be caused due to processing
techniques if not corrected causes premature contacts
resulting in increased stress.
• Selective grinding should be done to minimize lateral
stress and resulting tissue trauma.
 Overclosure
• The loss of proper vertical dimension after the insertion
of complete dentures results in the triggering of a cyclic
series of events detrimental to the health of the residual
alveolar ridge.
• Overclosure causes the mandible to be moved or rotated
in an upward and forward direction causing occlusal
disharmony and excessive trauma to anterior region .www.indiandentalacademy.comwww.indiandentalacademy.com

Bone resorption and Ca homeostasis:
The only sources of Ca for the body are
•Diet
•Bone reservoir.
Ca homeostasis is maintained by controlling Ca obtained
from these 2 sources. This can occur by altering internal
absorption mechanisms (income) or tubular reabsorption
(recycling) or by liberation of Ca from the skeleton via
resorption (savings).
There is a reciprocal relationship between Ca
concentration and bone resorption to maintain Ca
homeostasis. As the level of serum calcium develops,
resorption is stimulated and factors that would inhibit
resorption are depressed.

•Skeletal depletion of calcium occurs as a result of
stimulation of parathyroid gland and the alveolar bone is
the first to be affected. This is due to the function of
parathyroid hormone in maintaining the blood calcium
level by mobilizing it from bones by osteoclastic activity.
•Simultaneously , there is an increased renal excretion of
phosphate, which disturbs the blood
calcium:phosphorous ratio by raising the blood calcium
level. This results in mobilization of phosphates from
bones by osteoclastic activity.
•Under these conditions , alveolar bone becomes
susceptible to diseases like osteoporosis.

Osteoporosis and RRR
•Osteoporosis is characterized by low bone mass and micro
architectural deterioration of the bone, which leads to
increased bone fragility and risk of fracture.
•It has two forms.
•The more prevalent Type I (post menopausal) affects
women for a decade or so after menopause.
•The Type II ( senile or idiopathic) attacks males and
females at any age for no obvious reason.
•RRR maybe a manifestation of Type I osteoporosis .
•Both cortical and trabecular bone are affected.www.indiandentalacademy.comwww.indiandentalacademy.com

Treatment for osteoporosis
•Estrogen replacement therapy
•Ca supplement
•Good nutrition and regular exercise
•New drugs for systemic osteoporosis are
under evaluation, including biophosphonates
to inhibit osteoclasts and injections and
calcitonin to reduce resorption.
Detection of bone loss i.e. radiographs
•Digital subtraction radiography
•Dual energy x-ray absorptiometry

Methods of evaluation of bone loss in RRR
• Radiographs:
- Cephalometrics .
- Panoramic.
• Tetracycline labeling
• Mercury porosimetry
• Anatomic studies
• Remount jig procedure

Management of RRRManagement of RRR

Systemic evaluation
Diet
Tissue treatment therapy
Pre prosthetic surgery
Prosthetic management:
-Impression techniques.
-Denture base selection.
-Teeth selection and arrangement.
-Implant supported prosthesis.

Systemic evaluation
•Any systemic condition that can contribute to the
degeneration of the bone condition should be
corrected and stabilized, for e.g.: osteoporosis,
hyperparathyroidism, diabetes mellitus.
•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.
•Patients with bone disease need a diet high in
proteins, vitamins and mineral content.
•Should reduce or stop intake of refined
carbohydrates, white flour, and white sugar.
•In all dietary prescriptions , the consistency of food
prescribed must take into account the patients ability
to masticate.
Tissue Treatment Therapy.
•Soft conditioning materials can be used to
rejuvenate the tissue-bearing area.
•Hypertrophied tissues, previously treated by
surgery, can be reconditioned by using this material.

Pre-prosthetic surgery
It aims at providing a good healthy surface for the
insertion of the dentures.
It includes all the surgical procedures by virtue of
which an ideal smooth, healthy U shaped ridge , without
any unfavourable undercuts or bony growths and with
sufficient vestibular depth is achieved.
It includes the following surgical procedures:
•Ridge correction.
•Ridge extension/vestibuloplasty.
•Ridge augmentation
•Surgical correction of maxillomandibular relation.

Ridge Corrective surgery
Soft tissue deformities
•Labial frenectomy.
•Lingual frenectomy.
•High buccal frenal attachments.
•Hyperplasia of soft tissues.
Bony deformities
•Sharp irregular ridge.
•Alveoloplasty.
•Alveolectomy.
•Excision of tori and genial tubercles.

Ridge extension surgery/vestibuloplasty
•Labial.
•Lingual.
•High mental foramen.
•Zygomaticoplasty.
•Tuberoplasty.

Ridge augmentation
It is aimed at :
•Increase in the ridge height and width
providing a large denture bearing area ,
•Protection of neuro vascular bundles
•Restoration of proper maxillomandibular arch
relationship.
Ridge augmentation has been tried with:
•Bone transplants
•Autogenous and homogenous cartilage
•Hydroxylapatite
•Acrylic implants. www.indiandentalacademy.comwww.indiandentalacademy.com

Prosthetic management.
Impression technique
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 and retention.
Thus the main aim of the impression procedure is to
gain maximum area of coverage. For e.g., in mandibular
ridge, obtaining a fairly long retromylohyoid flange
helps to achieve a better border seal and retention.
Selection of proper trays and the correct impression
procedure is very essential for an accurate impression.

• Selective pressure technique
This technique is most widely advocated to manage RRR.
It makes it possible to confine the forces acting on the
denture to the stress bearing areas .
This helps in better withstanding the mechanical forces
induced by denture wearing.
• Winkler describes a technique which uses tissue
conditioners. An over extended primary impression of
alginate is made. Occlusal wax rims are constructed and
the borders are adjusted so that the lingual flange and
sublingual crescent area are in harmony with the resting
and acting phases of the floor of the mouth by an open
and closed – mouth technique.

3 applications of conditioning material are used – each
application approximately 3-10 minutes. The third and
final wash is made with a light bodied material. This
technique results in the impression that has tissue
placing effect with relatively thick, buccal, lingual and
sublingual crescent area borders.
•Miller used mouth-temperature waxes instead of tissue
conditioners .

Mucodynamic technique.
It is intended to integrate the changes in the shape of
the vestibules when functional movements are made. A
highly viscous thermoplastic reversible impression
material is placed in the custom tray, then carefully
adapted to the residual ridge and held with light and
uniform pressure while the functional movements are
made. As soon as the entire surface is smooth and the
buccal and lingual borders are molded to the outer
circumference without any folds, the impression is
complete.

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 processed.
•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 bases.
•They maybe of gold, chromium cobalt or aluminium.
Processed resilient , lined denture bases.
Its greatest advantage is its cushioning effect on the
mucosa and its ability to distort and spring back.
Indications:
•Patients with severely undercut ridges, but for whom
surgery is contraindicated.
•Patients with parafunctional mandibular movement
habits.
•Patients with flat ridge and delicate tissues.www.indiandentalacademy.comwww.indiandentalacademy.com

Limitations:
•They can be used only under a hard-processed
acrylic resin base, and the lining works best when
there is a 2 mm thickness.
•Deterioration of the liner in some mouths.
In spite of this , it can be held up well in dentures
by proper cleansing and brushing with soft tooth
brush.

Teeth selection and arrangement
Teeth can be selected acc. to their form and size:
•Anatomic or cuspal teeth
•Semi anatomic teeth
•Non anatomic or zero degree teeth.
The following requirements have to be met during
teeth arrangement:
•Stability of occlusion in centric relation.
•Balanced occlusion for eccentric contacts.
•Unlocking of the cusps mesio distally to accommodate
the settling of denture bases.

•Control of horizontal force by buccolingual cusp height
reduction acc. to residual ridge shape and inter arch
space.
•Functional balance by favorable tooth to ridge crest
position.
•Cutting and shearing efficiency.
•Anterior clearance of teeth during mastication.
•Minimal occlusal stop areas for reduced pressure
during function.
•Teeth should be placed in neutral zone to create co
ordination between the primary and secondary
masticatory organs.

•Relative to each other, the maxillary and mandibular
residual ridges are known to be in a favorable position
for normal arrangement of posterior teeth if the
connecting line between the midridge line of the max.
and mand. residual ridges are at an angle of more than
80 degrees.
•An angle less than 80 degrees necessitates a cross bite or
reverse occlusion arrangement of posterior teeth.
•A prognathic mandible necessitates the arrangement of
anterior teeth in a reverse occlusion.www.indiandentalacademy.comwww.indiandentalacademy.com

•Non anatomic teeth have known to cause fewer
denture sore spots and lesser ridge resorption.
•Semi anatomic reverse curve posterior teeth favor
the lower ridge
•Anatomic posterior teeth cause more denture
soreness and ridge resorption.
•Few studies state that anatomic posterior occlusion
favors lower dentures and non anatomic posterior
teeth favor upper denture.

Implant supported prosthesis.
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
•Maintenance of occlusal vertical dimension.
•Height of alveolar bone is found to be maintained as
long as the implant remains healthy.
•Improved psychological health.

•Regained proprioception.
•Increased stability, retention and phonetics.
•Maintenance of structure and function of muscles of
mastication and facial expression.
•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.
•Preventive implant is given following extraction to retard
ridge resorption.

Prosthodontic classification of implants.
FP-1 : Fixed prosthesis replacing only crown.
FP-2 : Fixed prosthesis replacing crown and
portion of root.
FP-3 : Fixed prosthesis replacing missing crowns
and portion of the edentulous site.
RP-4 : Removable prosthesis : overdenture
supported by implants.
RP-5 : Removable prosthesis : overdenture
supported by both soft tissue and implant.

•The success of implant supported prosthesis,
however, depends on the technical
knowledge and mastery of the
implantologist, and is directly related to the
selection of patient and implant, surgical
technique, follow up procedures and patient
acceptability.

SummarySummary

•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.
•RRR 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.
•Construction of a stable functioning denture and a
regular follow up treatment can help in the restoration of
function, and thus, the restoration of the physical and
mental vitality of the patient.

ConclusionConclusion

•The preservation of supporting tissues is a sacred trust
that cannot be ignored.
•The application of the basic concepts and the advances
made in the basic sciences will help to keep this trust in
the hands of the dental profession.
•As prosthodontists, we need to perform the most
meticulous and intelligent prosthodontic care of the
patient within our capabilities.
•…and then , it would not seem a nebulous hope that
some day there will be control over residual ridge
resorption. www.indiandentalacademy.comwww.indiandentalacademy.com

ReferencesReferences

•Ortman HR: Factors of bone resorption of the residual
ridge. J Prosthet Dent 1962;12,3:429-440.
•Atwood DA: Reduction of residual ridges: A major oral
disease entity. J Prosthet Dent 1971;26:266-279.
•Atwood DA: Some clinical factors related to rate of
resorption of residual ridges. J Prosthet Dent 2001;86:119-
125.
•Wendt DC: The degenerative denture ridge – Care and
treatment. J Prosthet Dent 1974;32,5:477-492.
•Ortman HR : The role of occlusion in preservation and
prevention in complete denture prosthodontics. J Prosthet
Dent 1971;25,2:121-138.
•Sobolik FC : Alveolar bone resorption. J Prosthet Dent
1960;10,4:612-619. www.indiandentalacademy.comwww.indiandentalacademy.com

•Jahangiri L, Devlin H, Ting K et al :Current perspectives
in residual ridge remodelling and its clinical implications:
A review. J Prosthet Dent 1998;80;224-237.
•Atwood DA : Post extraction changes in the adult
mandible as illustrated by microradiographs of midsagittal
sections and serial cephalometric roentgenograms. J
Prosthet Dent 1963;13:810-824.
•Winkler S : Essentials of complete denture
prosthodontics. 2nd
edition,2000.
•Boucher CO : Prosthodontic treatment for edentulous
patients. 12th
edition,2004.
•Alfred H G :Color Atlas of Dental Medicine – Complete
Denture and Overdenture Prosthetics.2nd
edition,1993.
•Misch CE : Contemporary implant dentistry. 2nd
edition,1999.
•Eroshenko VP : di Fiore’s Atlas of histology. 7th
edition.1993.

Thank you

Rrr final/cosmetic dentistry courses

Recommended

Recommended

More Related Content

What's hot

What's hot (17)

Similar to Rrr final/cosmetic dentistry courses

Similar to Rrr final/cosmetic dentistry courses (20)

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

Rrr final/cosmetic dentistry courses