Satz/ oral surgery courses

INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

Contents
 Introduction
 Pathology of Residual Ridge Resorption

Gross Pathology

Microscopic Pathology
 Pathophysiology of Residual Ridge Resorption
 Pathogenesis of RRR
 Epidemiology of RRR
 Etiology
 Treatment Plan & Prognosis
 Journals Review
 Conclusion
 Bibliographywww.indiandentalacademy.com

Introduction
 Considerable study has been devoted to the physiology of
bone .
 The reaction of bone to a change in function is subjected
to the supreme test when the natural teeth are extracted
and replaced with denture.
 Wolff’s law states that a change in form follows the
change in function owing to alteration of internal
architecture and external conformation of the bone.

Residual Ridge
 When the alveolar process is made edentulous,by loss of
teeth,the alveoli that contained the roots of the teeth fill
in with new bone.
 This alveolar process becomes the residual ridge ,which is
the foundation for dentures.
 Residual ridge is that bone of the alveolar process that
remains after the teeth are lost
 Residual ridge consists of denture bearing mucosa ,the
submucosa ,periosteum and underlying residual alveolar
bone.

Contour & quality of
Residual ridge
 Ideal residual ridge is to support a denture base
would consist of cortical bone that covers
relatively dense cancellous bone with a broad
rounded crest with high vertical slopes & covered
by firm dense fibrous connective tissue. such a
residual ridge would optimally support vertical &
horizontal stresses placed on it by denture base.

Alveolar ridge vary greatly in size and shape and
their ultimate form is dependent on following
factors
 1.Developmental structure
 2.Size of natural teeth
 3.Amount of bone lost prior to extraction-
Periodontitits
 4.Amount of alveolar process removed during
extraction
 5.Rate and degree of resorption
 6.Effect of previous dentures

 RR may be said to have 2 forms
Anatomic form –surface contour of ridge when it is
not supporting an occlusal load
Functional form-surface contour of ridge when it is
supporting an occlusal load

Pathology of Residual
Ridge Resorption
 Gross Pathology
 Microscopic pathology

Gross pathology
 Reduction in the size of the bony ridge
 It is primarily a localized loss of bone structure
 In clinical examination, usually ,one can visualize
the residual ridge form.however this may be
masked with redundant or inflamed soft tissue.
 This can be accurately determined by palpation.

 Lateral cephalometric radiographs provide the most
accurate method for determining the amount of
residual ridge and rate of RRR over a period of
time.
 Numerous longitudinal radiographic studies have
provided excellent visualization of the gross
patterns of bone loss
 Superimposition of portions of tracings of lateral
cephalograms has clearly shown the gross reduction
of bone in size and shape that occurs on the
external surface on the labial ,crestal and lingual
aspects 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 –VI depressed

Microscopic pathology
 Studies have revealed evidence of osteoclastic
activity on the external surface of the crest of
residual ridges.where visible osteoclasts are seen.

Pathophysiology of
residual ridge resorption
 During growth- bone formation exceeds bone
resorption,and are in equilibrium.
 Osteoporosis-generalized disease of bone,where
bone resorption exceeds bone formation.
 RRR is a localized pathologic loss of bone

 Physiologic process of internal bone remodelling goes on
even in the presence of this pathologic external
osteoclastic activity that is responsible for the loss of so
much bone substance.
 Three types of endosteal bone on the crest of the residual
ridge:
A well-rounded compact cortical layer consisting of a
whorled,convoluted type of bone
A knife edge ridge that shows a lingual plate of whorled
convoluted bone & a labial plate of uninterupted
circumferential lamellae on its endosteal side

 A low depressed ridge that has no crestal cortical
layer but only trabecular bone,which is actually
medullary bone
 Yet the clinical facts are that RRR is not
inevitable,that the rate of RRR varies,that RRR
can proceed far beyond the ‘alveolar’ bone,and
that the rate of resorption in some patients is so
much greater than the rate of formation that the
patients ends up with no cortical bone on the
crest of the ridge.

Pathogenesis of RRR
 Order-II after extraction any sharp edges
are rounded off by external
osteoclastic resorption
Order –III leaving high well-rounded

 As resorption continues from the labial and lingual
aspects,the crest of the ridge becomes increasingly
narrow,ultimately becoming
knife edge (order IV)

knife edge becomes shorter &
eventually disappears,leaving flat
ridge
Order V
 eventually,this too resorbs,leaving a
depressed ridge
 Order VI

 RRR is chronic,progressive,irreversible &
cumulative,usually RRR proceeds slowly over a
long period of time flowing from one stage
imperceptibly to the next.
 The patient with the most RRR in the early post
extraction period continued to have the highest
rate of RRR in the later stages.

 Tallgren et al.,found that the mean ratio of
anterior maxillary RRR to anterior mandibular
RRR was 1:4
 On average, RRR is greater in the mandible than
in maxilla.

Epidemiology of RRR
 Epidemiology is the study of the distribution and
determinants of disease in man.
 To date it would appear that RRR is world
wide,occurs in males & females,young &
old,sickness & health,with or without dentures&
is unrelated to the primary reason for the
extraction of the teeth.

Rate of resorption of
residual alveolar ridges
 Depends on
The size,shape,density of the alveolar ridge
The cellular activity of the osteoblast and
osteoclasts
The duration,frequency and direction of any
previous occlusal forces to the bone
Forces generated from the present appliance
The patient’s resistance to these forces

Patterns of Bone Loss
 Tallgren in 1972,has stated that most of the bone
loss occurs in the first year of denture wearing and
it is ten times greater,than the loss seen in the
following years
 He also demonstrated four times more bone loss in
the mandible,than in maxilla over the years
(maxilla distributes the compressive forces over a
wider surface area)

 The direction of resorption in the maxilla differs
from the mandibular bone resorption.
 The usual resorption of the maxilla is on the
buccal and inferior portion of the alveolar
ridge.the pattern of edentulous bone loss results in
upward and inward loss of structures.In the
anterior maxilla,there is less horizontal bone loss
and posterior drift of the anterior crest is seen
more than in the edentulous mandible.In the
posterior maxilla,there is inward drift of the
posterior crest.the width of the maxilla is reduced.

 Because of the progressive resorption over the
years,the depth of the palatal vault decreases and
a very thin bone may be present between the floor
of the maxillary sinus and the nasal cavity
 The mandible resorbs downwards and outwards
causing rapid flattening of the ridge
 Tallgren has estimated that the edentulous bone
loss is upto 1mm per year,with the greatest loss
occuring within 12-18 months after extractions.

 Extractions of teeth done at different times with
long time gaps will exhibit irregular bony ridge
pattern.
 Skeletal morphology has got definite role on the
resorption pattern of the edentulous
maxilla.people with long faces have more alveolar
height than those with short faces.short face
patients have greater biting force,therefore are
predisposed to greater bone loss.
 Pre-existing skeletal deformity will also lead to
disturbance in the relationship of the bony ridges.

Resorptive pattern of
the edentulous ridge
(Mercier1995)
 The ridge is wide enough
at its crest to
accommodate the recently
extracted teeth
 The ridge becomes thin
and pointed
 The pointed ridge flattens
to the level of basal bone
 The flattened ridge
becomes concave as the
basal bone resorbs
 Type I –minor ridge
modelling
 Type II –sharp
atrophic residual ridge
 Type III –basal bone
ridge
 Type IV –basal bone
resorption

Etiology of RRR
 RRR is directly proportional to Anatomic factors
-It varies with the quality,quantity and density of
bone of residual ridges
 RRR varies directly with certain systemic or
localized bone resorption factors and inversely
with bone formation factors
 RRR Bone formation factors
Bone Resorbing factors

 Local bone resorbing factors –include local
biochemical factors,such as endotoxin,osteoclast
activating factor (OAF),prostaglandin's,human
gingival bone resorption stimulating factor,
heparin(which is a cofactor in bone
resorption)trauma(ill-fitting denture)resulting
increased or decreased vascularity and changes in
oxygen tension.

Systemic factors
 Some individuals may already be in a negative
bone balance owing to some form of osteoporosis
and may therefore be more vulnerable to
unfavorable local factors

Mechanical factors
 Some postulate that RRR- ‘disuse atrophy’ others
postulate that RRR is an ‘abuse’ bone resorption
due to excessive forces transmitted through
dentures.
 The fact is that with or without dentures some
patients have little or no RRR & some have severe
RRR.
 Force is a co-factor in RRR can be expressed as
RRR is directly proportional to force

 Design of dentures is to reduce the amount of
force to the ridge & thereby to reduce RRR
 These prosthetic factors include
broad-area coverage
decreased number of dental units
decreased buccolingual width of teeth
improved tooth form
avoidance of inclined planes
centralization of occlusal contacts

Formula relating to RRR
 RRR anatomic factors +
Bone resorption factors
Bone formation factors
Force factors
Damping effect factors

Clinical Application
 Consequences of residual ridge resorption
Apparent loss of sulcus width & depth,with
displacement of the muscle attachment closer to
the crest of the residual ridge.
Loss of the vertical dimension of occlusion
Reduction of the lower face height

An anterior rotation of the mandible and increase
in relative prognathic.
Changes in interalveolar ridge
relationship.Following progression of the residual
ridge resorption which is essentially centripetal in
the maxilla & centrifugal in the mandible
Morphological changes of the alveolar bone&
location of the mental foramina close to the top of
the residual ridge.

 In 1967,pietrokovski and massler demostrated that
,viewed from the occlusal aspect,the crest of the residual
alveolar ridge shifts lingually in the maxillae and in the
mandible.
 Denture patients with excessive ridge resorption report
lower calcium intakes and poor calcium-phosphorus ratios
than do other edentulous subjects.
 Based on study,calcium & vitamin D supplementation
significantly reduced alveolar ridge resorption following
tooth extractions & placement of immediate denture.

Journals Review
 Markovic D, etal., “ current knowledge on resorption ofMarkovic D, etal., “ current knowledge on resorption of
the edentulous alveolar ridge”the edentulous alveolar ridge”
it has been proved that there is direct relationit has been proved that there is direct relation
between the pressure under the mobile denture and thebetween the pressure under the mobile denture and the
residual ridge resorption level on the other side.it seemsresidual ridge resorption level on the other side.it seems
that the frontal areas of the edentulous are morethat the frontal areas of the edentulous are more
susceptible to resorption..orthopantomography is the mostsusceptible to resorption..orthopantomography is the most
acceptable method in level measuring of the RRR.acceptable method in level measuring of the RRR.
 Morris Et Al Have Conducted Studies On The ResidualMorris Et Al Have Conducted Studies On The Residual
Ridge Resorption In Five Years After Implant PlacementRidge Resorption In Five Years After Implant Placement
The Rate Of Resorption Decreases Significantly From ThatThe Rate Of Resorption Decreases Significantly From That
Seen In Conventional Mandibular DenturesSeen In Conventional Mandibular Dentures

 Hirai T et al., “ osteoporosis and reduction of
residual ridge in edentulous patients” the residual
ridge in women was lower than that of the
men.The parathyoid hormone level was high in the
patients with a low residual ridge,and the
calcitonin level was low.This study indicates that
osteoporosis strongly affects reduction of the
residual ridge in edentulous patients.

 Xie Q, et al., “oral status & prosthetic factors related to
residual ridge resorption in elderly subjects” he concluded
that the local factors related to RRR more often in the
maxilla than in the mandible,thus suggesting that severe
resorption in the mandible is influenced more by systemic
factors
 Wyatt CC “the effect of Prosthodontic treatment on
alveolar bone loss” concluded that an implant-supported
fixed prosthesis to restore missing teeth in partially or
completely edentulous jaws seems to be the best means of
preserving residual alveolar bone.

 Klemetti E et al., “ fluoridated drinking
water,oestrogen therapy and residual ridge
resorption.” Artificially fluoridated water may
also reduce the degree of residual ridge resorption
 Ainamo A et al., “ association of residual ridge
resorption with systemic factors in home-living
elderly subjects” concluded that asthma due to
corticosteroid treatment is to be considered a risk
indicator for severe resorption of the edentulous
mandible,alcohol intake in the elderly may be
related to a lesser degree of resorption of the
edentulous maxilla.

 Carlsson GE .,”responses of jawbone to pressure”
he stated the best way to reduce bone resorption is
to avoid total extraction,preserve a few teeth and
fabricate over dentures.In edentulous
jaws,placement of implant-supported prosthesis
will lead to less bone loss and may even promote
bone growth.

Conclusion
 Edentulous alveolar ridges are not natural structures.
They are what is left of a bone after disease and
surgery have affected it.
 RESIDUAL RIDGE RESORPTION is a localized
pathologic loss of bone that is not built back by simply
removing the causative factors.
 It is a multifactorial disease in which different
variables in an infinite variety of combinations may
combine to cause the disease .

 In summation ,RRR is a chronic,progressive,irreversible
and cumulative.
 Clinical experience strongly suggests a definite
relationship between healthy periodontal ligaments and
maintained integrity of alveolar bone.Hence the dentists
commitment to preservation and protection of any
remaining teeth to minimize or avoid advanced residual
ridge reduction.

Bibliography
 Essentials of complete denture-Winkler
 Syllabus of Complete Denture-Heartwell
 Prosthodontic treatment for edentulous patient-
Boucher
 Clinical Dental Prosthetics-Fenn
 Removable Partial Prsothodontics-McCracken

 Xie Q et al., “association of residual ridge
resorption with systemic factors in home living
elderly subjects” acta odontol scand.1997
oct;55(5):299-305
 Klemetti E et al., “ fluoridated drinking
water,oestrogen therapy and residual ridge
resorption.”j oral rehabil 1997 jan:24(1):47-51
 Carlsson GE .,”responses of jawbone to pressure”
gerodontology.2004jun21(2):65-70

 Ainamo A et al., “ association of residual ridge
resorption with systemic factors in home-living
elderly subjects” acta odontol scand.1997
oct;55(5):299-305
 Hirai T et al., “ osteoporosis and reduction of
residual ridge in edentulous patients” J prost dent
1993 jan :69(1):49-56

Thank you

Satz/ oral surgery courses

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (16)

Similar to Satz/ oral surgery courses

Similar to Satz/ oral surgery courses (20)

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

Satz/ oral surgery courses