Residual Ridge Resorption in Prosthodontics .ppt

Residual Ridge Resorption in Prosthodontics

1. RESIDUAL ALVEOLAR RIDGE
RESORPTION
Presented by-
Dr. SANJANA AGRAWAL
M.D.S 1
ST
Year
1
RUNGTA COLLEGE OF DENTAL SCIENCES & RESEARCH
Department of Prosthodontics and Crown & Bridge

2. Sr. No. Core area Domain Category
1 -Introduction
-Classification
-Pathology
-Pathophysiology
-Pathogenesis
-Factors affecting rate of resorption
Cognitive Must Know
2-Conclusion
-Take home message
Affective Must Know
2
SPECIFIC LEARNING OBJECTIVES

3. •Introduction
•Classification
•Pathology
•Pathophysiology
•Pathogenesis
•Pattern of Bone Resorption
•Factors Affecting Rate of Resorption
•Conclusion
•Take Home Message
•References
3
CONTENTS

4. INTRODUCTIONINTRODUCTION
•Resorption of residual ridges is a progressive, irreversible and cumulative
process.
•Studies reported that after extraction, the total amount of bone loss and the
rate of resorption varied among different patients.
•In addition, the rate of resorption varied for a given patient at different times.
4

5. RESIDUAL RIDGE
•The portion of the residual bone and its soft tissue
covering that remains after the removal of teeth. (GPT9)
RESIDUAL RIDGE RESORPTION
•The diminishing quantity and quality of the residual
ridge after the teeth are extracted. (GPT9)
DEFINITIONDEFINITION
5

6. CLASSIFICATIONCLASSIFICATION
6
ATWOOD
•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

7. CAWOOD AND HAWELL
Class I - Dentate.
Class II -Immediately post extraction.
Class III- Well-rounded ridge form, adequate in height and width.
Class IV - Knife-edge ridge form, adequate in height and inadequate in width.
Class V- Flat ridge form, inadequate in height and width.
Class VI - Depressed ridge form, with some basilar loss evident.

10. 10
WICAL and SWOOPE
•Class I: upto 1/3
rd
of the original vertical height loss.
•Class II: from 1/3
rd
to 2/3
rd
of the vertical height
loss.
•Class III: 2/3
rd
or more of the mandibular height loss.

11. PATHOLOGY OF PATHOLOGY OF
RESIDUAL RIDGE RESORPTIONRESIDUAL RIDGE RESORPTION
11

12. GROSS PATHOLOGY
•The primary structural change in the reduction of residual ridges is the
loss of bone under mucoperiosteum.
•The superimposition of tracings of cephalograms made in various
studies clearly shows that reduction of the ridge occurs labially, on the
crest, and lingually.
Sheldon Winkler. Essentials of complete denture prosthodontics. The problem of reduction of residual ridges. 2
nd
edition:22-38

13. •Grossly, this localized pathologic process can remove incredible amounts of
bone.
•While complete resorption of the body of the mandible has not been recorded, it
is clear that RRR does not stop with the residual ridge but may go well below
where the apices of the teeth.
•Clinically, the soft tissues, overlying residual ridges that have undergone RRR
may range from normal to inflamed, edematous, ulcerated, indented, or
otherwise abused tissue.

14. MICROSCOPIC PATHOLOGY
•Microscopic studies have revealed evidence of osteoclastic activity on the
external surface of the crest of residual ridges.
•The scalloped margins of Howship's lacunae sometimes contain visible
osteoclasts.
•The scal
­loped external surface seems inactive, without visible bone-
resorbing cells, and is covered by fibrous non-osteogenic periosteum.
•Inflammatory cells have included lymphocytes and plasma cells.

15. PATHOPHYSIOLOGY OF PATHOPHYSIOLOGY OF
RESIDUAL RIDGE RESORPTIONRESIDUAL RIDGE RESORPTION
15

16. •It is a normal function of bone to undergo con
­stant remodelling throughout
life through the processes of bone resorption and bone formation.
• Except during growth, when bone formation exceeds bone resorption,
bone resorption and bone formation are normally in equilibrium .
•Osteoporosis is a generalized disease of bone in which bone is in negative
balance, because bone resorption exceeds bone formation.
• In periodontal disease, there is a localized destruction of the bone around
teeth, perhaps due to certain local pathologic processes.
Sheldon Winkler. Essentials of complete denture prosthodontics. The problem of reduction of residual ridges. 2
nd
edition:22-38

17. •RRR is a localized pathologic loss of bone that is not built back by simply
removing the causative factors.
•The process of RRR has not been reversed such that the residual ridge has
increased in size.
•Yet the physiologic process of internal bone remodelling goes on even in the
presence of this pathologic external osteoclastic activity.
•The structural product of this inward growth is called “endosteal
bone” and is characterized either by a convoluted whorled
appearance

18. PATHOGENSIS OF PATHOGENSIS OF
RESIDUAL RIDGE RESORPTIONRESIDUAL RIDGE RESORPTION
18

19. •RRR is chronic, progressive, irreversible, and cumulative.
•RRR proceeds slowly over a long period of time, flowing from one
stage to the next.
Sheldon Winkler. Essentials of complete denture prosthodontics. The problem of reduction of residual ridges. 2
nd
edition:22-38

22. •Tallgren and Atwood and Coy found that the mean ratio of anterior
maxillary RRR to anterior mandibular RRR was 1:4
•RRR is greater in the mandible than in the maxilla, the reverse may be true
in any given patient who comes for treatment.

23. Maxilla resorbs
upward and inward
to become
progressively small.

23
PATTERN OF BONE RESOPRTIONPATTERN OF BONE RESOPRTION
The mandible incline
outwards and become
progressively wider.

24. FACTORS RELATED TO RATE OF FACTORS RELATED TO RATE OF
RESORPTION RESORPTION
OF RESIDUAL RIDGESOF RESIDUAL RIDGES
24

25. 25

26. ANATOMIC FACTORS ANATOMIC FACTORS
26

27. Quantity of bone
•Tracings of cephalometric
roentgenograms of 18 patients reveal.
• Considerable variation in the shape
and size of the jaws.
•Different degrees of resorption of the
residual ridges for varying times.
27
Douglas Allen Atwood. Some clinical factors related to rate of resorption of residual ridges. The journal of prosthetic dentistry.

28. •Although the broad, high ridge may have a greater potential 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.
•We should also try to evaluate the present status of the residual ridge to
determine what has gone before. If a ridge has existed as high and well-
rounded for several years it will continue to do like so.
28Douglas Allen Atwood. Some clinical factors related to rate of resorption of residual ridges. The journal of prosthetic dentistry.
2001.86(2):119-125

29. Quality of Bone
•McLean and Urist state that a loss of 24-30% of bone salt is necessary to
produce an appreciable change in roentgenograms of bone.
•On theoretic grounds, with everything else equal, the denser the bone, the
slower the rate of resorption, merely because there is more bone to be
resorbed per unit of time.
•The density at given moment does not signify the current metabolic activity
of the bone and bone can be resorbed by the osteoclastic activity regardless
of its calcification.
29

30. METABOLIC FACTORS METABOLIC FACTORS
30

31. •In general body metabolism, anabolism exceeds catabolism during growth
and convalescence, levels off during most of adult life, and is exceeded by
catabolism during disease and senescence.
31
Douglas Allen Atwood. Some clinical factors related to rate of resorption of residual ridges. The journal of prosthetic dentistry.

32. 32

33. 33
Douglas Allen Atwood. Some clinical factors related to rate of resorption of residual ridges. The journal of prosthetic dentistry.

34. •In growth, although resorption is constantly taking place in the remodeling
of the bones as they grow, increased osteoblastic activity more than makes
up for the bone destruction.
• In osteoporosis, osteoblasts are hypoactive, whereas in the resorption of
hyperparathyroidism, increased osteoblastic activity is unable to keep up
with the increased osteoclastic activity.
34

35. 35

36. •Certain local bone resorbing factors are also important.
1.Endotoxins – from dental plaque
2.Osteoclast activating factor
3.Heparin – cofactor in bone resorption secreted by the mast cells
4. Others include trauma under ill-fitting denture, which leads to increased or
decreased vascularity and changes in oxygen tension.
5.Systemic factors – include circulating oestrogen, thyroxine, growth hormone,
androgens, calcium, phosphorus, vitamin D, proteins and fluorides.
36
Kaur R, Kumar M, Jindal N, Badalia I. Residual ridge resorption–revisited. Dental Journal of Advance Studies. 2017

37. FUNCTIONAL FACTORS FUNCTIONAL FACTORS
37

38. 38
FORCE REMODELLING OF BONE
Compressive
Tensile
Shearing Bone Resorption + Bone Formation
•The functional factors of frequency, intensity, duration, and
direction of force are somehow translated into biologic cell activity.

39. •Disuse atrophy and fracture are examples of extremes of
functional forces.
•On the other hand, disuse atrophy may be generalized, as seen
in a chronic bed patient, or localized, as in the alveolar bone
around an unused, unopposed molar tooth.
•Bruxism has long been recognized as a pathologic function
leading to overstimulation of the stomatognathic system. 39

40. •The amount of force applied to the bone may be affected
inversely by the damping effect or the energy absorption.
•The damping effect may take place in mucoperiosteum and
since mucoperiosteum varies in its viscoelastic properties
patient from patient and from maxilla to mandible, its energy
absorption qualities may also influence the rate of RRR.
•The fact that maxillary residual ridge is frequently broader,
flatter and more cancellous than mandible so it may be
considered as a cofactor in differences in the RRR of the jaws.

41. PROSTHETIC FACTORS PROSTHETIC FACTORS
41

42. •Ridge resorption may or may not occur in patients for whom dentures
are not made.
•If resorption does occur, it is attributed either to disuse atrophy or, as
Lammie suggests, to an atrophying mucosa seeking a reduced area,
thereby causing pressure resorption of the ridge.
42

43. •Often, a new technique, a new impression material, a new
denture base, or a new tooth has been heralded as the answer
to the problem of ridge resorption.
a)Broad area coverage – to reduce force per unit area
b) Decreased number of dental units
c)Decreased buccolingual width of the teeth
d)Improved tooth form –to decrease the amount of force
required to penetrate bolus of food
43
Sheldon Winkler. Essentials of complete denture prosthodontics. The problem of reduction of residual ridges. 2
nd
edition:22-38

44. e) Avoidance of inclined planes- to minimize dislodgment of dentures and
shear forces
f) Centralization of occlusal contacts –to increase stability
g) Provision of adequate tongue room for proper speech
h) Adequate interocclusal distance
44

45. •The knowledge of and the control of all the factors involved in ridge
resorption are so imperfect that resorption may occur despite our best
efforts.
•There were no prosthetic factors which were exclusively favorable or
unfavorable.
45

46. •It has been seen that one of cofactor for RRR is low calcium and vitamin D
metabolism.
•Denture patients with high RRR reported with low calcium intake, low
calcium and phosphorus ratio along with less vitamin D.
•Dietary counselling of edentulous patients is necessary to correct
imbalances in nutrition intake.
NUTRITION as Co-FACTOR NUTRITION as Co-FACTOR

47. CONCLUSION
•Bone resorption of residual ridges is common.
•The rate of resorption varies among different individuals and within the
same individual at different times.
•There is complex relationship of residual ridge resorption with the anatomic,
metabolic, prosthetic and functional factors.

48. 48
•Residual ridge resorption is a multifactorial disease in which different
variables of combinations in an infinite variety of combinations to combine
to cause disease in a given patient.
TAKE HOME MESSAGE

49. •Sheldon Winkler. Essentials of complete denture prosthodontics. The problem of reduction of
residual ridges. 2
nd
edition:22-38
•Boucher’s Improving the patient’s denture foundation and ridge relations, 11
th
edition:98-116
•Douglas Allen Atwood. Some clinical factors related to rate of resorption of residual ridges. The
journal of prosthetic dentistry. 2001.86(2):119-125
•Kaur R, Kumar M, Jindal N, Badalia I. Residual ridge resorption–revisited. Dental Journal of
Advance Studies. 2017;5(02):076-80.

REFERENCES

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