INTRODUCTION DEfINITION ETIOLOGY OF RIDGE RESORPTION CLASSIFICATION OF RESIDUAL RIDGE PREVENTION AND TREATMENT SUMMARY

1. Management of resorbed
mandibular ridges
Dr.Ashitha Dominic

2. INTRODUCTION
DEfINITION
ETIOLOGY OF RIDGE RESORPTION
CLASSIFICATION OF RESIDUAL RIDGE
PREVENTION AND TREATMENT
SUMMARY
2

3. • Residual ridge is the portion of the residual bone
and its soft tissue covering that remains after the
removal of teeth.
• It consists of the denture-bearing mucosa,
submucosa and periosteum, and the underlying
residual alveolar bone.
3

4. “The diminishing quantity and
quality of the residual ridge after
teeth are removed (GPT8)
4
.

5. 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
5

6. 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
factors)
◈ 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)
6

7. • 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.
7

8. • 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.
• Ridge resorption varies directly with some systemic or localized bone
resorptive factors and inverselywith some bone formation factors.
8

9. • Some local biochemical factors in relation to periodontal disease
which affects the ridge resorption-
• Endotoxins from dental plaque on unclear dentures.
• Osteoclast activating factor (OAF).
• Prostaglandins.
• Human gingival bone resorption stimulating factors.
• Heparin acts as a cofactor in bone resorption which is produced
from mast cells
9

10. • 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-
Estrogen.
Thyroxin.
Growth hormone.
Androgens.
Calcium.
Phosphorus.
Vitamin D.
Protein.
Fluoride.
10

11. Functional 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 underlying tissue.
– 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.
11

12. 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
deformation.
12

13. 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).
13

14. 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 denture bases.
• 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.
14

15. Chewing efficiency
• 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
degree.
15

16. 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.
16

17. 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 ridges.
• It is said that porcelain tooth when placed causes more resorption
of ridge than acrylic tooth.
17

18. Loss of occlusal vertical dimension (over
closure)
• 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.
18

19. CLASSIFICATION
19

20. • 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.
20

21. 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.
– CLASS I: Up to one third of the original vertical height lost. – CLASS
II: From one third to two thirds of the vertical
height resorbed.
– CLASS III : Two thirds or more of the mandibular height
lost.
21

22. TREATMENT & MANAGEMENT
SWENSON stated, “ The ideal ridge is one that is broad in its bearing
surface and has practically parallel sides.”
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.
22

23. • 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.
23

24. • The best treatment is to avoid total tooth extraction, preserve a
few teeth, and make overdentures, which are associated with
much lower rates of bone resorption.
• The placement of dental implants and the insertion of an
implant-supported prosthesis have been shown to reduce bone
loss in the edentulous jaw.
Clinical morbidity and sequelae of treatment with complete dentures. J Prosthet Dent 1997;79:17-23.
24

25. 1. Physical health.
• Any systemic illness that is contributing to the degenerative
bone condition must be corrected or stabilized.
• In cases where only limited help can be rendered, the
patient must be carefully counseled as to the effect this will
have on dental health.
25

26. 2. Diet.
• The patients need a diet high in protein, vitamin, and mineral content.
• They should totally eliminate refined carbohydrates, white flour, and
white sugar or, specifically, sucrose and glucose.
26

27. 3. Pre-prosthetic surgery.
• Its role may be considered where the following procedures are
necessary:
(1) removal of local prosthetic problems such as high frenal attachments,
(2) increase in the height of the alveolus,
(3) repositioning of attachments of the soft tissues to the jaws,so
increasing the denture-bearing area,
(4) insertion of subperiosteal implant dentures.
27

28. It includes the following surgical procedures:
•Ridge correction.
•Ridge extension/vestibuloplasty.
•Ridge augmentation
•Surgical correction of maxillomandibular relation.
28

29. VESTIBULAR EXTENSION PROCEDURE
• Indicated when there is high muscular and
mucosal attachments.
• The reduction of alveolar ridge size is
frequently accompanied by an apparent encroachment ofmuscle
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.
29

30. RIDGE AUGMENTATION
These are the procedures designed to enlarge or
increase the size, extent, or quality of deformed
residual ridge.
30

31. • Onlay bone grafting - autogenous / allogenic grafts.
• Onlay grafting by alloplastic material.
• Interpositional or Sandwich grafts.
• Sinus lift procedure.
31

32. • Superior border augmentation
– Bone grafts
– Cartilage grafts
– Alloplastic grafts.
• Inferior border augmentation
– Bone grafts (autogenous or allogenic freeze dried cadaveric mandible)
– Cartilage grafts.
• Interpositional or Sandwitch bone grafts
– Bone grafts
– Cartilage grafts
– Hydroxyapatite blocks.
32

33. 4. Tissue treatment therapy.
• The use of soft conditioning material to rejuvenate the tissue-
bearing area.
33

34. Soft liners.
• Used routinely for patients with severe
alveolar resorption, in two clear instances:
(1) Where non-surgically removable alveolar irregularities are traumatizing
the denture-bearing mucosa and
(2) where maximum stability and minimum soft-tissue loading have been
incorporated into a prosthesis and the denture-bearing mucosa is still
unable to accept the load.
34

35. Disadvantages:
• A soft liner will not aid denture stability, and care must be taken to
ensure that the prosthesis to which it is fitted has good balanced
occlusion.
• The soft liner should be used where there is adequate bulk is and
must be carefully processed if its properties are to be retained and
separation from the denture base avoided.
35

36. Accessory aids to retention
36

37. Magnets:
Magnets have been employed embedded either in the alveolar process
and denture, so as to attract the denture to the alveolus, or in the
dentures alone, normally in the molar region, with the poles placed so
that they repel each other.
37

38. Springs
• Used as an aid to retention although they tend to stabilize the
denture antero-posteriorly.
• Also, the constant pressure they produce on the bone may be a
factor in further alveolar resorption.
• The length and site of insertion of the springs must be very carefully
chosen, for if too short they tend to expel the dentures from the mouth
when opened, and if too long they impinge upon the cheeks.
38

39. • Impression techniques.
• Denture base selection.
• Teeth selection and arrangement.
• Implant supported prosthesis.
39

40. 1.Impression techniques
• 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.
40

41. 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 and support.
41

42. 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
impressionmaterial.
Exaggerated tongue movements should be made.
Impression for Complete Denture, by Bernard Levin
42

43. Mc-Cord and Tyson’s admixed technique
• Impression compound and green tracing stick compound in the
ratio of 3 : 7 parts by weight are placed in a bowl of water at 60 C
and kneaded to a homogenous mass that provides a working time of
about 90 seconds.
• Wax spacer is removed; this homogenous mass is loaded and
patient is made to do various tongue movements.
43

44. All Green Technique
• Green stick compound is kneaded to a
homogenous mass and is loaded on the
special tray and border movements are
done.
• Final impression is made using zinc oxide
eugenol.
44

45. Winkler’s technique (Closed mouth functional
impression)
• In this technique, denture bases with occlusal rim are
fabricated on primary cast.
• Jaw relations are done to record
appropriate horizontal and vertical
dimensions.
• Three applications of tissue conditioner
material are done at an interval of 8–10
minutes and functional movements are
made by the patients.
45

46. • Tissue conditioning material is applied on the
tissue surface of mandibular denture base and
patient is asked to close the mouth in the
prerecorded vertical dimension and do various
functional movements such as puffing, blowing,
whistling, and smiling.
• Final impression is made with light body
addition silicone material with closed mouth
technique.
46

47. Dynamic Impression Method
Its significance:
– Avoids the dislocating effect of the muscles on improperly formed
denture border.
– Complete utilization of the possibilities of active andpassive tissue
fixation of the denture.
– Dynamic impressions in contrast to non dynamic
impression records the tissues in an immobile
condition.
47

48. Fabrication of the special tray is done.
A ridge of self curing resin is built up in the premolar molar region on each
sideto 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.
48

49. Lingually the mandibular rests should be concave to provide space for the
tongue.
Sufficient amount of an irreversible hydrocolloid is mixed with 50% extra
water material and is placed directly into the mouth to cover all tissues .
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.
49

50. The patient should swallow three to four times at 10 seconds interval while
the final impression material is still in a moldable condition.
This procedure develops a registration of the denture space which
ordinarily results in a proper extension of the lingual flanges of the
finished dentures.
Forceful protrusion of the lips brings the mentalis and orbicularis oris muscles
into action and is responsible for forming the labial part of the impression.
50

51. Cocktail Impression Technique
• In this technique customized tray is fabricated with
autopolymerizing acrylic resin
according to Dynamic Impression
Technique.
• A tray with 1 mm wax spacer
and cylindrical mandibular rests
in the posterior region is made
at increased vertical height.
51

52. • Patient is advised to close his mouth so
that the mandibular rests fit against the
maxillary alveolar ridge. This helps to
stabilize the tray in position by preventing
anteroposterior and mediolateral
displacement of the tray during definitive
impression.
• Lingual surfaces of mandibular rests are
made concave to provide space for the
tongue to move freely during functional
movements.
52

53. • McCord and Tyson’s technique for flat
mandibular ridges is followed for definitive
impression.
• For recording the functional state, patient is
instructed to run his tongue along his lips, suck in
his cheeks, pull in his lips, and swallow by keeping
his mouth closed, as in closed mouth impression
technique, till the impression material hardens.
• The retrieved impression is visually inspected for
surface irregularities and disinfected and is poured
in dental stone.
53

54. Elastomeric Technique
• Tray adhesive is applied over the border,
internal and external surface of the acrylic
custom tray, to facilitate the retention of the
silicone border moulding material.
• An addition silicon putty with an extended
working time is loaded along the borders of
special tray.
54

55. • The special tray is placed in the mouth and its border is
molded; the patient is asked to move the tongue according to
standard impression procedures.
• The tray is removed from the mouth, and the impression is
examined.
• Light-body addition of silicon impression material is loaded
in the impression and inserted in the mouth.
55

56. • The patient is instructed to repeat the tongue movements,
more vigorously, while the light-body impression material is
border molded along the buccal and labial flange areas.
• After the material has set, the impression was removed
from the mouth and examined for any discrepancy
56

57. ◈ Klein in 1957, suggested three distinct types of
impression techniques for mandibular dentures
depending on the type of foundation.
(J. Pros. Dent. September, 1957)
57

58. 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.
58

59. ◈ 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 poured.
◈ 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.
59

60. Second Condition-
•In cases with almost complete resorption and with a spiny
ridge of dense bony tissue along the crest of the residual
ridge.
60

61. ◈ 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.
61

62. Third Condition-
• In cases where ridge is flat or concave.
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
62

63. Neutral Zone Technique
◈ The preliminary impressions are made in
stock tray with a mucocompressive
impression material like as impression
compound or alginate
◈ Secondary impression is made in a
custom- made tray with a low viscosity
mucostatic impression material like zinc
oxide eugenol impression paste
63

64. ◈ These help with the retention of the low fusing compound.
The lower special tray with the softened low fusing
compound was placed in the patient's mouth; this tray
was very carefully adjusted in the mouth to be sure that it
was not overextended and remained stable during
opening, swallowing, and speaking. The patient was then
asked to talk, swallow, drink some water, etc. After 5–10
min, the set impression was removed from the mouth and
examined
64

65. ◈ Wire loops or acrylic pillars can be embedded in the
record base to facilitate retention of rim
◈ Prior to making the mandibular neutral zone impression,
the maxillary occlusal rim is inserted to support the facial
muscles and allow the tongue to be placed comfortably
on the palatal contours during function.
◈ Neutral zone impression material- mixing
◈ • 2 parts of high fusing impression compound
◈ • 1 parts of low fusing impression compound
65

66. ◈ Instruct patient to
◈ perform functional
◈ movements
66

67. 2. 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
The degenerative denture ridge—Care and treatment. J Prosthet Dent. 1974 Nov;32(5):477-
92
67

68. • 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.
68

69. •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.
Advantages:
Prevention of acrylic warpage,
More strength,
Increased accuracy,
Less tissue change under the base
Less porosity and therefore easier to clean
Thermal conductivity
Less deformation in function. 69

70. • 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.
70

71. 3.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.
71

72. The following requirements have to be met during teeth
arrangement:
• Stability of occlusion in centric relation.
• Balanced occlusion for eccentric contacts.
• 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.
72

73. • 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

74. 4.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.
74

75. • 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.
75

76. • 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.
76

77. 77

78. ◈ Sheldon Winkler. Essentials of complete denture prosthodontics. 2nd edition
◈ Cocktail Impression Technique: A New Approach to Atwood’s Order VI Mandibular
Ridge Deformity. J Indian Prosthodont Soc (Jan-Mar 2011) 11(1):32–35.
◈ Clinical morbidity and sequelae of treatment with complete dentures. J Prosthet Dent
1997;79:17-23.
◈ Impression for Complete Denture, by Bernard Levin
◈ Comparison of Different Final Impression Techniques for Management of Resorbed
Mandibular Ridge: A Case Report Bhupender Yadav
◈ The management of gross alveolar resorption : (JPD 1973, vol. 29, Pg.397).
78