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4. INTRODUCTION
The residual ridges have been described as plastic in
nature, always changing in topography and morphology from
many causes, some known and some unknown.
The clinical efforts that aim at prolonging the
useful life of complete denture involve a refitting of the
impression surface of a denture by means of a reline or a
rebase procedure.
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5. Definitions
According to GPT 8 :
Relining :
The procedure used to resurface the tissue side of a
denture with new base material, thus producing an accurate
adaptation to the denture foundation area.
Rebase :
Rebasing is a process of replacing all the base material
of a denture. The purpose of which is to fill the space between
the tissue and denture base without changing the position of the
teeth and the relation of the dentures.
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6. PATTERN OF RESORPTION
vertical changes in basal seat area
horizantal changes in basal seat area
Changes in the maxilla
Changes in the mandible
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7. General considerations
A through examination of the patient and of the
existing denture must be accomplished before commencing
therapy.
1. vertical dimension
2. Centric occlusion should coincide with centric relation
3. The size, shape, shade, and arrangement of the artificial teeth
must be satisfactory.
4. The oral tissues should be in optimum health.
5. The posterior limit of the maxillary denture is correct.
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8. 6. The denture base extensions
7. Distribution of masticatory forces over as large an area as
possible.
8. The interocclusal distance is correct
9. Speech
10. redundant tissue or severe osseous undercuts.
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9. INDICATIONS
Immediate dentures at three to six months
Adaptation of the denture base is compromised
Cost
physical or mental stress, such as for geriatric and
chronically ill patients.
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10. Contraindications
1. Excessive resorption
2. Abused soft tissues are present.
3. Temporomandibular joint problems.
4. Poor esthetics
5. Unsatisfactory jaw relationships.
6. Speech problem
7. Severe osseous undercuts
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11. Tissue preparation
Hypertrophic tissues
Free of areas of irritation.
Removal of the dentures from the mouth during sleep is a must
for several weeks.
The dentures should be left out of the mouth at least two to
three days before making final impression.
Daily massage of the soft tissue
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12. Denture preparation
Pressure areas of the tissue surface of the denture
Minor occlusal disharmony is corrected by selective grinding.
Small border inadequacies are corrected.
A correct posterior palatal seal area should be established
before the final impression.
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14. Hard and soft materials for modifying the
impression surface of dentures
• Rigid materials
• Short-term soft lining materials
• Long-term soft lining materials
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15. Rigid materials
Frequently described as chair side reline
materials, which can be used to modify the impression
surface of an existing denture.
Composition :
Powder – polyethylmethacrylate
Liquid monomer – butylmethacyrlate
Many of the products include a primer to enhance
the adhesion of the material to the existing denture
polymer. The available materials vary in working time,
setting time and viscosity.
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16. Manipulation:
Relieve the fitting surface of the denture.
Mix powder and liquid in 1:2.5 to attain a fluid mix.
Applied to the fitting surface of the denture and seated in
patients mouth while it is still fluid.
The reline soon becomes rubbery and the impression of the
patients soft tissue is recorded.
The denture is allowed to bench cure after removal from the
patients mouth. Warm water will accelerate the curing.
The relined denture is ready within 30 minutes.
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17. Short term soft relining materials
Composition :
Powder : Polyehtylmethacrylate
Liquid : mixture of
An aromatic ester, such as dibutyl pthalate which acts as a
plasticizer.
Ethyl alcohol
The setting process :
After the powder and liquid have been mixed, the ethyl
alcohol causes swelling of the polymer particles and permits
penetration by the ester so that a gel is formed. This is a
physical change ; there is no chemical reaction.
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18. Clinical applications :
Short-term soft lining materials are placed in the existing
dentures for the following reasons.
Tissue conditioning
Temporary soft reline – improve fit of denture
Functional impression
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19. Long-term soft lining materials
Thin atrophic mucosa
Replacing an existing denture which has a soft lining
Sharp bony ridges or spicules
Superficially placed mental nerve
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20. Types of long-term soft lining
Soft liners are made either of
Silicon rubber - Cold curing
Heat curing
Soft acrylic - Cold curing
Heat curing
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29. Open mouth technique ( boucher )
Relining of both dentures at same time
New centric relation is recorded
Selective pressure technique
Interocclusal record with quick setting plaster
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30. FUNCTIONAL METHOD (WINKLER)
Easy to use
Excellent for refitting of denture
Good dimensional stability
Good in bonding to denture base resins
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32. This material undergoes through
Plastic stage - few hrs – few days.
Elastic stage - 1 – 2 weeks.
Firm stage - after 15 days.
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33. CHAIRSIDE RELINE PROCEDURE
DISADVANTAGES:
chemical burn
material is porous and
develops a bad odour
poor color stability
material not easy to remove
if not placed correctly
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34. VISIBLE LIGHT CURE ( VLC )
Similar to tisssue conditioners
Select appropriate viscosity and partial intraoral
polymerisation with hand-held curing light
Taken to laboratory for unpolymerised molecules
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37. Modeling clay application Stone over lower member
Positioning denture in stone Stone placed on cast basewww.indiandentalacademy.com
38. Modeling clay removed Removing all impression material
Impression surface reduction Border reduction – 2-3 mm
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39. Resin grindings removed with
Stream of air
Providing posterior seal
Separating medium application
resin application over the denturewww.indiandentalacademy.com
40. Resin placed on the cast Denture seated in indentations
Cured in pressure container
- 20 psi for 30 minutes
Relined denturewww.indiandentalacademy.com
42. Procedure
Denture seated on lower
Member of jig
Mounting stone smoothened with
spatula
Locknuts ,modeling clay
removed
Jig openedwww.indiandentalacademy.com
43. Denture carefully lifted Blowing air to lift
Preparing basal surface prepared Cleaned prepared denture seated
In stone index
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44. Application of separating media Moistening with monomer
Resin mixed & placed on cast Resin placed in denturewww.indiandentalacademy.com
46. Rebasing with jig method
Hooper Duplicator used to rebase the denture
Denture seated in the index in Hooper Duplicator
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47. Removal of porcelain teeth
Using alcohol torch Using Spatula
Porcelain teeth replaced back A layer of baseplate wax
adapted to the castwww.indiandentalacademy.com
48. If insufficient space is there
Baseplate wax is removed
wax can be added
Completed wax-up on jigwww.indiandentalacademy.com
49. Waxed denture removed & flasked. Rebased denture is replaced on jig
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58. CONCLUSION
clinical evidence suggest that the rate of osseous change
can be retarted when complete dentures are readapted to the
residual ridges at the first signs and symptoms of loss of
adaptation. The clinical efforts that aim at prolonging the
useful life of complete denture involve a refitting of the
impression surface of a denture by means of a reline or a
rebase procedure.
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59. Thank you
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