relining and rebasing in complete dentures / labial orthodontics courses
TRANSCRIPT
RELINING AND REBASING IN COMPLETE DENTURES
INDIAN DENTAL ACADEMY
Leader in continuing dental education www.indiandentalacademy.com
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CONTENTSIntroductionGeneral considerations Indications Contraindications Tissue preparation Denture preparationRelining materials
Rigid materials Short term-soft lining materials Long term-soft lining materials
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Relining proceduresStatic methods:
open mouth technique closed mouth techniqueFunctional methodsChair side technique
Laboratory procedures articulator method jig method flask methodconclusion
References www.indiandentalacademy.com
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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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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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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General considerations A through examination of the patient and of the
existing denture must be accomplished before commencing therapy.
1. vertical dimension2. Centric occlusion should coincide with centric relation3. 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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6. The denture base extensions7. Distribution of masticatory forces over as large an area as
possible. 8. The interocclusal distance is correct9. Speech10. redundant tissue or severe osseous undercuts.
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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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Contraindications
1. Excessive resorption2. 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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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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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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RELINING MATERIALS
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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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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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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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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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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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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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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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Relining procedure
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Relining procedure
Clinical procedure Laboratory procedure
1. Static methods
2. Functional method
3. Chair-side technique
1. Articulator method
2. Jig method
3. Flask method
closed–mouthtechnique
Open- mouthTechnique(Bouchers)
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Relining procedure
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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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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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Tissue conditioners
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This material undergoes through
Plastic stage - few hrs – few days.Elastic stage - 1 – 2 weeks.Firm stage - after 15 days.
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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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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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LAB PROCEDURES
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Beading Boxed impression
Stone pouringIndexing separating media applied
Articulator method
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Modeling clay application Stone over lower member
Positioning denture in stone Stone placed on cast basewww.indiandentalacademy.com
Modeling clay removed Removing all impression material
Impression surface reduction Border reduction – 2-3 mmwww.indiandentalacademy.com
Resin grindings removed withStream of air
Providing posterior seal
Separating medium applicationresin application over the denturewww.indiandentalacademy.com
Resin placed on the cast Denture seated in indentations
Cured in pressure container- 20 psi for 30 minutes
Relined denturewww.indiandentalacademy.com
Jig method
Hooper duplicator Jectron jig
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Procedure
Denture seated on lowerMember of jig
Mounting stone smoothened with spatula
Locknuts ,modeling clay removed Jig openedwww.indiandentalacademy.com
Denture carefully lifted Blowing air to lift
Preparing basal surface prepared Cleaned prepared denture seatedIn stone index
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Application of separating media Moistening with monomer
Resin mixed & placed on cast Resin placed in denturewww.indiandentalacademy.com
Jig assembled & locknutstightened
Jig separated & denture Examined for voids
Polished Relined denturewww.indiandentalacademy.com
Rebasing with jig method
Hooper Duplicator used to rebase the denture
Denture seated in the index in Hooper Duplicator
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Removal of porcelain teeth
Using alcohol torch Using Spatula
Porcelain teeth replaced back A layer of baseplate waxadapted to the castwww.indiandentalacademy.com
If insufficient space is thereBaseplate wax is removed
wax can be added
Completed wax-up on jigwww.indiandentalacademy.com
Waxed denture removed & flasked. Rebased denture is replaced on jig
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Flask method
Denture half - flasked Painting silicone mold material
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Flask opened Porcelain teeth removed & Replaced in silicone mold
Resin teeth replaced, Cure denture www.indiandentalacademy.com
Rebasing with Articulator method
Mandibular denture with porosities
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Border trimmed-2mm Border molding with green stick compound
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Final impression with Zinc-oxide Eugenol
Master cast fabricated
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Indentations of the teeth made Cast mounted on upper member
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Denture trimmed Wax build-up donewww.indiandentalacademy.com
Invested waxed denturewww.indiandentalacademy.com
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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Thank you
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