Relining and rebasing in complete dentures / Labial orthodontics courses

RELINING AND REBASING IN COMPLETE DENTURES

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

www.indiandentalacademy.com

CONTENTSIntroductionGeneral considerations Indications Contraindications Tissue preparation Denture preparationRelining materials

Rigid materials Short term-soft lining materials Long term-soft lining materials


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.


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.


PATTERN OF RESORPTION

vertical changes in basal seat area horizantal changes in basal seat area Changes in the maxilla Changes in the mandible


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.


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.


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.


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


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


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.


RELINING MATERIALS


Hard and soft materials for modifying the impression surface of dentures

• Rigid materials • Short-term soft lining materials • Long-term soft lining materials


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.


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.


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.


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


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


Types of long-term soft lining

Soft liners are made either of Silicon rubber - Cold curing

Heat curing Soft acrylic - Cold curing

Heat curing


Relining procedure


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)


Relining procedure


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


FUNCTIONAL METHOD (WINKLER)

Easy to use Excellent for refitting of denture Good dimensional stability Good in bonding to denture base resins


Tissue conditioners


This material undergoes through

Plastic stage - few hrs – few days.Elastic stage - 1 – 2 weeks.Firm stage - after 15 days.


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


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


LAB PROCEDURES


Beading Boxed impression

Stone pouringIndexing separating media applied

Articulator method


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


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


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


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


Flask method

Denture half - flasked Painting silicone mold material


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


Border trimmed-2mm Border molding with green stick compound


Final impression with Zinc-oxide Eugenol

Master cast fabricated


Indentations of the teeth made Cast mounted on upper member


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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Relining and rebasing in complete dentures / Labial orthodontics courses

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