retainers fpd althhima hshmsaina

7/27/2019 Retainers Fpd Althhima Hshmsaina

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DEFINITION:Any type of device used for

stabilization or retention ofprosthesis -- GPT

RETAINERS


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Retainer for an FPD

That component of an FPD whichtakes support from the abutmenttooth and provides retention tothe prosthesis


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SELECTION OF RETAINERS

Retainer selection for abutment is criticaland is dictated by the followings:

1) Age

2) DMF rate3) Edentulous space-Partial veneer crown

contraindicated in long span FPD

4) Periodontal support5) Arch position of the tooth

6) Skeletal relationship


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7) Inter occlusal & intraocclusal

condition such as crown length8) Oral hygiene of the patient

9) Vitality of the abutment teeth---endodontically treated teeth mayhave to be restored with core &

post before designing theretainer


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10) Condition of the abutment teeth

11) Cost12) Preservation of the tooth

structure----Buccal surfaceshould be conserved. Partialveneer crown is more

conservative than full crown . Allceramic crowns are leastconservative


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Types of retainers

Classified as:

I. Based on tooth coverageFull veneer crown

Partial veneer crown

Conservative (minimal prep.)retainers


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II. Based on material used

All metal retainersMetal ceramic retainers

All ceramic retainersAll acrylic retainers


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Full veneer crowns

Covers all 5 surfaces of abutment

Most retentive of the veneer preparations

Compared to partial veneer designs,fullveneer crown exhibits superior resistancend retention

Used on those teeth whose restorationdemands max. retention.


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VariationsMetal ceramic crowns and allceramic crowns used in situations that

requires a good cosmetic results The full veneer crown should be used

when less extensive and less destructive

design have been considered and foundlacking in retention ,resistance ,coverageor esthetics to properly restore the tooth


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Partial veneer crown

Preferred than full veneer crown becausethey requires less tooth reduction

Crown does not cover the entire abutment

Facial surface is left intact for superioresthetics

Used when minimal retention is sufficientand when abutment tooth is healthy


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Contra indications

In long span FPDs

Endodontically treated toothDentition with active caries or

periodontal diseasePoorly aligned abutment tooth


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Advantages

Conservation of tooth structure

Reduced pulpal and periodontalinsult during tooth prep

Improved access for finishing by

dentist & oral hygiene by patient


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Less of margin approximate softtissues subgingivally and henceless gingival involvement than

complete coverage

Remaining intact facial or buccaltooth surface permits electricvitality test


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Disadvantages

Less retention & resistance thancomplete crowns

Some metal displayed in completedrestorationunaesthetic

Tooth prep is difficult because onlylimited

adjustments can be made in the

path of placement


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Resin bonded retainers

(Maryland bridges) Require minimal tooth preparation

Acid etched Esthetically appealing

Economical , conservative ,functional & do not irritate soft orhard tissues


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Indication

As retainers of FPD for abutmentwith sufficient enamel to etch

Splinting of periodontallycompromised teeth

Stabilizing dentition afterorthodontic treatment


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Contraindication

In patients with sensitivity to basemetal alloys

When facial esthetic of abutment

require improvement Inadequate enamel surface to

bond eg;caries,existingrestoration

Incisor with extremely thin facio-

lingual dimension


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Advantages

Non invasive to dentin with lingualand proximal tooth preparationincluding occlusal rest

Conservative with undeniable patientappearance

Tissue tolerant because of

Supragingival margin,without pulpalirritation

Reduced cost and less chair side time


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Disadvantage

Demanding technique and toothprep.

Plaque accumulation Bulky contour

Restricted to single ponticplacement

Graying out of teeth that are thin

labiolingually


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Based on material used

All metal retainers

Metal ceramic retainersAll ceramic retainers


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All metal retainers

Partial or full veneer crown

Require minimal toothreduction

Strong even in thin sections


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Metal ceramic retainers

Indicated on teeth that requirecomplete coverage & esthetic

demand

Can accommodate cast or soldered

connectors Can afford high forcemetal

Require more teeth reduction


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Indication

Extensive tooth destruction as aresult of caries or trauma

Existing previous restoration thatprecludes the use of a moreconservative restoration

Need for superior retention andstrength

Endodontically treated tooth


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Contraindication

Whenever a more

conservative retainer isfeasible


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All ceramic

Primary purpose ---to achievebest possible esthetic results

Risk of reduced restorationlongevitypotential for fracture,inferior marginal adaptation thanPFM retainer


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Telescopic retainers Used when path of insertion of FPD does

not coincide with long axis of abutment

Design involves fabricatin of two copings

one over the other Internal or primary coping function to

modify the morphology of toothpath pf

insrtn changed Secondary coping designed to fit over

primary


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REFERENCES

1. Fundamentals of Fixed Prosthodontics

Herber T.Shillingburg

2. Contemporary Fixed ProsthodonticsRosenstiel,Land,Fujimoto

3. Tylmans Theory and Practice of Fixed

Prosthodontics4. Textbook of Prosthodontics-Deepak

Nallaswamy


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Thanking you..

retainers fpd althhima hshmsaina

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