unconventional fpd

GOOD MORNING

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UNCONVENTIONAL FIXED PARTIAL DENTURES

Contents Introduction Classification Resin bonded fixed partial dentures

DefinitionAdvantages Disadvantages IndicationsContraindicationsTypes

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Procedures

1. Tooth preparation

2. Fabrication of the frame work

3. Bonding of the restoration

Fiber Reinforced Composite Resin FPD

F i x e d / d e t a c h a b l e ( h y b r i d )

Summary

References

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Introduction

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Fixed-fixed

Fixed-movable

Cantilever

H.T Shillingburg, . Fundamentals of fixed Prosthodontics. 1st ed

Spring cantiliver

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hybrid prosthesi

s


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Resin retained fixed partial dentures

DEFINITION

According to the glossary of prosthodontic

terms

Resin bonded prosthesis: A prosthesis that is

luted to tooth structures primarily enamel

which has been etched to provide mechanical

retention for the resin cement.

Goal:

Replacement of missing teeth and maximum

conservation of tooth structure. 9

Advantages

1. Minimal removal of tooth structure.

2.Non invasive to dentin

3. Minimal potential for pulpal trauma.

4. Tissue tolerant because of supragingival

margins without gingival irritation.

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H.T Shillingburg, . Fundamentals of fixed Prosthodontics. 3rd ed

5. Esthetically more appealing since only lingual surface

of anterior teeth are covered

6. No anesthesia hence less trauma to patient.

7. Simplified impression procedures

8. Interim restorations usually not required.

11H.T Shillingburg, . Fundamentals of fixed Prosthodontics. 3rd ed

9. Reduced chair side time

10. Reduced patient cost…

11. Re-bonding possible.

12Rosenstiel, Land, Fujimoto. Contemporary fixed prosthodontics. 3rd ed. Mosby Harcourt brace and Co; 2001

Disadvantages

1. Reduced restoration longevity

2. Enamel modifications are required

3. Good alignment of teeth are needed

4. Very thin or translucent anterior teeth are limiting factor because of esthetics.

5. Usually restricted to single tooth replacement

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Rosenstiel, Land, Fujimoto. Contemporary fixed prosthodontics. 3rd ed.

6. No space and alignment correction.

7. Difficult temporization.

8. Uncertain longevity.

9. Esthetics is compromised on posterior teeth replacement.

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INDICATIONS

1. Replacement of congenitally missing tooth or teeth lost by traumatic injuries especially in young patients.

2. Splinting of periodontally compromised teeth.

3. Stabilizing dentition after orthodontic treatment or movement.

4. Short span and in case on open bite.15


5. Retainers of FPD for abutment with sufficient enamel to etch for retention.

6. Significant crown length.

7. Unrestored abutments.

8. Medically compromised and adolescent patients.

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CONTRAINDICATIONS

1. Patients sensitivity to base metal alloy.

2. Parafunctional habits.

3. Long span involving 3 or more abutments.

4. Restored or damaged abutments.

5.Compromised enamel.

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6. Significant pontic discrepancy.

7. Deep vertical overlap.

8. When facial esthetics of abutment require improvement eg: stained, malformed or malposed teeth.

9. Insufficient occlusal clearance to provide 2-3 mm vertical retention. eg: abraded teeth.

10. Incisors with extremely thin facilingual dimension

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Types Of Resin Bonded Fixed Partial Denture Designs

1) Rochette

2) Maryland

3) Virginia 4)Fungs

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CAST PERFORATED RESIN-RETAINED FPDS: (ROCHETTE BRIDGE)

Alain Rochette in 1973 introduced this type of bridge.

Bonding through mechanical retention.

The metal retainer had flared perforation so that the bonding material gets locked mechanically.

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To prevent weakening of the framework- Too large and too closely placed perforations should be avoided.

The perforations should be approximately 1 mm apart and have a maximum diameter of 1.5mm.

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Replacement of posterior teeth –Livaditis

Extension –interproximally and onto occlusal surfaces.

Survival rate -3 years

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ADVANTAGES

1) It is easy to see the retentive perforations in the metal.

2) If the bridge must be replaced, the composite resin can be cut away in the perforations to aid in the removal process.

3) No metal etching is required.

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Disadvantages1) The perforations would weaken the

retainers if improperly sized or spaced.

2) The exposed resin is subjected to wear.

3) It is not possible to place perforations in proximal surface or in the rest.

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ETCHED CAST RESIN RETAINED FPDS: (MARYLAND BRIDGE)

Thompson and Livaditis developed this type of FPD at University of Maryland.

The retention is micro mechanical ie, through electrolytic etching of Ni-Cr and Cr-Co alloys.

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Lividatis and Thompson used a

3.5% solution of nitric acid with a current of 250 mA/cm for 5 min,

Followed by immersion in an 18% hydrochloric acid solution in an ultrosonic cleaner for 10 min

This technique was specific to non beryllium nickel chrome alloy.

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Thompson et al reported that 10% sulphuric acid at 300 mA/cm2, followed by same cleaning methods,

would produce similar results in beryllium containing nickel chrome alloy.

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Advantages

1. It is reported to have improved bond strength.

2. Retention is improved because the resin-to-etched metal bond can be substantially stronger than the resin-to-etched enamel.

3. Instead of perforations, the tooth side of the framework is electrolytically etched, which produces microscopic undercuts. 28


4. It can be used for both anterior and posterior bridges

5. The retainers can be thinner and still resist flexing.

6. The oral surface of the cast retainers is

highly polished and resists plaque accumulation.

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Disadvantages

Although this design has been reported to be stronger, it is more technique sensitive because the retainers may not be properly etched or may be contaminated before cementation.

Because the retentive features are not seen with the unaided eye the etched surface must be examined with a microscope to verify proper etching.

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3. MACROSCOPIC MECHANICAL RETENTION RESIN RETAINED FPD: (VIRGINIA BRIDGE)

Moon and Hudgins et al produced particle roughened retainers by incorporating salt crystals into the retainer patterns to produce roughness on the inner surfaces.

This method is also known as lost salt technique

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LOST SALT TECHNIQUEThe framework is outlined on the die with a

wax pencil and the area to be bonded is coated first with model spray and then with lubricant.

Sieved cubic salt crystal (NaCl), ranging in size from 150 to 250ųm are sprinkled over the outlined area.

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The retainer patterns are fabricated from resin leaving 0.5 to 1.0mm wide crystal free

margin from the outlined area.


Application of resin pattern

Pattern investment,salt crystals are dissolved

from the surface

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Cast mesh retainers

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Fung shells

Advantages 1. It is of lower cost compared to custom made

resin – bonded bridges.

2. No need of impression making and laboratory work.

3. Can be given to patient in a single appointment.

4. Good esthetics no exposure of metal in proximal areas.

5. Longevity comparable to resin bonded bridges

http://www.fung-international.com/pdf/DI.pdf

FABRICATION of RBFPD

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In fabrication of resin retained fixed partial dentures, all three phases are necessary for predictable success:

1) Preparation of abutment teeth.

2) Design of restoration

3) Bonding of restoration.

Whether anterior or posterior teeth are prepared common principles dictate tooth preparation design.


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Anterior tooth preparation and frame work design


The finish line on the proximal surface

adjacent to the edentulous space should

be placed as far facially as is practical.

Abutments should have parallel proximal

surfaces.

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An optional slot, O.5mm in depth, prepared with a tapered carbide bur, may be placed slightly lingual to the labial termination of the proximal reduction.

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Leave the margins about 1mm for the incisal or occlusal edge and 1mm supragingival if

possible.

Wherever possible to enhance resistance more than half the circumference of the

tooth should be prepared.H.T Shillingburg, . Fundamentals of fixed Prosthodontics. 1st ed

Preparation of mandibular anterior teeth is similar to that for the maxillary incisors. Lingual enamel thickness is 11 to 50 percent less than for maxillary teeth and consequently tooth preparation must be more conservative.

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Posterior tooth preparation and framework design

The basic framework consists of three major

components.

1. The occlusal rest (for resistance to gingival

displacement)

2. The retentive surface (for resistance to

occlusal displacement)

3. The proximal wrap (for resistance to

torquing forces).44


A spoon shaped

occlusal rest seat is

placed in the

proximal marginal

ridge area of the

abutments adjacent

to the edentulous

space. An additional

rest seat may be

placed on the

opposite side of the

tooth.

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To resist occlusal displacement, the

restoration is designed to maximize the

bonding area without unnecessarily

compromising periodontal health or

esthetics.

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Proximal and lingual walls are reduced to

lower their height of contour to

approximately Imm. The proximal wall

are prepared so that parallelism results

without undercuts.47


The bonding area can be increased through extension onto the occlusal surface provided it does not interfere with the occlusion.

Generally a knife-edge type of margin is recommended.

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.

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In general, the preparation differs between maxillary and mandibular molar teeth on the lingual surface only. The lingual wall of mandibular tooth may be prepared in a single plane and the palatal surface of maxillary molars dictates a two plane reduction due to taper of these centric cusps in the occlusal two thirds and occlusal function.

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Resin to metal bondingMetal resin bonding can be classified as

either

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Electrolytic etching:

In this procedure microscopic porosity is

created in the fitting surface of a nickel chromium framework by electrolysis.

Procedure

Clean the fitting surface of metal restoration with an air abrasion unit with aluminium oxide.

Cover the polished surfaces with wax and attach the prosthesis to an electrolytic etching unit following the manufacturers instructions.

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Michel Degrange: Minimally invasive restoration with bonding

A typical etching cycle will be 3 minutes in 10% H2SO4 with a current of 300 milliamp per square centimeter of casting surface.

Clean the etched surface ultrasonically in 18% HCI, then wash and air-dry it.

The etched surface must not be handled after this stage.

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Chemical etchingA gel consisting of nitric and hydrochloric acid is applied to the internal surface of the metal framework for approximately 25 minutes.

As electrolytic etching is extremely sensitive, many authors believe that chemical etching provides more reliable results due to procedural simplicity.

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Silicoater ClassicalTiller et al (1984)Procedure – sand blasting of alloyFlame coating of silica-carbon for 5

minutes,thus the surface bonds to composite

Disadvantage – 1. Expensive 2. Uneven distribution of flame3. Chemically unstable silica layers4. Protection of the layer formed

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Rocatec SystemIntroduced in 1989

The metal surface is abraded with 120microns alumina

Followed by abrasion with silicate particle-containing alumina.

Silane application thus adhesive to composite resin.

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MACROSCOPIC RETENTION

In non-perforated retainer, porosity is

cast in the pattern itself rather than subsequently obtained by etching.

This is done in variety of ways:

1. Lost salt technique.

2. One techniques uses a special pattern to form a meshwork on the fitting surface and the external lingual surface is waxed to give a smooth finish that can be highly polished.

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Advantages1. any alloy can be selected, whereas with

electrolytic or chemical etching the alloy

usually must be nickel chromium.

2. try-in and bonding of the prosthesis can

be accomplished at the same

appointment.

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Disadvantages 1. Difficulty on adapting the mesh to create a

closely fitting metal framework

2. A potentially thicker metal framework than

can be obtained with a etched metal

retainer

3. The rate of microleakage along the cast

mesh composite resin interface is

significantly greater than along an etched

metal resin interface 59

Tin plating is a recently introduced

procedure that can improve the strength of

adhesive cement to most metals.

Precious alloys can be plated with tin and

used as frameworks for resin retained fixed

partial dentures.

Tin forms organic complexes with several

specific adhesive resin cements that result

in significantly greater bond strength.60

TIN PLATING (CHEMICAL BONDING)

BONDING AGENTS

Composite resins play an important role in the

bonding of the metal framework to etch

enamel. They conatin

I) Filled BisGMA composite resin (Bisphenol A

glycidil methacrylate).

2) TEGDMA (Triethylene glycel dimethacrylate).

3) 4META (4 methacrylyloxethyl trimellifate

anhydrite).

4) UDEMA (Urethane dimethacrylate). 61

Cements with adhesion promotersPANAVIAComponents: low viscosity paste, radio

opaque composite resin pasteUniversal and catalystComposition : Bisphenol-A-Polyethoxy

dimetharyclate,MDP or 10-Methacrloxydecyl dihydrogen

phosphate, 77%silanated organic fillers.

Mixing time : 20-30 sces

Film thickness: 19 microns

Metal surface must be sandblasted or tin coated.

Recent version – PANAVIA F

C&B METABONDCOMPOSITION:

Methylmethacrylate polymer powder

Mma liquid modified with 4-META or

4 Methacryloxyethyl Trimellitic Anhydride.

Tri-n-Butyl Borane catalyst.

Disadvantage-poor hydrolytic stability

Cementation procedure

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Post operative careRegular recall visits

Check for any debonding

Caries

Periodontal health


Fiber Reinforced Composite Resin FPD

1. Consists of a fibre reinforced substructure

2. Veneered with composite material

3. Increased flexural strength , fracture resistance & increased tensile strength

4. Transluscent


Types Of Fibres

1. Glass

2. Polyethylene

3. Polypropylene

4. Carbon


Orientation of the fibre1. Unidirectional

2. Braided

3. Woven

Procedure 1. Preparation of

abutment teeth

2. Measurement of fiber length

3. Moistening of fiber

4. Fiber bar pressed into the preparation & polymerised with resin

5. Pontic build up & curing


FIXED REMOVABLE FPD

Fixed-movable Bridge–

These are similar to fixed-fixed bridges but have a movable joint (not detectable by the patient) allowing the use of a bridge when retaining teeth that are not favourably aligned.

Eg:- Andrews bridsge

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FIXED REMOVABLE FPDAndrews bridges:-

Fixed removable partial dentures are particularly indicated for patients with extensive supportive tissue loss and when the alignment of the opposing arches and/or esthetic arch position of the replacement teeth create difficulties

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J Prosthet Dent. 1983 Aug;50(2):180-4

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A FIXED REMOVABLE PARTIAL DENTURE TREATMENT FOR SEVERE RIDGE DEFECT

Int J Dent Case Reports 2011; 1(2): 112-118

SPRING CANTILEVER BRIDGE

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. DEFINITION : It is a bridge that carry the pontic by a tooth not immediately related to it and connect to it by a flexible palatal bar. . .The bar must sufficiently flexibile to allow it to be pressed on to and gain support from the mucoperiosteum during mastication

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1.Where aesthetics is of prime importance .

2.Where the teeth on either side of the space are unsuitable as abutments because there is insufficient retention or the teeth are periodontal disturbed and unable to carry additional load .

3.Where a Diastema is need to be preserved on one or both sides of the pontic .

INDICATIONS :

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1.In young patients where the clinical crowns are short and of inadequate retention .

2.When the teeth on either side of the space need crowning in replacement of lower tooth .

3.When the shape of the palate is unfavorable .

4.Where there is sever soft tissue loss .

5. When the proposed abutment tooth is unopposed or lacking mesial or distal contact which might move after the bridge is placed

CONTRAINDICATIONS :

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Pier abutments Tilted molars

CONCLUSION

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References Textbook references: 1. Rosenstiel, Land, Fujimoto. Contemporary fixed

prosthodontics. 3rd ed. Mosby Harcourt brace and Co; 2001

2. H.T Shillingburg, Sumiya Hobo, Lowell D. Whitsett. Fundamentals of fixed Prosthodontics. 3rd ed. Quintessence Publishing CO, Inc; 1997

3. W.F.P. Malone, D.L Koth, E. Cavazos, Jr. Tylman's theory and practice of fixed th prosthodontics. 8 ed. Ishiaku Euro America .p.219-228.

4.Direct bonded retainers.Gerald McLaughlin5.Minimally invasive restorations with bonding: Michel

Derange/Jean-Francois Roulet6.Resin Bonded Bridges:technique for success;

K.A.Durey,P.J.Nixon BDJ2011;211:113-1187.Quintessence International;Jul/Aug2009, Vol. 40 Issue

7, pe3 83

THANK YOU

unconventional fpd

Education

fixed partial denture

types of resin

replacement of missing

posterior teeth replacement

perforated resin

resin cement

exposed resin

malposed teeth