Finals Lecture Directcompositehistory 120317054329 Phpapp02

7/28/2019 Finals Lecture Directcompositehistory 120317054329 Phpapp02

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Introduction


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I. Class 1 DirectComposite Restoration

Preparation design:

Conventional (class I,II,V)in amalgam/90or buttjoint

Modified (classV)

Bevealed conventional(rarely used)


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I. Class 1 Direct

Composite RestorationB. Inverted cone with rounded

caries

Provide flat floorsProduces a more stronger margin on the

occlusal cavosurface

Creates preparation walls that converge

occlusallyOcclusally more conservative facial

lingual preparation width


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Class II Conventional

direct compositeB. Proximal Box:

Facial, lingual and gingival extensions

dictated by extend of caries or oldrestoration; may not be extended beyondthe contact with the adjacent tooth.

Walls at 90, axial wall to 0.2mm in

dentinGingival floor flat with minimal extension

Retained by micromechanical retention,no secondary retention necessary.


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Indirect tooth colored

RestorationIndications:

Esthetic

Large defects or previous restorationsEconomic factors

Contraindications:

Heavy occlusal forcesInability to maintain a dry field

Deep subgingival preparation


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Definition of terms

Indirect:Inlay

- restoration of metal, porcelain/ceramic orcomposite made to fit a tapered cavitypreparation and luted into it by a cementingmedium.

Onlay (overlay)

- an inlay that includes the restoration of allof the cusp of a tooth.


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Definition of terms

Taper-permits an unobstructed removal of the wax

pattern and subsequent seating of the

material. The wax pattern should be removedfrom the tooth without distortion.

TaperIntracoronal

-divergence from the floor of thepreparation outwards.


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Definition of terms

Extracoronal- converge from the cervical to the

occlusal or incisal surface.shallow cavities (vertical walls unusually short)Requires minimal taper of 2 occlusal divergenceto enhance resistance and retention.

deep cavities (increased gingivo-occlusal height ofvertical walls)

As much as 5 taper to facilitate:

Pattern withdrawal, trail seating and cementingof restoration


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Types of restorative

materialsLaboratory-processed inlays and

onlays

Ceramic inlays and onlaysMachinable ceramics or CAD/CAM

Feldspathic porcelain

Hot-pressed ceramic


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Laboratory-processed

inlays and onlaysPolymerized under pressure, vacuum, inert gas,intense light, heat, or a combination of thesedevices to optimize physical properties of

composite resins.More resistant to occlusal wear vs directcomposites but less wear resistance thanceramics.

Easily adjusted, low wear of opposing teethgood esthetics and has potential for repair.


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Laboratory-processed

inlays and onlaysIndications:

If maximum resistance is desired from

composite restoration.Achievement of proper contour and

contacts would be difficult with directcomposite.

If ceramic restoration iscontraindicated because of wear ofopposing dentition.


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Advantages of heat curedcomposite inlay/onlay restoration

Improved physical properties/durability andwear resistance compared to direct compositesystems.

Depth of cure not a problem unlike with directcomposite where there is limited depth of cure.

Excellent marginal adaptation since the lutingcomposite fills any marginal contraction gap

present.Non-extent polymerization shrinkage except inluting resin cement.

Post-operative sensitivity seldom encounetered


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Ceramic inlays and onlays

Esthetics, durable, improvedmaterials, fabrication techniques,

adhesives and non based lutingagents.


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Fabrication steps for

ceramic inlays and onlaysAfter tooth preparation, an impression

is made and a master working cast is

poured of die stone.The die is duplicated and poured with a

refractory investment capable ofwithstanding porcelain firing

temperatures. The duplication methodmust result in the master die and therefractory die being accuratelyinterchangable.


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Fabrication steps for

ceramic inlays and onlaysPorcelain is added into the preparation

area of the refractory die and fired in

an oven. Multiple increments and firingsare necessary to compensate forsintering shrinkage.

The ceramic restoration is recovered

from the refractory die, cleaned of allinvestment, and seated on the masterdie and working cast for finaladjustments and finishing.


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Partially crystalline minerals (feldspar,silica, alumina) dispersed in a glass

matrix.Porcelain restorations are made from

finely ground ceramic powders that aremixed with distilled water or a special

liquid, shaped into the desired form,then fired and fused together to form atranslucent material that looks liketooth structure.


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Some ceramic inlays and onlays arefabricated in the dental laboratory by

firing dental porcelains on refractorydies.

Advantage:Low start-up cost

Disadvantage:its technique sensitivity


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Hot Pressed Glass

ceramicsGlass could be modified with nucleating

agents and on heat treatment, be

changed into ceramics with organizedcrystalline forms.

Such glass ceramics were stronger,had a higher melting point than non

crystalline glass, and had variablecoefficients of thermal expansion.


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Hot Pressed Glass

ceramicsAdvantages:

Similarity to traditional wax-up processes

Excellent marginal fitRelatively high strength

The surface hardness and occlusal wear ofthese ceramics are similar to those of

enamel.Stronger than porcelain inlays made on

refractory dies, they are still quite fragileuntil cemented.


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Hot Pressed Glass

ceramicsDisadvantges:

its translucency, which necessitated

external application of all shading.Not significantly stronger than fired

feldspathic porcelains they do seemto provide better clinical service.


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Chronological Events of

Restorative MaterialsHistory

First recommended over 25 years ago

for posterior use.1907 cast gold

1908 silicate cement

First direct tooth colored restorativematerial.

Disadventage:Insoluble to oral fluid


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Restorative Materials1962 composite resin

According to the size of the filler:

Macrofill for class V(problem: abfraction)

Microfill anterior restoration

Hybrid

Microhybrid composite

Nanofilled composite


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Two types of composite:

1. Packable compositealternative to amalgam

Supplied: unit dose, compules or insyringe

Higher filler loadingFibers

Porous filler particles

Irregular filler particles

Viscosity modifiers


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Advantages:

Produce acceptable class II restorationHigh depth of cure possible

Bulk fill technique

Filler loading: 80%

Medium to high strengthHigh stiffness

Low wear rate: 3.5um/year

Molecules of elasticity :similar to amalgam


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Disadvantages:

New techniqueLess polishable

Limited shades

Increased post-operative sensitivity

Increased sensitivity to ambient light


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Recommended uses:Class I restoration

Class II restoration


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2. Flowable composites

Low viscosity compositesLow filler content

Ideal for cervical lesion

Ideal for non stress bearing area

Ideal for first increment in Class Icomposite


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Advantages:

SyringeableDispensed directly into cavity

Adequate strength

Disadvantages:Higher polymerization shrinkage

Greater potential for microleakage

Low wear resistance


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Restorative Materials1968 Glass ionomer cement

Different types:

Luting or cementing medium

Liner or base

Restorative material


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Restorative Materials1970microfill polishable

composite

1973 ultraviolet light1977 microfill composite

Advantages: polishability, wear and

resistance and color stabilityDisadvantages: low flexural/tensil

strength, localized wear and thus

limited uses posteriorly.


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Restorative Materials1978 visible light curing

composite

Mid 1980s hybrid:Hybrid 0.04-3um particle size

range

Examples: brands of hybridHerculite

Prisma APH

P-30


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Restorative MaterialsMid 1980s hybrid

Intended for universal use

Disadvantage of hybrid:Generalized wear


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Restorative MaterialsMid 1980s microhybrid:

Microhybrid 0.6-0.7um particle

size rangeExamples: brands of microhybrid

Prisma TPH

Herculite XRV

Charisma

Tetric ceram


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Restorative MaterialsMid 1980s microhybrid:

Advantages:

Excellent physical propertiesGood finishing and polishing

characteristics

Relatively non sticky materials

Disadvantage:Do not hold a high polish over time


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Restorative Materials1985 CEREC ceramic system

1991 CEREC 1 as modified by

siemens1994 CEREC 2 with an upgrade

dimensional camera

2000 CEREC 3 with splitacquisition/design


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CEREC

Chairside Economical Restoration ofEsthetic Ceramiics


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Restorative Materials1986 Heliomolar

The sole exception to the microfill

group of resins that were introducedfor posterior use.

70% filled anterior/posteriormicrofill resin.

very good wear characteristic

Less than perfect esthetics


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Thank you!

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Finals Lecture Directcompositehistory 120317054329 Phpapp02