Finals lecture- direct composite & history

Introduction

I. Class 1 Direct Composite Restoration

Preparation design:Conventional (class I,II,V) in amalgam/90˚or buttjointModified (classV)Bevealed conventional (rarely used)

I. Class 1 Direct Composite Restoration

B. Inverted cone with rounded caries

Provide flat floorsProduces a more stronger margin on

the occlusal cavosurfaceCreates preparation walls that

converge occlusally Occlusally more conservative facial –

lingual preparation width

Class II Conventional direct composite

A. Occlusal preparation:330 or 245 diamond made parallel to

the long axis of the tooth.Pulpal depth is 1.5 mm from the

central groove (about 0.2mm in dentin); follows the rise and fall of DEJ mesiodistally but relatively flat faciolingually.

Class II Conventional direct composite

B. Proximal Box:Facial, lingual and gingival extensions

dictated by extend of caries or old restoration; may not be extended beyond the contact with the adjacent tooth.

Walls at 90˚, axial wall to 0.2mm in dentin

Gingival floor flat with minimal extension

Retained by micromechanical retention, no secondary retention necessary.

III. Class VI Composite Restoration

A. Preparation designThe typical class VI tooth preparation

should be as small in diameter and as shallow in depth as possible.

B. Flame - shape or round diamond

Either a flame-shaped or round diamond instrument to roughen the prepared surfaces.

Indirect tooth colored Restoration

Indications:EstheticLarge defects or previous

restorationsEconomic factors

Contraindications: Heavy occlusal forcesInability to maintain a dry fieldDeep subgingival preparation

Definition of terms

Indirect:Inlay

- restoration of metal, porcelain/ceramic or composite made to fit a tapered cavity preparation and luted into it by a cementing medium.

Onlay (overlay) - an inlay that includes the restoration of

all of the cusp of a tooth.

Definition of terms

Taper -permits an unobstructed removal of the

wax pattern and subsequent seating of the material. The wax pattern should be removed from the tooth without distortion.

TaperIntracoronal

-divergence from the floor of the preparation outwards.

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 divergence to enhance resistance and retention.

●deep cavities (increased gingivo-occlusal height of vertical walls)

As much as 5˚ taper to facilitate:Pattern withdrawal, trail seating and

cementing of restoration

Types of restorative materials

Laboratory-processed inlays and onlaysCeramic inlays and onlaysMachinable ceramics or

CAD/CAMFeldspathic porcelainHot-pressed ceramic

Laboratory-processed inlays and onlays

Polymerized under pressure, vacuum, inert gas, intense light, heat, or a combination of these devices to optimize physical properties of composite resins.More resistant to occlusal wear vs direct

composites but less wear resistance than ceramics.Easily adjusted, low wear of opposing

teeth good esthetics and has potential for repair.

Laboratory-processed inlays and onlays

Indications:If maximum resistance is desired

from composite restoration.Achievement of proper contour and

contacts would be difficult with direct composite.If ceramic restoration is

contraindicated because of wear of opposing dentition.

Advantages of heat cured composite inlay/onlay

restorationImproved physical properties/durability and

wear resistance compared to direct composite systems.Depth of cure not a problem unlike with direct

composite where there is limited depth of cure.Excellent marginal adaptation since the luting

composite fills any marginal contraction gap present.Non-extent polymerization shrinkage except in

luting resin cement.Post-operative sensitivity seldom encounetered

Ceramic inlays and onlays

Esthetics, durable, improved materials, fabrication techniques, adhesives and non based luting agents.

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 of withstanding porcelain firing temperatures. The duplication method must result in the master die and the refractory die being accurately interchangable.

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 firings are necessary to compensate for sintering shrinkage.The ceramic restoration is recovered

from the refractory die, cleaned of all investment, and seated on the master die and working cast for final adjustments and finishing.

Feldspathic porcelain

Partially crystalline minerals (feldspar, silica, alumina) dispersed in a glass matrix.Porcelain restorations are made from

finely ground ceramic powders that are mixed with distilled water or a special liquid, shaped into the desired form, then fired and fused together to form a translucent material that looks like tooth structure.

Feldspathic porcelain

Some ceramic inlays and onlays are fabricated in the dental laboratory by firing dental porcelains on refractory dies.

Advantage: Low start-up cost

Disadvantage: its technique sensitivity

Hot Pressed Glass ceramics

Glass could be modified with nucleating agents and on heat treatment, be changed into ceramics with organized crystalline forms.Such “glass ceramics” were

stronger, had a higher melting point than non crystalline glass, and had variable coefficients of thermal expansion.


Advantages:Similarity to traditional “wax-up” processesExcellent marginal fitRelatively high strengthThe surface hardness and occlusal wear of

these ceramics are similar to those of enamel.Stronger than porcelain inlays made on

refractory dies, they are still quite fragile until cemented.


Disadvantges:its translucency, which

necessitated external application of all shading.Not significantly stronger than

fired feldspathic porcelains they do seem to provide better clinical service.

Chronological Events of Restorative

MaterialsHistory

First recommended over 25 years ago for posterior use.

1907 – cast gold1908 – silicate cement

First direct tooth colored restorative material.Disadventage:

Insoluble to oral fluid


Materials1950 – bonding agents1955 – acid etching by

Micheal J. Buonocore

1960 – sealants1962 – composite resin

-direct filled restorative material


Materials1962 – composite resin

According to the size of the filler:

Macrofill – for class V (problem: abfraction)

Microfill – anterior restorationHybrid

Microhybrid compositeNanofilled composite



Two types of composite:1. Packable composite

alternative to amalgam Supplied: unit dose, compules or in syringeHigher filler loading

FibersPorous filler particles Irregular filler particlesViscosity modifiers



Advantages:Produce acceptable class II restorationHigh depth of cure possibleBulk fill techniqueFiller loading: 80%Medium to high strengthHigh stiffnessLow wear rate: 3.5um/yearMolecules of elasticity :similar to amalgam



Disadvantages:New techniqueLess polishableLimited shadesIncreased post-operative sensitivityIncreased sensitivity to ambient light



Recommended uses:Class I restorationClass II restoration



2. Flowable compositesLow viscosity compositesLow filler contentIdeal for cervical lesionIdeal for non stress bearing areaIdeal for first increment in Class I

composite



Advantages:Syringeable Dispensed directly into cavityAdequate strength

Disadvantages:Higher polymerization shrinkageGreater potential for microleakageLow wear resistance


Materials1968 – Glass ionomer cement

Different types:Luting or cementing

mediumLiner or baseRestorative material


Materials1970 – microfill “polishable”

composite1973 – ultraviolet light1977 – microfill composite

Advantages: polishability, wear and resistance and color stabilityDisadvantages: low flexural/tensil

strength, localized wear and thus limited uses posteriorly.


Materials1978 – visible light curing

composite

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

rangeExamples: brands of hybrid

HerculitePrisma APHP-30


MaterialsMid 1980’s hybrid

Intended for universal use

Disadvantage of hybrid:Generalized wear


MaterialsMid 1980’s microhybrid:

Microhybrid – 0.6-0.7um particle size range

Examples: brands of microhybridPrisma TPHHerculite XRVCharisma Tetric ceram


MaterialsMid 1980’s microhybrid:

Advantages:Excellent physical propertiesGood finishing and polishing

characteristicsRelatively non sticky materials

Disadvantage:Do not hold a high polish over time


Materials1985 – CEREC ceramic system

1991 – CEREC 1 as modified by siemens 1994 – CEREC 2 with an upgrade

dimensional camera2000 – CEREC 3 with split

acquisition/design

CEREC

Chairside Economical Restoration of Esthetic Ceramiics


Materials1986 – Heliomolar

The sole exception to the microfill group of resins that were introduced for posterior use.70% filled anterior/posterior

microfill resin. very good wear characteristicLess than perfect esthetics

Thank you!

Technology

Finals lecture- direct composite & history