TOOTH COLOURED TOOTH COLOURED RESTORATIVE RESTORATIVE MATERIALSMATERIALS

TOOTH COLOURED TOOTH COLOURED RESTORATIVE RESTORATIVE MATERIALSMATERIALS

GLASS IONOMER GLASS IONOMER CEMENTCEMENTSS

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COMPOSITESCOMPOSITES ByAfeefa cRoll no;2

• RESTORATION• Filling material or prosthesis used to restore or replace a

tooth, a portion of tooth ,multiple teeth, or other oral tissues

• Requirement of ideal restorative materials• Esthetic• Maintenance of physical strength of crown• Preserving anatomy of occlusal surface thus preventing inter

relation ship with opposing and adjacent tooth long term adhesion between restoration and tooth to ensure

complete isolation

GLASS IONOMER CEMENT

DEFINITIONAn aqueous based material that hardens following acid

based reaction between fluro alumino silicate glass powder and poly acrylic acid solution

• HISTORY– It was developed byWILSON and KENT in the early 1970s– The design of earliest glass ionomer cement was hybrid

formulation of silicate and poly carboxylate cement– Earliest commercial product-Acronym for hybrid

formulation –Alumino silicate poly acrylic acid(ASPA)– The original poly acrylic acid in the liquid component was

modified by copolymerisation with Itaconic acid,maliec acid &tartaric acid

– Ag-Sn particle is admixed to produce amalgam substitutes combination -MIRACLE MIXTURE

• In early 1990s original glass Ionomer formulations with alternate filler particle categorised as resin modified glass Ionomer

• Continued evolution polyacid modified resin composite - compomers

• Advantages• It is a tooth colored material• It will adhere directly to enamel &dentin

through ion exchange mechanism• Biologically active releasing fluorides

• Disadvantages• Its physical properties are not

sufficient to enable it to withstand• Heavy occlusal forces in large

restorations

• CLASSIFICATION• According to WILSON & KENT• Type 1-LUTING• Cementation of crowns, bridges, orthodontic devices• p:l ratio 1.5:1• Type2 –RESTORATIVE• type2.1- restorative esthetic• auto cure or resin modified• P:l ratio-3:1• type2.2-restoration under high occlusal load• auto cure or resin modified• P:l ratio-3:1

• Type 3 –lining or base• Simple lining under metallic restoration• P:l ratio-1.5:1

• According to Intented application• Type1 –luting• Type2-restorative• Type3- lining &base• Type4-fissure sealant• Type 5-orthodontic cement

• Type 6-core build up• Type 7-fluoride releasing• Type 8-GIC for ART• Type 9-gediatric &pediatric GIC

• Composition• Powder• fluoro alumino silicate glass• silica-increase translucency• alumina-Skeletal structure & increase opacity• calcium fluoride-increase opacity &act as flux• Aluminium fluoride• Sodium flouride• Aluminium phosphate

• Liquid• 40-55% soln of poly acrylic or itaconic acid copolymer in

water or• Copolymer of maleic acid & poly acrylic acid-improve storage• Tartaric acid-maintain working time

• SETTING REACTION• Acid base reaction• When powder &liquid are mixed to form paste, the acid

etches surface of glass particle and calcium ,aluminium, sodium & fluorine ions are released in to aqueous medium. The poly acrylic acid chains are cross linked by the calcium ions that are replaced by aluminium ions in next 24 hours. The remaining ions are dispersed uniformly within the set cement with fluorine ions . The cross linked phase hydrated over time with the same water used for mixing .the process is called MATURATION

• Setting reaction depends on• Temperature of mixing slab-• lower temperature of mixing slab , longer working time• P:L Ratio• Higher powder content , higher physical properties• Water plays critical role in GIC. If freshly mixed cement are

exposed to ambient air with out protective covering the surface will crack as a result of desication

• Contamination by water –dissolution of matrix

• GIC must protected against desiccation and water changes

• Manipulation• Hand mixing• divide powder in to two equal compartment

• gently spread liquid drop over the glass slab• roll first half of the powder in to liquid incorporate two

together rapidly , this is completed in 10 sec rest of powder is brought in to mix

• Mixing time 25-30 sec• setting time type 1 4 to5• type2 7sec

• Conditioning the cavity• After cavity preparation there will be smear layer on

surface of floor and walls• To remove smear layer 10% polyacrylic acid is applied

followed to remain in place for10 sec• The cavity should be washed thoroughly and dried

lightly ,cement followed in to place immediately• Do not over dry the cavity

• Physical properties• Compressive strength—150Mpa• Tensile strength-6.6Mpa• Hardness-48KHN• Solubility-0.4

• Biological Properties• Ion exchange adhesionThe union b/n glass Ionomer and tooth structure arises as a

result of an exchange of ions• Because of low ph of poly alkanioc acid it will attack

tooth surface and release ca & phosphate ions which will be free to mix with matrix of cement ,further release of ion buffer the reaction and anew material containing ions from both cement and tooth will begin to form and set at the interface .The new material will be firmly attached to both sides of the union will be stronger and more resistant to acid attack

• Anticariogenic properties• GIC release fluoride which prevent

formation of secondary caries• Esthetics• Inferior to silicate and composite• Lack translucency

• Mechanism of adhesion• Chelation of carboxyl groups of polyacids

with the apatite of enamel and dentin

• Biocompatibility• Glass Ionomer show high degree of biocompatibility

with living tissues• Poly acrylic acid are mild acids with high molecular wt

and long complex chain formation .this make difficult for acid to penetrate through dentinal tubules even it does not produce vigorous action

• Due to presence of Free fluoride ion ,bacteria such as streptococcus can not thrive in presence of fluoride

• Uses• Esthetic restoration of anterior teeth• Restoration of class 3&class 5 cavity• Luting• Orthodontic bracket• Pit& , and fissure• Liner &base• Core build up• Intermediate restoration

modifications• Anhydrous• Freeze dried poly acid powder and glass powder are

placed in same bottle as powder• Liquid-water or water with tartaric acid• Powder mixed with water the acid powder dissolves to

re constitute the liquid acid process followed by acid base reaction

• Metal modified GIC• To improve strength &fracture toughness of GIC• Two methods are employed• Silver alloy admixed –spherical amalgam alloy

powder+type2 GIC• Cermet -silver particle Are bonded to glass powder

particle by fusion this s achieved by sintering of particle at too high temperature

• Properties• Compressive strength-150 Mpa• Esthetics-poor esthetics

• Resin modified• To over come moisture sensitivity& low early strength• Powder-ion leachable fluoro alumino silicate glass• Initiator-light curing or chemical curing• Liquid-water & poly acid or poly acid modified with

methacrylate & HEMA monomer

• Properties• Improved translucency• Increased strength• Compressive strength-105Mpa• Tensile stregth-20Mpa• Hardness -39KHN•

• Highly viscous GIC• USED IN ART

• Properties• Less fluoride than conventional GIC• Restoration of low stress bearing areas• Fluoride release similar to that of conventional GIC

composites• Definition• A HIGHLY CROSS LINKED POLY MERIC MATERIAL

REINFORCED BY DISPERSION OF AMORPHOUS SILICA GLASS.CRYSTALINE OR ORGANIC RESIN FILLER PARTICLE AND OR SHORT FIBERS BONDED TO MATRIX BY COUPLING AGENTS

• History• 1930s first mention of methyl methacrylate • 1948-acrylic resin introduced• Buonocore-micromechanical adhesion-acid etching• Bowen introduced BIS GMA ,filled composite resin ,UV

cured composite• 1980s-light cured composite ,hybrid resin• 1990-packable composite• 1996-flowable• 2000-nano fill introduced

• Advantages• Good esthetics

CLASS PARTICLE SIZE

Traditional composite 1-50micro glass

Hybrid large particle 1-20 micro meter glass0.04 micro meter silica

Hybrid midifiller 0.1-10 micro meter glass.04 micro meter silica

Hybrid minifiller 0.1-2 micro meter glass.04 micro meter silica

packable Midifiller /mini filler hybrid

flowable Midifiller hybrid

homogenous microfill 0.04 micron silica

Heterogenous microfill

0.04micron silicaPrepolymerised particle-0.04 micro meter silica

• Composition• An organic resin component that forms the matrix• Eg ; Bis GMA• Inorganic filler these may be• A)macro filler with particle size of about 5-10 mm• eg; glass ,quartz ,ceramic etc• B)Micro filler with particle size of 0.04mm• eg;amorphous silica• Coupling agent applied to filler to the resin silane -titanate

or zirconate• Initiator system to activate setting mechanism-light or

chemical activation• Inhibitors-BHT

• OPTICAL MODIFIERS-aluminium oxide

• Curing of resin based composite• Chemical activated systems• Two paste• One-benzoyl peroxide-initiator• Aromatic tertiary amine-N-N dimethyl para toludine• Two paste r mixed together result in polymerisation

• Light activated systems• Single paste containing in a light proof syringe• Photosensitizer –camphoroquinone • Amine initiator-dimethyl aminoethyl methacrylate

(DMAEMA)• Light source of activation• Exposure time-40 second to light cure a2mm thick

layer

• Advantage• Mixing not required• Control of working time

• Disadvantage• Limited curing depth• Poor accessibilty in posterior areas

Curing lampsLED LAMPSQTH LAMPSPAC LAMPSARGON LASER LAMPS

• DEGREE OF CONVERSION• MEASURE OF PERCENTAGE OF CARBON CARBON

DOUBLE BOND THAT HAVE BEEN CONVERTED TO SINGLE BOND TO FORM POLYMERIC RESIN

• Higher degree of conversion’ better strength• degree of conversion depends on• Transmission of light through the material• Time of exposure• Amount of photo initiator or inhibitor present

• Polymerisation shrinkage• Shrinkage of 1 -1.7%• It leads to marginal leakage• Chemically activated resin shrink towards center of

bulk material• Light cured material first polymerise at surface,

contraction towards light source

• Incremental build up and cavity configuration

• Limitation of depth of cure of photo initiated resin dictates, use of incremental build up of composite

• Over comes limited depth of cure& residual stress concentration

• Clinical steps• Etching and bonding Acid etching -one of most efficient way to

improve bond and marginal seal between resin and enamel

Mode of action- it creates micro porosities it increases surface areaMost commonly used etchant-37% phosphoric acid

• Delivery and placement• The chemical cure and dual cure materials will be packaged

as paste /paste system or a powder /liquid system• Light activated material will always be delivered in light proof

syringes• Incremental build up-placement of composite in small

quantities in selected areas of the cavities and direct the light source

• Depth of cureDepth of cure of composite resin is quite significant activator light should be placed within 1-2 mm of surface of the

newly placed restorationFactors considered during curingDegree of cure will decrease with in creasing depthIncreased time of exposure to light will increase depth of cure

property

Unfilled acrylic

traditional

Hybrid small particle

Hybrid all purpose

Micro filled

flowable

packable

Size - 8-12 0.5-3 0.4-1 0.04-0.4

0.6-1 fibrous

Inorganic filler volume

0 60-70 65-77 60-65 20-59 30-55 48-67

In organic filler

0 70-80 80-90 75-80 35-67 40-60 65-81

Compressive strength

70 250-300

350-400 300-350 250-300

- -

Tensile strength

24 50-65 75-90 40-50 30-50 - 40-45

Elastic modulus

2.4 8-15 15-20 11-15 3-6 4-8 3-13

Water sorption

7 .5-1..7 05-.6 .5-.7 1.4-1.7

- -

shrinkage

8-10 - 2-3 2-3 2-3 3-5 2-3

s

• Properties• Marginal leakage• When gingival margins are of cavity are located in dentin

or, cementum or both; the resin is firmly anchored to etched enamel and other margins, ;material pull from margin due polymerization shrinkage; gap formation in interface

• Wear• Composite undergo occlusal wear• Wear rate-10-20 micrometer/year• posterior composite wear-0.1-2mm more than enamel

over 10 year

• Radiopacty• Resins are radiolucent

BiocompatiblityComposites are relatively biocompatibleComposite resin affect pulp from two aspects1-inherent chemical toxicity of the material2-pulpal involvement due to microleakage

• Improperly cured or uncured composites enter dentinal tubules cause pulpal inflammation

• Pulp protection-GIC and Calcium Hydroxide

CLASS CLINICAL USE

traditional High stress areas

Hybrid large particle

High stress areas requiring improved polishability-classes 1,, 2, 3 4

Hybrid midifiller high stress areas requiring improved polishability classes-3 ,4

Hybrid minifiller , Moderate stress areas requiring optimal polishability-classes-3 ,4

Packable hybrid situations in which improved condensability Needed(1&2)

flowable Situations in which improved flow is needed(class2)

microfill Low stress &sub gingival areas require high luture and polish

Heterogenous microfill

Low stress areas reduced shrinkage is essential

• Limitations• Pulpal irritation due to un reacted

monomer • Tissue cell response is less

• Compomer POLY ACID MODIFIED COMPOSTEAcid base reaction presence of saliva

COMPOSITIONOne paste-light curable material-silicate glass particle

NaF2&poly acid modified monomer wit out waterSetting-photopolymerisation of acidic monomer

• Limitations• Gic susceptible to dehydration through life span• Resistance to fracture is one of d main use of

limitations to the use of glass Ionomer• Resistance to Abration and wear is little less than of

composite

• Conclusion• Tooth colored restorative material

provide better esthetic, they are used widely in dentistry

• Thank u