Tooth Colour Restorative Materials in Ped Dent

Tooth colour restorative materials in pediatric dentistry

Contents

• Ideal characteristics of restorative material

• Glass ionomer cements • Resin based composite material• Ormocers• Compomers• Giomers

Ideal characteristics of restorative materials

Kenneth J Anusavice. Phillips’ science of dental materials. 11th edition. Elsevier. 2004.

Glass-ionomer cement • Developed in Britain, and firstly described by

Alan Wilson and Brian Kent in 1972• Conserve tooth structure, assist in

remineralization while maintaining appeal.• Formed from the reaction of an ion--leachable ��

calcium alumino-silicate glass powder and a poly-alkenoic acid.

• “Glass polyalkenoate cements”• Types (1) Conventional (2) Resin Modified

Harry F. Albers. Tooth-colored restoratives principles and techniques. Ninth edition.

2002

Classification by use• Type I – Luting • Type II – Restorative• Type III – Liner/base• Type IV – Pit & fissure sealant• Type V – Luting for orthodontic purpose• Type VI – Core buildup material• Type VII – High fluoride releasing command

set • Type VIII – Atraumatic restorative treatment• Type IX − Pediatric Glass Ionomer cements

Harry F. Albers. Tooth-colored restoratives principles and techniques. Ninth edition

Advantages of glass-ionomers• Form a rigid substance on setting• Good fluoride release (bacteriostatic, inhibit caries)• Coefficient of thermal expansion similar to dentin• Filler–matrix chemical bonding• Resistant to micro-leakage• Non-irritating to pulp• Good marginal integrity• Adhere chemically to enamel and dentin in the presence of

moisture• Rechargeable fluoride component• High compressive strengthHarry F. Albers. Tooth-colored restoratives principles and techniques. Ninth edition

Disadvantages

• Susceptible to dehydration over lifetime• Sensitivity to moisture at placement• Poor abrasion resistance• Average esthetics• Less tensile strength than composites• Technique sensitive powder-to-liquid ratio and mixing• Less color-stable than resins• Contraindicated for Class IV or other stressbearing

restorations• Poor acid resistance


Composition of GIC

Kenneth J Anusavice. Phillips’ science of dental materials. 11th edition. Elsevier.

2004.

CERAMIC-METAL GLASS IONOMERS

• In 1987, McLean and Gasser developed the first cermet (ceramic + metal) glass ionomer, Ketac-Silver® (ESPE), was introduced.

• This improved abrasion resistance and compressive strength


RESIN-MODIFIED GLASS IONOMERS

• Resin-modified glass-ionomer materials attempt to combine the best properties of composite resins and glass ionomers.

• They have some cariostatic properties, a low thermal expansion, and the hydrophilic qualities of the glass-ionomer cements.

• The polymerizing resin matrix of resin-modified glass ionomers improves the fracture toughness, wear resistance, and polish of these materials compared with conventional glass ionomers.


• Antonucci introduced the lightcured glass-ionomer cements in 1988.

• Vitrebond, the first commercially viable cement of this type, was developed by Mitra in 1989.

• These early modified resin ionomers had two setting mechanisms: a lightintiated polymerization reaction and a glass ionomer acid–base reaction.

• In 1992, Mitra added the first autocured resin capabilities to resin-modified glass-ionomer cements.


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luting


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PROPERTY VALUES1.Setting time(min) 7.0

2.Film thickness(µm) 24

3.24 hr compressive strength(Mpa) 86

4.24 hr diametrical tensile strength(Mpa)

6.2

5.Elastic modulus(Gpa) 7.3

6.Solubility in water(Wt%) 1.25

7.Pulp response Mild to moderate

Restorative cements

PROPERTY GLASS IONOMER II

CERMET HYBRID IONOMER

1.Compressive strength(Mpa)

150 150 105

2.Diametrcal tensile strength(Mpa)

6.6 6.7 20

3.Knoop hardness(KHN)

48 39 40

4.Pulp response mild mild mild

Resin-based Composite Material

• Composite typically consists of a resin-based matrix, such as a bisphenol A-glycidyl methacrylate (BISGMA) resin like urethane dimethacrylate (UDMA), and an inorganic filler such as silica.

• The filler gives the composite wear resistance and translucency.

• A coupling agent such as silane is used to enhance the bond between these two components.

• An initiator package begins the polymerization reaction of the resins when external energy (light/heat, etc.) is applied.

Harry F. Albers. Tooth-colored restoratives principles and techniques. Ninth edition. 2002

http://en.wikipedia.org/wiki/Bisphenol_A

http://en.wikipedia.org/wiki/Bisphenol_A

http://en.wikipedia.org/wiki/Glycidyl_methacrylate

http://en.wikipedia.org/wiki/Glycidyl_methacrylate

http://en.wikipedia.org/w/index.php?title=Urethane_dimethacrylate&action=edit&redlink=1

http://en.wikipedia.org/w/index.php?title=Urethane_dimethacrylate&action=edit&redlink=1

http://en.wikipedia.org/wiki/Silicon_dioxide

http://en.wikipedia.org/wiki/Silane

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Composition

• Resin matrix – BisGMA , UDMA , TEGDMA• Fillers - used in dental composites to provide

strengthening, increased stiffness , reduced dimensional change when heated and cooled , reduced setting contraction , enhanced esthetics, and improved handling. Quartz , silica , barium glass

• Coupling agent - silanes• Activator –initiator systems – camphoroquinone• Inhibitors – butylated hydroxide toluedene • Optical modifiers/coloring agents – titanium and

aluminum oxidesKenneth J Anusavice. Phillips’ science of dental materials. 11th edition. Elsevier.

2004.

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ADVANTAGES

1. Strong and durable2. Tooth colored3. Single visit for fillings4. Resists breaking5. Maximum amount of

tooth preserved .6. Does not corrode

Frequency of repair or replacement is low


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DISADVANTAGES

1. Tooth sensitivity2. Technique

sensitive3. Costs more than

dental amalgam4. Shrinkage Leakage

over time

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2004.

Organically Modified Ceramics (Ormocers) Restorative Materials

• Organically Modified Ceramic [Ormocers] is a hybrid material which is made by special processing based on nanoscale technology, mixing organic and inorganic components at a nanoscopic scale rather than by conventional means of physical mixing of different component of a matrix.

• Ormocers have been developed as an alternative to the dimethacrylate based composites

• The chemical structure of Ormocers is based on organically modified alkoxides and functionalised organic oligomers/polymers

Moszner and Salz, 2001

Rosin et al 2002; Kournetas et al., 2004 and wear (Lutz and Krejci, 2000; Manhart et al. 2002)

• The organic constituent of Ormocers is used for cross linking the network whilst the inorganic component improves mechanical properties and other properties such as thermal and chemical stability.

• Another advantage of these materials is that the large size of the monomer molecule minimises polymerisation shrinkage.

• In a recent study, Ormocer-based material demonstrated the lowest decrease in hardness following immersion in solvent for a period of time compared with dimethacrylate-based composites and as a result it has been proved to be more resistant to solvent degradation than any other material tested

(Cavalcante et al., 2011).

Compomers• A type of translucent hybrid dental resin which has the benefits of compo

sites and of glass ionomers which are used forestorations of molars and cosmetic procedures

• Introduced in 1990s• Compomer is a polyacid-modified composite resin. • Compomer is made predominantly from resin composite (90%) with the

addition of a polyacid-modified molecule similar to that found in traditional GIC.

• Compomers are initially light-cured, but subsequently absorb water, allowing for an acid-based reaction to set the polyacid-modified molecule.

• They have normal adhesion to tooth structure and are always attached with resin dentin bonding agents


2002

• Consequently, the material shrinks, initially due to polymerization contraction, and expands subsequently as water is absorbed.

• The addition of a polyacid-modified molecule makes the material more hydrophilic.

• Compomers are, therefore, relatively easy to handle and apt for preparation.

• A dentin-bonding agent is required for their successful placement.


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• Physically, their properties are similar to those of a composite.

• The wear rates and fracture resistance are less than for a composite.

• Compomers and composites have the same advantages .

• Additional advantages of compomers include fluoride release and ease of handling.


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Giomers• The material unites the chemistries of composite and GIC in an

effort to combine the advantages of both materials, whilst minimizing the limitations of each.

• Giomers are newly introduced hybrid aesthetic restorative materials for dental restorative therapy.

• They are based on pre-reached glass-ionomer (PRG) technology. • Chemically, they consist of fluoroalumino silicate glass reacted with

polyalkenoic acid in water prior to inclusion into the silica-filled urethane resin.

• Giomers contain both of the essential components of glass-ionomer cements and resins but they cannot be classified as compomers, in which a variable amount of dehydrated polyalkeonic acid is incorporated in the resin matrix and the acid does not react with the glass until water uptake occurs.


2004.

• Giomers can be subdivided into two distinct groups of materials, namely those in which the glass ionomer particles have been surface reacted and those which have been fully reacted. – Surface pre-reacted glass ionomer giomers are

suitable for composite indications– Fully pre-reacted glass ionomer giomers are used in

dentin adhesive systems, fissure sealants, and as restorative material for nonloaded-bearing areas


2004.

References • Kenneth J Anusavice. Phillips’ science of dental

materials. 11th edition. Elsevier. 2004.• Harry F. Albers. Tooth-colored restoratives

principles and techniques. Ninth edition. 2002• Manappallil Basic Dental materials 3rd Edition• : "Where and When Is It Appropriate to Place

Monolithic vs. Layered Restorations," Inside Dentistry, August 2012, Vol. 8, Issue 8, E. McLaren, R. Margeas, N. Fahl.

Tooth Colour Restorative Materials in Ped Dent

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