restorative materials used in pediatric dentistry · restoration of permanent teeth •class v...

RESTORATIVE MATERIALS USED IN PEDIATRIC DENTISTRY

RESTORATIVE

MATERIALS

1. GLASS IONOMER CEMENT

2. AMALGAM

3. COMPOSITE RESIN

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Requirements of an Ideal Restorative Material

1) Restoration of esthetic.

2) Maintenance of the crown strength.

3) Preserve the anatomy of occlusal surface. Thus

preserving interarch relations.

4) Long working time and short sitting time.

5) Long term adhesion between tooth and restoration to

ensure complete isolation.

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GLASS IONOMER CEMENT

(Wilson and Kent 1972)

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• Known as Polyalkenoate cement, Man Made

Dentin and Dentin Substitute.

HYBRID = Silicate Cement [Powder] + PolyCarboxylate [Liquid]

Sikri VK. Textbook of Operative Dentistry. 4th ed. CBS Publishers & Distributors, 2017.

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McLean’S classification

1. Glass-Ionomer

Cements [Traditional]

2. Resin modified glass-

ionomer cements.

3. Poly acid modified

Composite resins.

.

According to Application

I. Luting.

II. Restoration.

III. Liner & bases.

IV. Fissure sealant.

V. As Orthodontic cement.

VI. Core build up.

VII. Fluoride Release.

VIII. ART ( Atraumatic

Restorative Technique)

IX. Deciduous Teeth.

CLASSIFICATION

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COMPOSITIONPowder

• Silica [SiO2]: 35–50 %

• Alumina [Al2O3]: 20–30 %

• Aluminium Fluoride [AlF3]: 1.5–2.5 %

• Calcium Fluoride [CaF2]: 15–20 %

• Sodium Fluoride [NaF]: 3.0–6.0 %

• Aluminium Phosphate [AlPO4]: 4.0–

12 %

• Lanthanum, Strontium, Barium in

traces (for Radio opacity.)

Fluorides act as Ceramic Flux

Liquid

• Polyacrylic acid: 45%

• Itaconic acid

• Maleic acid: 5% (Decreases

viscosity)

• Tricarballylic acid Tartaricacid:

Traces (Increases working

time & decreases setting

time)

• Water: 50% (Hydrates

reaction product

Setting reaction:1. Acid-Base Reaction

2. Light Activated Polymerization

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1. Acid-base Reaction

• Occurs between glass powder and ionic polymer.

• Divalent calcium ions release & react with poly acid, to

form calcium polysalts. Initial set- 5 minutes due to this

reaction.

• If cement comes in contact with moisture, then

aluminium ions are leached out. This will result in a weak

cement.

• Second stage aluminium ions replace divalent calcium

ions and form tighter network of crosslink between

polymer chains. This stage requires about 24 hours.

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• Auminium ions provide strength to set cement. Complete

reaction may take as long as seven days.

• Continuous leach of fluoride throughout lifetime of

cement seen.. Initial release is high followed by gradual

decrease to reach constant level.

• Whenever an increase in fluoride level in environment the

cement imbibes the lost fluoride and stores it like a

reservoir to release gradually over a period of time.


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2. Setting Reaction by Light Polymerization

• It is two stage process.

• Powder and liquid modified with hydroxy ethyl

methacrylate (HEMA) is responsible for polymerization by

light.

• Initial reaction lead to polymerization of methacrylate

groups and subsequently followed by acid-base reactions of

glass component of powder and polyacrylic acid of liquid.

• This is also known as dual cure cement


1. Restoration of permanent teeth

• Class V & Class III cavities.

• Abrasion/Erosion lesion.

• Root Caries.

2. Restoration of deciduous teeth

• Class I - Class VI cavities.

• Rampant caries, nursing bottle

caries.

3. Luting or cementing

4. Preventive restorations

5. Protective liner

6. Core build up.

7.Splinting of periodontally weak teeth.

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8. Other restorative technique

• Sandwich technique/Layered

restorations/

Laminated

restorations/Bilayered

Restorations.

• Atraumatic Restorative

Treatment [Fuji VII and Fuji IX].

9. Endodontics

• Repair of external root

resorption.

• Repair of perforation.

• Retrograde filling

Clinical Applications

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1. Short working time and long setting time

2. Low strength and toughness

3. Cracking and desiccation

4. Poor resistance to acid attack

5. Moisture sensitivity

MODIFICATION AND RECENT ADVANCES

OF GIC

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METAL MODIFIED GLASS-IONOMERS

i. Miracle Mix or Silver Cermet (Simmons 1983)

• Prepared by incorporation of Silver-Tin alloy into GIC

• Expected to improve toughness & abrasive resistance of

cement.

• Most properties of cement including compressive strength,

flexural strength, solubility and abrasive resistance remained

without improvement. In fact gave grey or blackish color to

cement, aesthetically unacceptable.

• It did not exhibit promising results, due to metal-carboxylate

interface failure.

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ii. Glass Cermet (McLean and Gasser 1985)

• It involves incorporation of continuous network / scaffold of

alumina and SiO2 ceramic fibers into the powder.

• Nano particles such as TiO2, nano tubes, nano fluroapatites are

incorporated into GIC matrix to enhance their mechanical strength.

• This allows a highly packed density of particles

Advantages:

• Increases the depth of cure,

• Reduces the polymerization shrinkage,

• Improves wear resistance

• Increases flexural strength of set cement

RESIN-MODIFIED GIC

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MODIFICATION IN POWDER

• BiSGMA, TEGDMA and

HEMA (Light/Dual cure GIC).

MODIFICATION IN LIQUID• HEMA -15-25%

Names:

Light cured GICs

Dual-cured GICs,

Hybrid ionomer,

Resin-ionomers

• They have a small quantity of resin into the liquid formula. Less than1% of photoinitiators are allowed for the setting reaction to beinitiated by light of correct wavelength

COMPOMER• Poly acid modified composite. Combination of Composite and

Glass ionomer

• Contain dimethacrylate monomer and two carboxylic groupsalong with ion leachable glass.

• Indication:

• Class V cavity

• Suitable for high caries risk patient.

• Contraindication:

• Stress bearing area like large class II and class IV.

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• Properties:

1. Hydrophilic expansion, by water uptake from saliva.

2. No loss of mechanical properties

3. Increased marginal integrity- less post operative sensitivity.

4. Reduced secondary caries- Fluoride release.

GIOMERS

• True hybridization of glass ionomer and composite restorative

materials.

• Properties of GIC (fluoride release and Fluoride exchange) and

resin composites excellent esthetics, easy poilshability and

biocompatibility)

• Concept is based on the fluro-aluminosilicate glass reacted with

polyalkenoic acid to yield a stable phase of GIC, this pre-reacted

glass (PRG) is then mixed with the resin depending on amount of

glass which is reacted.18

• PRG technology is divided into Full reaction type (FPRG) and surfacereaction type (SPRG).

• With FPRG the entire glass filler is reacted with poly acids while inSPRG only surface of glass filler is reacted

• S-PRG filler particles act as a fluoride reservoir that recharge withbrushing or rinsing with fluoridated products.

• Fluoride then releases when acid levels rise, providing sustainedpreventative benefits to adjacent tooth structure over the life of therestoration.

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• Incorporation of 1.56% CPP-

ACP into GIC significantly

increases its tensile strength,

compressive strength and

significantly enhances

release of calcium,

phosphate and fluoride ions

at neutral and acidic pH.

• CPP is a milk product whichhelps in remineralisation &helps in prevention ofcaries.

• CPP kills S. mutans bacteria& it binds to calcium &phosphate ions of toothstructure & also to CPP.

• CPP forms nanoclusterswith ACP and makes a poolof Calcium and phosphateions which maintains thesuper saturation of saliva.

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Casein Phosphopeptide Amorphous Calcium Phosphate Complex(CPP-ACP) (Aaron S Posener - mid 1960's)

ZIRCONIA REINFORCED GLASS IONOMER (ZIRCONOMER)

• A new class of restorative GIC with increased strength and durability

• It shows strength of amalgam, so it is also called white amalgam.

• Advantages:

– Reinforces the structural integrity of the restorative material

– Imparts higher mechanical properties for the restoration of

posterior teeth

– Provides esthetics of GIC,

– Completely eliminating mercury hazards

– Sustained fluoride release

Almuhaiza M. Glass Ionomer Cement in dentistry. Journal of contemporary dentistry practice 2016:17:4:331-336 21

HYDROXYAPATITE (CA10(PO4)6(OH)2) REINFORCED GLASS IONOMER CEMENTS

• The nano-HA (nHA) crystals favor remineralization of

enamel. Enhanced mechanical properties of apatite-

modified GICs are result of ionic interaction between the

polyacrylic acid and the apatite crystals.

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POWDER MODIFIED NANO GLASS IONOMERS

• Conventional GICs with nano-sized glass particles can decrease

setting time and enhance the compression strength and elastic

modulus. Increased density of filler content and smaller

particle size- 20 nanometers

• Main advantages of decreasing setting times of direct

restorative materials are enhanced ease of handling,

manipulation, shelf-life increasing masticatory and occlusal

forces.

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Nano Filled Resin Modified Glass Ionomer Cements

• Commercially available nano-filled RMGIC (contains

nanoclusters of silica fillers and supplied with a primer

• Nano-filled RMGICs exhibit similar bonding mechanism but

there is minimal infiltration of resin tags into dentin which is

indicative of more ionic bonding with tooth rather than

micromechanical retention.

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AMALGOMER

• Amalgomer technology (ceramic reinforced glass ionomer

cement) is introduced into restorative dentistry to match

strength and durability of dental amalgam.

• Contains high level of fluoride with good aesthetics and minimal

cavity preparation required.

• Bonds to tooth structure and has excellent biocompatibility and

shows all the advantages of GIC.

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CHLORHEXIDINE IMPREGNATED GIC

• To increase the anticariogenic action of GIC

• Still under experimental stage

• According to a study by Marti LM 2014 addition of CHX at

a concentration of 0.5% is the best option, since this

combination increased the antibacterial activity without

changing the physical-mechanical properties of the

material.

Marti, Luana Mafra, Mata, Margareth da, Ferraz-Santos, Beatriz, Azevedo, Elcilaine Rizzato, Giro, Elisa Maria Aparecida, & Zuanon, Angela

Cristina Cilense. Addition of Chlorhexidine Gluconate to a Glass Ionomer Cement: A Study on Mechanical, Physical and Antibacterial Properties. Brazilian Dental Journal, 2014, 25(1), 33-37.

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SILVER AMALGAM

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COMPOSITION:

Conventional Silver Alloy

Silver (Ag) 68–72% (wt %)

Tin (Sn) 25–27%

Copper (Cu) 2–6%

Zinc (Zn) 0–3%

Admixed/Blended Alloy

• This alloy is a mixture of two types of

particles viz. lathe cut low copper alloy

particles and spherical eutectic (silver

copper) alloy particles.

• The content of copper may vary from

9–20%.

Single Composition/All in One Alloy

• In this powder, each particle of the alloy has the same chemical

composition

• The copper content in various single composition alloys ranges from

13–30%.

Based on Zinc:

• Zinc Containing Alloys :Zn > 0.01%

• Zinc free alloys : Zn < 0.01%

small amount of zinc in high-

copper reduces brittleness

Based on Copper:

• Low copper : Cu < 5%

• High copper: Cu 6-30%

high early strength, low creep,

good corrosion resistance, marginal

fracture resistance

Classification

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Based on Particles’ Shape:

• Irregular(Lathe-cut)

• Spherical

• Admixed

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ALLOY MERCURY REACTION

• The reaction of low copper alloy and mercury, traditionally take

Silver and Tin, without taking copper and zinc.

The reaction is:

AgSn + Hg ⎯→ AgHg + SnHg + AgSn

γ γ1 γ2 γ

• The γ or the AgSn are the unreacted particles.

• γ2 is responsible for corrosion

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• In case of high copper admixed alloys the reaction is different. The

reaction occurs in two phases.

• The first phase is equivalent to the one as shown in conventional

alloys, i.e.

AgSn + Hg ⎯→ AgHg + SnHg + AgSn

γ γ1 γ2 γ

• The second phase is the eutectic of silver copper phase, which are

called α1 and α2.

• Here α1 is silver rich and α2 is copper rich.

AgSn + AgCu + Hg ⎯⎯⎯→ AgHg + AgCu + Cu3Sn + Cu6Sn5 + AgSn

γ α1 + α2 γ1 α1+ α2 ε η γ

Mercury Toxicity

.

The amount of mercury released from the amalgam in service issmall compared with other sources of mercury from air, water,and food.

Amalgam Alternative: Gallium Alloy

1. Mercury free.

2. Early setting can polished in the same visit

3. Better marginal Seal.

4. More costly.

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AgSn + Ga ⎯⎯→ AgGa + Sn

What about dental office personnel?

A potential hazard exists from long-term

inhalation of mercury vapor in the dental clinic.

The dental clinic should be well ventilated.

All mercury waste and amalgam scrap removed

during placement or removal of amalgam

restorations should be collected and stored in

well-sealed containers.

• When amalgam is cut, water spray and high-speed

evacuation should be used.

• Biologically contaminated wastes containing mercury,

including extracted teeth, should be cold sterilized with a

chemical agent before disposal.35

Modifications and Recent Advances in Amalgam

• However, instead of amalgam being such a durable materials it has many drawbacks associated with it one of which is microleakage.

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Bonded Amalgam Restoration

• To overcome one of the major disadvantage of silver, i.e. it does not adhere

properly to cavity walls, adhesive systems designed to bond amalgam to

enamel and dentin have been introduced.

• E.g. Superbond, Pnavia.

• Superbond was based on 4- META/Methyl methacrylate—Tri-n-butyl borane

(MMA-TBB) resins

• Panavia was based on a BisGMA phosphonated ester.

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Resin Coated Amalgam

• To overcome the limitation of microleakage with amalgams, a coating of unfilled resin over the restoration margins and the adjacent enamel, after etching the enamel, has been used.

• Resin may eventually wear away, it delays microleakage until corrosion products begin to fill the tooth restoration interface.

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Mertz-Fairhurst et al. evaluated conservative amalgam restorations

and conventional unsealed amalgam restorations and concluded

both types of sealed restorations exhibited superior clinical

performance and longevity compared with unsealed amalgam

restorations over a period of 10 years

Fluoridated Amalgam

• Fluoride, included in amalgam to deal recurrent caries associated with

amalgam restorations.

• Studies by Skartveit et al. investigated fluoride levels released from

amalgam and concluded fluoride release can occur for several weeks after

insertion of the material .

• Increase of up to 10-20-fold in the fluoride content of whole saliva could be

measured

• The fluoride amalgam thus serves as a "slow release device"

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Powder Coated Technology

• Direct Filling Silver Alternative to Amalgam

• A precipitated Ag powder was rinsed with dilute fluoro boric acid and

consolidated into a cohesive solid with a dental amalgam plugger at a

load of 15 N.

Properties:

• A flexural strength equal to that of amalgam.

• Smooth surface and hardening in Ag was obtained

• More resistance to wear-induced damage than amalgam.

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Advantages:• The amalgam adhesive restorations technique offers advantages over non-

adhesive treatment alternatives.

• It is a treatment option for extensively carious posterior teeth, with a lowercost than either cast metal restorations/ metal ceramic crowns.

• It allows the use of amalgam in teeth with low gingival- occlusal height.

• It permits more conservative cavity preprations.

• It eliminates the use of retentive pins and their inherent risks

• It reduces marginal leakage to minimum.

• It reinforces tooth structure weakened by caries and cavity preparation.

• It reduces the incidence of postoperative sensitivity commonly observed withamalgam restorations

• It allows definitive restorations of a tooth with badly broken down crown inone clinical session.

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Limitations

• It increases the time to perform a conventional amalgam and

may be technique sensitive.

• It requires practitioners to adapt to the new technique

• It increases the cost of amalgam restoration.

• No long clinical studies and evaluations reported.

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Restorative Resin

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The term composite material refers to a combination of at least

two chemically different materials with a distinct interface

separating the components. Its provides properties that could not

be obtained with any of the components alone.

In a resin composite dental restorative material, an inorganic filler

has been added to a resin matrix in such a way that the properties

of the matrix have been improved.

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The resin matrix of many currently available composite

materials is bisphenol A–glycidyldimethacrylate (bis-

GMA) or urethane dimethacrylate resin.

Fillers are ground particles of fused silica, crystalline

quartz, and soft glasses such as barium, strontium, and

zirconium silicate glass.

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The filler and the resin matrix must be chemically bonded

together with a coupling agent on the surface of the filler.

If this is not done, the particles may be easily dislodged,

water sorption at the filler- matrix interface may take place,

and stress transfer between matrix and filler may not occur.

The filler particles are coated with a reactive silane product.

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1. Esthetic.

2. Conservative cavity.

3. Low thermal conductivity.

4. Quite resistance to microleakage.

5. No corrosion.

6. Strengthening of the remaining tooth

structure.

to residual

1. Polymerization shrinkage.

2. High coefficient of thermal expansion.

3. Pulp irritation due

monomer .

4. Low wear resistance.

5. Technique sensitive.

Advantages

Disadvantages

Resin Restoration

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Classification based on method of curing:

1) Chemical cure.

2) Light cure.

3) Dual cure.

48

Classification based on size of partials:1. Conventional (Macro-filled) Composite

The fillers in conventional composites is in the 8 to 12 µm range.

wear resistance + surface roughness .

2. Micro-filled Composite

Use of an extremely small silica filler particle, whose size is 0.02 to0.04 µm.

microfine, microfilled, or polishable resins.

Improve the surface smoothness and polishability of composite resins

Softer composite and have a slightly higher coefficient of thermalexpansion, a higher water absorption, more polymerization shrinkage,and lower mechanical properties.

Use: 1) Esthetic Area 2) stress free areas (class III or class V ).

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3. Small-particle composites

have an average filler size of 1 to 5 µm, with a broad distribution of sizes.

Best combination of physical properties of all the currently available

composites.

Use: stress-bearing applications such as class IV and class II

restorations.

4. Hybrid composites

The most recent step toward smaller particle size.

They contain filler with an average size of 0.6 to 1.0 µm in addition

to 10% to 20% colloidal silica.

Use: 1) anterior teeth if carefully polished.

2) Material that could compare favorably with dental amalgam in

wear resistance in class I and II.

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5.Nanohybrid composites:

They have superior esthetic and wear resistance, high polishability, and

superior handling characteristics.

They are marketed as universal composites.

Because their handling and esthetic qualities make them suitable for

anterior buildups, while their micro sized particles gives them very

acceptable wear resistance.

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6. Flowable composites :• This material has made it possible to fill small cavities on occlusal

surfaces.

• Often used to seal the dentin of a tooth prior to placing the fillingmaterial.

• Due to the low level of filler particles, flowable composites are moreprone to shrinkage and wear, so they are generally not used in bulk to filllarge cavities.

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Posterior composite.

The improved strength, hardness, and modulus of elasticity of

some of the newer composite resins, with their low thermal

conductivity and superior esthetics, indicate that they may serve as

alternatives for amalgam.

Disadvantages

Posterior class II restorations often have gingival margins in dentin

or cementum >> No direct access to light cure >> physical

properties and colure changes >> management by increment

curing.

Curing shrinkage >> microleakage .

It compromised by moisture contamination during placement.

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Pits and fissure sealant

Types:

1. Opaque materials are available in tooth color or white.

2. Transparent sealants are clear, pink, or amber.

The clear and tooth-colored sealants are esthetic but are difficult todetect by examiner.

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The cariostatic properties of sealants:

• The physical obstruction of the pits and grooves.

• Prevents colonization of the pits and fissures with new

bacteria

• Prevents the penetration of fermentable carbohydrates

to any bacteria remaining in the pits and fissures.

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Indications :

1) Deep retentive fissures.

2) No evidence clinically / radiographicaly of proximal caries.

3) High caries risk patient.

4) Stained pits and fissures with appearance of declassification.

5) Tooth in the mouth less than 3 years.

• Contraindications:

1) Well coalesced , self cleansing pits and fissure.

2) Clinically / radiographically evidence of proximal caries.

3) Tooth not fully erupted.

4) Isolation not possible.

5) Dental caries

6) Tooth in the mouth 3 years and more.

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Acid Etching Technique

One of the most satisfactory methods for mechanical bonding of

resin to enamel .

The enamel is etched with a solution of phosphoric acid (usually

about 35%) for approximately 15 to 20 seconds.

57

Use a water rinse to remove the debris produced during

etching. A

minimum wash time of 30 seconds .

The acid cleans the enamel to provide better wetting of

the resin and creates pores into which the resin flows to

produce “tags” that greatly increase retention.

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Bonding Agent

Enamel bonding >> mechanical bonding to tooth structure.

The dentin-bonding systems >> removal of the dentin smear layer

and decalcification of the outer layer of intact dentin with an acid

(primer).

It is important that the etched dentin surface not be desiccated

before application of the primer when systems with hydrophilic

primers are used.

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Systems combine the primer and the resin adhesive

into one component.

Systems mix together the acid, primer and resin

adhesive before

They are placed on the tooth surface (self etching).

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GENERATION TIME

PERIOD

DEVELOPMENT

1 1950-1970 Experimentation with mineral acids for bonding acrylic

to enamel, concern about etching of dentin, bonding

agents not utilized with composites.

2 Early 1970s Acid etching of enamel, enamel bonding agents

3 Late 1970s Hydrophobic enamel bonding agents, hydrophilic

dentin bonding agents, light cured components.

4 Mid to late

1980s

Removal of dentin smear layer, acidic monomers and

acidic pretreatments,, reduction of steps in bonding

technique, multiuse bonding agents.

5 Early 1990s Etching to achieve hybrid layer in dentin, hydrophilic

agents for both enamel and dentin, bonding to moist

tooth structure, single bottle primer adhesives.

6 Mid to late

1990s

Self etching primers and primer adhesives, light and

dual cured options

7 Early 2000s No mix, self etching adhesives. 61

Ideal Requirements for Bonding Agent:

Biocompatible.

Non toxic, non irritant, non poisonous.

Low film thickness, low viscosity.

Form strong permanent bond.

Good dimensional stability.

Low thermal conductivity.

Good shelf life.

Prevent micro leakage.

.62

Indications:

All direct composite resin restoration, both anterior& posterior.

For bonding indirect composite resin inlays, onlays and

veneers.

For bonding indirect ceramic veneers , inlays and onlays.

Bonded amalgam restorations.

Management of dentin hypersensitivity

63

RECENT ADVANCES IN COMPOSITES

PACKABLE COMPOSITES

• It was as early as 1980s that the first packable composite

formulations were designed but the first packable composite to be

marketed i.e. Solitare was introduced in 1997.

64

The distinguishable feature are:

• less stickiness and higher viscosity(stiffness),

• increased depth of cure, increased resistance to wear.

• While it is important for the composite not to stick to the

instrument, it is important for it to stick to the cavity walls.

• Therefore the manufacturers have eliminated stickiness by

slightly altering the filler content, and at the same time

reducing the matrix viscosity by using varied matrix monomers

(Eg. Polyglass monomer, ethoxylated Bis-GMA, UDMA).

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• Polymerization shrinkage: similar to or greater that that of

non packable material solitaires highest value extending 3 %.

• Radiopacity: all packable composites, except solitaire have

radiopacity exceeding 2 mm of aluminimum. Solitaire may be

due to low volume of radiopaque filler and chemical

composition of the fillers.

66

FLOWABLE COMPOSITES

• Low viscosity materials having particle size and size distribution similar to

those of traditional hybrid composites.

• First generation: Introduced in late 1996, just before condensable

composites.

• Have reduced filler content ( 20-25% less) which allows increased amount

of resin to decrease the viscosity of the mixture.

• In general their mechanical properties are inferior to that of hybrid

composites. Based on these properties, all the flowable composites are

acceptable as filling materials in low-stress applications.

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Composition:

• Monomer matrix: Bis-GMA, UDMA, TEGDMA (31.5% wt.)

• Inorganic filler particles: Barium glass, Ytterbium fluoride, Ba-

Al-fluorosilicate glass, highly dispersed SiO2 and spheroid

mixed oxide (43.8% vol. 68.1% wt).

• Other components: Catalysts, Stabilizers & Pigments (0.4%

wt.)

68

BASES AND

LINERS

69

• ‘Base’ is the material, which is applied over the pulpal/axial

wall and act as a substitute for lost dentin.

• The thickness of the base depends upon the amount of

dentin lost.

• The total bulk (dentin + base) should be at least 2.0 mm.

• The bases provide mechanical, chemical and thermal

protection to the pulp.

70

• The term ‘liner’ is used for those materials, which can be

applied to a cavity surface in a relatively thin film.

• The thickness of liners usually does not exceed 0.1 mm

• Apart from providing thermal and chemical insulation, the

liners fill the minor intricacies between the tooth and the

restorative material.


LINING MATERIALS

1. ZINC PHOSPHATE CEMENT-

• Was used extensively coz it was thought to accept load

imparted to dentin

• It is now known to be irritating if close to pulp

• It is regarded as out dated now.

• pH of zinc phosphate cement is approximately 3.5, increases

rapidly approaching neutrality in 24-48 hrs. Thus, any damage

to pulp from acid attack occurs during first few hours after

insertion. Hence, pulp protective measures are required

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Zinc Phosphate Cement(Pierce in 1879)

LINING MATERIALS

2. ZINC OXIDE EUGENOL

• Became popular due to antibacterial properties of

eugenol and sedative effectiveness of zinc oxide.

• Used as a temporary sedative dressing over a large cavity

with an inflamed pulp, provides a seal around cavity.

• Weak, so cannot provide support to amalgam

restoration.

• EMBONTE ZOE- Creamy consistency with mixing tip for

direct application

Zinc Oxide- Eugenol

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POWDER• Zinc oxide 70%• Rosin 30%

LIQUID• Eugenol 100%

TYPES

• Conventional

• Resin reinforced

• EBA (Ortho Ethoxy Benzoic Acid) - Alumina reinforced

CONVENTIONAL ZOE

COMPOSITION

Theodore M, Roberson, Harald O, Heymann, Edward J. Swift Jr. Sturdevant's art & science of operative dentistry. 4th ed. Mosby, 2002.

75

RESIN REINFORCED

Powder: • 70% Zinc Oxide• 30% alumina 70%

EBA - ALUMINA REINFORCED

Liquid:• EBA-62.5%, • Eugenol-37.5%.

Theodore M, Roberson, Harald O, Heymann, Edward J. Swift Jr. Sturdevant's art & science of operative dentistry. 4th ed. Mosby, 2002.

ADVANTAGES

• Anti inflammatory effect: Eugenol in low doses causes resolution of

mild inflammation. It inhibits neutrophil function , removes harmful

free radicals and inhibit prostaglandins.

• Sedative effect: At low concentrations, eugenol acts like a local

anesthetic. It decreases intra-dentinal fluid activity minimizing the

sensitivity to hot, cold or sweet.

• Bactericidal effect: at high concentration 102–103 mol/L.

DISADVANTAGES

• Cytotoxic effect to pulp: at high concentration.

• Poor mechanical properties

• High solubility in the oral cavity.

3. CALCIUM HYDROXIDE-(Herman)

• Antibacterial properties as well as, excess calcium ions

present would be available for remineralization within

pulp chamber.

• Highly alkaline, ph=13, inability of bacteria to thrive.

• Lays down calcific barrier. Free calcium ions are available

in the blood allow pulp to carry out repair process.

• Dycal, the commonly available calcium hydroxide

preparation consists of two tubes; one containing

base and the other catalyst

LINING MATERIALS

Base

• Zinc oxide

• Calcium phosphate

• Calcium tungstate

• Iron oxide

• 1,3 butylglycoidisalicylate

Catalyst

• Calcium hydroxide

• Zinc oxide

• Zinc stearate

• Iron oxide

• N-ethyl p-toluene sulfonamide

COMPOSITION

Dycal


RECENT MODIFICATIONS IN RESTORATIONS

1. PREVENTIVE RESIN RESTORATION

2. ART RESTORATIONS

3. SMART MATERIALS

4. AMORPHOUS CALCIUM PHOSPHATE

5. ARISTON pHc ALKALINE GLASS RESTORATIVE

6. SMART CERAMICS

PREVENTIVE RESIN RESTORATION

• It utilizes the invasive and non-invasive treatment of borderline caries

• Types-

1. Gp-A: Deep pit and fissure susceptible to caries

2. Gp-B: minimal exploratory carious lesion

3. Gp-C: Isolated carious lesion

• Steps of placement and technique are same as for resin restoration

• Advantages: – Minimal cavity preparation is required.

– Seals caries thereby halting destruction of tooth.

– Loos of restoration and subsequent replacement proves to be less invasive

– Fluoride release benefits

– True adhesion to enamel & dentin

• Disadvantages:– Technique sensitive

– Poor wear resistance

ART RESTORATIONS

• Placement of a restoration in a large occlusal cavity can

be done by ART or atraumatic restorative technique

• Method: hatchet with blade used in opeing through

enamel. Spoon excavators to clean walls and floor to

remove infected dentin. A conditioner is used before

placement of GIC. Cover the cement with Varnish to keep

free from contamination.

• Adjust the occlusion using spoon excavators.

SMART MATERIALS

• A key feature of smart behavior includes its ability to return to theoriginal state even after the stimulus has been removed.

83

SMART GLASS IONOMER CEMENT

• Wide temperature fluctuations may occur in

the oral cavity due to the intake of hot or cold

food and fluids.

• Hence, the restorative materials placed in this

environment may show thermal expansion or

contraction in response to thermal stimuli.

• The coefficient of thermal expansion (CTE) is

normally used to describe the dimensional

changes of a substance in response to thermal

change.

84

SMART COMPOSITES

• “Term smart materials refer to a class of materials

that are highly responsive and have inherent

capability to sense and react according to the

changes in the surrounding environment.”

• Smart Materials:

a) Smart Alloys.- NiTi, Cu-Zn, Cu-Sn.

b) Smart burs

c) Smart Ceramics

d) Smart composites

85

SMART CERAMICS

• Were initially used to veneer teeth now also used for full coverage crowns and recently to replace missing teeth

• Uses:

1. Porcelain veneer restoration

2. Full-cast or porcelain-fused-to-metal crown restoration

Ariston pHc Alkaline Glass Restorative Material

• It is a light-activated alkaline, nano-filled glass

restorative material recommended for the

restoration of class I and II lesions in deciduous and

permanent teeth.

• It is an “intelligent” restorative material because it

releases calcium, fluoride, and hydroxyl ions when

intraoral pH values drop below the critical pH of

5.5; it counteracts the demineralization and

promotes remineralization.

• The material can be adequately cured in bulk

thicknesses of up to 4 mm 87

ACP-releasing Pit and Fissure Sealants

It is considered as a “smart material” because:

• It acts as a reinforcement of the natural defense mechanism of the tooth only

when needed.

• It has long life and there is no wash-out.

• Patient compliance is not required.

Examples include Aegis Pit and Fissure Sealant produced by Bosworth.

88

Fluoride-releasing Pit and Fissure Sealants

• There are two common methods of fluoride incorporation into fissure sealant materials: (a) The anion exchange system (organic fluoride compound chemically bound

tothe resin) and

(b) Addition of fluoride salt to the unpolymerized resin.

• The mechanism of fluoride release from the fluoride fissure sealant remains speculative. Fluoride release might occur from the insoluble sealant material as a resultof porosity.

• It might also occur because the fluoride ionor the fluoride glass is not tightly bound to the polymerized resin molecules.

• Examples are Fluoroshield and Deltonplus

89

Conclusion

• As the field of dentistry is dependent on the use of different

materials.

• The use of smart materials promises improved reliability and

long-term efficiency because of their potential to select and

execute specific functions intelligently in response to various

local changes in the environment, thereby significantly

improving the quality of dental treatment.

90

REFERENCES

• Dean JA. Dental materials. Dentistry for the Child and Adolescent, McDonald and Avery’s, 1st

South Asia ed. Elsevier; 2016.

• Casamassimo, Fields, Mctigue, Nowak. Dental materials. Pediatric Dentistry Infancy through

Adolescence, 5th ed. Elsevier; 2013.

• Theodore M, Roberson, Harald O, Heymann, Edward J. Swift Jr. Sturdevant's art & science of

operative dentistry. 4th ed. Mosby, 2002.

• Anusavice KJ, Shen C, Rawls HR. Phillip’s Science of Dental Materials, 12th ed. Elsevier, 2013.

• Sikri VK. Textbook of Operative Dentistry. 4th ed. CBS Publishers & Distributors, 2017.

• DentistryTandon S. Textbook of Pedodontics, Vol 1, 3rd ed. Paras Medical Publishers, Dharya

Ganj, New Delhi, 2018.

• Marwah N. Textbook of Pediatric Dentistry, 3rd ed. Jaypee; 2014.

• American Academy of Pediatric Dentistry: Pediatric Restorative Dentistry. Pediatric Dentistry,

2016; 40(6).

• Jain P, Kaul R, Saha S, Sarkar S. Smart materials making pediatric dentistry bio-smart.

International Journal of Pedodontic Rehabilitation, 2017; 2: 55-59. 91

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