Restorative Materials in Pediatric Dentistry: Recent Advancements

RESTORATIVE MATERIALS
USED IN PAEDIATRIC
DENTISTRY
(Along with Recent Advancements)

GUIDED BY - PRESENTED BY -
Dr. Jitendra Kamini Singh
B.D.S. 3rd year

CONTENTS
 INTRODUCTION: NEED FOR DECIDUOS
DENTITION IN CHILDREN
 NATURE OF RESTORATIVE MATERIALS
USED IN PAEDIATRIC DENTISTRY
 REQUIREMENT OF AN IDEAL
RESTORATIVE MATERIAL
 VARIOUS RESTORATIVE MATERIALS
USED IN PAEDIATRIC DENTISTRY:
GLASS IONOMER CEMENT
COMPOSITE RESINS
AMALGAM
LINING MATERIALS

CONTENTS
RECENT ADVANCEMENTS IN
RESTORATIVE MATERIALS USED IN
PAEDIATRIC DENTISTRY
• ALTERNATIVE TO AMALGAM
• RECENT ADVANCEMENTS IN FIELD OF COMPOSITE
RESIN RESTORATIVE MATERIAL
• RECENT ADDITIONS TO G.I.C.
• SMART MATERIALS

INTRODUCTION : NEED FOR
RESTORATION IN PAEDIATRIC DENTISTRY
• Preservation Of Deciduous Teeth Until Their Normal
Exfoliation Is Essential Because:
1)They are considered essential in the development of the
oral cavity and maintaining a healthy oral environment free
of pain.
a) In adulthood , the face and jaws are smaller size are
present ,which are known as Deciduous or Primary
teeth.
b) With the growth , the jaw bones grow in size but the
teeth once fully formed do not grow in size. Hence ,
permanent teeth of large sizes erupt in oral cavity,
replacing deciduous teeth of smaller size.

INTRODUCTION : NEED FOR
RESTORATION IN PAEDIATRIC DENTISTRY

2) They provide a guide for permanent tooth eruption.
3) The root of deciduous teeth provides an opening for
the permanent teeth to erupt.
4) These teeth also help in speech and mastication.
6) Promote an aesthetic appearance.
7) Maintenance of arch length.

Nature of Restorative Materials Used
In Pediatric dentistry

In view of the limited lifespan of the deciduous teeth,
plastic restorative materials are used, which can be
placed directly into the cavity, especially for the first
molars because of the difficulties which may be
encountered in placing restorations such as gold inlays
or gold foils in a young patient.

Requirements of an Ideal Restorative
Material
1) Restoration of aesthetic
2) Maintenance of physical strength of the crown.
3) Preserving the anatomy of the occlusal surface and
thus preserving the inter arch relationship with the
opposing and adjacent teeth.
4) Prevention of further ingress of bacteria or their
byproducts into the micro spaces between the
restoration and tooth.
5) Long term adhesion between the restoration and
tooth to ensure complete isolation.

Various Restorative Materials used in
Pediatric Dentistry
1) Glass Ionomer Cement
2) Composite Resins
3) Amalgam

Glass Ionomer Cement

This material was developed by Wilson and Kent in
1971.
• These are adhesive tooth color anticariogenic
restorative material.
• It can be used as a luting cement, a lining under
another restorative material or as a restoration.
• It also known as Poly Alkenoate Cement and Alumino
Silicate Polyacrylic Acid (ASPA)

Classification of Glass Ionomer Cement

– On the basis of use:
• Type I: For Luting Cements
• Type II: For Restorations
• Type III: Liners and Bases
• Type IV: Fissure Sealants
• Type V: Orthodontic Cement
• Type VI: Core Build Up
• Type VII: Fluoride Releasing
• Type VIII: ART (Atraumatic Restorative Technique)
• Type IX: Deciduous Teeth


• According to other uses:
– For Intermediate Restoration
– In Sandwich Technique (As Adhesive Cavity Liners)
– In ART (Atraumatic Restorative Technique)
– In Deciduous Tooth


• Chemical Classification
1) Conventional Glass Ionomer Cement
2) Resin Modified Glass Ionomer Cement
(Conventional with addition of HEMA)
3) Hydrate Ionomer Cement (Also known as Dual Cure
Glass Ionomer Cement)
4) Tri Cure Glass Ionomer Cement
5) Metal Reinforced Glass Ionomer Cement


• Widely Accepted Classification of Glass Ionomer
Cement
• Type I: Luting
 Used in cementation of crowns, bridges and orthodontic
devices
 Powder : Liquid is approximately 1.5:1
Radio Opaque
• Type II: Restorative
• Type IIA: Restorative Aesthetic
– Used in all types of aesthetic restoration
– Auto Cure or Resin Modified
– Powder: Liquid is 3:1 or greater
– Radio Opaque generally
– High physical properties


– Type IIB: Restorative
» Restoration under high occlusal load
» Auto cure or resin modified
» Powder : Liquid is 3:1 or greater
» Radio Opaque
» Used as a denting substitute or as interim restoration.

• Type III: Lining or Base
– Simple lining under metallic restoration
– Powder: Liquid is 1.5:1
– Auto Cure
– Radio Opaque
– High Strength bases for lamination technique.

Composition of Glass Ionomer Cement

Glass = Formulation of glass powder
Ionomer = Ionomeric Acid with Carboxyl group
The three essential constituents of dental Ionomer
glasses are –
Silica (Si02), Alumina (Al2O3) and Calcium Fluoride
(Cafl2) or Fluorite CaF2)

Glass Ionomer Cement is a product of an Acid-Base
reaction.

Composition of Glass Ionomer
Cement
Powder
• The basic component is a Calcium Alumino Silicate Glass containing fluoride.
Its constituents are:
Calcium Fluoro Alumino Silicate Glass,
Lanthanum,
Strontium,
Barium or
Zinc Oxide
• It is possible to substitute the Calcium with Strontium and the percentage of
Fluoride in the formula can be varied.
• Phospate can be added to decrease the melting temperature and modify the
setting characteristics.
• Fine colloidal Silver can be sintered to the particles and amalgam alloy particles
can be added to the mix in an attempt to enhance the properties.

Cement
Liquid
Liquid is essentially a poly Alkenoic Acid.
• The usual acid is 40-55% solution of 2:1 poly acrylic or
Itaconic acid copolymer in water or a copolymer of malic
acid and poly acrylic acid.
• Its constituents are –
– Poly Acrylic Acid
– Itaconic Acid (Increases the reactivity and reduces the viscosity
and tendencies for gelation)
– Maleic Acid or Tricarboxylic Acid
– Tartaric Acid – Improves handling characteristics, increases
viscosity and working time and reduces setting time.

Cement
Role of Fluoride in Glass Ionomer Cement
• It lowers the temperature of fusion
• Improves the working characteristics of the cement
paste
• It increases markedly the strength of the set cement
• In moderate amount it enhances translucency
• Contributes to therapeutic value of the cement by
releasing fluoride over a prolonged period.

Setting reaction of Glass Ionomer
Cement

– When the glass ionomer cement powder and liquid
are brought together to form a paste the glass
powder which is basic reacts with liquid, that is
Acid, to form a salt hydrogel which is the binding
matrix
– Here water in the reaction medium forms a part of
Hydrogel.

Different Stages in the Setting
reaction
– Initially the surface of glass is attacked resulting in
decomposition of glass and release of aluminum
and calcium ions
– These aluminium and calcium ions then migrate
into the aqueous phase of the cement
– As the reaction proceeds the concentration of ions
and the viscosity of the paste increases
– Initially calcium ions form part of the cross linkage
with poly acrylic acid change to form solid mass.

Different Stages in the Setting
reaction
• Later within next 24 hours new phase is formed with
aluminium ions becoming bound to cement matrix
leading to more rigid set cement
• Calcium polyacrylate is responsible for final hardening
of the matrix.
• Sodium and Fluoride do not participate in the cross
linking of the cement
• Some sodium ions may replace Hydrogen ions of
carboxylic group, but rest combine with fluoride to
form NaFl which is uniformly dispersed

Different Stages in the Setting reaction

within the cement.
– Unreacted glass particles are coated by silica gel (that
form during removal of the cations from the surface of
the particles)
– Final set cement consists of agglomerated unreacted
powder particles surrounded by a silica gel in an
amorphous matrix of hydrated calcium and aluminium
polysalts.
ROLE OF MOISTURE CONTAMINATION AND
DEHYDRATION
During the setting process the cement should to protected
from two extremes-dessiccation and aqueous environment.

ROLE OF MOISTURE CONTAMINATION
AND DEHYDRATION
• This can be achieved in an atmosphere of 80%
relative humidity.
• The cement should be protecting by varnish or
petroleum jelly.
• After initial set but before the cement is fully
hardened a proportion of cement containing
Aluminium Calcium , Fluoride and Polyacrylate
containing ions are in a soluble form and so can be
dissolved out of the cement by aqueous fluid leading
to permanently weakened cement.

ROLE OF MOISTURE CONTAMINATION
AND DEHYDRATION
• If at this stage water is released out due to excessive
drying restoration will lose aesthetic appeal ,shrink and
become brittle.
• It may take one hour until the cement remains
vulnerable to moisture.
• Hardening continues for 24 hrs.
• Slow maturation continues over the period of months
and becomes more rigid and gather strength.

FACTOR AFFECTING SETTING
CHARECTERSTICS OF GLASS IONOMER
CEMENT

Role Of Fluorides: Fluoride forms metal complexes
that restore the binding of cations to anionic sites on
the polyelectrolyte chain and thereby delaying gelation
and prolonging working time. It also delays pH
dependent gelation .

ROLE OF TARTARIC ACID
It improves manipulation of the cement and increases
the strength of set cement.

FACTORS AFFECTING RATE OF SETTING OF
GLASS IONOMER CEMENT

• Glass composition -especially the Al2O3 / SiO2 ratio and
fluoride content.
• Fluoride prolongs the working time. Increased ratio –faster is
the set , shorter is the working time.
• Particle size- Finer the particles size-Faster is the set and
shorter is the working time..
• Addition of tartaric acid sharpens the set without shortening
the w.t
• Relative proportion of constituents in the cement mix i.e. glass
/ polyacid /tartaric acid / water .
• Greater proportion of glass and lower is the working time.
• Temperature of mixing-In higher temperature the faster is set
shorter is w.t.

PROPERTIES OF GLASS IONOMER
CEMENT
•Physical Properties
•Sets rapidly in the mouth
•Initial compressive strength is low (24 hrs.)-6.6MPa
•Hardness-70KHN
•Solubilty-0.7%
•Bioactive and possesses chemical bonding with the
tooth.
•Coefficient of thermal expansion is close to that of
tooth causing less micro leakage around the restoration.

PROPERTIES OF GLASS IONOMER CEMENT

ESTHETICS
Translucent material
Color is more stable. Resistance to stain is dependent on
good surface finish.
ADHESION
Permanently adheres to the unreacted enamel and dentin
chemically.
Principle barrier to adhesion is water.
Mechanism of adhesion-chelation of carboxyl group of the
polyacids with the calcium ions in the apatite of enamel and
dentin forming strong ionic bonds which increases the
strength as the material sets.
Surface conditioning also improves adhesion.

PROPERTIES OF GLASS IONOMER CEMENT

BIOCOMPATIBILTY
o Excellent marginal seal and fluoride release-Reducing the risk of secondary caries.
o Continuous Fluoride release occurs around the restoration- tooth interface(3mm) for a
period of 18 months.
o Acid groups are attached to the polymer molecule which have limited diffusibilty ,
hence the pulp affects are limited to areas immediate . It adjacent to the material.
o When fluid filled dentinal tubules are in direct contact with the unset material and
problem occurs
o High ionic concentration in the material cause dentinal fluid to rapidly diffuse outward
into the cement producing a change in the pulpal pressure creating pain and sensitivity.
o Hydrogen ions may move into the tubules towards the pulp and cause chemical
irritation.
o When the dentin thickness is less there is less fluid to buffer the acid.
o Inflammatory response of pulpal tissue towards G.I.C. is more than Zinc Phospate
cement and resolves in 20 days without formation of reparative dentin.
o It is said that lining of calcium hydroxide or zinc oxide eugenol is required , when less
than 0.5-1mm of sound dentin remains over the pulp.

MODIFIED GLASS IONOMER
CEMENT ”ANHYDROUS”
• In this modification , the liquid is delivered in a freeze dried
form that is incorporated in powder. The liquid to be used is
clean water only and this may enhance shelf life and facilitating
mixing.
• Another alternative is to use a dilute tartaric acid as the liquid
with dehydrated polyacrylic acid included in the powder.
• These alternatives makes it possible to use a polyacrylic acid with
a higher molecular weight, thus improving physical properties.
• The term anhydrous is actually a misnomer as its not possible
for ion transfer to occur in any material in the absence of water.

RESIN MODIFIED GLASS IONOMER
CEMENT
• These are materials which have a small quantity of a resin
into the liquid formula.
• Less than 1% of photo initiators are allowed for the
setting reaction to be initiated by light of the correct
wavelength .
• The advantages include early resistance to water uptake in
the nearly set cement as well as enhanced translucency.
• The resin utilized in these materials is Hydroxy Ethyl
Meth Acrylate(HEMA) and its incorporated into the
liquid in about 15-25% so as to have a powder liquid ratio
of about 3:1

NANO IONOMERS

• Nano-ionomers delivers greater wear resistance ,
esthetics and polish compared to other glass
ionomers while affecting fluoride release similar
to conventional and resin modified Glass ionomer
• In the first ever paste glass ionomer restorative
featuring nano filler technology, the product is
designed to be quickly and easily be mixed and
dispensed using dispenser.
• Eg.- Ketac Nano Light Curing Glass Ionomer
Restorative Material.

COMPOMER
• This is the term developed by manufacturer with a
claim to incorporate with a composite resin
• A compomer is a composite resin that was an
ionomer glass which is the major constituents of a
glass ionomer as the filler.
• There is also a small quantity of a dehydrated
polyalkenoic acid incorporated with the filler particles.
• The filler particles are held within an anhydrous resin
matrix and there is complete absence of water.
• Hence there can be no ion exchange, acid/base
setting reaction and material remains inert.

COMPOMER
• The setting reaction is lightly activated and there has
been a degree of water uptake into the restoration.
• a composite resin that was an ionomer glass which is
the major constituents of a glass ionomer as the filler.
• There is also a small quantity of a dehydrated
polyalkenoic acid incorporated with the filler particles.
• The filler particles are held within an anhydrous resin
matrix and there is complete absence of water.
• Hence there can be no ion exchange, acid/base setting
reaction and material remains inert.
• The setting reaction is lightly activated and there has
been a degree of water uptake into the restoration.

COMPOMER
• After water uptake there will be an ion exchange between
the glass and the rehydrated polyalkenoic acid followed by a
low grade fluoride release , but this will not be sustained at a
higher level.
• Since Fluoride uptake cannot take place a compomer cannot
be regarded as a fluoride reservoir.
• The most significant difference between the two materials is
the absence of ion exchange adhesion.
• The adhesive system used with a compomer is based on the
acid etch resin bond system found with all composite resins
• The %age of filler content is relatively low compared to
hybrid composite resins. However ,both water uptake and
wear factor are relatively high.

CERAMIC REINFORCED GLASS IOMOMER
• Ceramic reinforced polymer G.I.C. featured stronger
compressive , flexural and tensile strength as compared to
Amalgam.
• The main advantages is its excellent wear characteristics.
• Some other features include superior radio-opacity, high level
of Fluoride release, good biocompatibility and natural
adhesion to tooth structure.
• Material is excellent for core build-ups and posterior
restorations.
• Its available in white and a universal tooth shade.
• Also , water mix and powder/liquid versions are available.
• This material was mainly designed to match the strength and
durability of amalgam . The presently available ceramic
reinforced G.I.C. includes Amalgomer-CR

SETTING RECTION OF RESIN MODIFIED
GLASS IONOMER

The setting reaction of resin modified glass ionomer
is similar to the acid base reaction though at a
slightly slower pace.
The usual ionomer salt hydrogel will form along
with a poly HEMA matrix will be stimulated by light
activation subsequently an oxidation / reduction
reaction resin chains so that in the long run the
entire restoration will be set . This has been
designated as , “Tri-cure setting reaction”.

FACTORS AFFECTING SETTING RATE OF
R.M.G.I.
• Temperature of mixing slab: Lower the temperature of mixing slab , The
longer the working time and vice versa.
• However the temperature should always be above the dew point
• Powder-Liquid ratio-
• The higher the powder content the higher the physical properties.
• However the care should be taken too ensure that the materials are
properly dispensed before mixing.
• Setting reaction of compomer.
• These are essentially two different systems for initiating polymerizations in
a composite resin.
• The original material were all chemically activated , however they exhibit
an undesirable color shift.
• Subsequently, a system for light activation was developed and this has
proven to be relatively color stable.
• Its also possible to combine the two systems.

STEPS INVOLVED IN CLINICAL PLACEMENT
OF GLASS IONOMER CEMENT
Shade selection
Isolation of tooth , rubber dam is the material of choice.
Cavity Preparation – the objective is to remove all caries
and unsupported enamel.
Minimal extension is the keyword.
If the dentin thickness is 0.5-1mm,lining of calcium
hydroxide should be placed.
Surface prep-The surface smear is removed by pumice
wash. The tooth surface is conditioned with 10%
polyacrylic acid application for 10-15 seconds ,followed
by 30 seconds water rinse.

Cement is mixed according to the manufacturer
instructions
It should be mixed rapidly to gain working time and
should not be more than 45-60 seconds. The tooth
should be isolated all through.
Place matrix wherever possible and fill the cavity
with G.I.C.
Remove the matrix and immediately protect it with
waterproof material like varnish or Vaseline.
Trim the excess with scalpel, Rotary cutting
instruments should be used.

After the removal of excess material a layer of
protective material a layer of protective material is re
applied.
Finishing and polishing is done after 24 hrs.
Re-apply the protective material after finishing and
polishing .

CRITICAL PROCEDURES FOR GLASS
IONOMER RESTORATIONS
Surface conditioning to remove smear layer
P:L ratio must be maintained.
Mixing time- not more than 45-60 secs and
surface should be glossy due to polyacid that
has not participated in the reaction which helps
in bonding.

CRITICAL PROCEDURES FOR GLASS
IONOMER RESTORATIONS
Placement of material-with plastic instrument or injected.
Mixed material should be used within 5 minutes.
Surface finishing-Delayed for 24 hrs.
MODIFICATIONS OF GLASS IONOMER CEMENT
Its done to improve strength, fracture toughness and resistant
to wear.
SILVER ALLOY ADMIX-Mixing spherical amalgam alloy powder
with Type-I glass ionomer.
B.CERMET FUSING GLASS POWDER TO SILVER PARTICLES.
C.RESIN MODIFIED G.I.C.- to overcome moisture sensitivity and
low early strength.
Also, called as Light cured , Dual cured (LC and Acid Base
Reaction) , Tricure (dual cure and chemical cure) resin ionomer
compomers or hybrid ionomers.

COMPOSITION OF RESIN MODIFIED G.I.C.

Powder-Ion leachable glass
Initiator for light or chemical cure or both.
Liquid-Water
Polyacrylic acid/Polyacrylic acid with carboxylic
group modified with methacrylate and Hydroxy
ethyl meth acrylate monomer.

SETTING REACTION OF RESIN MODIFIED
Physical Properties
The difference is due to presence of polymerized resin
and less amount of water and carboxylic acid in liquid.
Tensile strength is higher than that of conventional
G.I.C.
Greater amount of plastic deformation.

SETTING REACTION OF RESIN MODIFIED
Bonding similar to conventional G.I.C.
Higher bond strength compared to composite
resin.
Greater degree of shrinkage due to
polymerization, lower water and carboxylic
content.
Reduced water sensitivity.
Transient temperature increase during
polymerization.

ADVANTAGES AND USES OF GLASS
IONOMER CEMENT
•Extended working time
•Improved physical properties
•More resistant to dehydration and cracking.
•It is a tooth colored material.
•It will adhere directly to both enamel and dentin
through an ion exchange method.
•Its biologically active, as its capable of releasing
fluoride , calcium and phosphate ions.

DISADVANTAGES OF GLASS IONOMER
CEMENT
•Its physical properties are not sufficient to
withstand heavy occlusal load in large restorations.
•Resistance to fracture is one of the main limitation
to the use of G.I.C.. Its generally quite satisfactory
for one surface lesion , but a two surface lesion is
always at risk.
•Resistance to fracture also depends on the particle
size of the powder and particle size distribution.

DISADVANTAGES OF GLASS IONOMER
CEMENT
Improvement in enhancement of strength of
G.I.C. can only be of chemical origin or through
of microporosities.
Resistance to abrasion and wear is a little less
than that of a composite resin.
They also remain susceptible to dehydration
throughout the lifespan, so patients with a dry
mouth, should not have their teeth restored
with glass ionomer.

COMPOSITE RESINS
Composite Resins were developed by R.L.BOWEN.
Since epoxy reins have some disadvantages or
shortcomings like slow cure and some tendency to
discolor, So , He combined the advantages of epoxy resins
and acrylic resins leading to the development of BIS-GMA
molecule . It has an aromatic ester of Dimethacrylate with
epoxy resin as the backbone and acrylic as the functional
reactive group.
Composite Resins are the only restorative material other
than glass ionomer cement ,to that has the ability to
restore esthetics and to develop and maintain adhesion in
oral environment.

CLASSIFICATION OF COMPOSITE RESINS

Classification Based on Filler Particle Size:
Megafillers >100 microns (megafilI)
Macrofillers =10-100 microns(macrofill)
Midfillers =1-10 micron (microfill)
Minifillers =0.1-1 micron (minifill)
Microfillers =0.01-0.1 micron (microfill)
Nanofillers =0.05-0.01 microns( Nanofill)
Picofillers =0.005 microns


Heavily Filled Materials contain inorganic filler
about 75 % Wt. or more
Lightly Filled Materials contain inorganic filler
about 66 Wt. %


CLASSIFICATION BASED UPON MASS PARTICLES SIZE OF
THE MAJOR FILLER
1.Conventional=8-12 micron meter
2.Small Particle=1-5 micron meter
3.Microfilled=0.04-0.4micron meter
4.Hybrid=0.1-1.0micron meter.


Classification based upon the method of polymerization
Self cure
Light cured

Composition Of composite materials
Resin Matrix : BIS-GMA is the most commonly used resin followed by Urethane
Dimethacrylate
Diluent monomer like methyl methacrylate monomer or Dimethacrylate monomers
such as : TEGDMA(TRIETHYL GLYCOL DIMETHACRYLATE),are used to attain higher filler
levels and to produce pastes of clinically usable consistencies.
TEGDMA allows extensive cross linking to occur between chains resulting in a matrix
that is more resistant to solvents , but also increase the polymerisation shrinkage.
Filler Particle: Improves the properties of the matrix material.
Reduces polymerization shrinkage, Reduces polymerization ,shrinkage, Reduces water
sorption and coefficient of thermal expansion.


Improves Tensile strength , compressive strength and
modulus of elasticity and abrasion resistance.
Materials used as fillers are-
Colloidal silica ,
Quartz ,
Barium ,
Strontium ,
Zirconium .

: Materials used as fillers
QUARTZ
It has been extensively used as filler in particularly in
conventional composites.
Advantages : Its chemically inert but its so hard that its difficult
to polish and may abrade opposing teeth are restoration.
Other materials are not as stable as quartz and may leach out
into aqueous medium.
Translucency of the filler must be similar to that of tooth
structure and its index of refraction must closely match that of
resin.
For BIS-GMA+TEGDMA combination refractive index is about 1.5
Most of the glass or quartz that are used as fillers have R.I. of
1.5

Coupling Agent
It provides a bond between the resin matrix and fillers ,
thus improving the physical and mechanical properties
and providing stability by preventing water from
penetrating along the resin filler interface.
Eg. - Organosilanes are commonly used
1) Titanates
2) Zirconates

INHIBITORS
Hydroquinones butylated hydroxytoluene (<0.01%)
Minimizes or prevents spontaneous polymerization . It
reacts with free radicals if formed.


UV Absorbers
To improve color stability
Eg - 2-Hydroxy-4-Methoxy Benzophenols

Activators
For self cure-Tertiary amine
For Light Cure-Light

Initiators
Self Cure- Benzoyl Peroxide ,
Light CURE-Alpha diketones like camphor quinones,
UV light- Benzoin Methyl Ether,

Pigments

PROPERTIES OF COMPOSITE RESINS

•Linear coefficient of thermal expansion is twice as
much as the value of Amalgam and 3-4 times greater
than that for tooth structures.
•Most composites can be practically cured only to
levels of 55-65% conversion of monomer sites.
Usually due to inadequate curing energy from visible
light cure unit and is improved by post curing.

•Water absorption swells the polymer portion and promotes diffusion and
desorption of any unbound monomer . Water plasticizes the composite and
chemically degrades the matrix into the monomer . Increased filler content
lower is water absorption.
•Microfill composites are the least wear resistant.
•Composite with high matrix content and self cured have more tendency to
undergo yellowing . Addition of white light absorbs and antioxidants reduce
the chance of yellowing.
•Beveling tend to blend any color difference associated with margins and
provide more surface area of bonding.
•Good Marginal integrity-
•Butt joint margin wear slowly but create a meniscus appearance against
enamel . Beveling produces thinner ledges of material that are prone to
fracture.
•Biocompatible, but unemployed materials are potentially cytotoxic. They are
very poorly soluble in water and are polymerized into a bound state before
dissolution or diffusion.


•Compared to unfilled resins ,filled resins are more
stronger ,increased modulus of elasticity(increased
modulus of elasticity= less is the flexibility and vice
versa) , good abrasion resistance and lower coefficient
of thermal expansion.

CLINICAL STEPS
• 1)Etching and Bonding
• 2)Delivery and Placement
• 3)Incremental Build Up
• 4)Depth of cure

CLINICAL STEPS - Etching & Bonding
An essential pre-requisite for the micro-mechanical attachment
is that the enamel should be etched with 37% Orthophosphoric
acid. To demineralize the enamel to a depth of 20-30 mm and
render it porous.
A very low viscosity unfilled resin is then flowed over the surface
and allowed to soak into the porosities for about 30 secs. before
its light activated . Composite resin is then built over resin bond.
Pre-Requisite for etching
First the enamel at the cavity margins must be fully mineralized
and based on healthy dentin.
There must be no crack on the tooth.
Best union will be at the ends of enamel rods rather than along
the long sides , so its desirable to develop a reasonably long
bevel at the cavosurface margin

In juvenile enamel there is less mineral or more organic
collagen. There will be more water present because of
the presence of dentinal tubules and their direct access
to pulp and the amount of fluid and their direct access
to pulp and the amount of pulp and the amount of fluid
flow will only be enhanced following acid etching
because it will lead to opening and funneling of tubules
Even a small cavity will be relatively close to pulp and
therefore there will be a greater density of tubules on
the floor of cavity and a relatively greater fluid flow.


The goal of resin dentin bonding agent is
to attach composite resins to healthy dentin and
to seal the dentinal tubules against the entry of
bacteria and their toxins.
This will avoid post restoration sensitively caries
and loss of restoration.
Its possible to demineralize some of the dentin.

PRINCIPLES TO SUCCESSFUL RESIN DENTIN BONDING
Dentin should be etched to remove smear layer and
dentin tubule plugs
Etching should be sufficient to demonstrate the
surface layer of intertubular and intratubular dentin
leaving collagen fibers exposed and available for a
mechanical interlock with resin.
Surface should be washed thoroughly to remove all
remaining etchant.

Surface should remain wet but not flooded.
Apply a hydrophilic primer containing acetone
or similar to guide and facilitate penetration of
resin adhesive around the exposed collagen
fiber.
Finally apply the resin adhesive and cure before
applying composite resins.

CLINICAL STEPS : Delivery &Placement

Chemical cure and the dual core materials will be
packaged as a paste /paste system or a powder /
liquid system.
To ensure proper adaptation to the cavity floor ,its
desirable to place the freshly mixed material into the
disposable syringe and then temp the material into
the cavity with a small plastic sponge .
Light activated materials will always be delivered in
light proof carpules or which have been loaded under
vacuum. This means they are free of porosity at the
time of delivery.

CLINICAL STEPS : Delivery and placement
Placement must be undertaken with care and attention
to detail with particular reference to the depth of cure
available through a curing light , by checking periodically
to ensure that lower layers are also cured adequately.
INCREMENTAL BUILD UP
Due to problems posed by light activation of composite
resins , its essential to any restoration deeper than that
about 2.0mm.
Incremental placement means placement of the
composite in small quantity in selected areas of the
cavity and then directing the light activating unit in such
a way that while curing the resin will shrink towards the
tooth structure rather than away from it.

• Its recommended that increments be as small as
possible . The activator be applied from many positions
during Buildup.

• DEPTH OF CURE
• In a child , its imperative that the activator light be
placed within 1-2mm of the surface of the newly placed
restoration , otherwise the depth of cure will be
limited.
• Factors to be considered while curing
• The degree of cure will decrease with increased depth
of cure, greater the translucency deeper the cure.
• Light activator units vary in their light output over time
as well as with power fluctuations.

• Tip of the light source should be placed as close as possible to the
restoration and should never be more than 4mm away.
• The depth of cure should be measured from the face of the activator light.
• Curing through tooth structure will reduce the depth of cure to the same
extent as if curing through a composite resin of similar opacity.

LIMITATIONS OF COMPOSITE RESINS
• Both resins and fillers are used anhydrous and completely inert .However ,
some of the minor constituents such as HEMA , have been identifiable in the
pulp tissue in certain mer chain may be an irritant to the pulp in circumstances
and care should be exercised in its use.
• Any unreacted polymer chain may be an irritant to the pulp and lead to post
insertion sensitivity.
• The tissue cells respond less favorably to composite resins then do to glass
ionomer and it has been postulated that incomplete cure of resin is the prime
cause of this.

CLINICAL CONSIDERATIONS
• IN Pediatric dentistry , a restoration will not be
expected to last for more than few years , so a limited
amount of wear an be tolerated.
• However , a relatively large setting shrinkage will be
undesirable.
• Esthetics and fracture resistance will not be of great
significance but the ability to bond effectively to both
the enamel and dentin will not be relevant
• A relatively shorter concentration span from the
patient as well as limited access to oral cavity , to
simplicity of placement technique will be important


• The operator must be aware of the relevant
properties of both composite resins and G.I.C. , so
that a logical decision regarding use can be made.

Amalgam
• Silver Amalgam restorative material is obtained by
the trituration of Amalgam alloy with mercury.
• It’s the most reliable and inexpensive dental
restorative material of all.

TYPES OF DENTAL AMALGAM ALLOYS

Based On the content:
• High Copper alloy : copper content more than
12%
• Low copper alloy : copper containing less than
6%
• Gallium alloy

Based on particle shape and type
• Lathe cut: Irregularly shaped filings produced by
cutting an ingot of alloy on a lathe.
• Spherical particles: Produced by atomizing the alloy
whilst still liquid into a stream of inert gas.

Based on Zinc content
• Zinc containing :Alloys with more than 0.01% Zinc
• Zinc free: Alloys with less than 0.01% Zinc

Based on Gamma2 content
• Amalgams may be classified as gamma 2
containing or gamma2 free
• A) low cu amalgam contain the Sn-Hg phase
which is called Gamma2 phase to distinguish it
from gamma2 phase of silver tin and silver
mercury alloy systems.
• B)Within several hours after amalgamation all
correctly manipulated High cu amalgams are
gamma2 free.

According to size
• Fine cut (particle size is 36 micron)
• Micro cut(particle size is 26 micron)

According to the method of dispensing
• As powder and liquid
• As a capsule
• As pellets or pills of alloy powder(3% of the Hg is
mixed with the alloy powder and this facilitates
faster reaction)

PROPERTIES OF AMALGAM

• Increased mercury – leads to increased expansion , creep
and corrosion.
• Compressive strength-Admixed is 430 Mpa after 7 days
• Tensile strength-Admixed is 50MPa after 24 hrs.
• Surface hardness – 3-8 mins.
• Setting Time-5-10 mins.
• Increased expansion is due to increased mercury ,short
trituration , low condensation pressure and water
contamination.
• Creep is associated with increased or decreased trituration
, time lags between trituration and condensation ,
increased mercury , less condensation force.

Criterion for selection of Amalgam
Alloy
• Small particles are selected ; Better strength, easy
to carve ,good surface finish , good marginal
adaptation , poor corrosion resistance.
• Spherical is selected: Better strength , easy to curve
, good finish , good marginal adaptation , good
corrosion resistance and easy condensation (Lathe
cut resists condensation, may result in poor
corrosion resistance , porous restoration with rough
surface and poor marginal adaptation).

Criterion for selection of Amalgam
Alloy
• High copper is preferred : Better strength less creep
, good corrosion resistance due to absence of
alpha2 phase.

DRAWBACKS OF SILVER AMALGAM
• Good conduction of Heat(Requires good insulation).
• Poor marginal adaptation : so varnish is applied.
• Poor esthetics

DRAWBACKS OF SILVER AMALGAM

• Poor modulus of elasticity , proportional limit,
and tensile strength.
• Electrolyte corrosion
• Poor adhesion to tooth structure.
• Ditched amalgam

CONDENSATION AND CARVING OF
SILVER AMALGAM
• Amalgam alloy and mercury is dispensed and mixed as per the
manufacturer’s instructions
• Material is loaded into the amalgam carrier
• Proximal box is first filled in a class II cavity
• In other cavities its started from one side slowly moving and filling the
entire cavity
• The material is firmly condensed into the cavity.
• Amalgam is condensed using condensers.
• Initial condenser should be small enough to condense the material into
the line angles.
• Each condensing stroke should be small enough to condense the material
into the line angles.
• Each condensing stroke should overlap the previous condensing stroke to
ensure that entire mass is well condensed
• Cavity is overfilled and condensed with a large condenser.
• Parallelogram condenser is used to condense narrow occlusal cavity.

CONDENSATION AND CARVING OF SILVER
AMALGAM
• This is followed by pre-carve burnishing of the amalgam . Its form
of condensation done with a large ball burnisher , using heavy
strokes mesiodistally and faciolingually . This helps to remove all
she excess Amalgam and blends the restorative material with
cavity margins.
• Initial gross carving of the restoration is done followed by fine
carving of cuspal inclines , triangular fossa and grooves .
Hollenbeck , wards or diamond amalgam carvers are used for the
purpose of carving amalgam
• Wedges and matrix placed can be removed after initial carving
• Post carve burnishing is done using a ball burnisher : It involves the
light rubbing of the carved surface to improve smoothness and
produces satin appearance.(not a shiny).insertion.
• Finishing and polishing is done after 24 hrs of insertion.

CONDENSATION AND CARVING OF SILVER
AMALGAM
• Mercury Hygiene - Precautions that should be taken regarding the
mercury exposure in dental office staff and the patients are:
• When removing an old amalgam restoration rubber dam should be
in place and high vacuum evacuation should be used . Glasses and
disposable free masks are worn
• Amalgam capsules should be preferred to the conventional
dispensing
• Closed amalgamator should be used
• Free mercury and amalgam scraps should be stored in an
unbreakable tightly closed container away from any source of heat
preferably in water.
• Since, mercury vaporizes at room temperature operatories should
be well ventilated to minimize the mercury level in air.
• Its necessary to place a lining material on the floor of the cavity
prior to placement of final restoration.

LINING MATERIALS
MATERIALS USED IN PAST AND
REASONS FOR USE

1)ZINC PHOSPHATE CEMENT
• This was used extensively may years ago on the theory
that it was strong enough to accept the load imparted
to the dentin by condensation of an amalgam
restoration.
• It was accepted that there was no therapeutic value in
this material and in fact , it has shown to be mildly
irritating if placed close to the pulp.
• Its outdated in the present.

LINING MATERIALS : MATERIALS USED IN
PAST AND REASONS FOR USE

2) ZINC OXIDE EUGENOL
This became popular because of the antibacterial property of
Eugenol as well as the sedative effectiveness of Zinc oxide
• Its used a s a temporary sedative dressing over a large cavity
with a n inflamed pulp.
• Its effective as it provides a seal around the periphery of a
cavity as a bacteria can not penetrate through Eugenol.
• Fast setting type were developed to allow this to be used
alone as a lining but as its relatively weak , it does not offer
support for an amalgam restoration placed over the top.

RECENT MODIFICATION
• Embonte Zinc Oxidizing Eugenol Temporary Cement
which is conveniently packaged in an Auto mix
delivery system.
• This is engineered with pure essential oil extracts.
• Creamy consistency of Embonte Auto mix allows
easy application from static mixing tip to crown.

LINING MATERIALS : MATERIALS USED IN PAST
AND REASONS FOR USE
3) CALCIUM HYDROXIDE
• Used as a liner because of its antibacterial property
as well as because of the theory that the excess
calcium ions present in the cement would be
available to the pulp and would encourage
remineralization within the pulp chamber.
• Its very alkaline with a pH 13 ensures the fact that
its very presence will make the bacteria unable to
thrive and help in stabilizing conditions on the floor
of the cavity.

• If placed to close necrosis of the subjacent soft tissue , but in
the absence of bacteria the pulp is likely to survive beyond
the necrotic area.
• It will then lay down a calcific barrier a short distance away
and it was assumed that it was calcium ions from the lining
which promoted the repair.

4 ) GLASS IONOMER
This is now a material of choice for lining the cavity because its
an effective barrier to temperature change and also – Gallium
alloy : A mercury free metallic substitute to silver amalgam ,
provides barrier to temperature change and also provides ion
exchange adhesion that is most effective barrier to micro
leakage of bacteria under a restoration

RECENT ADVANCEMENTS IN
RESTORATIVE MATERIALS USED
IN PEDIATRIC DENTISTRY
1) ALTERNATIVE TO AMALGAM-
• In view of hazards of mercury present in amalgam a
mercury free alloy has been suggested .
• Eg. - Gallium alloy : A mercury free metallic
substitute to silver amalgam

RECENT ADVANCEMENTS IN RESTORATIVE
MATERIALS USED IN PEDIATRIC DENTISTRY

2) RECENT ADVANCEMENTS IN FIELD OF
COMPOSITE RESIN RESTORATIVE MATERIAL
A) Dentil flow- Its a new flowable composite having
acceptable shear bond strength for bonding orthodontic
bracket , when used with an intermediate unfilled low
viscosity resin.
B) Packable composites - Its obtained by varying particle
size and size distribution through the water uptake and
wear factor will remain standard and acceptable .
Material is less sticky

RECENT ADVANCEMENTS IN FIELD OF COMPOSITE
RESIN RESTORATIVE MATERIAL

C) TETRIC EVOFLOW -It’s the new nano optimized
flowable composite form.
• Ivoclar vivadent and successor product of Tetric
flow
• Characterized by optimum surface affinity.
• Penetrates even into areas that are difficult to
reach.

RECENT ADVANCEMENTS IN
RESTORATIVE MATERIALS USED IN
PEDIATRIC DENTISTRY
3) RECENT ADDITIONS IN G.I.C.
a) Interval II Plus- Interval II Plus is a dependable , one
component , ready mixed , temporary filling material
with glass ionomer and leachable fluoride.
• With no ZnO /Eugenol , Its safe on resin based
materials.

RECENT ADVANCEMENTS IN RESTORATIVE
MATERIALS USED IN PEDIATRIC DENTISTRY
4) SMART MATERIALS -These materials though not
available commercially , retain the potential to
replace currently used ones
• These have been termed as ,”SMART”, as they are
consistent with the newer generation of materials
that support the remaining tooth structure with
cavity preparation done in a conservative manner.
• Some of these materials are biomimetic in nature
wherein there may be properties that mimic natural
tooth substance such as enamel and dentin better.

Ariston pHc restoration of tooth 24, class II, DO cavity (image
in a mirror) 12 months after the
filling placement. No signs of marginal leakage or fracture.

SMART MATERIALS IN DENTISTRY CAN BE
CLASSIFIED AS
RESTORATIVE DENTISTRY TYPES
A. Passive Smart Restorative Material Glass Ionomer Cement
Resin Modified Glass Ionomer Cement
Compomer
Dental Composite

B. Active Smart Restorative Material Smart Composites
Ariston pHC
ACP Composites
C. Prosthetic Dentistry Smart Ceramics
Smart Impression Material

SMART MATERIALS IN DENTISTRY CAN BE
CLASSIFIED AS
D. Prosthetic Dentistry Shape Memory Alloy
E. Preventive Dentistry Fluoride releasing pits and fissures
sealants
F. Endodontics Niti Rotary instruments

BRIEF INTRODUCTION : ACTIVE SMART
MATERIALS
1) AMORPHOUS CALCIUM PHOSPHATE-ACP: it’s a
vital antecedent in the biological formation of
hydroxyapatite .
ACP has two properties :
Preventive
Restorative
Due to the above mentioned properties its used in
dental cements and adhesives pits and fissure
sealants and composites.

Mechanism Of Action : ACP
- DEMINERALIZATION

- REMINERALIZATION

- BENEFITS OF ACP

BRIEF INTRODUCTION : ACTIVE SMART
MATERIALS
2) Ariston Phc : Alkaline Glass Restorative Material
3) Ivoclar – Vivadent (Liechenstien), introduced a
material in 1998 , Ariston pHC (pH control),which is
claimed to release fluoride , hydroxide and calcium
ions , when the pH in restorations of this material
falls to the critical Ph.
• This is said to neutralize acid and counteract the
decalcification of enamel and dentin.

Restorative Materials in Pediatric Dentistry: Recent Advancements

Restorative Materials in Pediatric Dentistry: Recent Advancements

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