Basic of composites

Chemistry of syntheticChemistry of synthetic
resinsresins ::
Synthetic resins are often called plastics.
Therefore It is these synthetic resins which impart property of a plastic workability
to the composites.
Now, These synthetic resins are composed of very large molecules. The particular
form and morphology will determine whether the plastic is a fiber, hard rigid
resin, or a rubber like product depending on this structure (we will get the final
rigidity of the composite.
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polymerizationpolymerization
process in which there occur a series ofprocess in which there occur a series of
chemical reactions by which a polymer ischemical reactions by which a polymer is
formed from the monomer is known asformed from the monomer is known as
polymerization.polymerization.

curing time would also affect the degree ofcuring time would also affect the degree of
polymerization, which is important.polymerization, which is important.
Clinically because the higher the mol. wt.Clinically because the higher the mol. wt.
the greater the stiffness. This stiffness isthe greater the stiffness. This stiffness is
an important. Clinical requirement.an important. Clinical requirement.
(according to PROFFIT.)(according to PROFFIT.)

PolymerizationPolymerization
.Condensation polymerization..Condensation polymerization.
.Addition polymerization..Addition polymerization.
Condensation polymerization:Condensation polymerization:
Condensation reactions result inCondensation reactions result in
polymerization plus the production of lowpolymerization plus the production of low
molecular weightmolecular weight by products.by products.

Addition polymerizationAddition polymerization ::
there is no change in composition duringthere is no change in composition during
additionpolymerization.Theseadditionpolymerization.These
macromolecules are formed from smaller.macromolecules are formed from smaller.
Units, or monomers, without change inUnits, or monomers, without change in
composition, because the monomer andcomposition, because the monomer and
the polymer have the same empiricalthe polymer have the same empirical
formulas. The structure of the monomer isformulas. The structure of the monomer is
repeated many times in the polymer.repeated many times in the polymer.

STAGES IN ADDITIONSTAGES IN ADDITION
POLYMERIZATIONPOLYMERIZATION
Induction :Induction :
To start addition polymerization process,To start addition polymerization process,
free radicals must be present. Freefree radicals must be present. Free
radicals can be generated by activation ofradicals can be generated by activation of
monomer molecules with U.V. Light,monomer molecules with U.V. Light,
visible light, heat or energy transfer fromvisible light, heat or energy transfer from
another compound that acts a free radicalanother compound that acts a free radical

 This free radical is known as the initiator. MostThis free radical is known as the initiator. Most
commonly employed initiator iscommonly employed initiator is benzyl peroxidebenzyl peroxide
which decomposes into 2 free radicals.which decomposes into 2 free radicals.
 Another term is activator. This activatorAnother term is activator. This activator
activates the initiator of in turn this initiatoractivates the initiator of in turn this initiator
initiates the polymerization.initiates the polymerization.

Thus, the process of polymerization canThus, the process of polymerization can
be activated in 3 ways.be activated in 3 ways.
-- HeatHeat which activates this initiator.which activates this initiator.
ChemicalChemical – most commonly used is– most commonly used is
tertiary amines (self-cure)tertiary amines (self-cure)
2 are separated, when mixed then2 are separated, when mixed then
polymerization begins.polymerization begins.
lightlight activatedactivated -- here photons (ofhere photons (of
energy) activate the initiator.energy) activate the initiator.

 Thus systems developed with visible lightThus systems developed with visible light
activated materials having a wave length ofactivated materials having a wave length of
470mm.470mm.
 In this system the initiation are camphorquinoneIn this system the initiation are camphorquinone
and dimethylaminoethylmethacrylate (DMAEM)and dimethylaminoethylmethacrylate (DMAEM)
 In this light intensity (therefore check machine)In this light intensity (therefore check machine)
and distance for light source are importantand distance for light source are important
(therefore keep gun as possible with out(therefore keep gun as possible with out
touching)are important.touching)are important.

Propagation.Propagation.
 Ideally, chains reactions should continue until allIdeally, chains reactions should continue until all
of the monomer has been converted to aof the monomer has been converted to a
polymer. However, the polymerization reactionpolymer. However, the polymerization reaction
is never complete.is never complete.

Termination :Termination :
 Can take place in 2 ways.Can take place in 2 ways.
 Direct coupingDirect couping
 Exchange of hydrogen atomsExchange of hydrogen atoms

Inhibition of polymerization.Inhibition of polymerization.
 Impurities in the monomer, as stated, inhibitImpurities in the monomer, as stated, inhibit
polymerization this impurity can react with thepolymerization this impurity can react with the
activated initiator or a growing chain, causingactivated initiator or a growing chain, causing
the inhibition.the inhibition.
 Eg.Eg. HydroquinoneHydroquinone is often added as anis often added as an
inhibitor in the monomer, to preventinhibitor in the monomer, to prevent
polymerization during storage.polymerization during storage.
 More importantly the presence of oxygen alsoMore importantly the presence of oxygen also
retards the polymerization reaction becauseretards the polymerization reaction because
oxygen reacts with the free radicals.oxygen reacts with the free radicals.
 Therefore we say that air thinning of bondingTherefore we say that air thinning of bonding
resins should be avoided to optimise curing.resins should be avoided to optimise curing.

CopolymerizationCopolymerization ::
 To custom design the physical properties of a polymerTo custom design the physical properties of a polymer
,two or more chemically different monomers, each with,two or more chemically different monomers, each with
some desirable property can be combined. The polymersome desirable property can be combined. The polymer
thus formed is called athus formed is called a copolymercopolymer. And its process. And its process
formation known asformation known as copolymerizationcopolymerization , thus the, thus the
polymer that would be formed would have propertiespolymer that would be formed would have properties
intermediate to those of the individual monomers,intermediate to those of the individual monomers,
depending on each components concentration.depending on each components concentration.

TYPES OF RESINS :TYPES OF RESINS :
 Acrylic resins :Acrylic resins :
These imbibe water, this water tends toThese imbibe water, this water tends to
separate the chains and to cause generalseparate the chains and to cause general
softening and loss of strength.softening and loss of strength.
- Methyl methacrylate.- Methyl methacrylate.
-Supplied as a liquid monomer and a powder-Supplied as a liquid monomer and a powder
these are mixed to form a dough and then curedthese are mixed to form a dough and then cured
like in fabrication of dentures in prosthodontics.like in fabrication of dentures in prosthodontics.
-However, a volume shrinkage of 21% accurs-However, a volume shrinkage of 21% accurs
during the polymerization of the pure methylduring the polymerization of the pure methyl
methacrylate monomer. This is too high.methacrylate monomer. This is too high.

Polymethyl methacrylatePolymethyl methacrylate ..
It is hard resin with a high tensile strength.It is hard resin with a high tensile strength.
It does not discolor, but has a tendency toIt does not discolor, but has a tendency to
absorb water by imbibition.absorb water by imbibition.

Multifunctional methacrylateMultifunctional methacrylate
systems.systems.
-These include the-These include the bis GMA, TEGDMA andbis GMA, TEGDMA and
UEDMAUEDMA which are used in compositeswhich are used in composites
and will be discussed later.and will be discussed later.

compositioncomposition
 Consists of following components.Consists of following components.
 Resin matrixResin matrix
 Inorganic fillerInorganic filler
 Coupling agent.Coupling agent.
 Activator - initiator system.Activator - initiator system.
 InhibitorInhibitor
 Other additivesOther additives
 Those to improve color stabilityThose to improve color stability
 PigmentsPigments

Resin matrix.Resin matrix.
Bis GMABis GMA
UEDMA (Urethane dimethacrylate)UEDMA (Urethane dimethacrylate)
TEGDMA (Triethylene glycolTEGDMA (Triethylene glycol
dimethacrylate)dimethacrylate)

The bis GMA have a high mol. Wt., but areThe bis GMA have a high mol. Wt., but are
very viscous at room temperature, the usevery viscous at room temperature, the use
of diluent monomers is essential to attainof diluent monomers is essential to attain
high filler levels and to use pastes ofhigh filler levels and to use pastes of
clinically usable consistencies. Diluentsclinically usable consistencies. Diluents
are usually TEGDMA However, theare usually TEGDMA However, the
addition Of TEGDMA increasesaddition Of TEGDMA increases
polymerization shrinkage, a factor thatpolymerization shrinkage, a factor that
limits the amount of TEGDMA that can belimits the amount of TEGDMA that can be
used in a composite. Also TEGDMAused in a composite. Also TEGDMA
increases crosslinking, which makes inincreases crosslinking, which makes in
material more resistant to degradation.material more resistant to degradation.

Filler ParticlesFiller Particles
 Filler particles commonly usedFiller particles commonly used silicon particlessilicon particles ofof
colloidal size ranging from 0.1 to 100 um. Compositescolloidal size ranging from 0.1 to 100 um. Composites
are often classified on the average size of the major fillerare often classified on the average size of the major filler
component.component.
 In addition to filler volume, level, the size, theIn addition to filler volume, level, the size, the
size distribution index of retraction, radiopacity andsize distribution index of retraction, radiopacity and
hardness are important in determining the properties andhardness are important in determining the properties and
clinical application of resultant composites to incorporateclinical application of resultant composites to incorporate
maximum amount of filler. It is obvious that if a singlemaximum amount of filler. It is obvious that if a single
particle, since is used, even with close packing, a spaceparticle, since is used, even with close packing, a space
will exsists between particles consider filling a box withwill exsists between particles consider filling a box with
marbles.marbles.

 But on important Aspect of composites used inBut on important Aspect of composites used in
orthodontics it itsorthodontics it its fluidityfluidity. It should be fluid. It should be fluid
enough. So as to provide adequateenough. So as to provide adequate micromicro
mechanical inter lockingmechanical inter locking the fluidity of thethe fluidity of the
composite depends upon the fluidity of the resincomposite depends upon the fluidity of the resin
and amount of filler. As the filler surface areaand amount of filler. As the filler surface area
increase this fluidity decreases. If there is aincrease this fluidity decreases. If there is a
large amount of small particle filler then thelarge amount of small particle filler then the
surface area of the filler particle increasessurface area of the filler particle increases
therefore we use composites with slightly largetherefore we use composites with slightly large
filler particle size.filler particle size.

 In order to ensure acceptable esthetics of aIn order to ensure acceptable esthetics of a
composite resin, the translucency of the fillercomposite resin, the translucency of the filler
must be similar to that of tooth structuremust be similar to that of tooth structure
becoming increasingly important in orthodonticsbecoming increasingly important in orthodontics
with the advent of transparent bracket systems.with the advent of transparent bracket systems.
 The radiopacity it provided by a number ofThe radiopacity it provided by a number of
glasses such asglasses such as barium, strontiumbarium, strontium andand
zirconium(zirconium(Barium may leach out in saliva ?)Barium may leach out in saliva ?)

Coupling agent:Coupling agent:
 It is important that the filler particles areIt is important that the filler particles are
bonded to the resin matrix, these allow thebonded to the resin matrix, these allow the
more flexible resin matrix tomore flexible resin matrix to transfer stressestransfer stresses toto
the stiffer filler particles.this bond is providedthe stiffer filler particles.this bond is provided
by the coupling agent.by the coupling agent.
 The coupling agent, therefore, improvesThe coupling agent, therefore, improves
physical and mechanical properties andphysical and mechanical properties and
provides hydrolytic stability by presenting waterprovides hydrolytic stability by presenting water
from penetrating along the filler resin interface.from penetrating along the filler resin interface.
Organosilanes such as r– methocryloxypropylOrganosilanes such as r– methocryloxypropyl
trimethoxy slane.trimethoxy slane.
 (MOPTM ) 1s used most commonly.(MOPTM ) 1s used most commonly. zirconateszirconates
may also be used.may also be used.

Activator initiator system. :Activator initiator system. :
This would depend on the type ofThis would depend on the type of
composite used,composite used,
-Chemically or self cured.-Chemically or self cured.
-Light cured.-Light cured.

Self curedSelf cured..
Here the initiator isHere the initiator is benzyl peroxidebenzyl peroxide..
While the activator is aWhile the activator is a
teritiaryamine(N-N dimethyl-P-teritiaryamine(N-N dimethyl-P-
toulidine)toulidine)

Light activated:Light activated:
 Initially the light activated systems used UVInitially the light activated systems used UV
light .light .
 however, exposure to light at the correcthowever, exposure to light at the correct
wavelength (approx. 468nm) produces anwavelength (approx. 468nm) produces an
excited state of the photo initiator and anexcited state of the photo initiator and an
interaction with the amine to form free radicalsinteraction with the amine to form free radicals
that initiate addition polymerization.that initiate addition polymerization.
 The commonly use photo initiator isThe commonly use photo initiator is
comphorginonecomphorginone (C-0 has an absorption range(C-0 has an absorption range
b/w 400-500 mm that is in the blue region of theb/w 400-500 mm that is in the blue region of the
visible light spectrum.visible light spectrum.

InhibitorsInhibitors
To minimize or prevent spontaneousTo minimize or prevent spontaneous
polymerization of monomers, inhibitors arepolymerization of monomers, inhibitors are
added to resin systems. A typical inhibitoradded to resin systems. A typical inhibitor
isis butylated hydroxytoluene.butylated hydroxytoluene.

Optical modifiers:Optical modifiers:
To match the appearance of teeth dentalTo match the appearance of teeth dental
composites must have visual colorationcomposites must have visual coloration
(shading) and translucency that can(shading) and translucency that can
simulate tooth structure.This is ofsimulate tooth structure.This is of
importance when using transparentimportance when using transparent
bracket systems. Shading is achieved bybracket systems. Shading is achieved by
adding differentadding different pigments.pigments. TheseThese
pigments often consist of metal oxides thatpigments often consist of metal oxides that
are added in minute amount.are added in minute amount.

All Optical modifiers affect the lightAll Optical modifiers affect the light
transmission ability of a composite, darkertransmission ability of a composite, darker
shades and opacifiers should be placed inshades and opacifiers should be placed in
thinner layers to optimize polymerization.thinner layers to optimize polymerization.
It is not of much clinical significance inIt is not of much clinical significance in
orthodontics because we use a very thinorthodontics because we use a very thin
layer of composite.layer of composite. However, it must beHowever, it must be
remembered thisremembered this property may affect theproperty may affect the
cure of a bonding agent covered with acure of a bonding agent covered with a
composite layer.composite layer.

Curing :Curing :
 The first composites were cured by a chemicallyThe first composites were cured by a chemically
activated polymerization process, calledactivated polymerization process, called cold curingcold curing..
Cold curing is initiated by mixing two pastes.Cold curing is initiated by mixing two pastes.
 This hadThis had 2 disadvantages2 disadvantages;;
 The operator had no control of the working time.The operator had no control of the working time.
 During the mixing process, it is almost impossible toDuring the mixing process, it is almost impossible to
avoid incorporating air bubbles into the mix. Oxygenavoid incorporating air bubbles into the mix. Oxygen
present hampers the polymerization.present hampers the polymerization.
 However, to over come these problems,materials thatHowever, to over come these problems,materials that
required no mixing were developedrequired no mixing were developed the light curethe light cure
composites, where light is used for the activation of thecomposites, where light is used for the activation of the
initiator system.initiator system.

 Advantages :Advantages :
 Insertion and proper placement of bracket can beInsertion and proper placement of bracket can be
completed before starting curing.completed before starting curing.
 Takes onlyTakes only 40 seconds40 seconds for curing while self-cure mayfor curing while self-cure may
take longer.take longer.
 Also, these are no so sensitive to oxygen inhibitionAlso, these are no so sensitive to oxygen inhibition
during polymerization.during polymerization.
 Drawbacks :Drawbacks :
 Tendency to shrink to towards the light source, resultingTendency to shrink to towards the light source, resulting
in a pull back in areas away for light source.in a pull back in areas away for light source.
 Complicating factors associated with a light source.Complicating factors associated with a light source.

 Modern light sources are hand-held devices that containModern light sources are hand-held devices that contain
the light source. The light source is usually athe light source. The light source is usually a tungstentungsten
halogen bulb.halogen bulb. White light generated by the bulbWhite light generated by the bulb
passes through a fitter that removes the infrared andpasses through a fitter that removes the infrared and
visible spectrum for wavelengths greater than 500nm.visible spectrum for wavelengths greater than 500nm.
There can be a significant difference in the output forThere can be a significant difference in the output for
various manufactured lights. For example, if the lightvarious manufactured lights. For example, if the light
intensity manufactured by a factor of four then 80-40intensity manufactured by a factor of four then 80-40
seconds may be required for a low intensity light toseconds may be required for a low intensity light to
achieve the same results as that produced by 20 to 60achieve the same results as that produced by 20 to 60
second exposure with a high intensity light.second exposure with a high intensity light.
 When attempting to polymerize resin through a ceramicWhen attempting to polymerize resin through a ceramic
bracket, the exposure time should be 2-3 times longer, tobracket, the exposure time should be 2-3 times longer, to
compensate for the reduction in light intensity.compensate for the reduction in light intensity.

PremmiadAbdul Wahabvarying light intensiPremmiadAbdul Wahabvarying light intensi

Light sources also generate different lightLight sources also generate different light
intensities over time, depending on theintensities over time, depending on the
quality of age of the lamp presence ofquality of age of the lamp presence of
contamination such as composite materialcontamination such as composite material
residue on the light tip, and the composite.residue on the light tip, and the composite.
Consequently, the light source should beConsequently, the light source should be
checked regularly and the operator shouldchecked regularly and the operator should
always place the light tip as close asalways place the light tip as close as
possible to the restorative material.possible to the restorative material.

 Composites are now available that combine coldComposites are now available that combine cold
curing and visible light curing components in thecuring and visible light curing components in the
same material. These are available as twosame material. These are available as two
pastes, one contains benzyl peroxide and thepastes, one contains benzyl peroxide and the
other a tertiary amine. When the Clinician mixesother a tertiary amine. When the Clinician mixes
the two pastes, and exposes them to light, boththe two pastes, and exposes them to light, both
cold curing and light curing are achieved withcold curing and light curing are achieved with
the same material. These materials are calledthe same material. These materials are called
dual – cure materials.dual – cure materials.

 Polymerization stress initially is relieved byPolymerization stress initially is relieved by
composite until it reaches the co-calledcomposite until it reaches the co-called “gel“gel
point”point” before this point the resin-basedbefore this point the resin-based
composite is flexible and accommodates tocomposite is flexible and accommodates to
relieve stress. After this gel point is reached, therelieve stress. After this gel point is reached, the
composite changes to an un-yielding state incomposite changes to an un-yielding state in
which shrinkage stress is transmitted to the toothwhich shrinkage stress is transmitted to the tooth
structure.structure. It has been observed that the longerIt has been observed that the longer
the pre-gel point time, the less the stress in thethe pre-gel point time, the less the stress in the
past-gel phase.past-gel phase.

 Now a days, high intensity energy out put lightNow a days, high intensity energy out put light
sources such assources such as plasm arc curing lightsplasm arc curing lights oror
laser curinglaser curing lights allow a reduction inlights allow a reduction in
polymerization rate. This results in a decreasepolymerization rate. This results in a decrease
of the pre-gel point time and may increase theof the pre-gel point time and may increase the
shrinkage stress. Another concern is that someshrinkage stress. Another concern is that some
of these light sources presents narrow band ofof these light sources presents narrow band of
light emission may not correspond to thelight emission may not correspond to the
absorption band of the photo initiators, resultingabsorption band of the photo initiators, resulting
in an incompletely cured resin. The operatorin an incompletely cured resin. The operator
should be cautious other using these alternateshould be cautious other using these alternate
sources of light to polymerize resin-basedsources of light to polymerize resin-based
composites.composites.

CLASSIFICATION OFCLASSIFICATION OF
COMPOSITECOMPOSITE
based on the size of the filler particles.based on the size of the filler particles.
On this basis we haveOn this basis we have
TraditionalTraditional - 8-12 um- 8-12 um
Small particleSmall particle -1-5 um-1-5 um
MicrofilledMicrofilled -0.04-04um-0.04-04um
HybridHybrid - 0.6-1.0um- 0.6-1.0um

PROPERTIES OF DIRECTPROPERTIES OF DIRECT
BONDING RESINS.BONDING RESINS.
 In light cured resins, the working time is thatIn light cured resins, the working time is that
chosen by the operator Setting and workingchosen by the operator Setting and working
times.times.
 The setting times for chemically activatedThe setting times for chemically activated
composite resin ranges from 3-5 minutes.composite resin ranges from 3-5 minutes. NowNow
composites are available with setting times of 60composites are available with setting times of 60
seconds.seconds. This short setting time has beenThis short setting time has been
accomplished by control of the concentration ofaccomplished by control of the concentration of
the initiator and accelerator., and the materialsthe initiator and accelerator., and the materials
harden rapidly once theyharden rapidly once they are exposed to curingare exposed to curing
light.light.

 . As mentioned earlier the. As mentioned earlier the depthdepth of the cure isof the cure is
limited and is dependent on several variableslimited and is dependent on several variables
such as material, color, location of light sourcesuch as material, color, location of light source
and the quality of the light source. The resinand the quality of the light source. The resin
paste should not be dispensed until it is to bepaste should not be dispensed until it is to be
used. Exposure to operatory lights for anyused. Exposure to operatory lights for any
appreciable time can initiate polymerization ofappreciable time can initiate polymerization of
the material, because these lights emit radiationthe material, because these lights emit radiation
in the 400-500nm range. About 75% of thein the 400-500nm range. About 75% of the
polymerization takes place during first 10polymerization takes place during first 10
minutes. The curing reaction occurs till about 24minutes. The curing reaction occurs till about 24
hrs, until when optimum physical properties arehrs, until when optimum physical properties are
not achieved.not achieved.

Polymerization shrinkagePolymerization shrinkage
 Polymerization shrinkage occurs due to higherPolymerization shrinkage occurs due to higher
density of the polymer formed.density of the polymer formed.
 Due to this polymerization shrinkage createsDue to this polymerization shrinkage creates
tensile stresses at the interface between thetensile stresses at the interface between the
resin and the tooth. These stresses severelyresin and the tooth. These stresses severely
strain the bond create with a low-viscositystrain the bond create with a low-viscosity
unfilled resin bonding agents against acidunfilled resin bonding agents against acid
etched enamel at cavity margins and can lead toetched enamel at cavity margins and can lead to
marginal leakage and early failuremarginal leakage and early failure

. It has been shown that this stress can. It has been shown that this stress can
exceed the tensile resistance of theexceed the tensile resistance of the
enamel and result in stress resistance ofenamel and result in stress resistance of
the enamel and result in stress crackingthe enamel and result in stress cracking
and enamel fractures along the bondedand enamel fractures along the bonded
interfaces. This potential forinterfaces. This potential for
polymerization shrinkage is even greaterpolymerization shrinkage is even greater
for microfilled resins.for microfilled resins.

Thermal propertiesThermal properties
 Coefficient of thermal expansionCoefficient of thermal expansion whichwhich
gives us the amount of expansion per unitgives us the amount of expansion per unit
increase in the temperature.increase in the temperature.

Thermal diffusivityThermal diffusivity: how fast the heat: how fast the heat
spreads within the resin.spreads within the resin.

WATER SORPTIONWATER SORPTION
Water sorption is greatly reduced inWater sorption is greatly reduced in
composites as compared to acrylic resinscomposites as compared to acrylic resins
due to the bis-GMAdue to the bis-GMA and lower amount ofand lower amount of
resin.resin.

SOLUBILITYSOLUBILITY
Water solubility of compositesWater solubility of composites
depends on the resinous matrixdepends on the resinous matrix
more than the filler.more than the filler. The acrylicThe acrylic
resins had higher solubility than theresins had higher solubility than the
current composites.current composites. This wasThis was
because the amount of residualbecause the amount of residual
monomer remainingmonomer remaining

MECHANICAL PROPERTIESMECHANICAL PROPERTIES
Plaque accumulationPlaque accumulation
In conventional composites for example,In conventional composites for example,
which the resinous matrix wears out, thewhich the resinous matrix wears out, the
large particles project above the surface.large particles project above the surface.
This causes a roughening and results inThis causes a roughening and results in
increased plaque accumulation.increased plaque accumulation.
 The smaller the particle size, the lesserThe smaller the particle size, the lesser
would he the plaque accumulation.would he the plaque accumulation.

Colour stabilityColour stability
This has gained importance due to theThis has gained importance due to the
advent of transparent bracket systems.advent of transparent bracket systems.
As mentioned color stability would not beAs mentioned color stability would not be
as good due to incomplete polymerization,as good due to incomplete polymerization,
due to water sorption and solubility.due to water sorption and solubility.
Otherwise, resins have observableOtherwise, resins have observable
change only over a 3 year period, which ischange only over a 3 year period, which is
more than sufficient for orthodonticmore than sufficient for orthodontic
treatment.treatment.

PRESENTATIONSPRESENTATIONS
These are available asThese are available as
light curedlight cured
self cured composites.self cured composites.

MATERIAL SELECTION.MATERIAL SELECTION.
According to Proffit.According to Proffit.
 The requirements of a bonding materialThe requirements of a bonding material
are.are.
Dimensional stability.Dimensional stability.
Adequate fluidityAdequate fluidity
StrengthStrength
Easy to use clinically.Easy to use clinically.
Less plaque accumulation.Less plaque accumulation.

GLASS IONOMERGLASS IONOMER
CEMENTSCEMENTS
Glass lonomer cements are adhesiveGlass lonomer cements are adhesive
tooth colored restorative materials whichtooth colored restorative materials which
were orignially used for restorations ofwere orignially used for restorations of
eroded areas.eroded areas. Now, it has been modifiedNow, it has been modified
to allow its use in other areas.to allow its use in other areas.

The name of the cementThe name of the cement is glass ionomeris glass ionomer
because, the powder isbecause, the powder is glassglass and theand the
setting reaction andsetting reaction and adhesive bonding toadhesive bonding to
tooth structure is due totooth structure is due to ionic bondionic bond..

synonymssynonyms
Poly (alkenoate )cementPoly (alkenoate )cement
GLC (galss lonomer cement)GLC (galss lonomer cement)
ASPA ( alumino silicate polyacrylic acid).ASPA ( alumino silicate polyacrylic acid).

APPLICATIONAPPLICATION
Anterior esthetic restorative materials forAnterior esthetic restorative materials for
class III cavitiesclass III cavities
For eroded areas and class V restorationsFor eroded areas and class V restorations
As a luting agentAs a luting agent
As liners and basesAs liners and bases
For core build up.For core build up.
To a limited extent as pit and fissureTo a limited extent as pit and fissure
sealant.sealant.

CLASSIFICATIONCLASSIFICATION
Type I – For lutingType I – For luting
Type II – For restorationsType II – For restorations
Type III – Liners bases.Type III – Liners bases.
 (Some authors include Type IV-fissure(Some authors include Type IV-fissure
sealant,sealant, Type V- ortho-dontic cemtnsType V- ortho-dontic cemtns andand
Type VI-core build up as part of theType VI-core build up as part of the
classification).classification).

COMMERCIAL NAMESCOMMERCIAL NAMES
Aquacem, Fugi I – Type IAquacem, Fugi I – Type I
 Chem Fil - Type IIChem Fil - Type II
Ketac bond - Type IIIKetac bond - Type III
Vitra bond - Light cureVitra bond - Light cure

AVAILABLE ASAVAILABLE AS
Power/liquid in bottlesPower/liquid in bottles
Pre-proportioned power/quid in capsulesPre-proportioned power/quid in capsules
Light cure systemLight cure system
Powder/distilled water (water settablePowder/distilled water (water settable
type)type)

compositioncomposition
POWDERPOWDER
silicasilica
aluminaalumina
Al flourideAl flouride
Ca flourideCa flouride
Na flourideNa flouride
Al PO4Al PO4

LIQUID:LIQUID:
poly acrylic acidpoly acrylic acid
tartaric acidtartaric acid
waterwater

Setting reaction :Setting reaction : ::
 When the powder & liquid are mixed together,When the powder & liquid are mixed together,
the acid liquid attacks the glass particles. Thusthe acid liquid attacks the glass particles. Thus
calcium, aluminium, sodium and flouride ionscalcium, aluminium, sodium and flouride ions
are leached into the aqueous mediumare leached into the aqueous medium , probably, probably
in the form of complexes.in the form of complexes.
 Calcium polysalts form first and later aluminiumCalcium polysalts form first and later aluminium
polysalts cross link the polynion chains.polysalts cross link the polynion chains.
 The salts hydrate to form a gel matrix, and theThe salts hydrate to form a gel matrix, and the
unreacted glass partcles are covered by a silicaunreacted glass partcles are covered by a silica
gel which arises from removal of cations fromgel which arises from removal of cations from
the surface of the particles.the surface of the particles.

Adhesion :Adhesion :
 GICs bonds chemically to toothGICs bonds chemically to tooth
structure. The bonding is due to thestructure. The bonding is due to the
reaction between the carboxyl groups ofreaction between the carboxyl groups of
the polyacids and the calcium in thethe polyacids and the calcium in the
enamel.enamel.

Anticariogenic propertiesAnticariogenic properties ::
 Glass ionomer releases flourides andGlass ionomer releases flourides and
continue to do so over an extended periodcontinue to do so over an extended period
of time.of time.
In addition due to its adhesive effect theyIn addition due to its adhesive effect they
have the potential for reducing infiltrationhave the potential for reducing infiltration
of oral fluids at the cement – toothof oral fluids at the cement – tooth
interface, thereby preventing secondaryinterface, thereby preventing secondary
caries.caries.

Resin modified glass ionomer:Resin modified glass ionomer:
These are relatively new materials havingThese are relatively new materials having
various names likevarious names like compomer, resin –compomer, resin –
inomers, RMGI, light cured GIC, dual cureinomers, RMGI, light cured GIC, dual cure
GIC and tricure GIC.GIC and tricure GIC.

Classification :Classification :
Depending on which is theDepending on which is the
predominant component. Thesepredominant component. These
materials may be classified as (materials may be classified as ( McMc
Clean et al).Clean et al).
ResinResin - modified glass ionomers- modified glass ionomers
cement (RMGI), e.g. Fuji II LC,cement (RMGI), e.g. Fuji II LC,
Vitremer, Photac fil.Vitremer, Photac fil.
Poly acidPoly acid – modified composites– modified composites
(PMC), e.g. Dyract, Variglass VLC.(PMC), e.g. Dyract, Variglass VLC.

Composition :Composition :
The powder contains.The powder contains.
Ion leachable glasses (silica,Ion leachable glasses (silica,
abumina)abumina)
Photointiators or chemical intiatorsPhotointiators or chemical intiators
or bothor both
Polymerizable resin.Polymerizable resin.

The liquid containsThe liquid contains
Polyacrylic acid.Polyacrylic acid.
Water.Water.
Methacrylate monomerMethacrylate monomer
Hydroxyethyl methacrylateHydroxyethyl methacrylate
monomers.monomers.

Properties :Properties :
StrengthStrength ::
The compressive strength is slightlyThe compressive strength is slightly
lower 105 Mpa when compared tolower 105 Mpa when compared to
conventional GIC. The diametralconventional GIC. The diametral
tensile strength is however, greatertensile strength is however, greater
20 Mpa because of the plastic20 Mpa because of the plastic
nature of the resin component.nature of the resin component.

Hardness:Hardness:
The hardness 40 KHN isThe hardness 40 KHN is
comparable to that of conventionalcomparable to that of conventional
GIC.GIC.

AdhesionAdhesion ::
The bonding mechanism to tooth structureThe bonding mechanism to tooth structure
is similaris similar to that of conventional GIC.to that of conventional GIC.
Micromechanical retentionMicromechanical retention also plays aalso plays a
role in the bonding process.role in the bonding process.

Anticariogenecity :Anticariogenecity :
These materials have a significantThese materials have a significant
anticariogenic effect because of theanticariogenic effect because of the
fluoride release.fluoride release.

Esthetics :Esthetics : They are lessThey are less
translucent because of thetranslucent because of the
significant differences in thesignificant differences in the
refractive index between the resinrefractive index between the resin
matrix and powder particles.matrix and powder particles.

GICGIC:-:- variety of compositions andvariety of compositions and
changes in the evolution of glasschanges in the evolution of glass
ionomers materials.ionomers materials.

1)1) Traditional GICTraditional GIC (lines, bases, cements)(lines, bases, cements)
Modified by adding comonomers toModified by adding comonomers to
polyacrylic acid small powder particlepolyacrylic acid small powder particle
size.size.
2)2) Metal modifiedMetal modified glass ionomerglass ionomer
Miracle mixtures (with Ag alloy admixedMiracle mixtures (with Ag alloy admixed
with cement)with cement)
Cement particle reinforced.Cement particle reinforced.

3)3) LC GICLC GIC (linen, bases)(linen, bases)
HEMA added to liquidHEMA added to liquid
component;monomers in liquid modifiedcomponent;monomers in liquid modified
with acrylic functional groups.with acrylic functional groups.
Other powder particles mixed withOther powder particles mixed with
alumino-silicate glassalumino-silicate glass

4) Hybrid (resin modified ) GIC4) Hybrid (resin modified ) GIC
-Silicate glass of composite substituted for-Silicate glass of composite substituted for
some of powder component.some of powder component.
-Polymer and other phones added to-Polymer and other phones added to
powder component .powder component .
-HEMA and other monomers added to-HEMA and other monomers added to
liquid component.liquid component.
-Pre cured GI blended into composites-Pre cured GI blended into composites

6) Polyacid – modified resin6) Polyacid – modified resin
composite (component)composite (component)
cements, restorative filing materials,cements, restorative filing materials,
corescores
-methacrylate monomers which multiply-methacrylate monomers which multiply
carboxylic groups; addition of ioncarboxylic groups; addition of ion
leachable glass (as in a conventionalleachable glass (as in a conventional
glass ionomer).glass ionomer).

Acid – Etching :Acid – Etching :
Objectives :Objectives :
1. To remove all debris and pellicle to1. To remove all debris and pellicle to
increase adaptation of resin.increase adaptation of resin.
2.Dissolution of exposed ends of enamel2.Dissolution of exposed ends of enamel
rods.rods.
3.Create surface irregularities that increase3.Create surface irregularities that increase
surface area for increased bondsurface area for increased bond
strength.strength.

Mechanism :Mechanism :
1.Acid solution1.Acid solution affects prismatic structure byaffects prismatic structure by
preferential removal of either prism core /preferential removal of either prism core /
periphery .periphery .
 2.Adsorption2.Adsorption of highly polar phosphate groupsof highly polar phosphate groups
oil the enamel surface, e the result strong polaroil the enamel surface, e the result strong polar
bonding to the acrylic may result.bonding to the acrylic may result.
 3.Removal of old, fully reacted and inert3.Removal of old, fully reacted and inert
enamel surfaceenamel surface exposing a fresh, reactiveexposing a fresh, reactive
surface more favorable for adhesion.surface more favorable for adhesion.
 Tremendous increase in surface area /Tremendous increase in surface area /
wettability.wettability.

EFFECTS OF ACID ETCHINGEFFECTS OF ACID ETCHING
ON SURFACE ENAMEON SURFACE ENAME ::
Type 1 Etching patternType 1 Etching pattern ::
Prism core material is preferentiallyPrism core material is preferentially
removed, leaving the prism peripheriesremoved, leaving the prism peripheries
relatively intact, resulting in arelatively intact, resulting in a
“honeycomb” appearance.“honeycomb” appearance.

Type 2 Etching PatternType 2 Etching Pattern
The peripheral regions of the prisms areThe peripheral regions of the prisms are
dissolved preferentially, leaving the prismdissolved preferentially, leaving the prism
cores relatively intact resulting in acores relatively intact resulting in a
“cobblestone” appearance“cobblestone” appearance

PremmiadAbdul WahabGRABER VANS ACPremmiadAbdul WahabGRABER VANS AC

 Type 3 Etching Pattern :Type 3 Etching Pattern :
Surface loss occurs without exposing theSurface loss occurs without exposing the
underlying enamel prisms.underlying enamel prisms. Gwinnett (1971)Gwinnett (1971)
demonstrated that this etching pattern is usuallydemonstrated that this etching pattern is usually
observed at the cervical aspects of teeth whereobserved at the cervical aspects of teeth where
the enamel prisms do not extend to the surface.the enamel prisms do not extend to the surface.
--Denys and Retief (1982)Denys and Retief (1982) showed however,showed however,
that the type 3 etching pattern is not confined othat the type 3 etching pattern is not confined o
the cervical regions but is also found on otherthe cervical regions but is also found on other
aspects of an etched enamel surface.aspects of an etched enamel surface.

PremmiadAbdul WahabACID3.jpgPremmiadAbdul WahabACID3.jpg

.. Silverstone (1974)Silverstone (1974) showed thatshowed that
etching enamel surfaces with phosphoricetching enamel surfaces with phosphoric
acid resulted in ;acid resulted in ;
A superficial etched zoneA superficial etched zone
Under lying qualitative and quantitativeUnder lying qualitative and quantitative
porous zones.porous zones.

PremmiadAbdul Wahabmicromechanical rePremmiadAbdul Wahabmicromechanical re

The depth of the etched zone or the amountThe depth of the etched zone or the amount
of the surface enamel removed during theof the surface enamel removed during the
etching procedure depends on ;etching procedure depends on ;
The acid concentrationThe acid concentration
The duration of etchingThe duration of etching
The chemical composition of theThe chemical composition of the
surface enamel.surface enamel.

 The surface area of the enamel will increaseThe surface area of the enamel will increase
uptoupto 2000 times that of its original unetched2000 times that of its original unetched
surface areasurface area..
 4. It creates4. It creates valleys and depressionsvalleys and depressions and makesand makes
the enamel surface irregular at an averagethe enamel surface irregular at an average
depth of 25 microns.depth of 25 microns.
 5. Acid etching will expose proteinaceous5. Acid etching will expose proteinaceous
organic matrixorganic matrix substance of enamel, which cansubstance of enamel, which can
add to the restorations retention if it becomesadd to the restorations retention if it becomes
adequately embedded within the restorativeadequately embedded within the restorative
material.material.

 . It has been verified that enamel treatment with. It has been verified that enamel treatment with
phosphoric acid will add to the enamel surface aphosphoric acid will add to the enamel surface a
highly polar phosphate group, which willhighly polar phosphate group, which will
increase the adhesive ability of the enamelincrease the adhesive ability of the enamel
surface.surface.
 Several acidic agents have been evaluated bySeveral acidic agents have been evaluated by
various investigators like lactic acid, citric acid,various investigators like lactic acid, citric acid,
pyruvic acid Alpha-keto acarboxylic acid otherpyruvic acid Alpha-keto acarboxylic acid other
than the phosphoric acid.than the phosphoric acid.

Brauer and Termini (1972)Brauer and Termini (1972) reportedreported
that lactic acid, a Monohydroxycarboxyicthat lactic acid, a Monohydroxycarboxyic
acid was an effective adhesion promoter.acid was an effective adhesion promoter.
 Cadwell and Johannessen (1971)Cadwell and Johannessen (1971)
investigated the possible use of citric acidinvestigated the possible use of citric acid
as an etching agent.as an etching agent. Citric acid solutionsCitric acid solutions
are now being used to condition toothare now being used to condition tooth
surfacessurfaces

Pyruvic acid and a Alpha –Pyruvic acid and a Alpha –
KetocarboxyolicKetocarboxyolic lead to good bondlead to good bond
strengths when used for etching thestrengths when used for etching the
enamel surface.enamel surface.
 Rate of etching of enamel by pyruvic acidRate of etching of enamel by pyruvic acid
was significantly lower than that with 50%was significantly lower than that with 50%
H3PO4.H3PO4.
 The concern about the stability ofThe concern about the stability of
pyruvic acid solutions has limited the usepyruvic acid solutions has limited the use
of pyruvic acid as an enamel etchant.of pyruvic acid as an enamel etchant.

Classification of Adhesion:Classification of Adhesion:
 Physical bondingPhysical bonding
 Chemical bondingChemical bonding
 Mechanical bondingMechanical bonding

REQUIREMENTS FORREQUIREMENTS FOR
ADHESIONADHESION
 There must be good wetting in order toThere must be good wetting in order to
produce a good bonding.produce a good bonding.
 the surfaces being joined should to producethe surfaces being joined should to produce
and maintain. Clean surfaces are at a highand maintain. Clean surfaces are at a high
energy state and rapidly absorb contaminantsenergy state and rapidly absorb contaminants
such as the moisture or dust. If thesuch as the moisture or dust. If the
contaminants are not excluded, the adhesivecontaminants are not excluded, the adhesive
interface will be weak.interface will be weak.

CLINICAL FACTORSCLINICAL FACTORS
AFFECTING ADHESIONAFFECTING ADHESION
 Salivary and/or blood contamination.Salivary and/or blood contamination.
 Moisture contamination from handpiecesMoisture contamination from handpieces
or air-water syringes.or air-water syringes.
 Oil contamination from handpieces orOil contamination from handpieces or
air-water syringe.air-water syringe.
 Surface roughness of tooth surfaceSurface roughness of tooth surface
 Fluoride content of teeth.Fluoride content of teeth.
 Presence of plaque, calculus, extrinsicPresence of plaque, calculus, extrinsic
stain or debrisstain or debris

FACTORS AFFECTINGFACTORS AFFECTING
ADHESION TO MINERALIZEDADHESION TO MINERALIZED
TISSUETISSUE
as given byas given by GwinnetGwinnet (1990).(1990).
Physical and chemical properties of thePhysical and chemical properties of the
adhesive and the adherent.adhesive and the adherent.
Lack of homogeneity between them.Lack of homogeneity between them.
Manner of transmission of the appliedManner of transmission of the applied
loads through the bonded joint.loads through the bonded joint.
Thickness of the interface.Thickness of the interface.
Form of surface pretreatment or primerForm of surface pretreatment or primer
chosen for the substratechosen for the substrate

 Furthermore, the factors related to theFurthermore, the factors related to the
oral environmentaloral environmental
 MoistureMoisture
 Physical stressesPhysical stresses
 Changes in temperatureChanges in temperature
 Changes in pHChanges in pH
 Dietary componentsDietary components
 Chewing habits.Chewing habits.

Chemistry of Adhesive agentChemistry of Adhesive agent
 Chemical adhesionChemical adhesion
 Adhesion by coupling agentsAdhesion by coupling agents
 Adhesion by grafting reactionAdhesion by grafting reaction

CRYSTAL GROWTH ON THECRYSTAL GROWTH ON THE
ENAMEL SURFACEENAMEL SURFACE
An alternative to the conventionalAn alternative to the conventional
phosphoric and etch technique has beenphosphoric and etch technique has been
developed bydeveloped by R. Maijer and D.C.R. Maijer and D.C.
Smith.Smith.
 This system consists of aThis system consists of a polyacrylicpolyacrylic
acid treatment,acid treatment, liquid containing aliquid containing a
sulfate component that reacts with thesulfate component that reacts with the
calcium in the enamel surface to form acalcium in the enamel surface to form a
dense growth of small, needle – shapeddense growth of small, needle – shaped
crystals.crystals.

These crystals grow in so calledThese crystals grow in so called
spherulitic habitspherulitic habit
The crystal buildup on the enamel servesThe crystal buildup on the enamel serves
as an additional retentive mechanism foras an additional retentive mechanism for
the resin that bonds to the tooth surface.the resin that bonds to the tooth surface.
In this procedure the bond does not relyIn this procedure the bond does not rely
on extensive penetration into the enamel.on extensive penetration into the enamel.
This brings aboutThis brings about “micromechanical“micromechanical
interlocking”interlocking” at the enamel surface.at the enamel surface.

MICRO AIR ABRASIONMICRO AIR ABRASION
An alternative to acid etchAn alternative to acid etch
InIn 1943 Dr. ROBERT BLACK1943 Dr. ROBERT BLACK beganbegan
his studies using micro abrassive.his studies using micro abrassive.
InIn 19511951 an air abrassive instrumentan air abrassive instrument
was introduced(was introduced( AirdentAirdent))

This technique used high speed stream ofThis technique used high speed stream of
purifiedpurified aluminium oxidealuminium oxide (alpha(alpha
alumina) particles propelled by airalumina) particles propelled by air
pressure.pressure.

BONDING PROCEDURESBONDING PROCEDURES
 bonding of orthodontic attachment offersbonding of orthodontic attachment offers
severalseveral advantagesadvantages when compared towhen compared to
conventional banding.conventional banding.
 It isIt is estheticallyesthetically superiorsuperior
 FasterFaster andand simple.simple.
 Less discomfortLess discomfort for patient (no. bondfor patient (no. bond
seating and separationseating and separation

 Arch lengthArch length not increasednot increased by bandby band
materialmaterial
 AllowsAllows more precise bracket placementmore precise bracket placement
aberrant tooth shape does not result inaberrant tooth shape does not result in
difficult bonding and poor attachmentdifficult bonding and poor attachment
position )position )
 ImproveImprove gingival conditiongingival condition is possibleis possible
and there is better access for cleaning.and there is better access for cleaning.

 Partially erupted tooth or and fractured toothPartially erupted tooth or and fractured tooth
can be controlled.can be controlled.
 MesiodistalMesiodistal enamel reductionenamel reduction is possibleis possible
duringduring
 Interproximal areas are accessible forInterproximal areas are accessible for
composite buildupscomposite buildups..
 Caries riskCaries risk under loose bonds is eliminated.under loose bonds is eliminated.
interproximal caries can be detected andinterproximal caries can be detected and
treated. Dental invaginations on incisors cantreated. Dental invaginations on incisors can
be controlled.be controlled.

 No band spacesNo band spaces at the end of Rx toat the end of Rx to
closeclose
 No large supplyNo large supply of bands is needed.of bands is needed.

 Attachments may be bonded to fixedAttachments may be bonded to fixed
bridge work, particularly when the facialbridge work, particularly when the facial
surfaces of the abutment teeth are not insurfaces of the abutment teeth are not in
metal.metal.
 More hygienic.More hygienic.
 Improved appearanceImproved appearance
 Discomfort to patient is decreased.Discomfort to patient is decreased.
 Ease of application for clinician.Ease of application for clinician.

Disadvantages :Disadvantages :
 Bonded bracket has a weaker attachment thanBonded bracket has a weaker attachment than
a cemented band. Thus there is more chancea cemented band. Thus there is more chance
that a bracket will come off rather than a bandthat a bracket will come off rather than a band
become loosened.become loosened.
 Some bonding adhesives are not sufficientlySome bonding adhesives are not sufficiently
strong.strong.
 Butter access for cleaning does notButter access for cleaning does not
necessarily guarantee better oral hygiene andnecessarily guarantee better oral hygiene and
improved gingival condition, especially ifimproved gingival condition, especially if
excess adhesive extends beyond the bracketexcess adhesive extends beyond the bracket
base.base.

 Protect against interproximal caries of wellProtect against interproximal caries of well
contoured cemented bands is absent.contoured cemented bands is absent.
 Bonding is generally not indicates on teethBonding is generally not indicates on teeth
where lingual auxiliaries are required or wherewhere lingual auxiliaries are required or where
headgears are attached.headgears are attached.
 Rebonding a loose bracket requires moreRebonding a loose bracket requires more
preparation than rebonding or loose band.preparation than rebonding or loose band.

 Debonding is more time consuming thanDebonding is more time consuming than
debanding therefore removal of adhesivedebanding therefore removal of adhesive
is more difficult than removal of cement.is more difficult than removal of cement.

Bonding procedure :Bonding procedure :
CleaningCleaning
Enamel conditionongEnamel conditionong
SealingSealing
BondingBonding

SEALANTSEALANT
A CONTROVERSYA CONTROVERSY

Bracket bonding procedure.Bracket bonding procedure.
TRANSFERTRANSFER
POSITIONPOSITION
FITTINGFITTING
REMOVAL OF EXESSREMOVAL OF EXESS

PremmiadAbdul WahabBOND PROCD.jpgPremmiadAbdul WahabBOND PROCD.jpg

Type of adhesives :Type of adhesives :
ACRYLIC RESINSACRYLIC RESINS
DIACRYLATE RESINSDIACRYLATE RESINS

ACRYLIC RESINSACRYLIC RESINS
Eg; Orthomite , Directon, Bondeze, genie.Eg; Orthomite , Directon, Bondeze, genie.
Based on self curing acrylicsBased on self curing acrylics
MMC monomer + ultrafine powderMMC monomer + ultrafine powder

DIACRYLATE RESINSDIACRYLATE RESINS
 Based on acrylic modified epoxy resinBased on acrylic modified epoxy resin
Bowen’s resin or BisGMA may beBowen’s resin or BisGMA may be
polymerized by cross linking in to 3-Dpolymerized by cross linking in to 3-D
network..network..
FilledFilled
UnfilledUnfilled

Buzzitha etal 82Buzzitha etal 82 found that a highlyfound that a highly
filled diacrylate resinfilled diacrylate resin with large fillerwith large filler
particles gave the highest values of in vitroparticles gave the highest values of in vitro
bond strength for metal brackets.bond strength for metal brackets.

Two recent innovationsTwo recent innovations
 No mix adhesiveNo mix adhesive
Rely a Bond,Right On,System1Rely a Bond,Right On,System1
 Visible light-polymerizedVisible light-polymerized
adhesivesadhesives
Fotofil, DurafilFotofil, Durafil

Key to good success in bondingKey to good success in bonding
. Develop a technique that ensure. Develop a technique that ensure goodgood
moisture control .moisture control .
Fit the bracketsFit the brackets closelyclosely to the teethto the teeth
Be sure that the setting of the adhesive isBe sure that the setting of the adhesive is
undisturbedundisturbed
Use aUse a strongstrong adhesive.adhesive.

G.I.C BondingG.I.C Bonding
Introduced byIntroduced by Wilson and Kent ‘’71Wilson and Kent ‘’71
 IN 1986 ‘ WhiteIN 1986 ‘ White described a method ofdescribed a method of
bonding ortho brackets to and surfaces ofbonding ortho brackets to and surfaces of
teeth with GIC.teeth with GIC.
Cook ‘ 90Cook ‘ 90 Compared in vivoCompared in vivo bondbond
strength of GIC with composite andstrength of GIC with composite and
concluded that bond strength of GIC wasconcluded that bond strength of GIC was
not nearly as good as that of resinnot nearly as good as that of resin

Fajen etal ’90Fajen etal ’90 evaluated bond strengthevaluated bond strength
of 3 GIC against composite in vitro andof 3 GIC against composite in vitro and
like look included that their bond strengthlike look included that their bond strength
was significantly less.was significantly less.
Compton etal ’92 :Compton etal ’92 :
 Compared bond strengths of GIC,Compared bond strengths of GIC,
stated that they must not be contaminatedstated that they must not be contaminated
by moisture during bonding procedures.by moisture during bonding procedures.
In addition they suggestedIn addition they suggested

Fricker ‘ 94 :Fricker ‘ 94 :
 Worked with fuji similar LC GIC andWorked with fuji similar LC GIC and
found same rate of success as that offound same rate of success as that of
composite. He did mention however thatcomposite. He did mention however that
a dentine conditioner was utilizeda dentine conditioner was utilized
for10sec, then rinsed followed by lightlyfor10sec, then rinsed followed by lightly
drying the tooth surface before bondingdrying the tooth surface before bonding
the brackets with GIC.the brackets with GIC.

Kusy ‘ 94 :Kusy ‘ 94 :
 Discussed the damage to the teethDiscussed the damage to the teeth
when debonding techniques are used forwhen debonding techniques are used for
removing composite. He advocated theremoving composite. He advocated the
use of GIC for orthodontic bondinguse of GIC for orthodontic bonding
procedures. Because their cements do notprocedures. Because their cements do not
need etching or cause damage duringneed etching or cause damage during
debonding.debonding.

Advantages :Advantages :
SavesSaves a significant amount of chair timea significant amount of chair time
EliminatesEliminates need for working in dry field.need for working in dry field.
Eliminate need “ etching and primingEliminate need “ etching and priming
enamel surfaceenamel surface
Fluoride releaseFluoride release protects teeth againstprotects teeth against
decalcificationdecalcification
RepairsRepairs are quick and easy.are quick and easy.

Patient operatorPatient operator comfort.comfort.
Reduced risk ofReduced risk of cariescaries..
Have capacity toHave capacity to absorb Fluorideabsorb Fluoride fromfrom
fluoridated tooth paste, thus acting as afluoridated tooth paste, thus acting as a
rechargeablerechargeable sow release Fluoride devicesow release Fluoride device
(long term Fluoride releasing agent.)(long term Fluoride releasing agent.)

REVIEW OF LITERATUREREVIEW OF LITERATURE
Direct bonding of brackets using shortsDirect bonding of brackets using shorts
etching times.etching times.
Wolf gang castensen : 1986 JCOWolf gang castensen : 1986 JCO..
 They concluded that the shorter etchingThey concluded that the shorter etching
time oftime of 15 seconds15 seconds appears to beappears to be
sufficient for the bracket bondingsufficient for the bracket bonding

Russull Bert Forquhar – 1986Russull Bert Forquhar – 1986
AMJOAMJO..
-Share bond for phosphoric acid was-Share bond for phosphoric acid was
greater than polacrylic acid group.greater than polacrylic acid group.

. Dual Cement resin in bonding :. Dual Cement resin in bonding :
 Smith and Shivapuja.Smith and Shivapuja.
a dual cement, they can be useda dual cement, they can be used
where the depth of cure iswhere the depth of cure is
essential.essential.

 OslenetalOslenetal compaired the shear bond strengthcompaired the shear bond strength
and surface structure betweenand surface structure between conventional acidconventional acid
etching and air – abrasion of human enamel.etching and air – abrasion of human enamel.
And concluded Air abrasion technique forAnd concluded Air abrasion technique for
enamel preparation has lower and clinically unenamel preparation has lower and clinically un
acceptable shear bond strength and thisacceptable shear bond strength and this
technique for enamel preparation results in thetechnique for enamel preparation results in the
irriversible removal of both the inorganic andirriversible removal of both the inorganic and
organic component of enamel matrixorganic component of enamel matrix and saidand said
that air abrasion of enamel surface orthodonticthat air abrasion of enamel surface orthodontic
brackets is not advocated for routine clinical usebrackets is not advocated for routine clinical use
at this time.at this time. AJO – 1997 – vol 112.AJO – 1997 – vol 112.

ComparisonComparison of GIC a compositeof GIC a composite
AJO 1995 May (485-487)AJO 1995 May (485-487)
Miguel, Almeida and Chapel.Miguel, Almeida and Chapel.
They studied that composites showed aThey studied that composites showed a
statistically significant lover failure ratestatistically significant lover failure rate
compared to the GIC.compared to the GIC.

Roberts-Harry (1992)Roberts-Harry (1992) used a pulsedused a pulsed
Nd:YAGNd:YAG laser to etch the enamellaser to etch the enamel
surfaces of teeth in vivo prior to thesurfaces of teeth in vivo prior to the
bonding of orthodontic brackets withbonding of orthodontic brackets with
composite resin and concluded that thiscomposite resin and concluded that this
laser producedlaser produced a macroscopic etcha macroscopic etch
pattern similar to that found with acidpattern similar to that found with acid
etchingetching

J.A. Vonfraunhofer et al (1993)J.A. Vonfraunhofer et al (1993)
 Arcoria .C.J., Lippas M.G. andArcoria .C.J., Lippas M.G. and
Vitasek B.A., (1993)Vitasek B.A., (1993)

ADHESION BOOSTERADHESION BOOSTER
HypocalcifedHypocalcifed
FluorsedFluorsed
Exessive chalkyExessive chalky
Decidous enamelDecidous enamel
The do not present ideal surface forThe do not present ideal surface for
bondingbonding
ENHANCE ADHESION BOOSTERENHANCE ADHESION BOOSTER

THANK YOUTHANK YOU

Basic of composites

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