2. ))11((DEFINITION OF DENTALDEFINITION OF DENTAL
AMALGAMAMALGAM
It is the combination of dental amalgam alloyIt is the combination of dental amalgam alloy
composed of silver, tin and copper withcomposed of silver, tin and copper with
mercury (sometimes it contains zincmercury (sometimes it contains zinc(.(.
DEFINITION OF AMALGAMATIONDEFINITION OF AMALGAMATION
PROCESSPROCESS
It is the process of alloying of mercury being inIt is the process of alloying of mercury being in
liquid state to Ag-Sn metal alloy being in theliquid state to Ag-Sn metal alloy being in the
solid statesolid state..
3. ))II( TYPES OF AMALGAMII( TYPES OF AMALGAM
11((According to copper contentAccording to copper content::
11--Conventional amalgam (Cu is less than 6%Conventional amalgam (Cu is less than 6%((
22--High copper amalgam (Non-∂ 2 amalgam( (Cu isHigh copper amalgam (Non-∂ 2 amalgam( (Cu is
more than 6%more than 6%(.(.
22((According to Zinc contentAccording to Zinc content::
11--Zinc containing amalgamZinc containing amalgam..
22--Zink- free amalgamZink- free amalgam..
When zinc comes in contact with moisture (saliva(When zinc comes in contact with moisture (saliva(
delayed 2delayed 2ndryndry
expansion will occurexpansion will occur..
Zn + HZn + H22O ZnO + HO ZnO + H22
4. CLINICAL EFFECT OFCLINICAL EFFECT OF
MOISTUREMOISTURE
11--Secondary delayed expansionSecondary delayed expansion..
22--Delayed painDelayed pain..
33--Overhanging marginsOverhanging margins..
44--Recurrence of decayRecurrence of decay..
55--Weak & corrodible amalgamWeak & corrodible amalgam..
5. ACCORDING TO PARTICLES SHAPEACCORDING TO PARTICLES SHAPE
11--Lathe – cut alloy particles [IrregularLathe – cut alloy particles [Irregular
shape needlesshape needles[.[.
22--Spherical alloy particles. [ParticlesSpherical alloy particles. [Particles
are rounded or spherical in shapeare rounded or spherical in shape[[
33--Admixed alloy particlesAdmixed alloy particles..
9. ))11((IN CASE OF THE LATHE-CUT TYPE:IN CASE OF THE LATHE-CUT TYPE:
METHOD OF MANUFACTURINGMETHOD OF MANUFACTURING::
All the alloy ingredients are meltedAll the alloy ingredients are melted
forming an ingot (cast( then after coolingforming an ingot (cast( then after cooling
& solidification, we subject the ingot to a& solidification, we subject the ingot to a
milling machine & so, we get fillings,milling machine & so, we get fillings,
needle shaped typeneedle shaped type..
10. ))22((IN CASE OF THE SPHERICALIN CASE OF THE SPHERICAL
ALLOY PARTICLES: METHOD OFALLOY PARTICLES: METHOD OF
MANUFACTURINGMANUFACTURING::
Pour the melted ingot into an inert gasPour the melted ingot into an inert gas
chamber (Nchamber (N22 gas( [no Ogas( [no O22 to prevent theto prevent the
oxidation[ by spraying [Atomization[ whenoxidation[ by spraying [Atomization[ when
they are sprayed by inert gas uponthey are sprayed by inert gas upon
solidification, they will solidify in the form ofsolidification, they will solidify in the form of
spheresspheres..
11. ))33((IN CASE OF THE ADMIXED TYPEIN CASE OF THE ADMIXED TYPE::
They manufacture lathe-cut aloneThey manufacture lathe-cut alone
& spherical alone & then they are& spherical alone & then they are
mixed togethermixed together..
12. ))44((ACCORDING TO PARTICLE SIZEACCORDING TO PARTICLE SIZE::
11--Micro-cut alloy particleMicro-cut alloy particle..
22--Fine-cut alloy particleFine-cut alloy particle..
33--Coarse-cut alloy particleCoarse-cut alloy particle..
The best form is theThe best form is the Fine-cutFine-cut..
13. SHERICAL AMALGAM ALLOYSHERICAL AMALGAM ALLOY
PARTICLES CHARACTARISTICSPARTICLES CHARACTARISTICS::
11--Zinc content not requiredZinc content not required..
22--Less amount of Hg is neededLess amount of Hg is needed..
33--Amalgamates more easilyAmalgamates more easily..
44--Less technique sensitive (advLess technique sensitive (adv.(..(.
55--Increased early compressive strengthIncreased early compressive strength..
66--Easier to condense, carve & polishEasier to condense, carve & polish..
14. MICRO-CUT AMALGAM ALLOY PARTICLESMICRO-CUT AMALGAM ALLOY PARTICLES
less than 10 micronsless than 10 microns
**CHARACTARISTICSCHARACTARISTICS::
--Greater amount of Hg required (Greater S.A:Greater amount of Hg required (Greater S.A:
Surface appear granularSurface appear granular( .( .
--Less plastic massLess plastic mass..
--Decreased compressive strengthDecreased compressive strength..
16. COARSE-CUT AMALGAM ALLOY PARTICLESCOARSE-CUT AMALGAM ALLOY PARTICLES
[[Greater than 30 micronsGreater than 30 microns[.[.
**CHARACTARISTICSCHARACTARISTICS::
--Less amount of Hg required (adv but asLess amount of Hg required (adv but as
particles are rough & large less adaptationparticles are rough & large less adaptation((
--Rough surface textureRough surface texture..
--Decreased adaptation to cavity wallsDecreased adaptation to cavity walls..
--Increased compressive strengthIncreased compressive strength..
18. ))11(*(*COMPOSITION OF CONVENTIONALCOMPOSITION OF CONVENTIONAL
SILVER/ TIN AMALGAM ALLOYSILVER/ TIN AMALGAM ALLOY::
**SilverSilver : not less than: not less than 65% by wt65% by wt..
**TinTin : not less than: not less than 25% by wt25% by wt..
**CopperCopper:: not more thannot more than 6% by wt6% by wt..
**ZincZinc :: not more thannot more than 2% by wt2% by wt..
19.
20. **SilverSilver :: It is the main ingredient of amalgamIt is the main ingredient of amalgam
used toused to::
--strength & hardness of amalgamstrength & hardness of amalgam..
--flowflow..
--Some expansionSome expansion..
21. **Tin:Tin: tin is introduced to givetin is introduced to give
plasticity of mass as tin has a great affinity to Hgplasticity of mass as tin has a great affinity to Hg
so. It is attracted to Hg & so it gives plasticity toso. It is attracted to Hg & so it gives plasticity to
mass allows amalgamation process to take placemass allows amalgamation process to take place
easilyeasily
**StrengthStrength
**FlowFlow
**Cause contractionCause contraction
23. **ZincZinc::
Acts as a scavenger or deoxidizer duringActs as a scavenger or deoxidizer during
manufacturingmanufacturing..
It prevents the formation of oxides onIt prevents the formation of oxides on
Cu, Ag & SnCu, Ag & Sn..
Disadv.:Disadv.: if amalgam is applied below freeif amalgam is applied below free
gum margin , moisture contamination willgum margin , moisture contamination will
cause excessive delayed secondarycause excessive delayed secondary
expansion ( 3-5 days after placement ofexpansion ( 3-5 days after placement of
restorationrestoration(.(.
24. **Reaction of conventional amalgamReaction of conventional amalgam::
It is a crystallization reactionIt is a crystallization reaction::
AgAg33 + Hg Ag+ Hg Ag22HgHg33 + Sn+ Sn77Hg + AgHg + Ag33SnSn..
σσ + Hg+ Hg σσ11 ++ σσ 22 + unreacted+ unreacted σσ
intermediate weakest strongestintermediate weakest strongest
strength phase phasestrength phase phase
25. --The strongest phase isThe strongest phase is σσ , it gives, it gives
very strong amalgam restorationvery strong amalgam restoration
followed byfollowed by σσ11then the weakest phasethen the weakest phase
isis σσ22 which is susceptible towhich is susceptible to
corrosioncorrosion..
--We have to eliminate Sn-Hg phaseWe have to eliminate Sn-Hg phase
as much as possible to avoid weakas much as possible to avoid weak
amalgam restorationamalgam restoration..
26. ))22((COMPOSITION OF HIGH COPPERCOMPOSITION OF HIGH COPPER
AMALGAM ALLOYAMALGAM ALLOY::
**SilverSilver : not less than 40%: not less than 40%
**TinTin : not less than 25%: not less than 25%
**CopperCopper : 10 – 30%: 10 – 30%
**ZincZinc : 0-2%: 0-2%
--We cannot remove tin from the ingredientsWe cannot remove tin from the ingredients
otherwise amalgam will be granularotherwise amalgam will be granular..
--The increase in the % of copper is on theThe increase in the % of copper is on the
expense of Agexpense of Ag..
27. ****CHARACTARISTICS OF HIGHCHARACTARISTICS OF HIGH
COPPER AMALGAMCOPPER AMALGAM::
))11((Higher early compressive strengthHigher early compressive strength..
))22((Increased corrosion resistanceIncreased corrosion resistance..
))33((Improved marginal integrityImproved marginal integrity
))44((Lower creep valueLower creep value
28. ****TYPES OF HIGH COPPERTYPES OF HIGH COPPER
AMALGAMAMALGAM::
))11((Admixed ( Lathe cut + SphericalAdmixed ( Lathe cut + Spherical((
))22((Single composition (Spherical orSingle composition (Spherical or
Lathe –cutLathe –cut((
29. ))11((Admixed high copper amalgamAdmixed high copper amalgam::
**CompositionComposition::
10-20%10-20%coppercopper
--it is called Admixed type because someit is called Admixed type because some
particles are spherical & some are lathe-particles are spherical & some are lathe-
cutcut..
--2/32/3lathe-cutlathe-cut..
--1/31/3spherical Ag-Cu (eutectic phasespherical Ag-Cu (eutectic phase(.(.
30. **ReactionReaction : Mercury will penetrate bet. The: Mercury will penetrate bet. The
particlesparticles
**AgAg33Sn (Sn (σσ ( + Hg Ag( + Hg Ag22HgHg33((σσ11 ( +( +
SnSn77Hg (Hg (σσ22 ( + Ag( + Ag33Sn (Sn (σσ(.(.
**SnSn77Hg (Hg (σσ22 ( + AgCu Ag( + AgCu Ag22HgHg33 ((σσ11 ( +( +
Cu6Sn5(ECu6Sn5(E((
**σσ22 in the 1in the 1stst
reaction would be attacked by AgCureaction would be attacked by AgCu
of the eutecticof the eutectic..
**Cu has a very great affinity to Sn so, it forms aCu has a very great affinity to Sn so, it forms a
31. --The aim of this reaction is: How to get rid ofThe aim of this reaction is: How to get rid of
AgAg33Sn but at the same time presence of Sn isSn but at the same time presence of Sn is
v.imp as it has more affinity to Cu than Hg so, itv.imp as it has more affinity to Cu than Hg so, it
will react with Cu & form E formwill react with Cu & form E form..
**σσ2 phase is eliminated & the net result is2 phase is eliminated & the net result is::
σσ 11 ++ σσ11 σσ EE
Resultant is CuResultant is Cu66SnSn55 phasephase..
32. ))22((SingleSingle COMPOSITIONCOMPOSITION high copperhigh copper
amalgamamalgam::
**COMPOSITIONCOMPOSITION::
13-30%13-30%coppercopper..
--Ternary Ag-Sn-CuTernary Ag-Sn-Cu..
--Indium or palladium 10% ( to creep & corrosionIndium or palladium 10% ( to creep & corrosion
resistanceresistance((
--it is made of one type only of alloy lathe cut orit is made of one type only of alloy lathe cut or
spherical not a mixturespherical not a mixture..
--Each alloy particle contains Ag-Sn-Cu whether itEach alloy particle contains Ag-Sn-Cu whether it..
spherical or lathe – cut this is called ternaryspherical or lathe – cut this is called ternary
alloyalloy..
--Indium corrosion resistanceIndium corrosion resistance..
33. **ReactionReaction::
Ag- Sn Cu + Hg AgAg- Sn Cu + Hg Ag22HgHg33((σσ(+Cu(+Cu66SnSn55(E(E(.(.
Sn has more affinity to Cu than Hg So, we haveSn has more affinity to Cu than Hg So, we have
nono σσ22 phase no SnHg phase as it will not leavephase no SnHg phase as it will not leave
Cu& bond with HgCu& bond with Hg..
34. ))IV( PROPERTIES OF AMALGAMIV( PROPERTIES OF AMALGAM
RESTORATIONRESTORATION::
AdvantagesAdvantages::
))11((Adequate compressive strengthAdequate compressive strength..
))22((High abrasion resistanceHigh abrasion resistance..
))33((Insolubility in oral fluidsInsolubility in oral fluids..
))44((Adaptability to cavity wallsAdaptability to cavity walls..
))55((Convenience of manipulationConvenience of manipulation..
))66((Biocompatibility with oral & dental tissuesBiocompatibility with oral & dental tissues..
35. DisadvantagesDisadvantages::
]]11[[Dimensional changesDimensional changes..
]]22[[Creep or flow tendencyCreep or flow tendency..
]]33[[Inadequate tensile strengthInadequate tensile strength..
]]44[[Low edge strengthLow edge strength..
]]55[[Thermal conductivityThermal conductivity..
]]66[[GalvanismGalvanism..
]]77[[Tarnish & corrosionTarnish & corrosion..
]]88[[Inharmonious colorInharmonious color..
If it is properly manipulated we canIf it is properly manipulated we can
overcome some if not all of these dis-advovercome some if not all of these dis-adv..
36. ]]11[[Dimensional changesDimensional changes::
--Regarding the dimensional changes amalgamRegarding the dimensional changes amalgam
undergoes .3 stagesundergoes .3 stages::
a( First stagesa( First stages::
When Hg is added to the alloy powder & afterWhen Hg is added to the alloy powder & after
trituration by 10 min. Amalgam undergoes slighttrituration by 10 min. Amalgam undergoes slight
contraction due to the penetration of Hg into thecontraction due to the penetration of Hg into the
alloy particlesalloy particles..
37. b( Second stageb( Second stage::
After 10 min. of triturition & till the first 8 hours,After 10 min. of triturition & till the first 8 hours,
there will be sever expansion due to the formation ofthere will be sever expansion due to the formation of
σσ11 phase or silver – mercury phasephase or silver – mercury phase..
c( Third stagec( Third stage::
After 24 hours there will be very slight contractionAfter 24 hours there will be very slight contraction
as a result of the setting of amalgam mass, all theas a result of the setting of amalgam mass, all the
phases of amalgam approach each otherphases of amalgam approach each other..
38. ]]22[[Creep or flow tendencyCreep or flow tendency::
Deformation of amalgam under loadDeformation of amalgam under load..
**CreepCreep:: Deformation of amalgam restorationDeformation of amalgam restoration
under load after it has completelyunder load after it has completely
setset..
**FlowFlow:: Deformation of amalgam restorationDeformation of amalgam restoration
under load before it has setunder load before it has set..
41. ]]33[[Inadequate tensile strengthInadequate tensile strength::
--Amalgam can fracture at the isthmusAmalgam can fracture at the isthmus
(junction bet. Occlusal & proximal(junction bet. Occlusal & proximal
parts( due to its low tensile strengthparts( due to its low tensile strength
under tension loadunder tension load..
42.
43. ]]44[[Low edge strengthLow edge strength::
--The low edge strength is responsible for theThe low edge strength is responsible for the
fracture at the marginsfracture at the margins..
((11((Amalgam ditch can occur I.e. v-shapedAmalgam ditch can occur I.e. v-shaped
groove that occurs as a result of fracture of thegroove that occurs as a result of fracture of the
margins of amalgam between amalgam &margins of amalgam between amalgam &
cavity walls at the cavosurface margincavity walls at the cavosurface margin..
To prevent this, the cavosurface angle must beTo prevent this, the cavosurface angle must be
9090oo
to increase the bulk of amalgam at this areato increase the bulk of amalgam at this area
44.
45. ]]55[[Thermal conductivityThermal conductivity::
Amalgam can transmit thermal impulses to theAmalgam can transmit thermal impulses to the
pulp & this can be overcome by puttingpulp & this can be overcome by putting
cementcement..
--In deep cavities we put a liner to protectIn deep cavities we put a liner to protect
pulp from Thermal conductivitypulp from Thermal conductivity..
--In shallow cavities there is enoughIn shallow cavities there is enough
dentin to protect pulpdentin to protect pulp..
46. ]]66[[GalvanismGalvanism
--If we have two dissimilar metals on the sameIf we have two dissimilar metals on the same
side ex: amalgam & the other is gold, saliva acts asside ex: amalgam & the other is gold, saliva acts as
the electrolyte, amalgam acts as a node & goldthe electrolyte, amalgam acts as a node & gold
acts as cathode so, when they come in contactacts as cathode so, when they come in contact
ions are transmitted from amalgam to gold &ions are transmitted from amalgam to gold &
this causes pain. As an electric current will passthis causes pain. As an electric current will pass..
--This is associated with corrosion & it is calledThis is associated with corrosion & it is called
galvanic corrosiongalvanic corrosion..
47. ]]77[[Tarnish & corrosionTarnish & corrosion
TarnishTarnish
**It is an oxide film that causes discolorationIt is an oxide film that causes discoloration
(blackening(blackening(.(.
corrosioncorrosion
**It is the disintegration of the outer surfaceIt is the disintegration of the outer surface..
48. **IndicationsIndications::
--Class IClass I
--Class IIClass II
--Class vClass v
--and distal cavities of canine in class IIIand distal cavities of canine in class III..
**Contra IndicationContra Indication::
--Anterior cavitiesAnterior cavities..
--In the presence of other metallicIn the presence of other metallic
restorationrestoration..
To avoid galvanismTo avoid galvanism..
52. ManipulationManipulation
The ratio )or the alloy / mercury ratioThe ratio )or the alloy / mercury ratio(:(:
The amount of mercury needed is to coat all theThe amount of mercury needed is to coat all the
particles to produce homogeneous coherentparticles to produce homogeneous coherent
mass of amalgammass of amalgam..
11--Ratio 1:1 or 5:5 techniqueRatio 1:1 or 5:5 technique..
22--Ratio 5:8 techniqueRatio 5:8 technique..
**The ratio is by weight and not by volumeThe ratio is by weight and not by volume..
53. Excess mercury leads toExcess mercury leads to::
11--strengthstrength..
22--Flow and creepFlow and creep..
33--ExpansionExpansion..
44--Tarnish and corrosionsTarnish and corrosions..
54. Less mercury leads toLess mercury leads to::
11--non-coherentnon-coherent..
22--WeakWeak..
33--Less resistance to tarnish and corrosionLess resistance to tarnish and corrosion..
N.B:N.B: Each in Hg by 15% results in 1.5% excess in theEach in Hg by 15% results in 1.5% excess in the
final restorationfinal restoration..
55. Methods of proportioningMethods of proportioning::
11--Simple weighing balanceSimple weighing balance..
22--Tablets or pellets where amount of HgTablets or pellets where amount of Hg
is measured according to the manufactureis measured according to the manufacture
by a mechanical dispenserby a mechanical dispenser..
33--Automatic mechanical dispenserAutomatic mechanical dispenser..
Dispenser should beDispenser should be
11((clean and dryclean and dry..
22((Vertical to obtain proper measurementVertical to obtain proper measurement..
33((Half filledHalf filled..
56.
57.
58. DisadvantagesDisadvantages::
a)a) Some alloys can cling to the wallSome alloys can cling to the wall
of the dispenserof the dispenser..
b)b) Each dispenser is for one type ofEach dispenser is for one type of
alloy l.e. can’t be used universallyalloy l.e. can’t be used universally
for all types of alloysfor all types of alloys
59. 44--Preproportioning capsulesPreproportioning capsules (the best(the best
method) proper alloy and Hg ratio is done bymethod) proper alloy and Hg ratio is done by
manufacturing and are put in a capsulemanufacturing and are put in a capsule..
A disc or membrane separates Hg and alloy to preventA disc or membrane separates Hg and alloy to prevent
premature amalgamationpremature amalgamation..
Activation is done before trituration. This is done byActivation is done before trituration. This is done by
removal of the membrane, and provide contactremoval of the membrane, and provide contact
between alloy and Hgbetween alloy and Hg..
This could be done byThis could be done by - Pressure- Pressure..
--Twisting cover of capsuleTwisting cover of capsule
60.
61.
62. 55--Self-activated capsulesSelf-activated capsules::
The process of amalgamation activates the capsuleThe process of amalgamation activates the capsule
Advantages of proportioning capsuleAdvantages of proportioning capsule::
11--More convenientMore convenient..
22--Proper Hg alloy ratio variables of dentists areProper Hg alloy ratio variables of dentists are
eliminatedeliminated..
33--Prevent spill of Hg preventing Hg hazardsPrevent spill of Hg preventing Hg hazards..
63. II- TriturationII- Trituration::
**DefinitionDefinition::
It is the process by which the alloy and mercuryIt is the process by which the alloy and mercury
are amalgamated together intoare amalgamated together into::
--CoherentCoherent..
--HomogeneousHomogeneous..
--SmoothSmooth..
--Plastic mass of amalgamPlastic mass of amalgam..
64. **Methods of triturationMethods of trituration::
a.a. Manual trituration using Mortar and PestleManual trituration using Mortar and Pestle..
b.b. Mechanically using electric amalgamatorMechanically using electric amalgamator..
AA.. Hand triturationHand trituration::
i-i- Glass mortar and pestle are usedGlass mortar and pestle are used..
ii-ii-Should be cleaned to prevent contaminationShould be cleaned to prevent contamination..
iii-iii-The face of the Pestle must have the same shapeThe face of the Pestle must have the same shape
as the surface of the mortar for effective triturationas the surface of the mortar for effective trituration..
iv-iv- Both Mortar and Pestle should present an even roughBoth Mortar and Pestle should present an even rough
working surface for effective triturationworking surface for effective trituration..
v-v- The trituration process must be standardized by rate, timeThe trituration process must be standardized by rate, time
and pressureand pressure..
e.g:e.g: 2kg or 4 kg is 1 min. In 60 revolution2kg or 4 kg is 1 min. In 60 revolution..
65.
66.
67.
68.
69. Aims of triturationAims of trituration..
a.a. To rub off the oxide layer on the alloyTo rub off the oxide layer on the alloy
particlesparticles..
b.b. For further reduction of the size of theFor further reduction of the size of the
alloy particlesalloy particles..
c.c. To bring the mercury into contact withTo bring the mercury into contact with
the alloy particles to start the reactionthe alloy particles to start the reaction..
70. **Properly triturated amalgam will appearProperly triturated amalgam will appear::
A.A. HomogeneousHomogeneous
B.B. SmoothSmooth
C.C. Climb along the side of the mortar andClimb along the side of the mortar and
form a curl at its topform a curl at its top
71. **Under triturated leads toUnder triturated leads to::
A.A. WeakWeak..
B.B. Non-homogeneousNon-homogeneous..
C.C. Excess mercuryExcess mercury..
D.D. Appear dullAppear dull..
E.E. Non-coherentNon-coherent..
F.F. Undergo more expansionUndergo more expansion..
G.G. More tarnish and corrosionMore tarnish and corrosion..
72. Over triturated leads toOver triturated leads to::
A.A. Sets fasterSets faster..
B.B. Greater one hour strengthGreater one hour strength..
C.C. Smooth surfaceSmooth surface..
D.D. Less flowLess flow..
E.E. More tarnish and corrosion resistanceMore tarnish and corrosion resistance..
F.F. The only disadvantages is that it mayThe only disadvantages is that it may
undergo contraction farther than expansionundergo contraction farther than expansion..
73. B. Mechanical TriturationB. Mechanical Trituration::
..This methodThis method::
11--Saves timeSaves time..
22--Gives better standardization, for the trituratedGives better standardization, for the triturated
amalgamamalgam..
**Mulling of amalgamMulling of amalgam::
It is a process of mulling the properly trituratedIt is a process of mulling the properly triturated
amalgam for few sec. In a piece of rubber toamalgam for few sec. In a piece of rubber to
acquire a max. degree of plasticityacquire a max. degree of plasticity..
74.
75.
76. II. CondensationII. Condensation::
**DefinitionDefinition::
It is the process of packing of the properly trituratedIt is the process of packing of the properly triturated
amalgam in the prepared cavityamalgam in the prepared cavity..
**AimsAims::
11..The adaptation of amalgam to cavity walls andThe adaptation of amalgam to cavity walls and
marginsmargins..
22..The adaptation between successive layer ofThe adaptation between successive layer of
amalgamamalgam..
33..Express excess mercury and density of the alloyExpress excess mercury and density of the alloy..
44..The compressive strength of amalgamThe compressive strength of amalgam..
77.
78.
79.
80. **Requirements for proper condensationRequirements for proper condensation::
11..Only fresh mixes should be used. (Mixes moreOnly fresh mixes should be used. (Mixes more
than 3.5min. Should be discarded, this is tothan 3.5min. Should be discarded, this is to
avoid layering of amalgamavoid layering of amalgam..
22..We must use successive increments for effectiveWe must use successive increments for effective
condensationcondensation..
33..Great condensation pressure is required,Great condensation pressure is required,
directed, towards cavity wall, and marginsdirected, towards cavity wall, and margins..
44..Each condensed layer must be properly stableEach condensed layer must be properly stable
other wise weak amalgam will resultother wise weak amalgam will result..
81. 55--A proper sized and designed condenser must beA proper sized and designed condenser must be
usedused::
i.i. It should be small enough to exert great pressure,It should be small enough to exert great pressure,
but not too small to cause holes in the amalgambut not too small to cause holes in the amalgam..
iiii.. It should be properly angulated to reach all areas ofIt should be properly angulated to reach all areas of
the cavitythe cavity..
iii.iii. The face of the condensed must be either flat,The face of the condensed must be either flat,
smooth or serratedsmooth or serrated..
66--Condensation should be completed under cleanCondensation should be completed under clean
dry conditiondry condition..
82. **Condensation techniqueCondensation technique::
11--By hand condensation and it should be as followsBy hand condensation and it should be as follows..
a.a. The restoration is built from small successive incrementThe restoration is built from small successive increment..
b.b. In case of compound cavities, the box should be filled firstIn case of compound cavities, the box should be filled first
to the level of pulpal floor, then the occlusalto the level of pulpal floor, then the occlusal..
c.c. Small piece of amalgam is carried by amalgam carrier andSmall piece of amalgam is carried by amalgam carrier and
forced into the cavityforced into the cavity..
d.d. The first layer is condensed with great force using smallThe first layer is condensed with great force using small
condenser from the center of the cavity to cavitycondenser from the center of the cavity to cavity
marginsmargins..
83. e-e- The mercury rich amalgam on the surface isThe mercury rich amalgam on the surface is
removed with spoon excavatorremoved with spoon excavator..
f-f- The process is repeated until the cavity isThe process is repeated until the cavity is
completely filledcompletely filled..
g-g- A final dry piece is condensed to over fill theA final dry piece is condensed to over fill the
cavity and over come the excess mercury ofcavity and over come the excess mercury of
the last layer and then this layer is removedthe last layer and then this layer is removed
leaving the surface of amalgam with noleaving the surface of amalgam with no
excess mercuryexcess mercury..
84. 22--Mechanical condensation: byMechanical condensation: by
ultrasonic deviceultrasonic device
**Advantages of mechanical condensationAdvantages of mechanical condensation::
11--It is more standardizedIt is more standardized..
22--Less fatigue to the operatorLess fatigue to the operator..
33--It produces homogenous amalgamIt produces homogenous amalgam..
44--More strength property for the final amalgamMore strength property for the final amalgam..
55--Less flowLess flow..
66--More stabilityMore stability..
77--Less expansionLess expansion..
85. Carving of AmalgamCarving of Amalgam::
11--We use suitable amalgam carverWe use suitable amalgam carver..
22--Amalgam must not be carved unless itAmalgam must not be carved unless it
becomes hard enough to resist carvingbecomes hard enough to resist carving
instrument ( for about 3.5 mininstrument ( for about 3.5 min(.(.
33--Sharp instrument must be used for carving,Sharp instrument must be used for carving,
to not disturb the matrixto not disturb the matrix..
44--Avoid carving towards cavity margins toAvoid carving towards cavity margins to
avoid under filling and expression ofavoid under filling and expression of
excess mercury towards the marginexcess mercury towards the margin..
86.
87. Excess Hg at the margins may causeExcess Hg at the margins may cause::
a- Marginal disintegrationa- Marginal disintegration..
b- Marginal leakageb- Marginal leakage..
c- Tarnish and corrosionc- Tarnish and corrosion..
88. 55--In compound cavities, the occlusal portionIn compound cavities, the occlusal portion
is carved 1is carved 1stst
before removal of matrixbefore removal of matrix..
66--After carving of the occlusal portion , theAfter carving of the occlusal portion , the
matrix holder is unscrewed and band ismatrix holder is unscrewed and band is
removed either buccally or lingually.removed either buccally or lingually.
Avoid its removal occlusally to avoidAvoid its removal occlusally to avoid
fracture of the marginsfracture of the margins..
77--The proximal contour is carved and thenThe proximal contour is carved and then
contact is checked by using dental flosscontact is checked by using dental floss
silksilk..
89. Double burnishing techniqueDouble burnishing technique
Means the amalgam is pre and post carvingMeans the amalgam is pre and post carving
burnishedburnished
Pre carving burnishingPre carving burnishing
Using large sized burnisher with heavyUsing large sized burnisher with heavy
pressurepressure
90. Benefits of precarvingBenefits of precarving
burnishingburnishing
A-Increase adaptation of amalgam to cavityA-Increase adaptation of amalgam to cavity
walls and marginswalls and margins
B-Bring the mercury to the surfaceB-Bring the mercury to the surface
C- More cohesive amalgamC- More cohesive amalgam
D-Continue the process of condensationD-Continue the process of condensation
91. Post carving burnishingPost carving burnishing
Small sized burnisher with gentle strokesSmall sized burnisher with gentle strokes
just to smoothen the amalgamjust to smoothen the amalgam
92. Finishing and polishing of AmalgamFinishing and polishing of Amalgam::
It should be done to give a luster-like smooth surfaceIt should be done to give a luster-like smooth surface
after at least 24 hrsafter at least 24 hrs..
**Finishing and polishing is achieved by usingFinishing and polishing is achieved by using::
11--Rotating finishing instruments which includeRotating finishing instruments which include::
a- Finishing stones as carburundum green stones ina- Finishing stones as carburundum green stones in
form of : coarseform of : coarse..
mediummedium
finefine
they are used to correct surface discrepanciesthey are used to correct surface discrepancies..
93. b-b- InterproximalInterproximal finishing instrumentsfinishing instruments
asas::
i-i- finishing strips in form of : coarsefinishing strips in form of : coarse..
mediummedium
finefine
ii- Abrasive discsii- Abrasive discs..
they are used to correct over hangs and givethey are used to correct over hangs and give
smooth interproximalsmooth interproximal surfacesurface..
c- Finishing burs12 flutedc- Finishing burs12 fluted..
94. 22--Rotating polishingRotating polishing instrumentsinstruments
includeinclude::
a- Rubber cups in form of coarse, medium ora- Rubber cups in form of coarse, medium or
fine applied with polishing paste at low speedfine applied with polishing paste at low speed..
b- Rotating soft brush applied with polishingb- Rotating soft brush applied with polishing
pastepaste..
95. **If amalgam restoration is not finishedIf amalgam restoration is not finished
and polished, then the surface remainsand polished, then the surface remains
rough leads torough leads to::
a-a- Surface porositiesSurface porosities..
b- Food and plaque accumulationb- Food and plaque accumulation..
c- Tarnish and corrosionc- Tarnish and corrosion..
d- Concentration of stressesd- Concentration of stresses..
96.
97.
98.
99.
100.
101.
102. ADVANTAGESADVANTAGES::
11--High compressive strength propertiesHigh compressive strength properties
(45000PSI(45000PSI(.(.
22--Low coefficient of thermal expansionLow coefficient of thermal expansion..
33--Indestructibility in oral fluidIndestructibility in oral fluid..
44--Easy of manipulationEasy of manipulation..
55--It is capable to take and maintain a goodIt is capable to take and maintain a good
polishpolish..
103. DISADVANTAGESDISADVANTAGES::
11--Low tensile strengthLow tensile strength..
22--Bad esthetics due to unnatural color and theBad esthetics due to unnatural color and the
tendency for corrosiontendency for corrosion..
33--High thermal conductivityHigh thermal conductivity..
44--Slight changes in dimension during settingSlight changes in dimension during setting..
