JOYLINE
‘D’SOUZA
JASEELA.B.P
MARIYA THOMAS
JAMSEERA
SIDHEEQ
JAHANA
NASRULLAH
JISNIYA DAVOOD
SILVER AMALGAM
 Introduction
 Classification of
amalgam alloy
 Composition
 Properties of amalgam
 Manipulation
 Advantages
 Disadvantages
 Indications
 Contraindications
 Mercury toxicity
INTRODUCTION
An amalgam is an alloy of any metal with mercury.
Dental amalgam is made by alloying pure mercury
with silver-tin-copper
G.V.BLACK
FATHER OF
DENTAL
AMALGAM
G.V.BLACK
Formulated the
alloy in 1896
Dental amalgam is a combination of one part liquid
mercury with one part of a metallic alloy which mainly
contains silver and tin. It has been used for over 150
years to restore decayed teeth, and its use has stirred
controversy from the earliest days. To make the
amalgam, mercury is mixed with the other metals to
form a paste that can be fitted to the tooth cavity. The
mixture sets relatively fast to form a hard alloy.
• At the time of the introduction of amalgam into
dentistry, gold could be used in some types of dental
restorations, but its cost prohibited widespread use. In
the 19th Century, there were no other synthetic
materials that had both the required mechanical
properties and the ease of placement. As a metallic
alloy, amalgam did not look particularly good, but the
increasing prevalence of dental caries at the time
meant that this was a minor consideration. The even
more profound increase in caries throughout the
twentieth century, through the widespread use of
refined sugars in foodstuffs, resulted in the increased
use of dental amalgam fillings.
CLASSIFICATION OF
AMALGAM ALLOY
 According to SHAPE
I.
Spherical (spherical in shape)
II.
Lathe cut (irregularly shaped)
III.
Mixed (mixture of lathe cut & spherical)
 According to the SIZE
I.
Fine cut (36 microns)
II.
Micro cut (26 microns)
CLASSIFICATION OF AMALGAM
ALLOY
 According to composition
I.
Low copper alloy (< 6%)
II.
High copper alloy (6-30%)
III.
Admixed alloy
 Zn containing/non Zn containing
 Gallium alloys
 According to method of dispensing
I.
Powder and liquid form
II.
Capsule form
III.
As pellets of alloy powder
IV.
As pre amalgamated powder
 Special treatment
 1.aged alloys
 2.acid washed alloys
 3.pre amalgamated alloys
COMPOSITION
Low copper alloys
POWDER
POWDER
Silver
Tin
High copper admix alloy
67-70%
26-29%
Copper 2-5%,<6%
Zinc
1-2%
In, Pd , Au in Traces
LIQUID
Triple distilled arsenic free
Mercury
Silver
Tin
50-60%
20-25%
Copper 13-30%
Zinc
1-2%
 Single composition high copper
alloys
POWDER
Silver
45-60%
Tin
15-25%
Copper 13-20%
Zinc
0%
Traces of In,Pt,Pd
PROPERTIES OF AMALGAM
1.
Increased mercury leads to increased expansion ,creep &
corrosion
2.
Compressive strength-Admixed is 430Mpa after 7 days
3.
Tensile strength-50Mpa after 24 hours
4.
Surface hardness-110KHN
5.
Working time 3-8 mins
6.
Setting time 5-10 mins
7.
Increased expansion is due to increased mercury , short trituration ,
low condensation pressure & water contamination
8.
Creep is associated with : increased or decreased trituration , time lag
between trituration & condensation, increased mercury, less
condensation force
PHYSICAL PROPERTIES
 Bio compatibility : it is biocompatibile
 Strength : of amalgam takes 24 hrs to reach max
 Corrosion : amalgam restoration shows corrosion & tarnish over a
period of time
 Thermal conductivity : it can transmit temp changes to the pulp
 Micro leakage : occur when there is 2-20 microns wide gap b/w the
amalgam and the tooth structure
 Diamensional changes : small amount of contraction occurs in the
first half an hour after trituration.
 Delayed expansion : large setting expansion of about 4%
sometimes takes place after few days in case of zinc containing
amalgam , if there is moisture trapping or contamination during
restoration
 Mercuroscopic expansion : inhomogenous condensation pressure
and wrong burnishing techniques can push mercury rich thin mix to
the margins of the cavity. this excess mercury slowly react the alloy
and powder more weaker points and large setting expansion at the
margins . this can cause marginal breakdown or fracture.
MANIPULATION OF SILVER
AMALGAM
SELECTION OF AMALGAM ALLOY
In wider cavities alloy with low creep value is prefered
Mercury alloy ratio
 EAME’s has preferred 1:1 ratio of alloy/mercury for best
result
TRITURATION
This is done to remove oxide layers from the alloy
particles so as to coat each alloy particle with mercury
,this can be done by hand or mechanical means
MULLING
It is done so that all alloy particles are coated
with mercury . this can be done manually or
mechanically
APPLICATION OF MATRIX BAND
Placing a matrix for an amalgam restoration
allows the dentist to insert restoration without
exceeding the limits of normal tooth structure
INSERTION OF AMALGAM
Pick a small amount of amalgam
alloy with the help of amalgam carrier
and transfer it to the preparation
CONDENSATION
It is the procedure of compacting hg+ alloy mix into the
prepared cavity.it reduces the number and size of voids in
the restoration.there are 2 methods
 Increased dryness technique
 EAME’s minimal mercury technique
BURNISHING
Pre carve burnishing is the process of rubbing done to
make the surface shiny
Post carve burnishing is done after completion of carving
with the help of small sized burnisher using light strokes
CARVING
 Objectives of carving are
 No over hanging and under hanging restoration
 Proper size , location and good inter proximal
contraction
 Proper contour
 Optimal occlusal anatomy
FINISHING AND POLISHING
 Finishing amalgam restoration involves removal of marginal
irregularities , retaining contour and smoothening the surface roughness
 Polishing is done to achieve a smooth shiny luster on the surface of
amalgam
 ADVANTAGES
 Reduces tarnish and corrosion
 Polished surface is plaque resistant
 Prevention of recurrent decay
 Maintenance of periodontal health
ADVANTAGES OF AMALGAM
 Adequate mechanical properties
 Sufficient long service time
 Can retain the anatomic forms
 Not expensive
DISADVANTAGES
 Poor corrosion resistant
 Poor esthetics
 Ditched amalgam
 Poor marginal adaptation
 Mercury contamination
 Allergic to few patients
INDICATIONS
Moderate to large class I preparation
Class II preparation , in which there is heavy occlusion
and problem of isolation
Class IV preparation
Used as post orthodontic restoration
CONTRAINDICATIONS
Small to moderate classI and classII preparation
should be restored with composite rather than
amalgam is former results in more conservative tooth
preparation
Amalgam should avoid in area where aesthetic is of
important
MERCURY TOXICITY
Mercury can enter into the body respiratory and circulatory system
by ingestion through skin or as vapors into the respiratory system
and through food diet in circulatory system.In dentistry mercury is
released during abrasion of amalgam restoration or trapped in the
restoration which can migrate easily to body system
In addition mercury vapors are inhaled during the time
in dentistry,only very small amount of mercury is excreted but large
amount is accumulated in the body.
 Causes Damage to Brain in Children
 Amalgam Fillings Linked to Neurological Problems,
Gastrointestinal Problems
 Mercury / Alzheimer's Disease Connection Found
 Amalgam Fillings Release Highly Toxic Elemental Mercury
 Gold Crowns, Gum, Bruxism, Computer Monitors Increase
Release of Mercury Significantly
 Cumulative Poison and Builds Up in Organs
 Potential Contribuatory Factor in Other Diseases like allergy
 Mercury Build Up in Brain, Organs and Breast Milk of
Fetuses of Mothers With Amalgam Fillings
 Proper Removal of Fillings Produces Eventual Health
Improvement
 World-reknowned Experts Agree About Potential Danger
 Birth defect may be due to brief exposure during critical
periods of featal development
PRECAUTIONS
 Keep the mercury always in air tight bottles
 Do not touch mercury directly without gloves
 Do not spill the mercury on the floor or carpet
 Do not open the capsules immediately after trituration
 Do not use ultrasonic amalgamators
 Collect all waste under water or sodium thiosulfate solution
 Waste should be disposed by burying at larger depth
 Keep the clinics well ventilated
Recent modification
Bowen’s hybrid composite resin
Modified visible light cure bowen’s hybrid composite
resin have desirable property to
Replace the silver amalgam
Gallium alloy(model)
Gallium is a greyish metal of low density, and melting point 29.8
degree Celsius, which can be used instead of mercury. Gallium
alloy with indium and tin is a liquid at room temperature.
Powder contains silver,tin,copper, and palladium. Liquid has
gallium,tin,indium. When triturated, palladium alloys of Ag, Cu
,In are formed with unreacted phases.
Indium alloys
Alloy containing higher percentage of indium has been tried.
Powder has silver ,copper and indium (4 to 30%). Indium replaces
some amount of mercury and decreases health hazards by
mercury vapour pollution. It has adequate mechanical properties
strength at I hour 240MPa ,low creep-0.8%Several composition,
low and high Indium-alloys are under research-investigations.
COPPER AMALGAM
Considering the antibacterial property of copper,copper amalgam was
formulated with 30-40% copper & 60-70% of mercury & is supplied in
pellet form
the pellets are heated in a steel spatula,in a gas flame until mercury
comes out of it.it is then triturated & condensed.it was suggested for
rampent carious cases &deciduous tooth restoration.now it is not used
since it has low corrosion resistance,poor mechanical property &
greater mercury causing more health hazards
Joyline
dsouza
Jisniya
Jaseela.b.p
davood
Mariya
Jahana
nasrullah
thomas
Jamseera
sidheeq