Amalgam
Preclinical Dentistry,  1st. Year
Autumn Semestr
L Roubalíková
Amalgam
Metal-like restorative material composed of silver-tin-copper alloy and mercury.
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Types of amalgam restorative
materials
Low - Copper	Amalc	iam (5% or k
Composition -	- wt%	
Silver		63 - 70 %
Tin		26 - 28 %
Copper		2 - 5%
Zinc		0 - 2%
Types of amalgam restorative
materials
Hiah- CoDDerAmalaam(13%-30%)
Composition - wt%
40 - 70 % 26 - 30 % 2 - 30% 0 - 2%
Particles of the alloy
^Irregulary shaped (filings - lathe cut)
^Microsphere
^Combination of the two
Particles shape
Hiqh - Copper Amalqam
Microsphers of the same composition (unicompositional)
Mixture of irregular and spherical particles of different or the same composition (admixed)
Production of irregular particles
Metal ingrediences heated, protected from oxidation, melted and poured into a mold to form an ingot. Phases of the alloy: Ag3Sn - y Cu3Sn - s Cu6Sn5- r| Ag4Sn - ß
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Production of irregular particles
Ingot cooled slowly
Ingot heated at 400°C (6-8 hours) (homogeneous distribution of Ag3Sn)
Ingot cut on the lathe, particles passed trough a fine sieve and ball milled to form the proper particle size.
Aging of particles (60 - 100°C, 6-8 hours)
Particle size: 60- 120 jum in length
10 - 70 jum in width 10-35 jum in thickness
Production of irregular particles
Molten alloy is spraying into water under high pressue
Irregulary shaped high-copper particles
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Production of spherical particles
Molten alloy is spraying   under
high pressue of inert gas through a fine
crack in a crucible into a large chamber
Diameter of the spheres: 2 - 43/um
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Amalgamation processes
Metal alloy is mixed with pure mercury
Trituration
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Amalgamation processes
Ag3Sn - y
Cu3Sn - s
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Amalgamation processes
Low copper amalgam
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Amalgamation processes
High copper amalgam
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