SlideShare uma empresa Scribd logo
1 de 33
Dental Amalgam
BY UZMA JAN
BDS 1ST
YEAR
Amalgam
 An alloy of mercury with another metal.
Why Amalgam?
 Inexpensive
 Ease of use
 Proven track record
- >100 years
 Familiarity
 Resin-free
- less allergies than composite
Composition Of Dental Amalgam
 Traditional or Convential amalgam alloys is based
on Black’s composition.
 63-70% silver
 26-28% tin
 Less than 6% Cu &
 Sometimes 0-2% Zn.
Composition Of High Ag-Sn Amalgam
 Ag 40-60%
 Sn 27-30%
 Cu 13-30%
Constituents in Amalgam
 Basic
• Silver
• Tin
• Copper
• Mercury
 Other
• Zinc
• Indium
• Palladium
Basic Constituents
 Silver (Ag)
 Increases strength
 Increases expansion
 Decrease creep
 Whitens the Alloy
 Increase tarnish resistance
 Tin (Sn)
 Decreases expansion
 Decreased strength
 Increases setting time
Basic Constituents
Copper (Cu)
 Ties up tin
 Reducing gamma-2 formation
 Increases strength & hardness
 Reduces tarnish and corrosion
 Reduces creep
 Reduces marginal deterioration
Basic Constituents
Mercury (Hg)
 Activates reaction
 Only pure metal that is liquid
at room temperature
 Spherical alloys
 * Require less mercury
 - Smaller surface area easier to wet
 40 to 45% Hg
 Admixed alloys
 Require more mercury
 lathe-cut particles more difficult to wet
 45 to 50% Hg
Other Constituents
 Zinc (Zn)
 Used in manufacturing
 Decreases oxidation of other elements
 Sacrificial anode
 Provides better clinical performance
 less marginal breakdown
 Causes delayed expansion with low Cu alloys
 If contaminated with moisture during condensation
H2O + Zn ZnO + H2⇒⇒
Other Constituents
 Indium (In)
 Decreases surface tension
 Reduces amount of mercury necessary
 Reduces emitted mercury vapor
 Reduces creep and marginal breakdown
 Increases strength
 Must be used in admixed alloys
 Example
 Indisperse (Indisperse Distributing Company)
 5% indium
Other Constituents
 Palladium (Pd)
 Reduced corrosion
 Greater luster
 Whitens the Alloy
 Example
 Valiant PhD (Ivoclar Vivadent)
 0.5% palladium
Basic Composition
 A silver-mercury matrix containing filler
particles of silver-tin
 Filler (bricks)
 Ag3Sn called gamma
 can be in various shapes
 irregular (lathe-cut), spherical,
or a combination
 Matrix
 Ag2Hg3 called gamma 1
 cement
 Sn8Hg called gamma 2
 voids
Basic Setting
Reactions
 Conventional low-copper alloys
 High Cu Alloys
1-Admixed high-copper alloys
2-Single composition high-copper alloys
Conventional Low-Copper Alloys
 Dissolution and precipitation
 Hg dissolves Ag and Sn
from alloy
 Intermetallic compounds
formed
Ag-Sn
Alloy
Ag-Sn
Alloy
Ag-Sn Alloy
Mercury
(Hg)
Ag
AgAg
Sn
Sn
Sn
Hg Hg
AgAg33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + AgSn + Ag22HgHg33 + Sn+ Sn88HgHg
γ γ γ1 γ2
Conventional Low-Copper Alloys

Gamma (γ) = Ag3Sn
 Unreacted alloy
 Strongest phase and
corrodes the least
 Forms 30% of volume
of set amalgam
Ag-Sn
Alloy
Ag-Sn
Alloy
Ag-Sn Alloy
Mercury
Ag
Ag
Ag
Sn
Sn
Sn
Hg
Hg
Hg
AgAg33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + AgSn + Ag22HgHg33 + Sn+ Sn88HgHg
γ γ γ1 γ2
Conventional Low-Copper Alloys
 Gamma 1 (γ1) = Ag2Hg3
 matrix for unreacted alloy
and 2nd strongest phase
 10 micron grains
binding gamma (γ)
 60% of volume
γ1
AgAg33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + AgSn + Ag22HgHg33 + Sn+ Sn88HgHg
γ γ γ1 γ2
Ag-Sn Alloy
Ag-Sn
Alloy
Ag-Sn
Alloy
Conventional Low-Copper
Alloys
 Gamma 2 (γ2) = Sn8Hg
 weakest and softest phase
 corrodes fast, voids form
 corrosion yields Hg which
reacts with more gamma (γ)
 10% of volume
 volume decreases with time
due to corrosion
AgAg33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + AgSn + Ag22HgHg33 + Sn+ Sn88HgHg
γ γ γ1 γ2
γ2
Ag-Sn Alloy
Ag-Sn
Alloy
Ag-Sn
Alloy
Admixed High-Copper
Alloys
 Ag enters Hg from Ag-Cu spherical
eutectic particles
 Eutectic
 An alloy in which the elements are
completely soluble in liquid solution
but separate into distinct areas upon
solidification
 Both Ag and Sn enter Hg from Ag3Sn
particles
AgAg33Sn + Ag-Cu + HgSn + Ag-Cu + Hg ⇒⇒ AgAg33Sn + Ag-Cu + AgSn + Ag-Cu + Ag22HgHg33 + Cu+ Cu66SnSn55
γ γ γ1 η
Ag-Sn
Alloy
Ag-Sn
Alloy
Mercury
Ag
AgAg
Sn
Sn
Ag-Cu Alloy
Ag
HgHg
Admixed High-Copper Alloys
 Sn diffuses to surface of
Ag-Cu particles
 Reacts with Cu to form
(eta) Cu6Sn5 (η)
Around unconsumed
Ag-Cu particles Ag-Sn
Alloy
Ag-Cu Alloyη
Ag-Sn
Alloy
AgAg33Sn + Ag-Cu + HgSn + Ag-Cu + Hg ⇒⇒ AgAg33Sn + Ag-Cu + AgSn + Ag-Cu + Ag22HgHg33 + Cu+ Cu66SnSn55
γ γ γ1 η
Admixed High-Copper Alloys
 Gamma 1 (γ1) (Ag2Hg3) surrounds
(η) eta phase (Cu6Sn5) and gamma
(γ) alloy particles (Ag3Sn)
Ag-Sn
Alloy
γ1
Ag-Cu Alloyη
Ag-Sn
Alloy
AgAg33Sn + Ag-Cu + HgSn + Ag-Cu + Hg ⇒⇒ AgAg33Sn + Ag-Cu + AgSn + Ag-Cu + Ag22HgHg33 + Cu+ Cu66SnSn55
γ γ γ1 η
Single Composition
High-Copper Alloys

Gamma sphere (γ) (Ag3Sn)
with epsilon coating (ε)
(Cu3Sn)
 Ag and Sn dissolve in Hg
Ag-Sn Alloy
Ag-Sn Alloy
Ag-Sn Alloy
Mercury (Hg)
ε
Ag
Sn
Ag
Sn
AgAg33Sn + CuSn + Cu33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + CuSn + Cu33Sn + AgSn + Ag22HgHg33 + Cu+ Cu66SnSn55
γ γ γ1 ηε ε
Single Composition
High-Copper Alloys
 Gamma 1 (γ1) (Ag2Hg3) crystals
grow binding together partially-
dissolved gamma (γ) alloy
particles (Ag3Sn)
 Epsilon (ε) (Cu3Sn) develops
crystals on surface of
gamma particle (Ag3Sn)
in the form of eta (η) (Cu6Sn5)
 Reduces creep
 Prevents gamma-2 formation
Ag-Sn Alloy
Ag-Sn Alloy
Ag-Sn Alloy
γ1
η
AgAg33Sn + CuSn + Cu33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + CuSn + Cu33Sn + AgSn + Ag22HgHg33 + Cu+ Cu66SnSn55
γ γ γ1 ηε ε
Classifications
 Based on Cu content
 Based on particle shape
 Based on Zn content
 Based on number of alloyed metals
 Based on size of alloy
Copper Content
 Low-copper alloys
 4 to 6% Cu
 High-copper alloys
 thought that 6% Cu was maximum amount
 due to fear of excessive corrosion and expansion
 Now contain 9 to 30% Cu
 at expense of Ag
Particle Shape
 Lathe cut
 low Cu
 New True
Dentalloy
 high Cu
 ANA 2000
 Admixture
 high Cu
 Dispersalloy, Valiant PhD
 Spherical
 low Cu
 Cavex SF
 high Cu
 Tytin, Valiant
Manufacturing Process
 Lathe-cut alloys
 Ag & Sn melted together
 alloy cooled
 phases solidify
 heat treat
 400 ºC for 8 hours
 grind, then mill to 25 - 50 microns
 heat treat to release stresses of grinding
 More Hg needed – high force needed due to irregular form
Manufacturing Process
 Spherical alloys
 melt alloy
 atomize
 spheres form as particles cool
 sizes range from 5 - 40 microns
 variety improves condensability
Spherical particles wet easier
( less Hg is required)
Admixture:
Lathe-cut + Spherical Eutectic (ALE)
 Composition
 2/3 conventional lathe cut (3% Cu)
 1/3 high Cu spherical eutectic (28% Cu)
 overall 12% Cu, 1% Zn
 Example
 Dispersalloy (Caulk)
Zn content
 If the Zn content is greater than 0.01% the
amalgam is called a Zn-containing Amalgam.
 If the content is less, then Amalgam is Non-Zn
Amalgam.
Number of alloyed metals
 Binary alloys : Ag-Sn
 Tertiary Alloys : Ag-Sn-Cu
 Quaternary alloys : Ag-Sn-Cu-In
Size of Alloy
 Micro cut
 Macro cut
THANK YOU

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Amalgam
AmalgamAmalgam
Amalgam
 
Dental ceramics
Dental ceramicsDental ceramics
Dental ceramics
 
Dental ceramics
Dental ceramicsDental ceramics
Dental ceramics
 
silver amalgam
silver amalgamsilver amalgam
silver amalgam
 
DENTAL AMALGAM/prosthodontic courses
DENTAL AMALGAM/prosthodontic coursesDENTAL AMALGAM/prosthodontic courses
DENTAL AMALGAM/prosthodontic courses
 
Abrasives and polishing agents in dentistry
Abrasives and polishing agents in dentistryAbrasives and polishing agents in dentistry
Abrasives and polishing agents in dentistry
 
Finishing and polishing materials
Finishing and polishing materialsFinishing and polishing materials
Finishing and polishing materials
 
DENTAL CERAMICS AN INTRODUCTION
DENTAL CERAMICS AN INTRODUCTIONDENTAL CERAMICS AN INTRODUCTION
DENTAL CERAMICS AN INTRODUCTION
 
Model and die material
Model and die materialModel and die material
Model and die material
 
Investment materials
Investment materialsInvestment materials
Investment materials
 
Investment materials and procedures
Investment materials and proceduresInvestment materials and procedures
Investment materials and procedures
 
Dental cement 1
Dental cement 1Dental cement 1
Dental cement 1
 
Dental Cements
Dental CementsDental Cements
Dental Cements
 
Dental Ceramics
Dental Ceramics Dental Ceramics
Dental Ceramics
 
DENTAL CERAMICS
DENTAL CERAMICSDENTAL CERAMICS
DENTAL CERAMICS
 
METAL FREE CERAMICS- AN UPDATE
METAL FREE CERAMICS- AN UPDATEMETAL FREE CERAMICS- AN UPDATE
METAL FREE CERAMICS- AN UPDATE
 
Dental ceramics
Dental ceramicsDental ceramics
Dental ceramics
 
Ceramics seminar
Ceramics seminarCeramics seminar
Ceramics seminar
 
Dental ceramics
Dental ceramicsDental ceramics
Dental ceramics
 
Dental waxes
Dental waxesDental waxes
Dental waxes
 

Semelhante a dental amalgam presentation

Semelhante a dental amalgam presentation (20)

Dental_Amalgam-Structure___Properties-16-12-14.ppt
Dental_Amalgam-Structure___Properties-16-12-14.pptDental_Amalgam-Structure___Properties-16-12-14.ppt
Dental_Amalgam-Structure___Properties-16-12-14.ppt
 
Amalgam
AmalgamAmalgam
Amalgam
 
dental amalgam May 2020....class 1 class 2
dental amalgam May 2020....class 1 class 2dental amalgam May 2020....class 1 class 2
dental amalgam May 2020....class 1 class 2
 
dental material Amalgam
dental material Amalgamdental material Amalgam
dental material Amalgam
 
Amalgam
AmalgamAmalgam
Amalgam
 
Dental amalgam - Recent advances
Dental amalgam - Recent advancesDental amalgam - Recent advances
Dental amalgam - Recent advances
 
Dental amalgam - Recent advances.ppt
Dental amalgam - Recent advances.pptDental amalgam - Recent advances.ppt
Dental amalgam - Recent advances.ppt
 
Amalgam seminar
Amalgam seminarAmalgam seminar
Amalgam seminar
 
Dental Amalgam (Dental Materials Course)
Dental Amalgam (Dental Materials Course)Dental Amalgam (Dental Materials Course)
Dental Amalgam (Dental Materials Course)
 
Amalgam
AmalgamAmalgam
Amalgam
 
Amalgam
AmalgamAmalgam
Amalgam
 
Amalgam
AmalgamAmalgam
Amalgam
 
Posterior restorations.....
Posterior restorations.....Posterior restorations.....
Posterior restorations.....
 
2462_20040305104400.ppt
2462_20040305104400.ppt2462_20040305104400.ppt
2462_20040305104400.ppt
 
Alloys in prosthodontics
Alloys in prosthodonticsAlloys in prosthodontics
Alloys in prosthodontics
 
Amalgam modified/cosmetic dentistry courses
Amalgam modified/cosmetic dentistry coursesAmalgam modified/cosmetic dentistry courses
Amalgam modified/cosmetic dentistry courses
 
Dental amalgam - material aspect
Dental amalgam - material aspectDental amalgam - material aspect
Dental amalgam - material aspect
 
13-Materials - Fertilizer Plant.pptx
13-Materials - Fertilizer Plant.pptx13-Materials - Fertilizer Plant.pptx
13-Materials - Fertilizer Plant.pptx
 
General Principles and Processes of Isolation of Elements.pptx
General Principles and Processes of Isolation of Elements.pptxGeneral Principles and Processes of Isolation of Elements.pptx
General Principles and Processes of Isolation of Elements.pptx
 
08.amalgam
08.amalgam08.amalgam
08.amalgam
 

Último

The Singapore Teaching Practice document
The Singapore Teaching Practice documentThe Singapore Teaching Practice document
The Singapore Teaching Practice documentXsasf Sfdfasd
 
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxEducation and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxraviapr7
 
General views of Histopathology and step
General views of Histopathology and stepGeneral views of Histopathology and step
General views of Histopathology and stepobaje godwin sunday
 
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdfMaximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdfTechSoup
 
Quality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICEQuality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICESayali Powar
 
Philosophy of Education and Educational Philosophy
Philosophy of Education  and Educational PhilosophyPhilosophy of Education  and Educational Philosophy
Philosophy of Education and Educational PhilosophyShuvankar Madhu
 
Practical Research 1 Lesson 9 Scope and delimitation.pptx
Practical Research 1 Lesson 9 Scope and delimitation.pptxPractical Research 1 Lesson 9 Scope and delimitation.pptx
Practical Research 1 Lesson 9 Scope and delimitation.pptxKatherine Villaluna
 
3.21.24 The Origins of Black Power.pptx
3.21.24  The Origins of Black Power.pptx3.21.24  The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptxmary850239
 
Human-AI Co-Creation of Worked Examples for Programming Classes
Human-AI Co-Creation of Worked Examples for Programming ClassesHuman-AI Co-Creation of Worked Examples for Programming Classes
Human-AI Co-Creation of Worked Examples for Programming ClassesMohammad Hassany
 
How to Make a Field read-only in Odoo 17
How to Make a Field read-only in Odoo 17How to Make a Field read-only in Odoo 17
How to Make a Field read-only in Odoo 17Celine George
 
CAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptxCAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptxSaurabhParmar42
 
In - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptxIn - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptxAditiChauhan701637
 
HED Office Sohayok Exam Question Solution 2023.pdf
HED Office Sohayok Exam Question Solution 2023.pdfHED Office Sohayok Exam Question Solution 2023.pdf
HED Office Sohayok Exam Question Solution 2023.pdfMohonDas
 
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdfP4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdfYu Kanazawa / Osaka University
 
Presentation on the Basics of Writing. Writing a Paragraph
Presentation on the Basics of Writing. Writing a ParagraphPresentation on the Basics of Writing. Writing a Paragraph
Presentation on the Basics of Writing. Writing a ParagraphNetziValdelomar1
 
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxPISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxEduSkills OECD
 
How to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesHow to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesCeline George
 
Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.raviapr7
 

Último (20)

The Singapore Teaching Practice document
The Singapore Teaching Practice documentThe Singapore Teaching Practice document
The Singapore Teaching Practice document
 
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxEducation and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptx
 
General views of Histopathology and step
General views of Histopathology and stepGeneral views of Histopathology and step
General views of Histopathology and step
 
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdfMaximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
 
Finals of Kant get Marx 2.0 : a general politics quiz
Finals of Kant get Marx 2.0 : a general politics quizFinals of Kant get Marx 2.0 : a general politics quiz
Finals of Kant get Marx 2.0 : a general politics quiz
 
Quality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICEQuality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICE
 
Philosophy of Education and Educational Philosophy
Philosophy of Education  and Educational PhilosophyPhilosophy of Education  and Educational Philosophy
Philosophy of Education and Educational Philosophy
 
Prelims of Kant get Marx 2.0: a general politics quiz
Prelims of Kant get Marx 2.0: a general politics quizPrelims of Kant get Marx 2.0: a general politics quiz
Prelims of Kant get Marx 2.0: a general politics quiz
 
Practical Research 1 Lesson 9 Scope and delimitation.pptx
Practical Research 1 Lesson 9 Scope and delimitation.pptxPractical Research 1 Lesson 9 Scope and delimitation.pptx
Practical Research 1 Lesson 9 Scope and delimitation.pptx
 
3.21.24 The Origins of Black Power.pptx
3.21.24  The Origins of Black Power.pptx3.21.24  The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptx
 
Human-AI Co-Creation of Worked Examples for Programming Classes
Human-AI Co-Creation of Worked Examples for Programming ClassesHuman-AI Co-Creation of Worked Examples for Programming Classes
Human-AI Co-Creation of Worked Examples for Programming Classes
 
How to Make a Field read-only in Odoo 17
How to Make a Field read-only in Odoo 17How to Make a Field read-only in Odoo 17
How to Make a Field read-only in Odoo 17
 
CAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptxCAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptx
 
In - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptxIn - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptx
 
HED Office Sohayok Exam Question Solution 2023.pdf
HED Office Sohayok Exam Question Solution 2023.pdfHED Office Sohayok Exam Question Solution 2023.pdf
HED Office Sohayok Exam Question Solution 2023.pdf
 
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdfP4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
 
Presentation on the Basics of Writing. Writing a Paragraph
Presentation on the Basics of Writing. Writing a ParagraphPresentation on the Basics of Writing. Writing a Paragraph
Presentation on the Basics of Writing. Writing a Paragraph
 
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxPISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
 
How to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesHow to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 Sales
 
Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.
 

dental amalgam presentation

  • 1. Dental Amalgam BY UZMA JAN BDS 1ST YEAR
  • 2. Amalgam  An alloy of mercury with another metal.
  • 3. Why Amalgam?  Inexpensive  Ease of use  Proven track record - >100 years  Familiarity  Resin-free - less allergies than composite
  • 4. Composition Of Dental Amalgam  Traditional or Convential amalgam alloys is based on Black’s composition.  63-70% silver  26-28% tin  Less than 6% Cu &  Sometimes 0-2% Zn.
  • 5. Composition Of High Ag-Sn Amalgam  Ag 40-60%  Sn 27-30%  Cu 13-30%
  • 6. Constituents in Amalgam  Basic • Silver • Tin • Copper • Mercury  Other • Zinc • Indium • Palladium
  • 7. Basic Constituents  Silver (Ag)  Increases strength  Increases expansion  Decrease creep  Whitens the Alloy  Increase tarnish resistance  Tin (Sn)  Decreases expansion  Decreased strength  Increases setting time
  • 8. Basic Constituents Copper (Cu)  Ties up tin  Reducing gamma-2 formation  Increases strength & hardness  Reduces tarnish and corrosion  Reduces creep  Reduces marginal deterioration
  • 9. Basic Constituents Mercury (Hg)  Activates reaction  Only pure metal that is liquid at room temperature  Spherical alloys  * Require less mercury  - Smaller surface area easier to wet  40 to 45% Hg  Admixed alloys  Require more mercury  lathe-cut particles more difficult to wet  45 to 50% Hg
  • 10. Other Constituents  Zinc (Zn)  Used in manufacturing  Decreases oxidation of other elements  Sacrificial anode  Provides better clinical performance  less marginal breakdown  Causes delayed expansion with low Cu alloys  If contaminated with moisture during condensation H2O + Zn ZnO + H2⇒⇒
  • 11. Other Constituents  Indium (In)  Decreases surface tension  Reduces amount of mercury necessary  Reduces emitted mercury vapor  Reduces creep and marginal breakdown  Increases strength  Must be used in admixed alloys  Example  Indisperse (Indisperse Distributing Company)  5% indium
  • 12. Other Constituents  Palladium (Pd)  Reduced corrosion  Greater luster  Whitens the Alloy  Example  Valiant PhD (Ivoclar Vivadent)  0.5% palladium
  • 13. Basic Composition  A silver-mercury matrix containing filler particles of silver-tin  Filler (bricks)  Ag3Sn called gamma  can be in various shapes  irregular (lathe-cut), spherical, or a combination  Matrix  Ag2Hg3 called gamma 1  cement  Sn8Hg called gamma 2  voids
  • 14. Basic Setting Reactions  Conventional low-copper alloys  High Cu Alloys 1-Admixed high-copper alloys 2-Single composition high-copper alloys
  • 15. Conventional Low-Copper Alloys  Dissolution and precipitation  Hg dissolves Ag and Sn from alloy  Intermetallic compounds formed Ag-Sn Alloy Ag-Sn Alloy Ag-Sn Alloy Mercury (Hg) Ag AgAg Sn Sn Sn Hg Hg AgAg33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + AgSn + Ag22HgHg33 + Sn+ Sn88HgHg γ γ γ1 γ2
  • 16. Conventional Low-Copper Alloys  Gamma (γ) = Ag3Sn  Unreacted alloy  Strongest phase and corrodes the least  Forms 30% of volume of set amalgam Ag-Sn Alloy Ag-Sn Alloy Ag-Sn Alloy Mercury Ag Ag Ag Sn Sn Sn Hg Hg Hg AgAg33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + AgSn + Ag22HgHg33 + Sn+ Sn88HgHg γ γ γ1 γ2
  • 17. Conventional Low-Copper Alloys  Gamma 1 (γ1) = Ag2Hg3  matrix for unreacted alloy and 2nd strongest phase  10 micron grains binding gamma (γ)  60% of volume γ1 AgAg33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + AgSn + Ag22HgHg33 + Sn+ Sn88HgHg γ γ γ1 γ2 Ag-Sn Alloy Ag-Sn Alloy Ag-Sn Alloy
  • 18. Conventional Low-Copper Alloys  Gamma 2 (γ2) = Sn8Hg  weakest and softest phase  corrodes fast, voids form  corrosion yields Hg which reacts with more gamma (γ)  10% of volume  volume decreases with time due to corrosion AgAg33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + AgSn + Ag22HgHg33 + Sn+ Sn88HgHg γ γ γ1 γ2 γ2 Ag-Sn Alloy Ag-Sn Alloy Ag-Sn Alloy
  • 19. Admixed High-Copper Alloys  Ag enters Hg from Ag-Cu spherical eutectic particles  Eutectic  An alloy in which the elements are completely soluble in liquid solution but separate into distinct areas upon solidification  Both Ag and Sn enter Hg from Ag3Sn particles AgAg33Sn + Ag-Cu + HgSn + Ag-Cu + Hg ⇒⇒ AgAg33Sn + Ag-Cu + AgSn + Ag-Cu + Ag22HgHg33 + Cu+ Cu66SnSn55 γ γ γ1 η Ag-Sn Alloy Ag-Sn Alloy Mercury Ag AgAg Sn Sn Ag-Cu Alloy Ag HgHg
  • 20. Admixed High-Copper Alloys  Sn diffuses to surface of Ag-Cu particles  Reacts with Cu to form (eta) Cu6Sn5 (η) Around unconsumed Ag-Cu particles Ag-Sn Alloy Ag-Cu Alloyη Ag-Sn Alloy AgAg33Sn + Ag-Cu + HgSn + Ag-Cu + Hg ⇒⇒ AgAg33Sn + Ag-Cu + AgSn + Ag-Cu + Ag22HgHg33 + Cu+ Cu66SnSn55 γ γ γ1 η
  • 21. Admixed High-Copper Alloys  Gamma 1 (γ1) (Ag2Hg3) surrounds (η) eta phase (Cu6Sn5) and gamma (γ) alloy particles (Ag3Sn) Ag-Sn Alloy γ1 Ag-Cu Alloyη Ag-Sn Alloy AgAg33Sn + Ag-Cu + HgSn + Ag-Cu + Hg ⇒⇒ AgAg33Sn + Ag-Cu + AgSn + Ag-Cu + Ag22HgHg33 + Cu+ Cu66SnSn55 γ γ γ1 η
  • 22. Single Composition High-Copper Alloys  Gamma sphere (γ) (Ag3Sn) with epsilon coating (ε) (Cu3Sn)  Ag and Sn dissolve in Hg Ag-Sn Alloy Ag-Sn Alloy Ag-Sn Alloy Mercury (Hg) ε Ag Sn Ag Sn AgAg33Sn + CuSn + Cu33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + CuSn + Cu33Sn + AgSn + Ag22HgHg33 + Cu+ Cu66SnSn55 γ γ γ1 ηε ε
  • 23. Single Composition High-Copper Alloys  Gamma 1 (γ1) (Ag2Hg3) crystals grow binding together partially- dissolved gamma (γ) alloy particles (Ag3Sn)  Epsilon (ε) (Cu3Sn) develops crystals on surface of gamma particle (Ag3Sn) in the form of eta (η) (Cu6Sn5)  Reduces creep  Prevents gamma-2 formation Ag-Sn Alloy Ag-Sn Alloy Ag-Sn Alloy γ1 η AgAg33Sn + CuSn + Cu33Sn + HgSn + Hg ⇒⇒ AgAg33Sn + CuSn + Cu33Sn + AgSn + Ag22HgHg33 + Cu+ Cu66SnSn55 γ γ γ1 ηε ε
  • 24. Classifications  Based on Cu content  Based on particle shape  Based on Zn content  Based on number of alloyed metals  Based on size of alloy
  • 25. Copper Content  Low-copper alloys  4 to 6% Cu  High-copper alloys  thought that 6% Cu was maximum amount  due to fear of excessive corrosion and expansion  Now contain 9 to 30% Cu  at expense of Ag
  • 26. Particle Shape  Lathe cut  low Cu  New True Dentalloy  high Cu  ANA 2000  Admixture  high Cu  Dispersalloy, Valiant PhD  Spherical  low Cu  Cavex SF  high Cu  Tytin, Valiant
  • 27. Manufacturing Process  Lathe-cut alloys  Ag & Sn melted together  alloy cooled  phases solidify  heat treat  400 ºC for 8 hours  grind, then mill to 25 - 50 microns  heat treat to release stresses of grinding  More Hg needed – high force needed due to irregular form
  • 28. Manufacturing Process  Spherical alloys  melt alloy  atomize  spheres form as particles cool  sizes range from 5 - 40 microns  variety improves condensability Spherical particles wet easier ( less Hg is required)
  • 29. Admixture: Lathe-cut + Spherical Eutectic (ALE)  Composition  2/3 conventional lathe cut (3% Cu)  1/3 high Cu spherical eutectic (28% Cu)  overall 12% Cu, 1% Zn  Example  Dispersalloy (Caulk)
  • 30. Zn content  If the Zn content is greater than 0.01% the amalgam is called a Zn-containing Amalgam.  If the content is less, then Amalgam is Non-Zn Amalgam.
  • 31. Number of alloyed metals  Binary alloys : Ag-Sn  Tertiary Alloys : Ag-Sn-Cu  Quaternary alloys : Ag-Sn-Cu-In
  • 32. Size of Alloy  Micro cut  Macro cut