Finals lecture  amalgam
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Finals lecture amalgam

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Finals lecture  amalgam Finals lecture amalgam Presentation Transcript

  • DENTAL AMALGAM
  • Terminology Silver paste an alloy, one of the constituent of which is mercury an alloy made by mixing Hg with Ag-Sn dental amalgam alloy
  • Components 1. Silver ( Ag) -increase expansion - retards setting time - enhances strength - decrease flow - resist tarnish/corrosion
  • 2. Copper (Cu)- unites with Hg with difficulty
  • 2. Copper- unites with Hg with difficulty - reduces setting time
  • 2. Copper- unites with Hg with difficulty - reduces setting time - increases expansion
  • 2. Copper- unites with Hg with difficulty - reduces setting time - increases expansion - increases strength and hardness
  • 2. Copper- unites with Hg with difficulty - reduces setting time - increases expansion - increases strength and hardness - reduces flow
  • 2. Copper- unites with Hg with difficulty - reduces setting time - increases expansion - increases strength and hardness - reduces flow -tarnishes readily
  • 3. Tin (Sn)
  • 3. Tin - unites readily with Hg
  • 3. Tin - unites readily with Hg -retards setting time
  • 3. Tin - unites readily with Hg -retards setting time -improves plasticity
  • 3. Tin - unites readily with Hg -retards setting time -improves plasticity -reduces expansion
  • 3. Tin - unites readily with Hg -retards setting time -improves plasticity -reduces expansion -increases flow
  • 4. Zinc
  • 4. Zinc (Zn)- combines readily with Hg
  • 4. Zinc - combines readily with Hg -causes expansion
  • 4. Zinc - combines readily with Hg -causes expansion -increases setting time
  • 4. Zinc - combines readily with Hg -causes expansion -increases setting time -increases flow
  • 4. Zinc - combines readily with Hg -causes expansion -increases setting time -increases flow -inhibits oxidation
  • 4. Zinc - combines readily with Hg -causes expansion -increases setting time -increases flow -inhibits oxidation -decreases porosity
  • Classification
  • Classification1. Amalgam alloy particle geometry and size
  • Classification1. Amalgam alloy particle geometry and sizee.g. Lathe-cut – regular, fine microfine cut,
  • Classification1. Amalgam alloy particle geometry and sizee.g. Lathe-cut – regular, fine microfine cut, Spherical
  • Classification1. Amalgam alloy particle geometry and sizee.g. Lathe-cut – regular, fine microfine cut, Spherical2. Copper Content
  • Classification1. Amalgam alloy particle geometry and sizee.g. Lathe-cut – regular, fine microfine cut, Spherical2. Copper Contente.g. Low Copper (conventional amalgam),
  • Classification1. Amalgam alloy particle geometry and sizee.g. Lathe-cut – regular, fine microfine cut, Spherical2. Copper Contente.g. Low Copper (conventional amalgam), High Copper
  • Classification1. Amalgam alloy particle geometry and sizee.g. Lathe-cut – regular, fine microfine cut, Spherical2. Copper Contente.g. Low Copper (conventional amalgam), High Copper3. Zinc Content
  • Classification1. Amalgam alloy particle geometry and sizee.g. Lathe-cut – regular, fine microfine cut, Spherical2. Copper Contente.g. Low Copper (conventional amalgam), High Copper3. Zinc Contente.g. Zinc,
  • Classification1. Amalgam alloy particle geometry and sizee.g. Lathe-cut – regular, fine microfine cut, Spherical2. Copper Contente.g. Low Copper (conventional amalgam), High Copper3. Zinc Contente.g. Zinc, Zinc-free
  • Alloy- Mercury Ratio
  • Alloy- Mercury Ratio irregular particle pack poorly and require a large amount of Hg (50%-60%)
  • Alloy- Mercury Ratio irregular particle pack poorly and require a large amount of Hg (50%-60%) precapsulated amalgam (spherical)has 42%- 45% mercury
  • Mercury rich mixtures – uses squeeze cloth to remove excess mercury
  • Mercury rich mixtures – uses squeeze cloth to remove excess mercury1960 -Eames technique or no squeeze cloth technique
  • Trituration
  • Trituration process of manual mixing of alloy with Hg
  • Trituration process of manual mixing of alloy with Hg done by proportioning mercury and Hg into a mortar and grinding the mixture with a pestle
  • Trituration process of manual mixing of alloy with Hg done by proportioning mercury and Hg into a mortar and grinding the mixture with a pestle mixing of alloy with mercury
  • Types of Trituration
  • Types of Trituration1. Hand
  • Types of Trituration1. Hand2. Mechanical
  • Types of Trituration1. Hand2. Mechanical –use of Amalgamator
  • Types of Trituration1. Hand2. Mechanical –use of Amalgamator reusable capsule
  • Types of Trituration1. Hand2. Mechanical –use of Amalgamator reusable capsule – a hallow tube with rounded ends constructed as two pieces that could be friction fit or screwed together
  •  precapsulated (preproportioned)-
  •  precapsulated (preproportioned)- the components are separated in the capsule by a special diaphragm that is broken when the capsule is placed in an amalgamator.
  • Reaction
  • ReactionMercury+Silver-Tin
  • ReactionMercury+Silver-Tin Silver-Tin phase+ Silver-mercury phase + Tin- mercury phase
  • ReactionMercury+Silver-Tin Silver-Tin phase+ Silver-mercury phase + Tin- mercury phase Silver-tin phase is called the gamma phase, composed of unreacted alloy particle
  •  Silver-mercury phase is called the gamma one
  •  Silver-mercury phase is called the gamma one Tin-mercury phase is called the gamma two
  •  Silver-mercury phase is called the gamma one Tin-mercury phase is called the gamma two amalgam can be thought of as particles of gamma surrounded by or bonded together by a matrix of gamma1 and gamma2
  • Hardening of amalgam
  • Hardening of amalgam2 Phenomena
  • Hardening of amalgam2 Phenomena1. Solution
  • Hardening of amalgam 2 Phenomena1. Solution2. Crystallization
  • Hardening of amalgam 2 Phenomena1. Solution2. Crystallization when Hg comes in contact with amalgam alloy, the particles (gamma) are wet by mercury and begins to absorb it.
  •  the solution of mercury into silver-tin particles leads to the formation of the surface of Ag-Hg and Sn-Hg phases
  •  the solution of mercury into silver-tin particles leads to the formation of the surface of Ag-Hg and Sn-Hg phases the crystallization of the gamma1 and gamma2 phases and their subsequent growth leads to hardening of amalgam
  • Mercury Management
  • Mercury Management Sources of Mercury Hazards
  • Mercury Management Sources of Mercury Hazards1. Mercury vapors released from stored materials
  • Mercury Management Sources of Mercury Hazards1. Mercury vapors released from stored materials2. Amalgamator aerosols
  • Mercury Management Sources of Mercury Hazards1. Mercury vapors released from stored materials2. Amalgamator aerosols3. Spillage during restoration procedure
  • Mercury Management Sources of Mercury Hazards1. Mercury vapors released from stored materials2. Amalgamator aerosols3. Spillage during restoration procedure4. Amalgam removal and replacement
  • 5. Amalgam waste on cotton rolls
  • 5. Amalgam waste on cotton rolls6. Amalgam and mercury in plumbing and sewer system
  • 5. Amalgam waste on cotton rolls6. Amalgam and mercury in plumbing and sewer system7. Amalgam scrap container
  • 5. Amalgam waste on cotton rolls6. Amalgam and mercury in plumbing ans sewer system7. Amalgam scrap container8. Mercury trapped in tiles and carpeting
  • THATS ALL FOLKS