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

ComponentsComponents

1.1. Silver ( Ag) Silver ( Ag) - - increase expansion- retards setting time- enhances strength- decrease flow- resist tarnish/corrosion

2.2. Copper (Cu)- Copper (Cu)- unites with Hg with difficulty

2.2. Copper- Copper- unites with Hg with difficulty

- reduces setting time

2.2. Copper- Copper- unites with Hg with difficulty

- reduces setting time- increases expansion

2.2. Copper- Copper- unites with Hg with difficulty

- reduces setting time- increases expansion- increases strength and hardness

2.2. Copper- 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 (Sn)

3. Tin3. Tin - unites readily with Hg

3. Tin3. Tin - unites readily with Hg-retards setting time

3. Tin3. Tin - unites readily with Hg-retards setting time-improves plasticity

3. Tin3. Tin - unites readily with Hg-retards setting time-improves plasticity -reduces expansion

3. Tin3. Tin - unites readily with Hg-retards setting time-improves plasticity -reduces expansion-increases flow

4. Zinc4. Zinc

4. Zinc4. Zinc (Zn)- combines readily with Hg

4. Zinc4. Zinc- combines readily with Hg-causes expansion

4. Zinc4. Zinc- combines readily with Hg-causes expansion-increases setting time

4. Zinc4. Zinc- combines readily with Hg-causes expansion-increases setting time-increases flow

4. Zinc4. Zinc- combines readily with Hg-causes expansion-increases setting time-increases flow-inhibits oxidation

4. Zinc4. Zinc- combines readily with Hg-causes expansion-increases setting time-increases flow-inhibits oxidation-decreases porosity

ClassificationClassification

ClassificationClassification

1. Amalgam alloy particle geometry and size

ClassificationClassification

1. Amalgam alloy particle geometry and size

e.g. Lathe-cut – regular, fine microfine cut,

ClassificationClassification

1. Amalgam alloy particle geometry and size

e.g. Lathe-cut – regular, fine microfine cut, Spherical

ClassificationClassification

1. Amalgam alloy particle geometry and size

e.g. Lathe-cut – regular, fine microfine cut, Spherical

2. Copper Content

ClassificationClassification

1. Amalgam alloy particle geometry and size

e.g. Lathe-cut – regular, fine microfine cut, Spherical

2. Copper Contente.g. Low Copper (conventional

amalgam),

ClassificationClassification

1. Amalgam alloy particle geometry and size

e.g. Lathe-cut – regular, fine microfine cut, Spherical

2. Copper Contente.g. Low Copper (conventional

amalgam), High Copper

ClassificationClassification

1. Amalgam alloy particle geometry and size

e.g. Lathe-cut – regular, fine microfine cut, Spherical

2. Copper Contente.g. Low Copper (conventional

amalgam), High Copper3. Zinc Content

Classification

1. Amalgam alloy particle geometry and size

e.g. Lathe-cut – regular, fine microfine cut, Spherical

2. Copper Contente.g. Low Copper (conventional

amalgam), High Copper3. Zinc Contente.g. Zinc,

Classification

1. Amalgam alloy particle geometry and size

e.g. Lathe-cut – regular, fine microfine cut, Spherical

2. Copper Contente.g. Low Copper (conventional

amalgam), High Copper3. Zinc Contente.g. Zinc, Zinc-free

AAlloy- Mercury Ratiolloy- Mercury Ratio

AAlloy- Mercury Ratiolloy- Mercury Ratio

irregular particle pack poorly and require a large amount of Hg (50%-60%)

AAlloy- Mercury Ratiolloy- 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 Mercury rich mixtures – uses squeeze cloth to remove excess mercury

1960 -Eames technique or no squeeze cloth technique

TriturationTrituration

TriturationTrituration

process of manual mixing of alloy with Hg

TriturationTrituration

process of manual mixing of alloy with Hg

done by proportioning mercury and Hg into a mortar and grinding the mixture with a pestle

TriturationTrituration

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 TriturationTypes of Trituration

Types of TriturationTypes of Trituration

1. Hand

Types of TriturationTypes of Trituration

1. Hand2. Mechanical

Types of TriturationTypes of Trituration

1. Hand2. Mechanical –use of Amalgamator

Types of TriturationTypes of Trituration

1. Hand2. Mechanical –use of Amalgamator reusable capsule

Types of TriturationTypes of Trituration

1. 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

Reaction

Mercury+Silver-Tin

Reaction

Mercury+Silver-Tin Silver-Tin phase+ Silver-mercury phase + Tin-mercury phase

Reaction

Mercury+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 amalgam

2 Phenomena

Hardening of amalgam

2 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

THAT'S ALL FOLKS