Session 6: Amalgam; Mercury Toxicity; Alloys

What is Amalgam

Metallic alloys of mercury

• Alloy= substance composed of 2 or + metals

What is Amalgamate

To unite metal in an alloy with mercury

What is dental amalgam

Alloys of mercury with silver, copper, & tin

• 3 metals used for amalgam

Triturate/Trituration

Triturare —> grind to fine powder

• Mix powdered substance in mortar with aid of pestle

Bfr mercury inside a jar, after mercury in capsule —>

Condense/Condensation

Make more compact, more dense

Accurate adaptation to cavity walls

Express excess mercury from amalgam

Dental amalgam short hx

1818 Bismuth —> lead + tin amalgam

1819 Bell —> silver amalgam

1896 Black —> high silver amalgam

1970 Innes & Youdelis —> high copper

Dental amalgam —> Composition

Alloy powder

• Silver (Ag)

• Tin (Sn)

• Copper (Cu)

Mercury

Ratio of alloy to mercury= 1:1, ½ mercury, ½ alloy

Classification of dental amalgams

Shape of the alloy particles

• Lathe cut

• Admixed

• Spherical

  • ***For lathe-cut, sphere= small surface area, so you need less mercury (look @ at the slides),

  • Sphere: 53% alloy, 47% Hg

Composition of the alloy

• Low copper (Cu < 3%)

  • Ag3Sn

    • Black introduced

• High copper (Cu > 6%)

  • Innes introduced —>

    • Mixed Ag3Sn + AgCu

    • Unicompositional AgSnCu

LOOK AT THE SLIDE DOCUMENTS

LOOK AT IT!!