Amalagam Safety Flashcards
1
Q
what is amalgam
A
- a mixture or blend
- an alloy of mercury with another metal
- silver, tin, copper and mercury
2
Q
how much mercury is in current dental amalgam alloys
A
- spherical: 42%
- mixed: 47-50%
3
Q
what are the forms of mercury
A
- organic: methyl Hg
- elemental: Hg0
- inorganic Hg salts: Hg+1 or Hg+2
4
Q
describe organic mercury- methyl Hg
A
- most toxic form
- fungicides, fish, water
- when taken up by fish, bioaccumulates up the food web
- 95% GI absorption
- lipid soluble, uniform distribution throughout body tissues
- toxicity: neurological damage
- most large scale poisonings
5
Q
describe elemental Hg0
A
- liquid metal
- vaporizes easily, passes through membranes, skin and blood brain barrier
- little or no oral or GI absorption
- lungs absorb vapor
- can have toxic CNS effects with breathing lots of vapor
- occurs through inhalation in occupational setting or mercury spills in poorly ventilated area
- used in dentisrty
6
Q
describe inorganic mercury
A
- compounds used extensively in industry
- mercuric chloride, bromide, sulfate, nitrate
- least toxic form
- GI absorption poor
- mercuric ions concentrate in kidneys, acute toxicity renal necrosis
- water soluble, environment water pollution
7
Q
what are the acute effects of elemental Hg vapor
A
- chills, cough
- metallic taste
- weak, dizzy
8
Q
what are the chronic effects of elemental Hg vapor
A
- tachycardia
- tremor, confusion
- depression
- excess salivation
- “mad hatter”
9
Q
what are the effects of organic Hg
A
- dizziness
- speech problems
- visual disturbances
- tingling, numbness
- weakness
- hearing loss
- confusion, memory loss
- renal failure
- fetal effects
10
Q
what are the sources of mercury
A
- food: inorganic and methyl Hg
- water: inorganic Hg
- air: Hg vapor elemental
11
Q
what are the food sources of mercury
A
- non-fish, inorganic Hg
- seafood, methyl Hg
- dont eat shark or swordfish
- 12 oz (2 meals) /week of lower Hg fish such as shrimp, light tuna, slamon, pollock, catfish,
- albcaore tuna- higher Hg than light tuna (6oz/week)
12
Q
where is Hg in water
A
- electronic manufacturing plants
- air emissions recycle into water
- dental office waste water
13
Q
where is Hg in air
A
- power plant emissions
- municipal combustors
- medical waste incinerators
- dental amalgams, Hg vapor = elemental mercury
14
Q
what is the daily mercury exposure
A
- food: 15 micrograms
- air: 1 microgram
- water 0.4 micrograms
- amalgam vapor: 1-4 micrograms
15
Q
what is the allowable Hg in industry workers
A
350-500 micrograms
- 40 hour work week
16
Q
do dental workers have a higher incidence of mercury related illness
A
no
17
Q
is mercury an allergy
A
rare- less than 1% of population