Amalgam Safety Flashcards
What is amalgam?
(3)
“a mixture or blend”
“an alloy of mercury with another metal, especially one used
for dental fillings.”
Silver, tin, copper, and mercury
Dental amalgam used for >– years
150
Dental amalgam used for >150 years
1800-1950’s: Hg to alloy ratio =
— technique, 1959
8:5
Eames
Eames technique, 1959
Hg:alloy ratio =
1:1
How much Hg in current dental amalgam alloys?
Spherical: ~–% Hg
Admixed: ~–% Hg
42
47-50
Mercury (Hg)
Naturally occurring —
Mercury forms:
Organic:
Elemental:
Inorganic Hg salts: (2)
element
methyl Hg
Hg0
Hg+1, Hg+2
Most toxic form
Organic Mercury -
Methyl Hg
Organic Mercury -
Methyl Hg
(3)
When taken up by fish, — up
the food web.
–% GI absorption
— soluble, uniform distribution
throughout body tissues
Toxicity: — damage
Most large scale —, organic Hg
Fungicides, fish, water
bioaccumulates
95
Lipid
neurological
poisonings
Hg Forms: Elemental Hg0
— metal
Vaporizes easily, passes through (3)
Little or no oral or —
— absorb vapor
Can have toxic — effects with breathing lots
of vapor
Occurs through — in occupational
setting or mercury spills in poorly ventilated
area
Used in —
Liquid
membranes,
skin, and blood brain barrier
GI absorption
Lungs
CNS
inhalation
dentistry
Hg Forms: Inorganic mercury
Mercurous Hg+1, Mercuric Hg+2 salts
Compounds used extensively in —
(4)
— toxic form
3. GI absorption —
4. Mercuric ions concentrate in kidneys, —
5. — soluble, environmental water pollution
industry
Mercuric chloride, bromide, sulfate, nitrate
Least
poor
acute toxicity renal necrosis
Water
ELEMENTAL Hg VAPOR
Acute
(3)
- Chills, cough
- Metallic taste
- Weak, dizzy
ELEMENTAL Hg VAPOR
Chronic
(4)
- Tachycardia
- Tremor, confusion
- Depression
- Excess salivation
ORGANIC Hg
(9)
- Dizziness
- Speech problems
- Visual disturbances
- Tingling, numbness
- Weakness
- Hearing loss
- Confusion, memory
loss - Renal failure
- Fetal effects
‘Mad Hatter
Sources of Mercury
1. Food, inorganic and methyl Hg
Non-fish, inorganic Hg
Seafood, methyl Hg (organic)
EPA recommendations → remember dose is important
Not eat shark, swordfish
12 oz (2 meals)/wk of lower Hg fish
Shrimp, light tuna, salmon, pollock, catfish
Albacore tuna, higher Hg than light tuna, 6 oz/wk2. Water, inorganic Hg
Electronics manufacturing plants
Air emissions recycle into water
Dental office waste water. (small amount)
- Water, inorganic Hg
(3)
Electronics manufacturing plants
Air emissions recycle into water
Dental office waste water. (small amount)
Sources of Mercury
3. Air, Hg vapor, elemental
(3)
Power plant emissions,
Municipal combustors,
Medical waste incinerators
Dental amalgams, HG vapor
Dental amalgams, HG vapor =
Elemental Mercur
Daily mercury exposure
1. Food: – g
2. Air: – g
3. Water: – g
4. Amalgam vapor: – g (~1% of max allowable in
industry workers)
(8-10 amalgam restorations) → DENTAL WORKERS ARE MOST
SUSEPTABLE. DENTAL WORKERS DO NOT HAVE A HIGHER
INCIDENCE OF “MERCURY RELATED ILLNESSES”
5. Maximum allowable: – g
a. Workers in Hg industry, 40-hr wk
15
1
0.4
1-4
350-500
Mercury Allergy
(2)
a. True hypersensitivity?
rare ( 1% population)
b. Documented by physician, patch
testing
skipped
Amalgam Mercury Toxicity?
Hal Huggins, DDS
Leading anti-amalgamist
Diagnosed “mercury toxicity” in all pts, even
some without amalgam restorations
Recommended extraction of any teeth with
root canal therapy
Lost dental license
“Mercury Toxicity” Scam: How anti-
amalgamists swindle people
http://www.quackwatch.org Dentalwatch.org
Anti-amalgam claims
Numerous emotional and physical disorders
skipped
Anti-amalgam,
mercury toxicity claims?
(5)
Hg migrates through tooth roots into bone and
gingiva
I.Q. and brain Hg level proportional to number of
fillings
Amalgams cause 50% reduction in kidney function
Hg causes immune disorders such as arthritis, lupus,
lichen planus, Crohn’s diease, Alzheimer’s disease,
amyotrophic lateral sclerosis, multiple sclerosis
Amalgam Related Syndrome (ARS) has no one typical
presentation. “Micromercurialism”: vague diffuse
symptoms.
No — Hg in dental amalgam
methyl
