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
Elemental Hg0 versus chemically bound Hg
(3)
In final restoration, Hg chemically bound to Ag (1)
Elemental H and O versus H2O
Elemental Na and Cl versus NaCl (table salt)
Mercury Vapor (elemental Hg)
(2)
Mixing, insertion, polishing, and removal
Mastication (minute amounts)
Facts about amalgam restorations
Over 150 years. Affordable, durable, safe. 80%
last 15+ years.
Composite:
(2)
Increased cost, Longevity (posterior): 5-10 yrs
Bisphenol A release?
Hg not enter (3)
pulp, bone, or gingiva
Hg vapor release
(2)
Mixing, insertion
Polishing & removal, heat
Small amounts Hg vapor absorbed by lungs,
concentrated in kidney, excreted in urine →
mercury levels are best measured through —.
urine
Composite, Sealant Safety
Bisphenol A release
(5)
BPA estrogenicity (Endocr J 2004)
Association diabetes and cardiovascular disease (JAMA 2008)
Editorial, MU Columbia researcher (JAMA 2008)
Concerns composites and sealants, Pediatrics 2010 (Bb)
How much BPA released?
O2 inhibited layer, unreacted monomer
Composites: —
Sealants: —
shape/polish
pumice
Dental Amalgam Biocompatibility
Mercury levels
1. Blood
(2)
a. Patients with amalgam restorations: 0.6-0.7 g/L
b. Patients with no amalgam: 0.3-0.8 g/L
Dental Amalgam Biocompatibility
Mercury levels
2. Urine
a. Better indicator
b. Patients with amalgam restorations:
c. Dental personnel:
d. One seafood meal:
5 g/L
10 g/L
5-20 g/L
Dental Amalgam Biocompatibility
Mercury levels
3. All these levels well within normal
(2)
a. Blood: 0-10 g/L (0-3 g/L)
b. Urine: 0-25 g/L (Neurologic changes: 500 g/L)
US Public Health Service: Review of 500
Dental Amalgam Studies, 1993
Dental amalgams, minute amounts of —
decrease with — of amalgam
No demonstrable clinical effects with exposure
Removing amalgam, no improvement of —
Hg vapor highest at —
elemental Hg vapor
(mastication)
age
symptoms or illnesses.
insertion or removal
Amalgam Exposure and Neurological Function,
NeuroToxicology 2005
(1)
1663 adults, no neurological effects from amalgams
Neuropsychological and renal effects of dental amalgam
in children, JADA 2007
(2)
5-year study, 534 children, 6-10 yo at baseline
Amalgam or composite, no difference
Neurobehavioral effects of dental amalgam in children,
JADA 2008
7-yr study, 507 children, 8-10 yo at baseline
Amalgam or composite, no difference
Interesting fact: at 5 yrs, –% more retxt in composite group
50
skipped
Amalgam Safety Reports
European Commission Health and Consumer Protection, 2008
(3)
a. Safety of amalgam and alternative (composite) dental restoration
materials
b. Amalgam safe, effective restorative
1) Material of choice in some situations
c. Despite possible hazards of composites, also deemed safe
- FDA 2009
a. Reclassified as Class —: same classification as dental
composites and other dental alloys
b. Hg vapor not a risk for patients …
c. Limited to no information on fetus or children under…
II (moderate risk)
6 and over
6
- ADA 2009 statement
(2)
Safe, affordable, durable material
Cite European Commission, FDA 2009
National Council Against Health Fraud
Position Paper on Amalgam Fillings (Bb)
1. Amalgam most thoroughly tested restorative
material
2. Conclusions of testing:
a. Rare true allergy
3. Durable, inexpensive material
4. “Mercury-free dentistry” considered
substandard practice
5. Cannot suggest amalgam removal for health
reasons
a. Lose dental license
AMALGAM IS SAFE
Future of Amalgam Restorations
No anti-amalgam/patient safety legislative bills have
passed in US
(2)
No evidence to support
Norway and Sweden ban for environmental reasons
–% of restorations currently placed are amalgam
Increased use of — and other materials
MO amalgam-free practices: –% rural; –% urban (2008)
More appropriate material in certain application
30
composites
30, 60
Economic impact of banning amalgam1
(2)
Increased cost of alternative restorations
Increased untreated disease, under- and uninsured
More important issue for future of amalgam:
Not mercury release from restorations
Mercury/Amalgam waste management (EPA regulations)
Mercury Management
1. Dental personnel at greater risk for mercury exposure. We are the
canary.
2. Appropriate techniques reduce mercury vapor in dental office
a. – g/m3 of air: maximum safe exposure level
50
Mercury Hygiene Recommendations
1. Avoid direct contact with Hg alloy
2. Clean up spills immediately
a. Mercury spill kit, Nitrile gloves
3. Well-ventilated office
4. No ultrasonic amalgamators
5. Use amalgamator lid
6. High-volume evacuation and water spray
7. Monitor Hg levels in office
8. Avoid carpeted operatories
9. Don’t heat, incinerate, or sterilize amalgam, Why?????
10. Scrap amalgam, store in air-tight container and then recycle
creates vapor
Mercury Hygiene Recommendations
6. High-volume evacuation and water spray
—fold decreased Hg vapor
— heat from cutting
—, decreased pt exposure
6
Decreased
Rubber dam
Overall Environmental
Mercury Release
–% fuel combustion
–% waste combustion
–% manufacturers and consumers
<–% from dentistry
To control dental Hg release, amalgam waste must be handled correctly.
53
34
13
1
Amalgam Waste
Amalgam capture device:
(3)
Chair side trap
Vacuum pump filter
Amalgam separator
Amalgam Waste
(5)
Amalgam capture device:
Contact amalgam, has contacted pt
Non-contact amalgam, leftover mix
Amalgam sludge
Empty amalgam capsules
Contact amalgam, has contacted pt
(1)
Carving scrap, extracted teeth, amalgam in traps, filters,
or screens
Evacuation System
Amalgam waste collection
—, collects amalgam particles
from evacuation line
—, upstream from central vacuum
pump, to remove amalgam from suctioned
water
Amalgam separator
Chairside Trap
Vacuum Filter
Amalgam separator
Collects amalgam prior to —
Sedimentation/filtration/ion exchange
Without separator, up to –% is captured at
the office and up to the remaining –% at the
waste water treatment plants.
ISO 11143 certification: ≥—% Hg removal
EPA mandated 2017. Compliance by 7/14/2020.
Chairside or central system, # operatories
Cost
central vacuum pump
80, 20
95
Amalgam Separators
Chairside
(2)
Need multiple.
Filters/collection needs sent off annually.
Amalgam Separators
Central
Problem:
Advantage:
Cost:
prophy paste cause system clogs
only one filter to replace
$1000 + 300 year
