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Advanced Restorative > Amalagam Safety > Flashcards

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
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2
Q

how much mercury is in current dental amalgam alloys

A
  • spherical: 42%
  • mixed: 47-50%
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3
Q

what are the forms of mercury

A
  • organic: methyl Hg
  • elemental: Hg0
  • inorganic Hg salts: Hg+1 or Hg+2
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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
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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
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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
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7
Q

what are the acute effects of elemental Hg vapor

A
  • chills, cough
  • metallic taste
  • weak, dizzy
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8
Q

what are the chronic effects of elemental Hg vapor

A
  • tachycardia
  • tremor, confusion
  • depression
  • excess salivation
  • “mad hatter”
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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
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10
Q

what are the sources of mercury

A
  • food: inorganic and methyl Hg
  • water: inorganic Hg
  • air: Hg vapor elemental
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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)
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12
Q

where is Hg in water

A
  • electronic manufacturing plants
  • air emissions recycle into water
  • dental office waste water
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13
Q

where is Hg in air

A
  • power plant emissions
  • municipal combustors
  • medical waste incinerators
  • dental amalgams, Hg vapor = elemental mercury
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14
Q

what is the daily mercury exposure

A
  • food: 15 micrograms
  • air: 1 microgram
  • water 0.4 micrograms
  • amalgam vapor: 1-4 micrograms
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15
Q

what is the allowable Hg in industry workers

A

350-500 micrograms
- 40 hour work week

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16
Q

do dental workers have a higher incidence of mercury related illness

A

no

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17
Q

is mercury an allergy

A

rare- less than 1% of population

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18
Q

what are the mercury toxicity claims in dentistry

A
  • Hg migrates through tooth roots into bone and gingiva
  • IQ and brain Hg level proprotional to number of fillings
  • amalgams cause 50% reduction in kidney function
  • Hg causes immune disorders such as arthritis, lupus, lichen planus, chron’s disease, alzheimers diease, amyotrophic lateral sclerosis, multiple sclerosis
19
Q

what is micromercurialism

A

vague diffuse symptoms

20
Q

no _____ Hg in dental amalgam

A

methyl

21
Q

describe elemental Hg0 vs chemically bound Hg

A
  • in final restoration Hg chemically bound to Ag
  • elemental H and O versus H2O
  • elemental Na and Cl vs NaCl
22
Q

how is mercury vapor produced in dentistry

A
  • mixing, insertion, polishing and removal
  • mastication
23
Q

mercury levels are best measured through:

A

urine

24
Q

describe bisphosphenol A release

A
  • BPA estrogenicity
  • association diabetes and cardiovascular disease
  • concerns composites and sealants
25
Q

what are the mercury levels in blood in patients with and without amalgam restorations

A
  • with: 0.6-0.7 mg/L
  • without 0.3-0.8 mg/L
26
Q

what are the urine levels of Hg in patients with amalgam, dental personnel, and one seafood meal

A
  • patients with amalgam: less than 5microg/L
  • dental personnel: less than 10microg/L
  • one seafood meal: 5-20 microg/L
27
Q

what is the normal blood and urine Hg levels

A
  • blood: 0-10 microg/L
  • urine: 0-25 microg/L
28
Q

when is Hg vapor highest

A

at insertion or removal

29
Q

what risk is amaglam classified as

A

class II moderate risk - same classification as composites or other dental alloys

30
Q

what percentage of restorations currently placed are amalgams

A

30%

31
Q

what would be the economic impact of banning amalgam

A
  • increased cost of alternative restorations
  • increased untreated disease for under and uninsured
32
Q

what is the maximum safe exposure level in the air

A

50 micrograms per cubic meter

33
Q

what are the mercury hygiene recommendations

A
  • avoid direct contact
  • clean up spills immediately
  • well ventilated office
  • no ultrasonic amalgamators
  • use amalgamator lid
  • high volume evacuation and water spray
  • monitor Hg levels in office
  • avoid carpeted operatories
  • dont heat, incinerate or sterilize amalgam
  • scrap amalgam, store in air tight container and then recycle
34
Q

why use high volume evac and water spray

A
  • 6 fold decrease in Hg vapor
  • decreased heat from cutting
  • rubber dam decreases patient exposure
35
Q

what is the overall enivronmental mercury release

A
  • 53% fuel combustion
  • 34% waste combustion
  • 13% manufacturers and consumers
  • less than 1% from dentistry
36
Q

how should amalgam waste be handled

A
  • amalgam capture device
  • contact amalgam has contacted pt
  • non contact amalgam leftover mix
  • amalgam sludge
  • empty amalgam capsules
37
Q

where is the amalgam capture devide

A
  • chair side trap
  • vacuum pump filter
  • amalgam separator
38
Q

what does the chairside trap do

A

collects amalgam particles from evacuation line

39
Q

what does the vacuum filter do

A

upstream from central vacuum pump to remove amalgam from suctioned water

40
Q

what does the amalgam separator do

A
  • collects amalgam prior to central vacuum pump
  • sedimentation/filtration/ion exchange
  • without separator up to 80% is captured at the office and up to remaining 20% at the waste water treatment plants
  • EPA mandated in 2017
41
Q

need _____ chairside amalgam separators

A

multiple

42
Q

filters/collection for chairside amalgam separators need sent off:

A

annually

43
Q

what is the problem and advantage of central amalgam separator

A
  • problem: prophy paste cause system clogs
  • advantage: only one filter to replace
44
Q
A

Advanced Restorative (9 decks)

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