Amalagam Safety

Question 1

what is amalgam

Answer 1

• a mixture or blend
• an alloy of mercury with another metal
• silver, tin, copper and mercury

Question 2

how much mercury is in current dental amalgam alloys

Answer 2

• spherical: 42%
• mixed: 47-50%

Question 3

what are the forms of mercury

Answer 3

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

Question 4

describe organic mercury- methyl Hg

Answer 4

• 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

Question 5

describe elemental Hg0

Answer 5

• 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

Question 6

describe inorganic mercury

Answer 6

• 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

Question 7

what are the acute effects of elemental Hg vapor

Answer 7

• chills, cough
• metallic taste
• weak, dizzy

Question 8

what are the chronic effects of elemental Hg vapor

Answer 8

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

Question 9

what are the effects of organic Hg

Answer 9

• dizziness
• speech problems
• visual disturbances
• tingling, numbness
• weakness
• hearing loss
• confusion, memory loss
• renal failure
• fetal effects

Question 10

what are the sources of mercury

Answer 10

• food: inorganic and methyl Hg
• water: inorganic Hg
• air: Hg vapor elemental

Question 11

what are the food sources of mercury

Answer 11

• 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)

Question 12

where is Hg in water

Answer 12

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

Question 13

where is Hg in air

Answer 13

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

Question 14

what is the daily mercury exposure

Answer 14

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

Question 15

what is the allowable Hg in industry workers

Answer 15

350-500 micrograms
- 40 hour work week

Question 16

do dental workers have a higher incidence of mercury related illness

Answer 16

no

Question 17

is mercury an allergy

Answer 17

rare- less than 1% of population

Question 18

what are the mercury toxicity claims in dentistry

Answer 18

• 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

Question 19

what is micromercurialism

Answer 19

vague diffuse symptoms

Question 20

no _____ Hg in dental amalgam

Answer 20

methyl

Question 21

describe elemental Hg0 vs chemically bound Hg

Answer 21

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

Question 22

how is mercury vapor produced in dentistry

Answer 22

• mixing, insertion, polishing and removal
• mastication

Question 23

mercury levels are best measured through:

Answer 23

urine

Question 24

describe bisphosphenol A release

Answer 24

• BPA estrogenicity
• association diabetes and cardiovascular disease
• concerns composites and sealants

Question 25

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

Answer 25

- with: 0.6-0.7 mg/L - without 0.3-0.8 mg/L

Question 26

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

Answer 26

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

Question 27

what is the normal blood and urine Hg levels

Answer 27

- blood: 0-10 microg/L - urine: 0-25 microg/L

Question 28

when is Hg vapor highest

Answer 28

at insertion or removal

Question 29

what risk is amaglam classified as

Answer 29

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

Question 30

what percentage of restorations currently placed are amalgams

Answer 30

30%

Question 31

what would be the economic impact of banning amalgam

Answer 31

- increased cost of alternative restorations - increased untreated disease for under and uninsured

Question 32

what is the maximum safe exposure level in the air

Answer 32

50 micrograms per cubic meter

Question 33

what are the mercury hygiene recommendations

Answer 33

- 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

Question 34

why use high volume evac and water spray

Answer 34

- 6 fold decrease in Hg vapor - decreased heat from cutting - rubber dam decreases patient exposure

Question 35

what is the overall enivronmental mercury release

Answer 35

- 53% fuel combustion - 34% waste combustion - 13% manufacturers and consumers - less than 1% from dentistry

Question 36

how should amalgam waste be handled

Answer 36

- amalgam capture device - contact amalgam has contacted pt - non contact amalgam leftover mix - amalgam sludge - empty amalgam capsules

Question 37

where is the amalgam capture devide

Answer 37

- chair side trap - vacuum pump filter - amalgam separator

Question 38

what does the chairside trap do

Answer 38

collects amalgam particles from evacuation line

Question 39

what does the vacuum filter do

Answer 39

upstream from central vacuum pump to remove amalgam from suctioned water

Question 40

what does the amalgam separator do

Answer 40

- 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

Question 41

need _____ chairside amalgam separators

Answer 41

multiple

Question 42

filters/collection for chairside amalgam separators need sent off:

Answer 42

annually

Question 43

what is the problem and advantage of central amalgam separator

Answer 43

- problem: prophy paste cause system clogs - advantage: only one filter to replace