Mercury toxicity can occur from exposure to mercury in various forms. Elemental mercury is a liquid metal that vaporizes at room temperature into an odorless gas. Inorganic mercury combines with other elements to form salts, while organic mercury combines with carbon. Dental amalgam used in fillings contains mercury. Exposure risks include inhalation of vapors during placement or removal of fillings. Mercury is a potent neurotoxin that can cross the blood-brain barrier and cause neurological and developmental effects. Symptoms of toxicity depend on the level and route of exposure, ranging from rashes to kidney damage.

1. MERCURY TOXICITY
DR ASHWINI M PATIL
Reader
Navodaya dental college
Raichur

2. Introduction
 Mercury (Hg) is a naturally occurring metal and exists in three forms:
elemental (metallic), inorganic, and organic. The form of mercury greatly
influences mercury’s distribution within the body and its health effects.
 Mercury is a heavy, silvery-white liquid metal known as quick silver. And its
the only common metal which is liquid at ordinary temperatures.
 A fair conductor of electricity, and poor conductor of heat if compared with
other metals.

3.  Mercury is a heavy silvery liquid metal with atomic number 80 a standard
atomic weight of 200.59. The amount of mercury in dental amalgam may be
specified as alloy – mercury ratio=1:1.
 The name comes from Greek name, hydrargyrum, which means "hydr-"
water and "argyros" silver to reflect its shiny surface, it has a silvery tinge
and it, as a liquid, flows quickly .
 It alloys easily with many metals, such as gold, silver, and tin, these alloys
are called amalgams.
Introduction

4. Mercury in the environment
 Mercury is a compound that can be found naturally in the environment as metal form,
mercury salts or as organic mercury compounds. Found mainly in cinnabar ore (HgS).
Also present as an impurity in many other minerals, in particular
the non-ferrous metals, and in fossil fuels, coal.
 Easily vaporize in room temperature into an odorless, colorless
vapor that can easily inhaled.

5. Elemental mercury
is a shiny, silver-white liquid (quicksilver) primarily obtained from the refining of
mercuric sulfide in cinnabar ore. Elemental mercury is used in dental amalgams.
Elemental mercury easily vaporizes at room temperature to an invisible, odorless
toxic gas referred to as elemental mercury vapor. Usually used in school science lab.

6. Inorganic mercury
Inorganic mercury
 compounds, or mercury salts, are formed when mercury combines with
other elements such as chlorine (e.g., mercuric chloride), sulfur, or oxygen.
Its exist in two oxidative states— mercurous (+1) and oxide mercuric (+2).
Mercury salts are highly toxic and corrosive. White in color except cinnabar
(Red). Enters body through mouth and skin from disinfectant and
fungicide. Usually used in school science lab.

7. Organic mercury
compounds are formed when inorganic mercury is methylated or combines
with organic agents. The most important organic form of mercury in terms of
human exposure is methylmercury, is formed by anaerobic methylation of
inorganic mercury by microorganisms in sediments. The primary source of
human exposure to mercury is through the consumption of fish and shellfish
containing methylmercury.

8. Other forms of organic mercury
may be found in outdated fungicides, antiseptics, and disinfectants. Most of
these uses have been discontinued, however, small amounts of these compounds
may still be found in some medicines.

9. Composition of amalgam
 50% Mercury
 35% Silver
 13% Tin
 2% Copper and Zinc

12.  γ
1 forms first and then γ
2.
 Alloy is mixed with mercury in the ratio of 1:1.
 Mercury is insufficient to completely consume the alloy particles.
 γ
1 - Dominant phase – 54-56%.
 Unreacted γ
- 27- 35%.
 γ
2 - 11-13%

16. Risks
 Easily crosses blood brain barrier and can enter breast milk.
 Potent neurotoxin.
 Neurological effects - tremors , mood swings, irritability, excessive shyness.
 Very high exposure can cause kidney effects, respiratory failure and death.
 Birth defects.
 Impairment of vision, speech, walking.

17. Mercury exposure in dental clinic.

18. In 1845, American Society of Dental Surgeons condemned the use of all filling
material other than gold as toxic, thereby igniting. The society went further and
requested members to sign a pledge refusing to use amalgam.
In mid 1920's a German dentist, Professor A. Stock. He claimed to have evidence
showing that mercury could be absorbed from dental amalgam, which leads to
serious health problems. He also expressed concerns over health of dentists,
stating that nearly all dentists had excess mercury in their urine.

19. Remarkably, the Food and Drug Administration (FDA) has separately approved
the mercury and the alloy powder for dental use; but the amalgam mixture has
never been approved as a dental device.
In 1980 primarily through the seminars and writings of Dr. Huggins. He was
convinced that mercury released from dental amalgam was responsible for
human diseases affecting the cardiovascular system and nervous system.
Also stated that patients claimed recoveries from multiple sclerosis,Alzheimer’s disease
and other diseases as a result of removing their dental amalgam fillings.

20. Due to the health effects of mercury exposure, industrial and commercial uses are
regulated in many countries. The World Health Organization (WHO), Occupational Safety
and Health Administration (OSHA), and National Institute for Occupational Safety and
Health (NIOSH) all treat mercury as an occupational hazard, and have established
specific occupational exposure limits. Environmental releases and disposal of mercury
are regulated in the U.S. primarily by the United States Environmental Protection Agency.

21. Amounts of Mercury released
 Trituration
 Placement of restorations
 Dry Polishing
 Wet Polishing
: 1-2 μ
g
: 6-8 μ
g
: 44μg
: 2.4 μ
g
 Removal of restorations using water spray and high volume suction : 1.5 - 2μg
 Additional evacuation for 1 minute to remove amalgam dust : 1.5 – 2 μ
g

22. Mercury management
 Spills of triturated materials are collected with vacuum aspirator.
 Vapor releases must be cleared by airflow system of room.
 During intra oral placement and condensation procedure rubber dam can be
used to isolate patient and high vacuum evacuation is used.

23.  Storages location should be near a vent that exhaust air out of the building.
 Before use : Store in a plastic container with threaded cover
 Scrap amalgam, from condensation is stored under water , glycine or spent x
ray fixer and tightly capped jar.
Mercury management

24. ADA Recommendations for dental mercury
hygiene.
 Train all personnel regarding mercury handling and hazards.
 Make them aware of the potential sources of mercury vapor in the clinic.
 Work in well ventilated spaces with an exhaust.
 Replace air conditioning filters periodically.
 Monitor the dental clinic atmosphere for mercury vapor.

25.  Design work area properly. Floor covering should be nonabsorbent, seamless
and easy to clean.
 Use precapsulated alloys.
 Use amalgamator with completely enclosed arm.
 Avoid skin contact with mercury or freshly prepared amalgam.
 Re-cap single use capsules after use if possible.
ADA Recommendations for dental mercury
hygiene.

26.  Use high volume evacuation while finishing or removing amalgam.
 Salvage and store all scrap amalgam.
 Dispose amalgam scrap and mercury contaminated items as per applicable
regulations.
 Clean up spilled mercury using trap bottles, tape or freshly mixed amalgam.
 Do not use household vacuum cleaner.
 Remove professional clothing before leaving the workplace.
ADA Recommendations for dental mercury
hygiene.

27. Management of mercury spills
In case of an accidental mercury spill (regardless of size),
 Never use a vacuum cleaner to clean up the mercury.
 Never use household cleaning products to clean up the spill, particularly
those containing ammonia or chlorine.
 Never allow mercury to go down the drain.
 Never use a broom or a paintbrush to clean up the mercury.
 Never allow people whose shoes may be contaminated with mercury to walk
around.

28. Mercury spillage kit
Spill kits are essential for the management of mercury spills and breakages.
Procedure:
Put on the Personal Protective Equipment which is provided in the kit.
 Using the scoop collect the amalgam or mercury waste.
 If it is mercury droplets use the syringe to pick up as many globules, then place
the full syringe in the waste container (provided in the kit).
 Open the container which contains calcium hydroxide and sulphur.
 Tip out onto the spillage area, close the center of the spillage.
 Using the scoop mix the powders with the spilt amalgam or mercury (which you
could not pick up).
 The powder may start to go grey as the mercury is absorbed.

29.  Brush the contaminated powder into the scoop and place in the waste
container.
 Close the lid on the waste container or sealable bag.
 Dispose of the Personal Protective Equipment in the waste container .
 Label the waste container or bag with ‘hazardous waste sign.
 Contact the licensed waste carrier company you use to remove the hazardous
waste.
 Cleanup of large mercury spills requires experienced environmental personnel.
Mercury spillage kit

30. Alternatives to Dental Amalgam
 Composite dental restoration.
 Glass ionomer filling.
 Ivoclar cention

33. Effects of Mercury toxicity on the body
 The toxic effects of mercury depend on its chemical form and the route of
exposure.
Allergy, Contact dermatitis represent the most likely physiologic side effect to
dental amalgam, an alternative material (e.g. Composite or ceramic) must be used.
Release of mercury induced an acute reaction which resulted in erythematous
lesions, severe burning and itchy sensation and difficulty in breathing

36. Inhalation of mercury vapors causes:
Chemical pneumonia, Pulmonary oedema, Gingivostomatitis, Increased salivation.
CNS symptoms like: Ataxia, Restriction of field of vision, Delerium, Polyneuropathy.
Symptomatic patients who have experienced acute high-dose elemental mercury
inhalation exposure should receive supportive care and be monitored for development
of acute pneumonitis and pulmonary edema in a hospital setting.
Mercury can be inhaled and absorbed through the skin and mucousmembranes,
so containers of mercury should be securely sealed to avoid spills and
evaporation.

37. Ingestion of Mercury
The signs and symptoms start immediately after swallowing the mercury:
 Hot burning pain in mouth, stomach and abdomen.
 Stools are blood stained , urine is suppressed and scanty,contain blood and
albumin is accompanied by necrosis of renal tubules and damage to the
glomeruli.

38.  Hoarseness of voice.
 Difficulty in breathing
 Acrid metallic taste in mouth.
 Feeling of constriction or choking of throat.
 Pulse is quick small and irregular.
 Thrombocytopenia and bone marrow depression.
Ingestion of Mercury

39. Chronic Mercury Poisoning/ Hydrargyrism
 Workers may get poisoned due to vapors or dust.
 When small doses are taken for prolonged time or used as ointment for long
period.
 The signs and symptoms of chronic mercury start at a blood level 100 mg/ml.
 Patient is symptomatic at daily urinary excretion more than 300 mg/ml

40. Hydrargyrism/ Signs and symptoms
 Excessive salivation with swollen and painful salivary glands.
 Foul smelling breathing, inflamed and ulcerated gums with brownish blue line
and loosening of teeth.
Mercura lentis: A brownish reflex from the anterior lens capsule
of both the eyes is seen when observed in slit lamp in person
exposed to mercury vapors for some years. It is bilateral and has
no effect on the visual acuity.

41. Oral cavity problems
 Inflammation of the mouth.
 Loss of bone around teeth.
 Ulcerated gums and other areas in the mouth.
 Darkening of gums.
 Taste of metal.
 Bleeding gums.

42. Acrodynia (Pink disease)
 There is generalized rashes over the body.
 Results from chronic exposure to mercury in any forms.
 Erythematous, eczematous (watery and weeping) popular type of skin lesion.
 Mostly in the hands and feet accompanied with thickening of skin.

43. Hunter-Russell syndrome
 The term Hunter-Russell syndrome derives from a study of mercury poisoning among
workers in a seed packing factory in England in the late 1930s who breathed methyl
mercury that was being used as a seed disinfectant and preservative.
 Syndrome is characterized by paresthesia, visual field constriction, ataxia, impaired
hearing, and speech impairment.

44. Erethism
(Mad hatter disease, or mad hatter syndrome)
 In 19th century, inorganic mercury in the form of mercuric nitrate was commonly
used in the production of hats.
 It caused a slow release of volatile free mercury.
 Erethism commonly characterized by behavioral changes such as irritability, low
self-confidence, depression, apathy, shyness and timidity.
 In some extreme cases delirium personality changes and memory loss occur.

45. Laboratory Tests
Urine test:Aurinary mercury concentration of less than four micrograms per liter
(μg/L) would be considered within the background range.

47. Blood test
 Blood level greater than 10 mcg/L indicates an unusual level of exposure for
someone who does not regularly work with mercury.
 Amount present will decrease by half about every 3 days as the mercury
moves into organs such as the brain and kidneys. Therefore, blood testing
must be done within days of suspected exposure

49.  Amount of exposure
 Length of exposure
 Length of mercury accumulation in body
 Amount of accumulated mercury
 Overall health of the patient ( for detoxification)
Toxic effect of Mercury depend on: