Mercury in Restorative Dentistry

Mercury in
Restorative
Dentistry
Presented by : Dr Aswin. S

Contents
 Introduction
 History
 Manufacturing of mercury
 Properties :- General
Physical Properties.
Chemical Properties.
 Compounds
Inorganic
Organic
Elemental (Vapour)
 Occurrence
 Applications:-
Medicine and Dental
Laboratory uses
Other uses

 Mercury cycle
 Mercury in dental amalgam
 Amalgam reactions
 Amalgam wars
 PHYSIOLOGICAL Hg CYCLE
 Toxicity and safety
 Mercury toxicity levels
 Effects of mercury toxicity on body
- Allergy
- Acute poisoning
-Chronic poisoning
-Oral cavity problems
- Acrodynia

-Minimata disease
-Hunter-Russell syndrome
- Erethism
 Treatment
 Laboratory test
 Methods to detect mercury vapor release.
 Mercury exposure in dental practice
 Mercury Management.
 ADA Dental Mercury hygiene recommendation.
 Amalgam waste management.
 Conclusion.
 References.
 Previous year questions.

INTRODUCTION
 Mercury is a heavy, silvery-white
liquid metal.
 Also known as quick silver.
 Mercury is the only common metal
which is liquid at ordinary
temperatures.
 Poor conductor of heat if compared
with other metals.
 A fair conductor of electricity.
 It alloys easily with many metals,
such as gold, silver, and tin.
 These alloys are called amalgams.

 ‘Mercury’ was the name of the Roman’s
messengers of the gods who were believed to
be really fast moving.
 The name comes from Greek name,
hydrargyrum, which means "liquid silver”
to reflect its shiny surface
 Mercury was named ‘Mercury’ because it, as
a liquid, flows quickly.
 It’s also called quicksilver because in addition
to its quick flowing property, it has a silvery
tinge.

History
 Mercury was a well-known metal in the ancient time in
China, India, and Egypt.
 1500 BC : Found in Egyptian tombs. It was used to
prolong life, heal fractures, and maintain generally good
health.
 500 BC :
Ancient Greeks-ointments.
Ancient Egyptians and Romans- cosmetics
Maya civilization-began making amalgams

 247 BC -221 BC: China’s first emperor, Qin Shi Huang
Di - who unified China was killed by mercury pills
intended to give him eternal life.
 1 AD :The Roman scholar Pliny described mercury
poisoning as a disease of slaves because mines
contaminated by mercury vapour were considered too
unhealthy for Roman citizens.

 659AD Amalgam -- First used by Chinese. There is a
mention of silver mercury paste by Sukung
in the Chinese medic
 1525 : Paracelsus, a Roman doctor developed
treatments using mercury and potassium salts.
 1528 : Germany-used for dental purposes.
 1800 : in France alloy of bismuth, lead, tin and mercury
plasticized at 100ºC poured directly into cavity.

 1816:Aguste Taveau of Paris developed was probably
the first dental amalgam by using filings from silver coins
mixed with mercury.
 1833:Crawcour brothers brought dental amalgam to the US.
 1844 : 50% of restorations were silver amalgam.
 1840 - 1850 : Bitter controversy about the merits and
deficiencies of mercury amalgam.(FIRST AMALGAM
WAR-1843)

 1856 : Dispute ended and formation of ADA in 1859.
 1895 : G.V.Black standardized both cavity preparation
and the amalgam manufacture.
 1900 : Introduction of copper amalgams
 1926 : Second amalgam war.
 1956 : Minamata disease officially acknowledged .

 1976 :FDA pronounced acceptance of amalgam filling
approved dental amalgam under safe category
 1980 : Third Amalgam War began.
 1990:First controlled research on dental amalgam effects
published.
 1991: National institute of health technology assessment
panel on dental materials issued a statement that
amalgam is safe.

 1997 Sweden banned dental mercury amalgam.
 In 2008, Norway and Denmark banned dental mercury
amalgam
 2013 The final mercury treaty session took place in
Geneva. Treaty requested countries to phase down the
use of dental amalgam.
 Dec. 8, 2016 The European Union (E.U.), with 28 member
nations declared , will prohibit the use of dental amalgam
in children under 16 and in pregnant and breastfeeding
women effective from July 1, 2018.

Manufacture of mercury
Mining
 Cinnabar is dislodged from the surrounding rocks by drilling and
blasting with explosives or by the use of power equipment.
Roasting
 The ore is first crushed in one or more cone crushers.
 The crushed ore is then ground even smaller by a series of mills.
 The finely powdered ore is fed into a furnace or kiln to be heated.
 The heated cinnabar (HgS) reacts with the oxygen (02) in the air to
produce sulfur dioxide (SO 2 ), allowing the mercury to rise as a
vapor. This process is called roasting.

Condensing
o The mercury vapor rises up and out of the furnace or kiln
along with the sulfur dioxide, water vapor, and other
products of combustion.
o The hot furnace exhaust passes through a water-cooled
condenser.
o As the exhaust cools, the mercury, which has a boiling point
of 357° C, is the first to condense into a liquid, leaving the
other gases and vapors to be vented.
o The liquid mercury is collected. Because mercury has a
very high specific gravity, any impurities tend to rise to the
surface and form a dark film or scum.
o These impurities are removed by filtration

Refining
o The most common refining method is
triple distillation, in which the temperature of the
liquid mercury is carefully raised until the
impurities either evaporate or the mercury itself
evaporates, leaving the impurities behind.
o This distillation process is performed three
times, with the purity increasing each time.

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) in Spain, Russia, Italy,
China and Slovenia.
 Also present as an impurity
in many other minerals, in
particular the non-ferrous
metals, and in fossil fuels,
coal.
Cinnabar ore
Lyman SN, Jaffe DA. Formation and fate of oxidized mercury in the upper troposphere
and lower stratosphere. Nature Geoscience. 2012 Feb 1;5(2):114-7.

 Mercury occurs uncombined in nature to a
limited extent.
 Mining and the burning of coal, has increased
the mobilization of mercury into the
environment
 Raising the amounts in the atmosphere,
soils, fresh waters, and oceans.

General properties:
Appearance Silvery
Atomic number 80
Standard atomic weight 200.592 g/mol
Element category Transition metal

Physical properties
Phase Liquid
Melting point 38.8290 ̊ C
Boiling point 356.73 ̊ C
Density 13.534g/cm3
Critical point 172.00 MPa
Heat of fusion 2.29KJ/mol

Chemical properties
Electronegativity according to
Pauling
1.9
Vanderwaals radius 0.157 nm
Isotopes 2

Forms of Mercury
I. Elemental mercury.
 Most common form
 It is metallic , silvery liquid
 Easily vaporize in room
temperature into an odorless ,
colorless vapor that can easily
inhaled.
Schaefer JK. Biogeochemistry: Better living through mercury.
Nature Geoscience. 2016 Jan 18.

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

II. Inorganic mercury
 White in color except cinnabar (Red).
 Enters body through mouth and skin from disinfectant
and fungicide.
 Usually used in school science lab.
 Least toxic of three forms
 Can damage GI tract, kidney and nervous system.
 it form two series of compounds
Mercuric: soluble and more toxic
Mercurous: less soluble, thus, less active

2. Mercuric chloride: (corrosive sublimate). Occurs as
odorless, white crystalline powder, nauseous, metallic
taste and soluble in water, alcohol, ether, glycerin.
Used in medicines and taxidermy.

 2.Mercurous chloride:
(ras kapoor, calomel).
Heavy amorphous white
tasteless powder,
insoluble in water, alcohol
and ether.
On exposure to light turns
to Mercuric chloride.
Used in laxatives.

 Mercuric sulphide:
(ras sindoor, cinnabar).
 Used as a red
pigment, it is known
as vermilion.
 Vapour is poisonous.

III. Organic mercury
 Methyl mercury most commonly found in environment
and most toxic form of Hg.
 Converted from its inorganic form by biological bacterial
process.
 Bio accumulates in environment most commonly found
in fish.
 Ingestion of fish is most common route of human
mercury exposure

Risk
 Birth defects
 Neurological problems
 Impairment of vision, speech, walking
 Extreme exposure leads to death

Applications of mercury
Medicine:Mercury and its
compounds have been used
in medicine.
 Less common today due to
toxic effects.
 Traditional medicine-diuretic,
topical disinfectant and
laxative.
 Once used to treat syphilis.
 Antibacterial agents
Dentistry: Amalgam alloy with
mercury-dental fillings.
Gasper JD, Aiken GR, Ryan JN. A critical review of three methods used for the
measurement of mercury (Hg 2+)-dissolved organic matter stability constants.
Applied Geochemistry. 2007 Aug 31;22(8):1583-97.

Laboratory uses:
 Medical thermometers
 Sphygmomanometer ,
thermometers
 Liquid mirror telescope

Other uses:
 mercury vapor lamps
 Fluorescent lamps
and neon signs
 barometers, batteries
 electrical switches
Cosmetics:
 used as thiomersal
for manufacture of
mascara.

 Natural and human activities release elemental mercury vapor
(Hg0) into the atmosphere.
 Once in the atmosphere, the mercury vapor can circulate for
up to a year.
 Mercury vapor can then undergo a photochemical oxidation to
become inorganic mercury that can combine with water vapors
and travel back to the Earth’s surface as rain.
 In water, inorganic mercury can be converted into insoluble
mercury sulfide which settles out of the water, or it can be
converted by bacteria that process sulfate into methylmercury.
 Now the methylmercury-processing bacteria may be consumed
by the next higher organism up the food chain.
 This pattern continues as small fish/organisms get eaten by
progressively bigger and bigger fish until the fish are finally
eaten by humans.

Dental amalgam
 Dental amalgam has been used for more than
150 years.
 Dental amalgam is a mixture of metals,
consisting of liquid (elemental) mercury and a
powdered alloy composed of silver, tin, and
copper.

ADA specification for mercury
 The mercury shall have a bright mirror like surface free
from any film or scum.
 Mercury has no surface contamination and less than
0.02% of nonvolatile residue.
 Should be triple distilled and pure.

 The most common refining method
 The temperature of the liquid mercury is
carefully raised until the impurities either
evaporate or the mercury itself
evaporates, leaving the impurities behind.
 This distillation process is performed
three times, with the purity increasing
each time.
Triple distillation

PROPOTIONING THE ALLOY AND MERCURY

 The amount of mercury in dental amalgam may be
specified as alloy – mercury ratio.
 Ratios varies for different technique and handling
characteristics used by dentist.
 The most obvious method to reduce mercury content is
minimal mercury technique or Eames technique
mercury:alloy=1:1.
Alloy- mercury ratio
Phillip’s science of dental materials south east edition 2015

 Use preweighted pellets of alloy and
dispense mercury from volumetric
dispenser.
 If amalgam alloy and mercury dispenser
are from different manufacturers pellet
must be weighed.
 The amount of mercury needed can be
calculated from pellet weight.
Measuring alloy and mercury

 Correct weight of mercury is calculated by
if X- weight of mercury
Y – weight of alloy
Then weight of mercury = X gram
Y

Removing excess mercury
 When mortar and pestle were used for mixing excess
mercury is added to achieve smooth and plastic
amalgam.
 Removal of excess mercury was done by
I) Initially removed with the help of the cloth by
squeezing through it.
II ) Increasing dryness technique, during
condensation of each increment a mercury
rich soft layer comes to the surface.
o Mulling is done to redistribute mercury within in mixed
, squeezed mass.

 They contain pre weighted mercury
and alloy in separate compartments.
 Mercury is released by twisting cap in
one type of capsule
 In other type motion of the
amalgamator arms bring mercury and
alloy together.
 Disadvantages are dentist have no
opportunity to make minor adjustment
in the mix
Amalgam capsule

Trituration
 The objective of trituration is to provide proper
amalgamation of the mercury and the alloy.
 The alloy particles are coated oxide layer that
hinder diffusion of mercury into alloy.
 This layer is removed by abrasion when alloy
particles and mercury are triturated .
 Types- hand mixing
mechanical mixing

Effect of mercury content
dry granular
mixrough & pitted
surfacecorrosion
high mercury
contentmore γ2
phase
low mercury
contentmore
unreacted AgSn
particlesimparts
strength to
restoration
sufficient mercury should be
mixed with the alloy to wet
each particle of the alloy

 More mercury , more will be the expansion, as
more crystals will grow.
 Low mercury: alloy ratio favors contraction
 During trituration, if more energy is used for
manipulation, the smaller the particles will become ,
mercury will be pushed between the particles,
discouraging expansion.
 More the condensation pressure used during
condensation, closer the particles are brought
together; more mercury is expressed out of mix
inducing more contraction.
Factors that affect the dimensional change of amalgam

Creep
 Creep occurs when a solid material slowly
deforms plastically under influence of stress.
High mercury content increases creep.
Mercury content beyond 46% produces
sudden increase in creep

Amalgamation Reaction – Low Copper Alloys
 A- Dissolution of silver and tin into mercury
 B- precipitation of 1crystals in mercury
Ag3Sn + Hg  Ag3Sn + Ag2Hg3 + Sn8Hg
  1 2

 C- consumption of the mercury by growth of 1 and 2
grains
 D - The final set amalgam

 γ1 forms first and then γ2
 Alloy is mixed with mercury in the ratio of 1:1
 Mercury is insufficient to completely consume the
alloy particles
 γ1 - Dominant phase – 54-56%
 Unreacted γ - 27- 35%
 γ2 - 11-13%
CRAIG’s Restorative Dental Materials;13th edition2012

 Gamma () = Ag3Sn
 unreacted alloy
 strongest phase and
corrodes the least
 forms 30% of volume
of set amalgam
 Gamma 1 (1) = Ag2Hg3
 matrix for unreacted alloy
and 2nd strongest phase
 60% of volume

 γ2 phase is extremely weak & soft, deforming
readily & the strength of amalgam is limited by
its presence
 Contributes to static creep of amalgam

Admixed High-Copper Alloys
Initial reaction
Ag3Sn + Ag-Cu + Hg Ag3Sn + Ag2Hg3 + Sn8Hg + Ag-Cu
Ag-Sn
Alloy
Ag-Sn
Alloy
Mercury
Ag
AgAg
Sn
Sn
Ag-Cu Alloy
Ag
HgHg
  1
2

Final reaction Ag-Cu Alloy
1
Ag-Sn
Alloy
Ag-Sn
Alloy
2 
Sn8Hg + Ag-Cu Cu6Sn5 + Ag2Hg3 + Ag-Cu
1

Single Composition High-Copper Alloys
Ag-Sn Alloy
Ag-Sn Alloy
Ag-Sn Alloy
1

 

Ag3Sn + Cu3Sn + Hg Ag2Hg3 + Cu6Sn5 + Ag3Sn +Cu3Sn
1

MERCURY FREE AMALGAM
 Gallium based alloy
It is metal With similar atomic structure and characteristics to
mercury.
Hence , by 1928 Puttkammer suggested Gallium as a
substitute for mercury
 DISADVATAGES
. Handling characteristics of alloy not favorable
. High level of corrosion
marginal disintegration
. Dimensional change of 21.5%
. Poor biocompatibility
. costly
Sturdevant's Art and Science of Operative Dentistry South east edition 2013

The first amalgam war
 In 1845, American Society of Dental Surgeons
condemned the use of all filling material other
than gold as toxic, thereby igniting "first
amalgam war'. The society went further and
requested members to sign a pledge refusing to
use amalgam.
The amalgam controversy-an evidence based analysis ; JADA,Vol.132,march 2001

What ended the amalgam war??
 Professional and consumer demand.
 In 1859, the leaders of the profession
regrouped to form the American Dental
Association.

Second amalgam war….
 In mid 1920's a German dentist, Professor A.
Stock started the "second amalgam war". 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.

 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
 Unfortunately now came the second world
war over Europe &" the second amalgam
war" fell in forgetfulness

3rd amalgam war in 1980s
 Third Amalgam War' began 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.

3rd amalgam war in 1980s
 But the ADA remained adamant that mercury
in patients' mouths is safe, and in 1986 it
changed its code of ethics, making it unethical
for a dentist to recommend the removal of
amalgam because of mercury
 But problem flared in 1990’s by the telecast of
television program ‘60 minutes’ in CBC
television

PHYSIOLOGICAL Hg CYCLE
Elemental
Hg
Inorganic
Hg
Organic
Hg
LUNGS
GI
TRACT
SKIN
BLOOD
All
other
sites
Brain
Hair,
Nails
URINE
FECES
EXFOLIATION of
Skin, Hair, Nails
BLOOD
Average Half-Life in Human Body = 55 Days
ABSORPTION
ROUTE
TRANSPORTION and
LOCALIZATION
EXCRETION
of Hg
Hg
FORM

Sources of Mercury Exposure
 Ingestion of contaminated fish
 Occupational exposure
 Coal burning and mining
 Outgassing of mercury from dental amalgam

Hg levels
OSHA
RECOMMENDED
TLV=0.05mg/m³
MOST Dental office mercury level lie below 0.05mg/m³

- Amount of exposure
- Length of exposure
- Length of mercury accumulation
in body
- Amount of accumulated mercury
- Overall health of the patient
( for detoxification)

Effects of Mercury toxicity on the body

ALLERGY
 Allergy responses represent an antigen-antibody reaction
marked by
itching, rashes, sneezing, or other symptoms
 Contact dermatitis or Comb's type IV hypersensitivity
reaction represent the most likely physiologic side effect
to dental amalgam
 When such a reaction has been documented by
dermatologist or allergist, an alternative material (e.g.
Composite or ceramic) must be used.
Bernhoft RA. Mercury toxicity and treatment: a review of the literature.
Journal of environmental and public health. 2011 Dec 22;2012.

Immediate Hyper sensitivity reaction associated with the mercury
component of amalgam restoration
 Release of mercury induced an acute
reaction which resulted in erythematous
lesions, severe burning and itchy sensation
and difficulty in breathing
 Skin patch test results indicated a very
strong positive reaction to mercury
 Amalgam restorations were replaced with
composite filling material

TOXIC EFFECT ON MERCURYFORM OF
MERCURY
ELEMENTAL INORGANIC METHYL
MERCURY
ROUTE OF
EXPOSURE
INHALTION ORAL ORAL –FISH
CONSUMPTION
TARGET
ORGAN
CNS , Kidney
Peripheral nervous
system
KIDNEY, PNS CNS
LOCAL
CLINICAL SIGN
Lung ;bronchial
irritation
GI-irritation
Skin – irritation
ulceration
SYSTEMIC
EFFECTS
Kidney-proteinuria
CNS –mood change
PNS - Tremors
Kidney –
proteinuria,
Tubular necrosis
PNS -
Tremors
Numbness
Developmental
defects in fetus
and newborn.
CNS - In adult
Tremors
Paraesthesia

 Inhalation of mercury vapors causes
 Chemical pneumonia
 Pulmonary oedema
 Gingivostomatitis
 Increased salivation
 CNS symptoms like
 Ataxia
 Restriction of field of vision
 Delerium
 Polyneuropathy.
Acute poisoning

 The signs and symptoms start immediately after swallowing
the mercury:
 Acrid metallic taste in mouth.
 Feeling of constriction or choking of throat.
 Hoarseness of voice.
 Difficulty in breathing
 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.
Ingestion of Mercury
Houston MC. Role of mercury toxicity in hypertension, cardiovascular
disease, and stroke. The Journal of Clinical Hypertension. 2011 Aug 1;13(8):621-7.

 Pulse is quick small and irregular
 Thrombocytopenia and bone marrow depression.

 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
Chronic Mercury Poisoning/ Hydrargyrism

 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.
Signs and symptoms

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

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.
Tunnessen WW, McMahon KJ, Baser M. Acrodynia: exposure to mercury from
fluorescent light bulbs. Pediatrics. 1987 May 1;79(5):786-9.

 Desquamating rash
 Hair loss
 Tachycardia, hypertension
 Photophobia
 Irritability, Constipation/Diarrhea
 Anorexia
 Insomnia
 Poor muscle tone

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.
Tokuomi H, Kinoshita Y, Teramoto J, Imanishi K. Hunter-Russell syndrome. Nihon rinsho.Japanes
journal of clinical medicine. 2004 Dec;35:518-9.

 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.
Erethism
(Mad hatter disease, or mad hatter syndrome)
Waldron HA (2003). "Did the Mad Hatter have mercury poisoning?" British Medical
Journal (Clinical Research Edition). 287 (6409): doi:10.1136/bmj
.287.6409.1961. PMC 1550196. PMID 6418283.
FDA. "Dental Amalgam" Retrieved 3 April 2014

Minamata disease
 A local chemical plant (Chisso Corporation) disposed methyl
mercury waste into the nearby bay, in Japan in 1952
contaminating the shellfish and causing toxic levels of
mercury of the fish eaten by the local population.
 By the time the source was identified, 52 individuals had died
by mercury poisoning.
 Since this time, mercury poisoning of this kind is known as
Minamata disease.
Harada M. Minamata disease: methylmercury poisoning in Japan caused
by environmental pollution. Critical reviews in toxicology. 1999 Jan 1;25(1):1-24.

Symptoms were:-
1.Ataxic gait
2.Convulsions
3.Numbness in mouth &
limbs
4.Constriction in the
visual field
5.Difficulty in speaking.

 Chelation therapy is the administration of chelating
agents which bind mercury ions and facilitate their
excretion through urine and feces.
 A chelating agent could be given orally, I.M, I.V .
 Only Dimercaptosuccinic acid (DMSA) is FDA
approved for treating children with Hg toxicity
 2,3-dimercapto-1-propanesulfonic Acid(DMPS)
 D-pencillamine(DPCN)
 Dimercaprol (BAL)
 DMSA is the most frequently used for severe
methylmercury poisoning.
Treatment
Hall JL. Cellular mechanisms for heavy metal detoxification and tolerance.
Journal of experimental botany. 2009 Jan 1;53(366):1-1.

 α-Lipoic acid (ALA)
 If Kidneys show signs of damage peritoneal
dialysis or hemodialysis may be necessary.
 Treatment of shock and collapse are also
required.
 5-10% sulphoxylate and 5% sodium bi
carbonate is used for stomach wash. This is
beneficial if given in the first half an hour

 If colitis has developed, high colonic lavage given with 1: 1000
solution of sulphoxylate.
 B.A.L is to be given in the dose of :
 3-5mg/kg 4 hourly for 2 days.
 2.5 mg/kg 6 hourly for1 day.
 2.5 mg/kg twice daily according to the severity.
 For diuresis5-10% glucose is used in normal saline.

 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.

Laboratory Tests
 Urine levels of mercury
provide the most appropriate
assessment of elemental
mercury exposure and are
useful for the assessment of
acute and chronic exposures.
 A urinary mercury
concentration of less than 4
micrograms per liter (μg/L)
would be considered within
the background range.
Urine test
Wilhelm M, Müller F, Idel H. Biological monitoring of mercury vapour exposure by scalp
hair analysis in comparison to blood and urine. Toxicology letters. 1996 Nov 30;88(1):221-
6

 Blood is primarily tested to detect the presence of
methyl 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
 Blood level greater than 10 mcg/L indicates an unusual
level of exposure for someone who does not regularly
work with mercury.
hair analysis in comparison to blood and urine. Toxicology letters. 1996 Nov 30;88(1):221-
6
Blood test

Analyzing Hair
 Hair analysis primarily
measures organic (methyl)
mercury exposure only and
is not useful for assessing
recent exposures.
 In cases of occupational
exposure to mercury vapour,
hair is an useful tool for
monitoring external
exposure.
hair analysis in comparison to blood and urine. Toxicology letters. 1996 Nov
30;88(1):221-6.

 A study was done by Michael Wilhelm and Frank
Miillerb, on ‘Biological monitoring of mercury vapour
exposure by scalp hair analysis in comparison to blood
and urine’. It concluded that hair may be used as an
indicator of internal uptake of mercury provided that it
was not externally exposed to mercury vapour.
hair analysis in comparison to blood and urine. Toxicology letters. 1996 Nov
30;88(1):221-6.

Methods of detect mercury vapour release

Photoionization detector
 PID is a type of gas detector.
 PIDs produce instantaneous readings,
operate continuously, and are
commonly used as detectors for gas
chromatography.
 Used to monitor.
Industrial hygiene and safety.
 Environmental contamination
 Hazardous materials handling
 Indoor air quality
Haag, W.R. and Wrenn, C.: The PID Handbook - Theory and Applications
of Direct-Reading Photoionization Detectors (PIDs), 2nd. Ed., San Jose,
CA: RAE Systems Inc. (2006)

Gold film mercury vapour detectives
 First reliable forms of detectors due to
gold’s affinity for elemental mercury.
 When a mercury rich air sample
passes over a thin gold film, the
mercury deposits on the gold and
changes the electrical resistance of the
foil.
 This change in resistance is directly
proportional to the mass of mercury
vapor taken from a known volume of
air, which can be calculated in mg/m3.
Urba A, Kvietkus K, Sakalys J, Xiao Z, Lindqvist O. A new sensitive and portable mercury
vapor analyzer GARDIS-1A. InMercury as a Global Pollutant 2008 (pp. 1305-1309).
Springer Netherlands.

Photoacoustic spectroscopy
 Photoacoustic spectroscopy is a
technique in which a substance absorbs a
pulsed beam of light and transforms the
absorbed energy into thermal energy of
the surrounding gas.
 The absorbed energy from the light
causes local heating and through thermal
expansion a pressure wave or sound, be
sensed by a microphone.
Rosencwaig A, Gersho A. Theory of the photoacoustic effect with solids.
Journal of Applied Physics. 1998 Jan;47(1):64-9.

Cold Vapor Mercury Analysis
 Involves the conversion of Hg salts to Hg
vapor using an strong acidic reducing agent
such as Sn/HCl
 Atomic absorption or Atomic fluorescence
are common detectors for this analysis.
 Now PID is also available for this analysis
96
KOPYsc E, PYRZYnska K, Garbos S, BULSKA E. Determination of mercury
by cold-vapor atomic absorption spectrometry with preconcentration
on a gold-trap. Analytical sciences. 2000;16(12):1309-12.

Dosimeter
 Dosimeter - Badge system may
be used in which mercury is
adsorbed on gold foil.
 Worn by the personnel in dental
office.

 MERCURY EXPOSURE IN DENTAL PRACTICE.

 Exposure of mercury may be either in the form of vapour
or particulate amalgam dust .
 Mercury vapors -> passes into intra oral air and then
enters lungs.
 Mercury ion (Hg2+) -> passes into saliva to enter GIT.

Amounts of Mercury released
 Trituration : 1-2 μg
 Placement of restorations : 6-8 μg
 Dry Polishing : 44μg
 Wet Polishing : 2.4 μg
 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 μg

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.

 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.

ADA RECOMMENDATIONS FOR DENTAL
MERCURY HYGEINE
 Train all personnel regarding mercury handling and
hazards.
 Make them aware of the potential sources of mercury
vapor in the operatory.
 Work in well ventilated spaces with an exhaust. Replace
air conditioning filters periodically.
 Monitor the dental operatory atmosphere for mercury
vapor.

 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.

 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.

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.
Dental mercury hygiene recommendation. J am Dent Assoc 2003;134:1498.

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.
Baughman TA. Elemental mercury spills. Environmental health perspectives.
2006 Feb 1:147-52.

 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.
Baughman TA. Elemental mercury spills. Environmental health perspectives.
2006 Feb 1:147-52.

Alternatives to Dental Amalgam
 Composite
 Glass ionomer cement
 Ivoclar cention
FDA. "Dental Amalgam" Retrieved 3 April 2014

Conclusion
 The risk of mercury exposure to dental personnel
cannot be ignored, but close adherence to simple
hygiene procedures helps ensure a safe working
environment.
 Dentist must observe strict amalgam hygiene
procedures so that the health of dental workers is not
put at risk.
 It is also necessary to safety dispose mercury.
 Prevention from reaching the sewage system to avoid
environmental contamination is necessary.

Reference
 história do amálgama em Odontologia A. History of
Amalgam in Dentistry. Rev. Clín. Pesq. Odontol. 2007
Jan;3(1):65-71.
 Lyman SN, Jaffe DA. Formation and fate of oxidized mercury
in the upper troposphere and lower stratosphere. Nature
Geoscience. 2012 Feb 1;5(2):114-7
 Schaefer JK. Biogeochemistry: Better living through mercury.
 Gasper JD, Aiken GR, Ryan JN. A critical review of three
methods used for the
 measurement of mercury (Hg 2+)-dissolved organic matter
stability constants.
 Applied Geochemistry. 2007 Aug 31;22(8):1583-97

 Sturdevant's Art and Science of Operative Dentistry
South east edition 2013
 Phillip’s science of dental materials south east
edition 2015
 CRAIG’s Restorative Dental Materials;13th
edition2012
 The amalgam controversy-an evidence based
analysis ; JADA,Vol.132,march 2001
 Bernhoft RA. Mercury toxicity and treatment: a
review of the literature.
 Journal of environmental and public health. 2011
Dec 22;2012.
 Houston MC. Role of mercury toxicity in
hypertension, cardiovascular
 disease, and stroke. The Journal of Clinical
Hypertension. 2011 Aug 1;13(8):621-7.

 Tunnessen WW, McMahon KJ, Baser M. Acrodynia:
exposure to mercury from fluorescent light bulbs. Pediatrics.
1987 May 1;79(5):786-9
 Tokuomi H, Kinoshita Y, Teramoto J, Imanishi K. Hunter-
Russell syndrome. Nihon rinsho.Japanese journal of clinical
medicine. 2004 Dec;35:518-9
 Waldron HA (2003). "Did the Mad Hatter have mercury
poisoning?" British Medical Journal (Clinical Research
Edition). 287 (6409): doi:10.1136/bmj
.287.6409.1961. PMC 1550196. PMID 6418283.
 FDA. "Dental Amalgam" Retrieved 3 April 2014
 Harada M. Minamata disease: methylmercury poisoning in
Japan caused by environmental pollution. Critical reviews in
toxicology. 1999 Jan 1;25(1):1-24

 Hall JL. Cellular mechanisms for heavy metal
detoxification and tolerance.Journal of experimental
botany. 2009 Jan 1;53(366):1-1
 Wilhelm M, Müller F, Idel H. Biological monitoring of
mercury vapour exposure by scalp hair analysis in
comparison to blood and urine. Toxicology letters. 1996
Nov 30;88(1):221-6
 Haag, W.R. and Wrenn, C.: The PID Handbook - Theory
and Applications of Direct-Reading Photoionization
Detectors (PIDs), 2nd. Ed., San Jose, CA: RAE Systems
Inc. (2006)
 Urba A, Kvietkus K, Sakalys J, Xiao Z, Lindqvist O. A new
sensitive and portable mercury vapor analyzer GARDIS-
1A. InMercury as a Global Pollutant 2008 (pp. 1305-
1309). Springer Netherlands

 Rosencwaig A, Gersho A. Theory of the
photoacoustic effect with solids. Journal of
Applied Physics. 1998 Jan;47(1):64-9.
 KOPYsc E, PYRZYnska K, Garbos S, BULSKA E.
Determination of mercury by cold-vapor atomic
absorption spectrometry with preconcentration on
a gold-trap. Analytical sciences.
2000;16(12):1309-12
 Baughman TA. Elemental mercury spills.
Environmental health perspectives. 2006 Feb
1:147-52.

Questions previously asked
 Discuss role of mercury in dental amalgam and
add a note on mercury hygiene.
(20 marks, RGUHS 2001)
 Concerns about mercury toxicity.
(7 marks, NITTE 2013)
 Discuss mercury toxicity in dental office.
 Discuss in detail on hazards of mercury.

Mercury in Restorative Dentistry

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