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MERCURY & ITS TOXICITY
PRESENTED BY DR. G. RADHIKA PG STUDENT DEPARTMENT OF PUBLIC HEALTH DENTISTRY SIBAR INSTITUTE OF DENTAL SCIENCES GUNTUR
CONTENTSIntroduction History Physical
and chemical properties Sources of mercury Usage of mercury Biotransformation Mercuralism- signs and symptoms
and normal levels Mercury exposure from dental office Methods to monitor mercury levels Precautions to avoid mercury toxicity Hygiene recommendations for mercury in dentistry Amalgam waste management Conclusion References Acceptable
INTRODUCTION Liquid
metal Used in dentistry Dental amalgam Acc to ADA > 100 million silver fillings/ year
The Amalgam Controversy-the Evidence Based AnalysisJADA,2001
HISTORY>
2000 years in preparations such as diuretics, anti-bacterial ointments, laxatives and skin ointments. original amalgamation process was demonstrated by a chemist in France
The Amalgam Controversy-the Evidence Based AnalysisJADA,2001
HISTORY In
1833, two English Entrepreneurs, The Crawcour Brothers
Strudevents Art and Science of Operative Dentistry; T.M. Robers
HISTORYdental restorations in China 600 AD First amalgam War 1980 controversy Huggins, a Practicing Dentist in Colorado publicly condemned amalgam Tin-mercury
Strudevents Art and Science of Operative Dentistry; T.M. Roberson
HISTORY Multiple
sclerosis, Alzheimers Disease -
no basis In Japan 1952, mercury was dumped in Minamata Bay by a local chemical plant (Chisso Corporation
The Amalgam Controversy-the Evidence Based AnalysisJADA,2001
PHYSICAL & CHEMICALPROPERTIES
number - 80 Atomic mass - 200.59 g.mol -1 Electronegativity - 1.9 Density - 13.6 g.cm-3 at 20C Melting point - - 38.9 C Boiling point - 356.6 C Atomic
PHYSICAL & CHEMICAL PROPERTIES ADA
Specification No. 6 Mercury exists in 3 chemical formsElemental mercury Half
Inorganic salts of mercury
Organic mercury
life of mercury 55 days Half life of methyl mercury 70 dayshttp:www.mercury.wikipedia.org.com
USES OF MERCURY Elementaly y
mercury:
Sphygmomanometers, thermometers, barometers Liquid at room temp volatilises easily
Inorganicy y y
mercury:
Traditional remedies (ayurvedic, chinese) Used in gold extraction, caustic soda manufacturing Rodenticides
Organicy y
mercury:
Fungicides, seed dressings Methylmercury in fish
SOURCE OF MERCURY 2,700
and 6,000 tons of mercury are released annually from the oceans and the Earths crust The greatest source - mercury vapor released during volcanic eruptions
2,000
to 3,000 tons are released from human activities, primarily burning household and industrial waste Swordfish and tuna - 1000 g/kg of mass
160
mg/kg in cattle and 25 mg/kg in humans mercury compounds are routinely used as fungicides and herbicides to coat seeds used to plant farm fields.
Methyl
http:www.mercury.wikipedia.org.com
Dental
fillings are composed of mercury, silver, tin, copper, and zinc. The approximate percentages are as follows: 50% mercury, 33-37% silver, 12.5-13.5% tin 0-3% copper 0-1% zinc
USES OF MERCURY & ITS EFFECTS Calomel
(mercurous chloride) was used for the treatment of syphilis. Inorganic mercury - electrical applications, chlorine production and dental restorations
Thimerosol
as medicine in Hepatitis B, Diptheria, Pertussis and Tetanus vaccines
Mercury
in vaccines have caused death of infants - diapers and kawasaki disease teething powder
Acrodynia
Gerald T. Charbenue; Principles and Practices of Operative Dentistry
BIOTRANSFORMATION Mercury
from dental amalgam is released in two forms Mercury vapors Mercuric ions
Inhalation
is the major route of entry into the human body. Metallic mercury is poorly absorbed to the skin or via the gastro intestinal tract. normal circumstances, mercury is biochemically processed and excreted
Under
The dental Amalgam Contraversy:A ReviewJCC,1996
ions (Hg0) circulate readily in the blood but pass the membrane barriers of the brain and placenta with difficulty Non-ionized mercury (Hg) is capable of crossing through lipid layers barriers and if subsequently oxidized within these tissues neuromuscular problems Mercury
Strudevents Art and Science of Operative Dentistry; T.M. Robers
MERCURALISM Acute
toxicity Chronic toxicity (Hydrargyrism) Erethism
William. G.Shafer, M.K. Hine; A Text book of Oral Pathology
Neurological
increase plasma creatine level Immunological Reproductive Cardiac Blood Liver Nervous system Oral manifestations Thyroid RenalWilliam. G.Shafer, M.K. Hine; A Text book of Oral Pathology
PINKS
disease, Acrodynia, Swift disease - 6 Ps hands & feet: puffy, pink, painful, peeling, parasthetia, perspiring
William. G.Shafer, M.K. Hine; A Text book of Oral Pathology
Women
who are exposed to mercury in pregnancy have given birth to children with serious birth defects due to mercury poisoning. In utero mercury exposure can lead to Minamata disease
Allergy Others
- White cell reaction, reaction to N2O, hyperventilation, reaction to diet pills, gall bladder, painful menstruation, hepatitis, severe complexion problems
William. G.Shafer, M.K. Hine; A Text book of Oral Pathology
TREATMENT Supportive
treatment
DMPS Chelation (2,3-Dimercapto-1propanesulphonate) - Chelation therapy of choice for mercury - For both acute and chronic mercury poisoning. - Urinary excretion of mercury two hours after DMPS administration - (Aposhian et. al, 1992)
Discontinuance
of exposure to mercury . The administration of BAL (British Anti-lewisite) pencillamine
William. G.Shafer, M.K. Hine; A Text book of Oral Pathology
Acute
mercurialism - Sodium ascorbate
Dr.
Olympio Pinto of Rio de Janeiro remove amalgams when the WBC remained over 11,000 for three months without visible medical cause
The dental Amalgam Contraversy:A ReviewJCC,1996
N-Acetyl-Cysteine
(NAC) For Mercury Detoxification
NAC
is produced in living organisms from the amino acid cysteine. Thus NAC is a natural sulfur-containing amino acid derivative found naturally in foods and is a powerful antioxidant
The dental Amalgam Contraversy:A ReviewJCC,1996
NORMAL LEVELSIntake of mercury vapor - 0.4 to 4.4 ug/day depending on number of amalgam fillings. Mercury concentration in urine - 15 ug/lt 4 nanograms in blood 1 micro gram/ m3 in air
Tolerable daily intake (TDI) of .014 g Hg0/kg-day (Richardson, 1996)
Richardson, GM; Allan, M. A Monte Carlo assessment of mercury exposure and risks from dental amalgam. Human and Ecol Risk Assess
(RICHARDSON, 1996)Age groups (yrs) No. of amalgam fillings0 -1 1-3 2-4 2-4
3 - 11 12 - 19 20 - 59 60 +
Tissue Whole blood Urine Tooth alveolar bone Gum mucosa Mouth papilla Tongue Parotid gland
ng Hg/g 9.0 4.7 318.2 323.7 19.7 13.0 7.8
Mercury vapor exposure established by OSHA is 50 micro grams urinary excretion of mercury is 2 to 20 mcg/liter
Mercury
in pure air - 0.002 g/m 3
Urban air - 0.05 g/m 3 near industrial parks - 3 g/m3
Air
Air in mercury mines - 300 g/m3. TLV for exposure to mercury vapor for a 40-hour work week is 50 /g/m3 is 100 g/m3 for clinical mercurism and 50 g/m3 for nephrotoxicity
LOAEL
The Amalgam Controversy: An Evidense-Based Analysis, JADA, 2001
Engle et al found that dry polishing of amalgam restorations resulted in release of 44ug of mercury vapor /restoration. 8 Vimy and Lorscheider (1985) showed that 829ug of mercury vapor was released every 24 hrs for 4-12 amalgams. 9 Berglund (1990) showed that 1.7ug of mercury vapor was released from amalgam in 24hr period.
MERCURY EXPOSURE IN DENTAL OFFICE Incorrect
storage of mercury or waste
amalgam Spillage
of mercury or waste amalgam
Mishandling
at any stage would result in mercury splashing on the bench or floor causing it to be scattered widely as small droplets.
Strudevents Art and Science of Operative Dentistry; T.M. Robers
How
would you clean up the mercury?
1. Spill on a non-porous surface: y lift the mercury with card or paper (remove gold rings and wear gloves) y place in a sealed container & dispose in general waste 2. Spill on a carpet: y Use a sulphur based (calcium polysulfide) powder p mercuric sulphide & then can vacuum upStrudevents Art and Science of Operative Dentistry; T.M. Robers
Mixed
but unhardened dental amalgam during trituration, insertion and intraoral setting. During finishing and polishing of amalgam Removal of amalgam restoration. Amalgam raw materials being stored for use. Amalgam scrap that has insufficient alloy to consume the mercury present completely
Strudevents Art and Science of Operative Dentistry; T.M. Robers
MONITORING MERCURY LEVELS Detection
meter mercury sniffer Paper discs impregnated with palladium chloride
Mercury vapour analyzer
A
badge system - mercury is adsorbed on gold foil Mercury in vapor and dust form absorbing system and then quantifying the absorbed mercury
Mercury monitoring system
PRECAUTIONS Mercury-containing
products should not be stored in the open, but rather in closets or cabinets Reusable capsules and precapsulated designs - vacuum aspirator During trituration Sprinkling sulfur powder Scrap amalgam from condensation procedures
Strudevents Art and Science of Operative Dentistry; T.M. Robers
PRECAUTIONS Mercury
during finishing & polishing procedures Spent capsules and mercurycontaminated cotton rolls or paper napkins
Strudevents Art and Science of Operative Dentistry; T.M. Robers
CANADIAN DENTAL ASSOCIATION, 1996 Recommendations
Avoid using mercury to restore children's teeth. Avoid placing or removing amalgam in the teeth of pregnant women. Avoid using dental amalgams in patients suffering from kidney ailments. Use methods and equipment to reduce the risks of exposure to mercury vapor
"The Safety of Dental Amalgam: Health Canada, Dept. of Supply and Services
Avoid
using amalgams in patients who risk suffering from allergic hypersensitivity. Remove amalgams from a patient who has become sensitive. Avoid placing amalgam in contact with other metal appliances in the mouth Fully inform patients of the risks and benefits involved. Recognize the patient's right to refuse treatment using a specific material.
The Safety of Dental Amalgam: Health Canada, Dept. of Supply and Services
MERCURY HYGIENE Minimize
the contamination Drain, vacuum cuspidor or sink is fitted with a filter, strainer or trap Spilled mercury - dusting with sulfur powder or spraying with a solution of sodium thiosulfate Mercury
spillage kit -->
Strudevents Art and Science of Operative Dentistry; T.M. Robers
Rubber
dam and high volume evacuation
Amalgam
should be polished at slow speed using water spray ventilation
Proper
Mercury
vapor level in office should be periodically monitoredStrudevents Art and Science of Operative Dentistry; T.M. Robers
Office
personnel should also be monitored alloys should be used
Pre-capsulated
Skin
contact with mercury should be avoided masks after removing amalgam restorationsStrudevents Art and Science of Operative Dentistry; T.M. Robers
Change
Mercury
contaminated items should be deposited in sealed bags mercury should be cleaned with trap bottles, taps or fresh mixes of amalgam removal of the defective mercury with air turbine
Spilled
The
Strudevents Art and Science of Operative Dentistry; T.M. Robers
AMALGAM WASTE MANAGEMENT Closed
system Newer systems Spent capsules Alternatives to amalgam
Strudevents Art and Science of Operative Dentistry; T.M. Robers
STUDIESbaseline mouth air of people with amalgams contains more mercury than that of people without amalgams as detected by Jerome Mercury Vapor Detector . Old amalgams contain significantly less mercury than new ones (Gay et al, 1979 ; Vimy and Lorscheider, 1990) The
Conclusion
HOW CAN IT BE SAFE?y
Saying that the mercury in amalgam can cause harm is a little like saying the chloride in table salt can kill you. Putting only chloride on food is a bad idea. The chemical will ruin the food. But combine the chloride with just the right amount of sodium and you create the tasty flavor enhancer called table salt.
y
y
Similarly
The mercury in silver fillings is not harmful because the mercury is transformed in the process of making an alloy. is made by mixing mercury with other metals, such as silver, copper and tin, Trajtenberg says. The mercury binds to the other metals to make a stable alloy, and therefore is safe for dental applications.
Amalgam
Where
there is Smoke there just might be fire there is Amalgam there just might be Mercury poisoning
Where
REFERENCES Strudevents
Art and Science of Operative Dentistry; T.M. Roberson, Herald. O. Heymann, Edward J.Swift; 5th edition pg 162- 172. T. Charbenue; Principles and Practices of Operative Dentistry; Dental Amalgam Restoration Pg: 248-249; 3rd edition; Varghese Publishing House.
Gerald
REFERENCES VIMAL
.K. SIKRI; Textbook of operative dentistry 2nd edition, CBS Publications& distributors; pg 257-260 Lund Bales, Vernetti; Operative Dentistry; Mercury Control, 4th edition; BI Publications.
Gilmore
William.
G.Shafer, M.K. Hine; A Text book of Oral Pathology; 4th edition; Pg: 578-579, W.B.Saunders company.
Gay
et al. Chewing Releases Mercury from Fillings. Lancet, 985, 5 May 1979. MJ; Lorscheider, FL. Dental amalgam mercury daily dose estimated from intro-oral vapor measurements: A predictor of mercury accumulation in human tissues. J Trace Elem Exper Med, 3:111-23, (1990). HV; et al. Urinary mercury after administration of 2,3-dimercaptopropane-lsulfonic acid: Correlation with dental amalgam score. FASEB J, 6:2472-6, 1992
Vimy,
Aposhian,
George
Feuer, H. S. Injeyan; The Dental Amalgam Contraversy- A Review; J.Can. Chiorpr. Assoc.; 40(3); pg: 169-178; 1996.
Richardson,
GM; Allan, M. A Monte Carlo assessment of mercury exposure and risks from dental amalgam. Human and Ecol Risk Assess. 2: 709-761 (1996).
"The
Safety of Dental Amalgam: Health Canada, Dept. of Supply and Services Canada Cat. H49-105/1996E ISBN 0-66281449-5 (1996)
John
E. Dodes; The Amalgam Controversy. An Evidence Based Analysis; J.Am.Dent.Assoc.; vol: 132; Pg: 348-356; 2001. Strudevents Art and Science of Operative Dentistry; T.M. Robers; Herald. O. Heymann, Edward J.Swift; 5th edition pg 162- 172. Dental Amalgam: update on safety concerns. ADA council on Scientific Affairs; JADA, vol 129; April 1998 pg 494-503
DONT METAL WITH YOUR TEETH
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