MERCURY TOXICITY & MANAGEMENT

"This advanced presentation provides a rigorous exploration of mercury toxicity, its sources, and systemic impacts, with a particular emphasis on evidence-based management strategies. Explore the molecular mechanisms behind mercury-induced pathologies, the nuances of diagnostic testing, and the latest advancements in chelation therapy and other treatment modalities. The presentation integrates current research findings, case studies, and clinical guidelines to offer a holistic view of both acute and chronic mercury exposures. Targeted at healthcare professionals, toxicologists, and researchers, this presentation aims to inform and update attendees on the best practices and emerging technologies for managing mercury toxicity."

1. Mercury Toxicity & Management in Dental Clinic

2. Contents Introduction History of mercury in Dentistry Overview of D ental Amalgam   Hazards of Mercury   Forms of Mercury Mercury in Dentistry Sources of Exposure Pharmacokinetics of Mercury Exposure   Regulation and Guidelines   Management of Mercury Toxicity Alternatives to Dental A malgam   Conclusion  References

3. Introduction Hydrargyrum Still used widely in developing countries Highly Toxic Less Technique Sensitive Durable Disposal Risks

4. History of mercury use in dentistry Hyson Jr JM. Amalgam: Its history and perils. Journal of the California Dental Association. 2006 Mar 1;34(3):215-29.

5. Amalgam war 1920 (First Amalgam war) 1980 (Dr Hal Huggins) 1991 V/s FDA 1926 (Alfred Stock) Mentioned his own accounts of mercury poisoning Argued with GV Black Dodes JE. The amalgam controversy: an evidence-based analysis. The Journal of the American Dental Association. 2001 Mar 1;132(3):348-56. Second amalgam war Third amalgam war

6. Overview of dental amalgam The most widely used restorative material Can last up-to 10 years 50% Failure: Faulty Restoration Composition ADA Specification No. 1 Manufacturing Melting Homogenization Particle Formation Cooling and Equilibrium Ball Milling Thermodynamic Equilibrium 150 – 400 ‘C Mackenzie, L. (2021). Dental amalgam: a practical guide. Dental Update. https://doi.org/10.12968/denu.2021.48.8.607.

7. Overview of dental amalgam PRIMARY PHASES Gamma (Ag3Sn) Gamma 1 (Ag2Hg3) Gamma 2 (Sn7-8Hg) Silver – Tin alloy powder before its mixed with Hg When Hg mixed with Silver-Tin alloy Silver reacts with Hg to form Ag2Hg2 (Gamma 1 Phase) DURABLE - MAKES AMALGAM USEFUL Weak phase formed when Hg reacts with Tin (Sn8Hg ) Most prone to corrosion and creep Less Corrosion Resistant Vimal K Sikri : Textbook of Conservative and Restorative Dentistry. 1st Edition. 2019

8. Advantages of amalgam Antony K, Genser D, Hiebinger C, Windisch F. Longevity of dental amalgam in comparison to composite materials. GMS health technology assessment. 2008;4. Durable Less Technique Sensitive Minimal Placement Time Can be used in many clinical situations Corrosion products provide marginal seal Less Expensive & Economical Excellent Compressive strength Proper Isolation not necessary Can be repaired easily

9. Role of mercury in amalgam ACTS AS A BINDING AGENT MERCURY RELEASES VAPOURS RISK FOR PATIENT AND OPERATORS Vimal K Sikri : Textbook of Conservative and Restorative Dentistry. 1st Edition. 2019

10. Double and Triple distilled mercury Mercury contains impurities which might interfere with dental amalgam Fractional Distillation Boiling the mixture Collecting vapours as they condense Less interference with properties More interference with properties Hulett GA, Minchin HD. The Distillation of Amalgams and the Purification of Mercury. Physical Review (Series I). 1905 Dec 1;21(6):388.

11. Pregnancy & mercury Dental amalgam releases mercury vapors which can be particularly harmful for the fetus as it’s organs are not fully developed Low Birth Weight Small Head Circumference Delayed Development Hearing & Vision problems Neurodevelopmental Disorders American Dental Association European Union US Environment Protection Agency World Health Organisation Golding J, Steer CD, Gregory S, Lowery T, Hibbeln JR, Taylor CM. Dental associations with blood mercury in pregnant women. Community dentistry and oral epidemiology. 2016 Jun;44(3):216-22.

12. HAZARDS OF MERCURY Mercury is a heavy metal Not Absorbed Methylmercury disrupts essential biochemical processes by binding to enzymes & proteins

13. FORMS OF MERCURY Elemental Mercury Odourless / Shiny liquid Vaporizes at room temperature Used in thermometers / amalgam / fluorescent light bulbs Ethyl Alcohol promotes rapid excretion of mercury Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

14. FORMS OF MERCURY Inorganic Compounds Found in batteries & skin creams Not r eadily absorbed Can be toxic if inhaled or ingested MERCURY SALTS Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

15. FORMS OF MERCURY Organic Compounds Methylmercury Organomercurials Bioaccumulation and bio-magnification Can cross blood brain barrier and placenta Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

16. Mercury in Dentistry What forms of mercury do we, as Dentists, encounter in daily clinical practice? Elemental Mercury Methyl Mercury Mercury Vapour Studies have suggested that dentists could experience adverse effects from air concentrations of mercury as low as 14 micrograms per cubic meter , which is much lower than the limit of 50 micrograms per cubic meter. Bernhoft RA. Mercury toxicity and treatment: a review of the literature. J Dent Res. 2006;85(1):1-19. doi:10.1177/0022034505283256

17. Mercury in Dentistry Leaching from amalgam restoration is minimal. Estimates are that 450-530 amalgam surfaces would be necessary to expose an individual to minimal toxic effect of mercury . (32 teeth 160 surfaces) Mackert Jr JR , Berglund A. Mercury exposure from dental amalgam fillings: absorbed dose and the potential for adverse health effects. Critical Reviews in Oral Biology & Medicine. 1997 Oct;8(4):410-36.

18. Sources of Exposure Improper d isposal of mercury from dental amalgam scraps Ingestion of contaminated fish Hg bonded to organic compounds Most human exposure to metallic mercury comes from mercury vapor outgassing from amalgam fillings, at a rate of 2 to 28 micrograms per facet surface per day, with about 80% being absorbed . Occupational exposure - Dental Clinics / Production of thermometers, barometers and fluorescent lamps / gold mining / coal fired power plants Volcanic Eruptions Bernhoft RA. Mercury toxicity and treatment: a review of the literature. J Dent Res. 2006;85(1):1-19. doi:10.1177/0022034505283256

19. Sources of Exposure Mercury Spills Expression of excess Hg from Amalgam Leakage from dispensers Improper Storage of scrap Amalgam Leakage from capsule while trituration Langan DC, Fan PL, Hoos AA. The use of mercury in dentistry: a critical review of the recent literature. The Journal of the American Dental Association. 1987 Dec 1;115(6):867-80.

20. Sources of Exposure Other Sources mercury vaporization from contaminated instruments placed in sterilizers grinding of amalgam during removal of restorations amalgam condensation with ultrasonic condensers Studies have found little or no difference in ambient air concentrations of mercury vapor between offices with carpeting and those with hard floor coverings Langan DC, Fan PL, Hoos AA. The use of mercury in dentistry: a critical review of the recent literature. The Journal of the American Dental Association. 1987 Dec 1;115(6):867-80. V/s

21. Pharmacokinetics of mercury exposure INORGANIC MERCURY Elemental / Metallic Mercury Hg0 80% 19% 1 % > > Mercury Vapour Sulphur containing amino acids Metallic Mercury Blood Brain Barrier Placenta Foetal Brain Influences T-Cell function Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012.

22. Pharmacokinetics of mercury exposure INORGANIC MERCURY Hg0 Elemental / Metallic Mercury Metallic Mercury Mercuric Mercury excretion Excretory Half Life Depends on Organ Redox State CNS – Hg has several years of half life Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012.

23. Pharmacokinetics of mercury exposure INORGANIC MERCURY Hg2Cl2 Mercurous Mercury / Calomel Poorly soluble / not readily absorbed Metallic Hg Mercuric Hg Pink disease & Acrodynia Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012.

24. Pharmacokinetics of mercury exposure INORGANIC MERCURY HgCl2 Mercuric Mercury Photographic film development Skin Lightening cream Only 2% absorbed – rest corrodes the intestine HgCl2 Sulfhydryl groups on erythrocytes Metallothionein Glutathione Mercuric Mercury Proximal Convoluted Renal Tubule Half Life 42 days for 80% Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012.

25. Pharmacokinetics of mercury exposure ORGANIC MERCURY CH3Hg Methyl Mercury Major form of organic mercury Relatively Stable 80% Sulfhydryl groups in cysteine Methyl Mercury Inorganic Mercury ( DEMETHYLATION ) Half Life 70 Days ( 90% excretion in stool ) Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012.

26. Symptoms of toxicity INORGANIC MERCURY Metallic Mercury Vapour Alters tertiary and quaternary structure of proteins Binds with sulfhydryl and selenohydryl groups ACUTE CHRONIC Erosive bronchitis Bronchiolitis Low Level Exposure High Level Exposure Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012.

27. Symptoms of toxicity INORGANIC MERCURY Mercuric Mercury ACUTE CHRONIC Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012. HgCl2 extensive precipitation of enterocyte i ntestinal cell proteins Abdominal pain / vomiting / bloody diarrhea Renal tubular necrosis Autoimmune glomerulonephritis Thyroid Dysfunction Decreased Spermatogenesis

28. Symptoms of toxicity ORGANIC MERCURY Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012. Renal tubular necrosis Autoimmune glomerulonephritis Thyroid Dysfunction Methyl & Ethyl Mercury Pre Natal Exposure Post Natal Exposure Massive Exposures C erebral P alsy Lesser Exposures Neurodevelopmental Delays Lesser Exposures Paraesthesia Moderate Exposures Ataxia / Visual-Auditory-Extrapyramidal impairments Severe Exposures Clonic Seizures

29. Acrodynia Pinks Disease Due to mercury poisoning ACRO + DYNIA (extremity) (pain) SYMPTOMS Peripheral Neuropathy Pain / Paraesthesia / Itching / Burning Physical Symptoms Discolouration / Oedema / Desquamation Blocks Catecholamine's Excessive Sweating & Salivation Rapid heart rate Pink discolouration

30. Acrodynia Pinks Disease Due to mercury poisoning ACRO + DYNIA (extremity) (pain) SYMPTOMS IN CHILDREN Red Cheeks Transient Rashes Red Lips Loss of Hair / Teeth / Nails

31. Acrodynia TREATMENT MAIN GOAL Remove Mercury from the body Fixing any electrolyte loss and nutritional imbalances Chelating Agent 2,3-dimercaptosuccinic acid (DMSA) Hemodialysis Patients with Acute Kidney Injury from Mercury Toxicity L - Cysteine added to clear out mercury from blood

32. Regulations and guidelines Estd . In 1971, is a U.S. Federal Agency under the Dept. of Labor Ensures safe and healthful working conditions for employees by setting and enforcing safety standards OSHA has established Permissible Exposure Limits (PELs) for mercury The current limit for mercury vapor established by OSHA is 50 m g/m3 ( time-weighted average) in any 8-hour work shift over a 40-hour work week. https:// ohsonline.com/Articles/2003/07/Mercury

33. Regulations and guidelines

34. Regulations and guidelines Staff handling mercury should be trained in management and hygiene protocols. The dental operatory should have good ventilation and fresh air circulation . The design of the operatory should allow easy cleanup after mercury spillage. All clinic personnel should be aware of potential mercury contamination sources. Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

35. Regulations and guidelines Preferably, use pre-capsulated alloys; avoid using bulk alloy and mercury Handle amalgam carefully, avoid skin contact, and re-cap single-use capsules Use high vacuum evacuators during the finishing and polishing of amalgam restorations Store scrap amalgam and excess mercury in an air-tight container with radiographic fixer solution FIXER Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

36. Regulations and guidelines Scrap and waste amalgam should be recycled whenever possible. Dispose of all mercury wastes and unused scrap amalgam according to waste disposal laws. Remove professional clothing before leaving the workplace. Periodically monitor mercury vapor in the operatory atmosphere using dosimeters or mercury vapor analyzers Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

37. Managing a mercury spill Determine the extent of the spill Block foot traffic for a 2 meter radius around the spill Ventilate the area https://ohsonline.com/Articles/2003/07/Mercury-Spill-Control--Cleanup.aspx?Page=1

38. Managing a mercury spill Wearing protective gloves and mask Use a mercury spill kit to clean the spill Join small droplets of mercury into a large mercury pool using a plastic or wooden spatula https://ohsonline.com/Articles/2003/07/Mercury-Spill-Control--Cleanup.aspx?Page=1

39. Managing a mercury spill The pool is then aspirated through a syringe Placed in a specially designed container Or if that’s unavailable, in a jar of water before sealing it off https://ohsonline.com/Articles/2003/07/Mercury-Spill-Control--Cleanup.aspx?Page=1

40. Managing a mercury spill Mix equal parts of Sulphur and Calcium Hydroxide powder over the spilt mercury Area is wiped with a damp cloth Dispose the cloth in a sealed polythene bag https://ohsonline.com/Articles/2003/07/Mercury-Spill-Control--Cleanup.aspx?Page=1

41. How much does a mercury spill kit cost? 2100 /- (PSI) 5000/- (U-Safe) 8200/- (Mercury Eater)

42. Managing of mercury vapor release in dental clinic DURING INSERTION OF AMALGAM Due to high vapor pressure of mercury, surrounding air immediately gets contaminated Once restoration is done, immediately ventilate the room Mercury can be recycled, gauze can be placed in non incinerated solid waste Amalgam hardens after insertion, less mercury vapor Amalgam scraps to be stored in the x-ray fixer solution in a tightly capped container Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

43. Managing of mercury vapor release in dental clinic DURING FINISHING & POLISHING OF AMALGAM Finishing and polishing generates heat Liquefies silver mercury (Ag2Hg3) Process creates a Mercury rich phase that smears over the amalgam surface Slow polishing and water coolant helps (melting point 127’C) Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

44. Managing of mercury vapor release in dental clinic DURING REMOVAL OF AMALGAM Removal generates heat Liquefies silver mercury (Ag2Hg3) This is accelerated by the heat generated by burs Water Coolant & High Vacuum Suction (melting point 127’C) Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

45. Managing of mercury vapor release in dental clinic DURING INSTRUMENT STERILIZATION Prior to sterilization Instruments used should be cleaned Contaminated instruments releases mercury on sterilization (liquid or vapor form) Adequate Ventilation Mahalakshmi , M. (2022). Dental materials. New Delhi, India: Jaypee Brothers Medical Publishers.

46. AMALGAM SEPARATORS A unit installed in the dental chair apparatus to filter out amalgam scraps and particles from wastewater Sedimentation Filtration Centrifuge https:// www.benco.com/benco-dental-u/article/why-you-need-amalgam-separators-in-your-clinic Khangura SD, Seal K, Esfandiari S, Quiñonez C, Mierzwinski -Urban M, Mulla SM, Laplante S, Tsoi B, Godfrey C, Weeks L, Helis E. Economic Evaluation. InComposite Resin Versus Amalgam for Dental Restorations: A Health Technology Assessment [Internet] 2018 Mar. Canadian Agency for Drugs and Technologies in Health. COST 200,000 Rupees or 2500$

47. Minamata Bay disaster Industrial Disaster occurred in Japan from 1930’s to 1960’s Industrial wastewater from the Chisso Corporation's chemical factory, which contained methylmercury, was discharged into Minamata Bay. The methylmercury bioaccumulated in fish and shellfish in the bay, a major food source for the local population. Minamata Bay Chisso Factory https://www.med.or.jp/english/pdf/2006_03/112_118.pdf

48. Minamata Bay disaster Minamata Disease Protestors at the gate of Chisso Factory Over 2,000 people suffered from severe mercury poisoning, known as Minamata disease . neurological symptoms like muscle weakness, numbness in the limbs, damage to hearing and speech severe cases, paralysis and death. https://www.med.or.jp/english/pdf/2006_03/112_118.pdf

49. Minamata Bay Convention January 19, 2013 – 140 countries signed up for safe use, disposal, alternatives to mercury Named after Minamata Bay, where the industrial disaster took place Primary mining, to safe storage, to the reduction of mercury in products and industrial processes. S pecifically mentions the phase-down of dental amalgam, recognizing the need for a gradual reduction in its use due to the challenges in immediately replacing it with alternatives. The convention encourages member countries to promote the use of cost-effective and environmentally sound alternatives to mercury-containing products. https://mercuryconvention.org/sites/default/files/2021-06/Minamata-Convention-booklet-Sep2019-EN.pdf

50. https://mercuryconvention.org/sites/default/files/2021-06/Minamata-Convention-booklet-Sep2019-EN.pdf Reference :

51. Alternatives to Mercury Gallium and Indium were used as alternatives to mercury in dental amalgam Gallium is slightly toxic after 8 hours of placement into the cavity Gallium Poisoning: patient progressed to dangerous episodes of tachycardia, tremors, dyspnea, vertigo, and unexpected black-outs Wataha JC, Nakajima H, Hanks CT, Okabe T. Correlation of cytotoxicity with elemental release from mercury-and gallium-based dental alloys in vitro. Dental Materials. 1994 Sep 1;10(5):298-303.

52. C onclusion Amalgam is a valuable restorative material, but its use is associated with mercury toxicity. Safer alternatives and effective waste management practices are essential to mitigate risks. The decision of whether or not to use amalgam fillings is a complex one that should be made on a case-by-case basis, weighing the risks and benefits carefully . In conclusion, amalgam is a valuable material with both risks and benefits. The best decision for each individual patient will depend on their specific needs and circumstances.

53. R eferences Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012 . Garg N Garg A Abu Tahun I.  Textbook of Operative Dentistry . 3E édition ed.; 2015 . Roberson TM Heymann H Swift EJ Sturdevant CM.  Sturdevant's Art and Science of Operative Dentistry . 5th ed. St. Louis Mo: Mosby; 2006 Vimal K Sikri : Textbook of Conservative and Restorative Dentistry. 1st Edition. 2019 Langford NJ, Ferner RE. Toxicity of mercury. Journal of human hypertension. 1999 Oct;13(10):651-6 . Bernhoft RA. Mercury toxicity and treatment: a review of the literature. Journal of environmental and public health. 2012 Oct;2012 . Hyson Jr JM. Amalgam: Its history and perils. Journal of the California Dental Association. 2006 Mar 1;34(3):215-29 . Mackenzie, L. (2021). Dental amalgam: a practical guide. Dental Update. https://doi.org/10.12968/denu.2021.48.8.607 . Antony K, Genser D, Hiebinger C, Windisch F. Longevity of dental amalgam in comparison to composite materials. GMS health technology assessment. 2008;4 . Golding J, Steer CD, Gregory S, Lowery T, Hibbeln JR, Taylor CM. Dental associations with blood mercury in pregnant women. Community dentistry and oral epidemiology. 2016 Jun;44(3):216-22 . Dodes JE. The amalgam controversy: an evidence-based analysis. The Journal of the American Dental Association. 2001 Mar 1;132(3):348-56 .

54. Thank You!