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Mercury in dental amalgam

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Feras Bilal

on 22 April 2015

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Transcript of Mercury in dental amalgam

Mercury in dental amalgam
Reactions of Mercury in dental amalgam
The aim of this review article is to review mercury’s reactions and release in dental amalgam.

- Mercury is a Heavy, unique, non viscous metal at room temperature

- Uses in the health care field include
* dental amalgam fillings
* manufacturing thermometers
Materials & Methods
- Books, reports, newsletters as well as electronic databases such as Pubmed, Wiley & Sagepub were used to search.

Amalgam reactions
Amalgam release
Oral environment
Release of Mercury in dental amalgam
- Dissolution of mercury is inversely related to the amount of mercury in the electrolyte.

- Mercury dissolves in 1) Electrochemical way
2) Atomic dissolution way

- The inhaled mercury vapor takes three pathways to enter our bodies;
1) To the blood by the lungs
2) Absorbed by the intestines
3) Pass through the blood brain barrier

- After inhalation, mercury is excreted outside our bodies through urine & feces.
(Un-reacted Phase)
Small amount of mercury is relaesed from amalgam restorations under cycles of chewing & brushing.

Mercury released from amalgam restorations contribute to mercury concentrations in blood and urine.
Fatima Abou Daher
Fatimah Alabdalal
Fatmah Alhammadi
Feras Mohamed Bilal
Ghaidaa Mahgoub

Chereen Marashde
Chrestien Haddad
Dana Al-Najjar
Dina Medhat
Eyas Shehadeh
Farah Ghanim

Ghazal Bahman
Hadiel Salem
Hawraa Alameri
Hawraa Shms Eddin
Haya Dygili

- In amalgamation, mercury liquefies Ag & other elements of the dental amalgam alloy to produce a plastic composition (Dental amalgam).

- All different types of dental amalgam alloys contain almost the same elements (Ag, Sn, Zn & Cu) but in different ratios.
Continue.. Reactions of mercury
Continue.. Reactions of mercury
Exposure to mercury from dental amalgam is not enough to inhibit the use of amalgam restorations since there are many other sources of mercury exposure such as air pollution & cosmetics.
Continue.. Release of mercury
- Nine studies were reviewed about the release of mercury:

1) A study by Lyttle H.A and Bowden G.H.

- Mercury (amalgam plaque) > un-restored enamel

2) Two studies by Olstad et al & Kingman A.

- A positive correlation were found between amalgam points\exposure & mercury concentrations in urine\blood & urine respectively. Fig(1).

3) A study by Ferracane J.L. et al

- Showed no differences in the behaviors at 37, 80, 110 degrees for : Dispersalloy (DIS), Zinc containing and zinc-free Velvallo (ZVE & NZU respectively).
Continue.. Release of mercury
1. Sakaguchi, R.L and Powers, J.M.. Craig’s Restorative Dental Materials, Thirteenth edition ed. Philadelphia: Elsevier Inc; 2012.

2. SCENIHR (Scientific Committee on Emerging and NewlyIdentified Health Risks), Scientific opinion on the Safety of Dental Amalgam and Alternative Dental Restoration Materials for Patients and Users, 6 May 2008. Pp.16,17.

3. Fusayama,T., Katayori, T. and Nomoto, S. . Corrosion of Gold and Amalgam Placed in Contact with Each other. Journal of Dental Research 1963; 42(5): 1193- 1195.

4. Soratur, S.H. Essentials of Dental Materials, 1st edition Ed. New Delhi: Jaypee Brothers Publishers; 2002, pp.73-74.

5. Roberts MC, Leroux BG, Sampson J, Luis HS, Bernardo M, Leitao J. Dental Amalgam and Antibiotic and/or Mercury-Resistant Bacteria. Journal of Dental Research.2008; 87(5): 475-479
6. Lyttle HA,Bowden GH. The Level of Mercury in Human Dental Plaque & Interaction in vitro between Biofilms of Streptococcus mutans & Dental Amalgam. Journal of Dental Research.1993; 72(9): 1320-1324

7. Marek,M. . Dissolution of Mercury from Dental Amalgam at Different pH Values. Journal of Dental Research 1997; 76(6): 1308, 1310, 1312-1314

8. Kingman, A., Albertini, T. and Brown, L.J. Mercury Concentrations in Urine and Whole Blood Associated with Amalgam Exposure in a US Military Population. Journal of Dental Research 1998; 77(3): 461.

9. Olstad, M.L., Holland,R.I., Wandel, N. and Pettersen, A. . Correlation between Amalgam Restorations and Mercury Concentrations in Urine. Journal of Dental Research 1987; 66(6): 1179, 1181

10. Lyttle, H.A. and Bowden, G.H. . The Level of Mercury in Human Dental Plaque and Interaction in vitro between Biofilms of Streptococcus mutans and Dental Amalgam. Journal of Dental Research 1993; 72(9): 1320

11. Okabe, T., Ferracane, J., Cooper, C., Matsumoto, H. and Wagner, M.. Dissolution of Mercury from Amalgam into Saline Solution. Journal of Dental Research 1987; 66(1): 33,35,36

12. Berdouses, E., Vaidyanathan, T.K., Dastane, A., Weisel, C., Houpt, M.and Shey, Z. Mercury Release from Dental Amalgams: An in vitro Study Under Controlled Chewing and Brushing in an Artificial Mouth. Journal of Dental Research 1995; 74(5): 1189, 1190

13. Ferracane,J.L., Hanawa, T. and Okabe, T.. Effectiveness of Oxide Films in Reducing Mercury Release from Amalgams. Journal of Dental Research 1992; 71(5): 1151, 1153

14. Marek, M. The Release of Mercury from Dental Amalgam: The Mechanism and in vitro Testing. Journal of Dental Research 1990 ; 69(5): 1167

15. Marek, M.. The Effect of the Electrode Potential on the Release of Mercury from Dental Amalgam. Journal of Dental Research1993 ; 72(9): 1315

5) A study by Marek M.
Showed dissolution rate by pH changes
pH 1 > pH 3-8

6) A study by Marek M.
Showed that average rate of dissolution of mercury from Ag-Hg matrix phase of dental amalgam

Short term exposures > long term exposures

- The dissolution depended on:
Time, solution volume, oxidation
& evaporation conditions.
4) A study by Okabe T et al
Showed that mercury concentrations:
Tytin > Dispersalloy > Velvalloy
(In saline solution)

- Due to higher corrosion potential
7) A study by Marek M.
Showed that the rate of mercury release from the γ1 phase of dental amalgam was not affected by potential changes due to alloying or galvanic contacts unless the potential exceeded some critical value.
- After amalgam is set, released mercury can react with other metals and structures in the oral cavity:

* Contact with gold:
Released mercury will form silver stains and swellings of gold amalgam alloy at the contact areas.

* Without contact (By galvanic actions):
Potential difference between the two metals and the oral environment creates an electric cell.
- It was found that mercury reduce the amount of metabolites (especially Carbohydrates & proteins) produced by the oral bacteria.
Continue.. Release of mercury
- 33 articles, 1 newsletter, 1 WHO report and 3 books were found. 30 Journal articles were summarized, however only 13 were used, as well as 2 books. The other resources found were excluded due to their irrelevance to the main subject.
Another study by Berdouses E.
Showed that release of mercury
Brushing cycles > chewing cycles.
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