Amalgam filling

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Tooth filling made of silver amalgam

An amalgam filling ( ancient Greek μαλακός malakos , "soft" - the "non-softening"); according to another etymology, Arabic أمل آل غاما amal al-gama , softening ointment), also known colloquially as “filler” (from Latin plumbum , lead), is a tooth filling made from mercury alloys .

history

There is evidence that dental amalgam was used as a filling material as early as the beginning of the Tang dynasty ( Chinese  唐朝 , Pinyin táng cháo ) in China (618–907 AD) , as described in the writings of the Chinese doctor Su Kung (蔌 哭嗯) from the year 659. Amalgam returns as a “silver paste” in Ta-Kuan Pent-ts'ao (大观 被 压抑 的 曹操) around 1107. The alloy is also mentioned in 1505 and 1596 (by Li Shi-Zhen李时珍) in the Ming period ( Chinese 明朝 , Pinyin míng cháo ) . In 1505, Liu Wen t'ai (刘 雯 台) describes the exact composition: “100 parts of mercury , 45 parts of silver and 900 parts of tin to be stirred in an iron pot.” The first use in recent times is the dentist I. Attributed to Regnart in 1818, although this is controversial and the names Thomas Bell and Taveau are also mentioned. Since 1820 it has been used en masse as a filling material, replacing the expensive gold that was previously common. Dental amalgam is created by mixing, so-called trituration , of around 50% pure mercury and a filing mixture of different metals to form a plastic mass that hardens after a short time (approx. 3–5 minutes).  

Use as a tooth filling

Tooth with approximal caries (caries between the teeth)
Old filling removed, caries is exposed
Caries removed
Amalgam filling

A common application of amalgams is as a filling for teeth , today exclusively in the form of silver amalgam . Silver amalgams consist of 50% mercury and 50% a file mixture. The filing mixture today consists of at least 40% silver , a maximum of 32% tin , a maximum of 30% copper , a maximum of 5% indium , a maximum of 3% mercury and a maximum of 2% zinc . These non-gamma-2-phase silver amalgams, which have been used in dentistry since the 1980s, contain slightly more copper and less tin than previous mixtures and are therefore more corrosion-resistant . Copper amalgam contains copper instead of silver as its second main component and was also used as a material for dental fillings until the first half of the 20th century. Because of its lower chemical resistance and environmentally harmful processing (it was delivered premixed and had to be softened by heating for processing) it was later replaced by silver amalgam.

The advantage of amalgam as a filling material lies in its relatively simple processing, which is largely fault-tolerant even under difficult conditions in the mouth, and in its durability, which even today cannot be achieved with any other plastic material with comparable correct processing. The time required to manufacture amalgam is less than that of plastic fillings. In addition, amalgam is sometimes cheaper than modern filling plastics, the advantages of which are mainly the tooth-like color and the possibility of adhesive attachment to the hard tooth substance .

Health concerns

The processing of pure mercury and the high mercury content (around 50%) caused a discussion very early on about possible health risks that could arise from the use of amalgam as a filling material. As early as 1833, after the forced introduction of amalgam as a filling material, the so-called "amalgam war" broke out in the USA, which led to a temporary ban on amalgam as a filling material. A similar discussion flared up in Germany in the 1920s. A multicenter study from 1998 could not find any connection between the number of amalgam fillings in patients and their subjective assessments of their state of health. The view from 2005 that the main source of mercury exposure in industrialized countries was inhalation of mercury vapor from dental amalgam was no longer upheld by two studies by the European Commission. She came to the conclusion that the risk was comparatively low.

In theory, two different mechanisms of damage are assumed: intoxication (poisoning) and allergy .

The Hamm Higher Regional Court ruled on March 4, 2016 that the use of amalgam for dental fillings is generally harmless.

Current concerns about amalgam

People who have several different (heavy) metals in their mouths (e.g. gold , amalgam, silver) have increased mercury levels in their blood, as the bimetal corrosion in the mouth can release mercury ions from the amalgam. The heavy metals copper and tin also enter the body through abrasion . Mercury is mainly absorbed in the processing of amalgam in the form of mercury vapor. When mercury is absorbed, there is increased excretion in the urine and storage of mercury in the body, especially in adipose tissue. This enables the heavy metal to have a neurotoxic effect, because nerve tissue is a. surrounded by fat. The Federal Institute for Drugs and Medical Devices (BfArM) recommends avoiding the use of amalgam in pregnant women and those with kidney damage.

In 1997 a consensus paper on the handling of amalgam was published in Germany by the Federal Ministry of Health , the BfArM and various dental societies and institutions. Similar recommendations have come from the EU in recent years.

The diagnosis of mercury poisoning includes blood, urine and / or stool examinations. Saliva tests and hair analyzes are considered unreliable and are not recommended.

If there is evidence of exposure to mercury, the use of chelating agents such as DMPS and DMSA can be considered. These form water-soluble complexes with mercury and other metal ions , which can then be excreted in the urine or stool. However, this treatment can lead to massive side effects due to the elimination of necessary trace elements.

Psychogenic amalgam intolerance

In the case of “psychogenic amalgam intolerance”, affected patients report almost all complaints in human pathology and attribute this to amalgam. However, there was no evidence of any connection between the number of amalgam fillings and the symptoms. There are people who suffer mentally when the doctor puts amalgam fillings on them. This also manifests itself physically: You suffer from malaise, hectic spots and stress. These problems will improve when you know that the dentist will remove the fillings.

X-ray image of amalgam filling
The amalgam shaker for mixing the amalgam has replaced mixing by hand for decades; Mixing time, depending on the make: 5–15 seconds.
The capsule with the mercury and the silver chips (separated by a foil) is clamped into the vibrator, the holder with the capsule then vibrates very quickly back and forth during mixing.
The soft, freshly mixed amalgam is introduced into the cavity with the "amalgam gun".
Amalgam separator SEDAS 4 - a sediment separator

Reasons for using amalgam

Amalgam fillings have been used in large numbers around the world for decades. The vast majority of epidemiological and toxicological studies have so far shown no health risks. Occasionally a harmless pigmentation of the oral mucous membrane ( amalgam tattoo ) occurs.

In Germany, the statutory health insurance companies only cover the costs for fillings in the “chewing pressure-bearing posterior region” if “amalgam” (silver amalgam) is used as a rule. In the field of statutory dental care , however, amalgam is "absolutely contraindicated if evidence of an allergy to amalgam or its components has been provided in accordance with the criteria of the contact allergy group of the German Society for Dermatology or if new fillings have to be placed in patients with severe renal insufficiency." In this case, "composite fillings in the posterior region (...) according to the adhesive technique" are covered by the health insurance.

An exchange of intact amalgam fillings is not part of the statutory health insurance obligation , as the Federal Social Court has repeatedly stated. If other fillings are used, the statutory health insurance companies usually only pay the costs that would result from an amalgam filling, so that the patient may have to bear additional costs himself.

Alternatives

Alternative plastic fillings ( composite , Ormocere ) are statistically not as durable as amalgam fillings. Their exclusive use would significantly increase the costs of the statutory health insurance for dental fillings, since the fillings have to be changed more often or tooth loss is to be expected more often. Composite fillings are possibly toxicologically questionable because they contain 200 chemical compounds that have not yet been investigated in great detail. Inlays (gold inlays, ceramic inlays) and gold hammer fillings , however, are harmless from a toxicological point of view. Ceramic inlays are not cemented like gold fillings, but glued in with plastic (chemically identical to plastic fillings), whereby there is an allergy potential in exceptional cases.

Restriction on the use of amalgam fillings

  • Dental amalgams should the primary dentition no longer be applied because of the growing organism no additional possible heavy metal contamination should be exposed and amalgams in the primary dentition significantly less favorable application properties than the adult teeth.
  • During pregnancy and lactation should not work amalgam (insert or remove amalgam fillings) are executed as possible. Should this be absolutely necessary in exceptional cases, then appropriate measures (e.g. rubber dam ) must be used to keep mercury exposure as low as possible.
  • Amalgams must not be used
  • with impaired kidney function .

These restrictions were taken as a precautionary measure.

A statement from the World Health Organization (WHO) formulated before 2007 comes to the conclusion: “According to the current state of knowledge, the currently available restoration materials, including dental amalgam, are to be regarded as safe and reliable. However, there are occasional biological contraindications. However, these are individually determined and must therefore be treated individually. The WHO recognizes the need for continued safety and effectiveness monitoring of all dental restorative materials. "

Amalgam use internationally

In the European Union , around 70 tons of mercury are used for amalgam every year , with dentists being the main consumers. In total, there are around 1300 to 2200 tonnes of mercury in the teeth of EU residents. The nine million citizens of Sweden carry around 40 tons of mercury in the form of amalgam tooth fillings, of which around 100 kg are excreted into the environment every year.

For US citizens it has been calculated that they have around 1000 tons of mercury in their dental fillings.

In the last decades of the Soviet Union , plastic was predominantly used for posterior fillings.

Mercury ban

According to a press release dated January 15, 2009, the Ministry of the Environment in Sweden decided to ban the use of mercury in general. The ban means that the use of amalgam in dental fillings will cease and that products containing mercury will no longer be allowed to be marketed in Sweden. Andreas Carlgren, the Swedish Environment Minister, said: "The ban is a strong signal for other countries and the contribution of Sweden to the goals of the EU and UN to reduce the use and emission of mercury." The new regulations came into effect on June 1st, 2009 Force. Norway and Denmark have also banned the use of amalgam.

In view of the health risks posed by mercury, the Governing Board of the United Nations Environment Program (UNEP) decided in February 2009 to develop a global agreement that would deal with all aspects of the mercury life cycle. The relevant negotiations were concluded in January 2013 and the agreement was signed in October 2013 as the "Minamata Convention" . On November 6, 2013, the United States government became the first state to ratify the Convention. With regard to dental amalgam, it was stipulated that all contracting parties must take measures to gradually phase out the use of dental amalgam.

Health and environmental hazard

In Germany, dental practices have to clean their wastewater using an amalgam separator. Wastewater containing mercury leads to increased expenditure in sewage treatment plants . Organic mercury compounds that can arise in wastewater are particularly harmful to the environment . Dental practices are subject to special water protection regulations . Amalgam separators installed at treatment stations must have general building authority approval in accordance with the Waste Water Ordinance (AbwV) or be approved under state law, have a separation efficiency of at least 95 percent and be regularly serviced and emptied. Before commissioning and at intervals of no longer than five years, amalgam separators must be checked to ensure that they are in good working order according to state law. The discharge of amalgam-containing wastewater is generally only permitted with an official permit.

The waste collected in the practice from the amalgam separators, amalgam residues and extracted teeth with amalgam fillings must be disposed of at specialist recycling companies for a fee . Due to the high proportion of mercury, they must dispose of the amalgam waste as hazardous waste ( waste key number 180110 *) with the aim of recovering metal.

In December 2004 a study by the "Life Sciences Research Office" of the USA was published: An evaluation of all research work since 1996 found no evidence of the risk from amalgam fillings.

A study published in 2008, in which 5000 patients were questioned, found, according to a report by Spiegel online (Wissenschaft), "no significant difference between patients with and those without amalgam fillings" in terms of symptoms. It was found, however, that "the inorganic mercury levels in the blood of patients with amalgam fillings were four times higher than in people without these fillings."

The 2008 study by the Technical University of Munich came to the result that removing amalgam lowers the inorganic mercury levels in the blood. The subjective complaints can be positively influenced both by the removal and by general health measures without removing the amalgam. An additional "biological detoxification" with vitamins and trace elements did not result in any additional improvement in the amalgam removal group.

On March 10, 2014, the European Commission 's Scientific Committee on Health and Environmental Risks (SCHER) published an opinion on the health and environmental effects of amalgam with the result that the health and environmental risks The environmental hazard from the mercury contained in dental amalgam is comparatively low. Only under exceptional circumstances (worst-case scenario) , i. H. In the case of a high density of dentists combined with a high degree of amalgam use with a simultaneous lack of amalgam separators, it cannot be ruled out that there are risks to health and the environment at the local level. This scenario is excluded for Germany, since amalgam separators are mandatory for dental practices in this country. The background to the study are the demands of Sweden to ban the use of amalgam containing mercury throughout Europe for reasons of environmental and health protection.

Because of the highly toxic mercury it contains , there is no other filler material in the world that has been examined so frequently and intensively for possible health hazards. As the German Dental Association noted in a position paper on the EU mercury regulation in June 2018, no study has yet been able to prove that amalgam fillings are causally related to degenerative diseases, other diseases or other unspecific symptoms.

Diagnosis

The individual load can be determined using laboratory tests. First, a saliva test is recommended, which measures the release of mercury from the tooth filling. To investigate possible absorption in the body, mercury in the urine is measured before and after the administration of DMPS . DMPS brings the mercury bound to body protein back into solution, which is excreted via the kidneys.

literature

  • DIN EN ISO 24234, edition: 2005–01, Dentistry - Mercury and alloys for dental amalgams, (ISO 24234: 2004); German version EN ISO 24234: 2004
  • Gottfried Schmalz, Dorthe Arenholt-Bindslev: Biocompatibility of Dental Materials . Springer, Berlin / Heidelberg / New York 2009, ISBN 978-3-540-77781-6 .

Web links

Commons : Fillings  - collection of images, videos and audio files

Individual evidence

  1. with "α" Alpha privativum
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  3. Ullrich Rainer Otte: Jakob Calmann Linderer (1771-1840). A pioneer in scientific dentistry. Medical dissertation, Würzburg 2002, p. 22.
  4. a b c Brochure of the Federal Institute for Drugs and Medical Devices : "Amalgams in Dental Therapy" (PDF; 286 kB)
  5. mercury alloys . In: Meyers Großes Konversations-Lexikon . 6th edition. Volume 16, Bibliographisches Institut, Leipzig / Vienna 1908, pp.  506–507 .
  6. Ingrid Müller-Schneemayer: The Amalgam Controversy in the Twenties of the 20th Century urn : nbn: de: bvb: 19-19471
  7. D. Melchart, E. Wühr, W. Weidenhammer, L. Kremers: A multicenter survey of amalgam fillings and subjective complaints in non-selected patients in the dental practice. In: Eur J Oral Sci. 106 (3), Jun 1998, pp. 770-777. PMID 9672099 .
  8. Bundesrat (Germany) , information from the Federal Government: "EU Community Strategy for Mercury"
  9. Tooth filling materials amalgams & alternatives European Commission, Health and Consumer Protection
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  11. ^ Dental care with amalgam, Az .: 26 U 16/15 , press release of the OLG Hamm, juris. Retrieved April 5, 2016.
  12. Consensus paper "Restorative materials in dentistry" ( Memento of December 3, 2013 in the Internet Archive )
  13. Amalgam . Laboratory dictionary
  14. Environmental medicine guideline: Mercury. AWMF
  15. G. Kreier: Tooth and Psyche. Bavarian Chamber of Psychotherapists
  16. G. Meyer: Amalgam removal primarily relieves the psyche. University of Greifswald in Focus online
  17. Minutes of the decision of the Extended Evaluation Committee for Dental Services of April 17, 1996.
  18. Uniform evaluation standard for dental services in accordance with Section 87 Paragraph 2 and 2d SGB ​​V , Item 13 e - g.
  19. BSG, judgment of October 6, 1999 , Az.B1 KR 13/97 R, full text.
  20. BSG, judgment of October 30, 2002 , Az.B1 KR 31/01 R, full text.
  21. Decision-making aid : which tooth filling should it be? kzbv.de
  22. Recommendations on dental amalgam. (PDF) Dental materials working group, Federal Ministry for Health, Family and Youth
  23. agz-rnk.de (PDF) World Health Organization (WHO): Consensus declaration on the subject of dental amalgam.
  24. a b c d Joachim Mutter, Johannes Naumann, Harald Walach: Risk assessment amalgam: Answer to Halbachs comment. (PDF; 521 kB). (PDF)
  25. ^ Government bans all use of mercury in Sweden ( Memento of 23 September 2012 in the Internet Archive ). Press release by the Ministry of Environment Sweden, January 15, 2009, accessed August 8, 2013.
  26. Jump up ↑ Richard F. Edlich, Samantha K. Rhoads, Holly S. Cantrell, Sabrina M. Azavedo, Anthony T. Newkirk: Banning Mercury Amalgam. (PDF; 118 kB). FDA , accessed May 29, 2013.
  27. Minamata Convention (PDF; 278 kB). Retrieved November 21, 2013.
  28. ^ UNEP: The Negotiating Process. Retrieved November 21, 2013.
  29. ^ United States Joins Minamata Convention on Mercury. ( Memento of November 22, 2013 in the Internet Archive ) Press release on state.gov of November 6, 2013. Retrieved on November 21, 2013.
  30. Ordinance on requirements for the discharge of wastewater into bodies of water (Wastewater Ordinance - AbwV) Annex 50 Dental treatment
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  32. ↑ Dispose of amalgam waste from dentistry safely. Waste manager medicine, accessed on July 12, 2018 .
  33. LSRO press release on the Little Evidence to Link Mercury Fillings to Human Health Problems study . (PDF; 25 kB).
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  35. D. Melchart et al. a .: Treatment of health complaints attributed to amalgam. In: J Dent Res . 87 (4), Apr 2008, pp. 349-353. PMID 18362317 .
  36. Opinion on the environmental risks and indirect health effects of mercury from dental amalgam (update 2014) (PDF) Scientific Committee on Health and Environmental Risks
  37. Klartext 04/14 (PDF) Federal Dental Association
  38. Position: EU Mercury Regulation (EU) 2017/852. (PDF) German Dental Association, accessed on July 12, 2018 .
  39. Amalgam: burdened or not? A simple test provides clarity . (PDF) LADR