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Mercury usage in Canadian Dentistry:

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Part 1:    The C.D.A.'s International Dental Expert Panel on Amalgam.

Dr. Murray J. Vimy
Clinical Associate Professor
Faculty of Medicine
University of Calgary

Contributions By:

Dr. Walter Pressey
Dr. Richard Riley
Dr. James Jenkinson

Background Information to Health Canada
Stakeholder Committee on Dental Amalgam
(February 16 and 17, 1996)
February 2, 1996

 

"Every creative spirit is hounded by a thousand angry men appointed to guard the past." [Anonymous]

Copyright © 1995 Murray J. Vimy All rights reserved. No part of this report may be copied or reproduced without the written consent of the Author.

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Introduction:

Even prior to the official release of Health Canada's report, Assessment of Mercury Exposure and Risks From Dental Amalgam(1), the Canadian Dental Association (C.D.A.) had instituted damage control by again promoting its official position of amalgam safety and criticizing the Health Canada report.(2) Such behaviour seriously questions the C.D.A.'s objectivity and suggests that the C.D.A. is unwilling to entertain serious debate on the issue. Before the ink was dry on the report, Canadian and American dental "authorities" were collaborating to disparage the findings and the methodology of the report.

On December 11, 1995, the C.D.A. convened an "international panel of experts" to review the Health Canada document.(3) The fact that the C.D.A. felt the need to import such "experts" confirms, in real terms, the findings of Part 1 of this document.(4), which employed standard publication productivity data from Medline® and established that:

1. Canadian Dental Schools demonstrate little research expertise on biocompatibility of dental materials;

2. Canadian dental academics, as a group, compare very poorly to their dental research colleagues in Europe and to medical researchers in Canada;

3. and finally, the C.D.A. was shown to rely upon the advice of medically and dentally unqualified materials engineers, in regard to the mercury filling issue.

In its own promotional material, the C.D.A. claims that it has convened an "international panel of experts" on the safety of mercury fillings. Therefore, one must assume that the best authorities from the vast array of international medical and dental experts were gathered. With this in mind, the specific purpose of this document is to examine the present C.D.A. "expert panel" to determine their medical research expertise on the safety of mercury fillings. As in Part 1 of this report, research expertise will be assessed from analysis of their real experimental research publication productivity. This analysis will help determine whether these individuals are properly qualified to make public pronouncements and to give medical health advice to the Canadian public on the safety of mercury filling .

 

Analyses:

Table 1 shows the academic publication record of the C.D.A.'s "international expert panel", from the Medline® data base, which covers the last 30-years. Information for this table was obtained from a standard search using the last name and initials of the individuals in the "expert panel". Under each panel member's name are the dates of their first and last publications, followed by the number of active years they have had from date of first publication to date. Only the number of amalgam articles published by each "expert" is noted. Such amalgam articles could have anything to do with amalgam, physical properties, clinical properties etc.. This total is then broken down into review and experimental papers. Finally, the number of experimental research publications specifically investigating the biocompatibility (oral and systemic) of amalgam is also presented for each "expert panel" member.

Table 1: Amalgam research expertise of the C.D.A.'s International Panel of Experts (1995): From Medline® DATA BASE search, 1966 - present.

Name

(1st-last publ; yrs)

Affiliation Primary Interest Area

No. Amalgam Studies

Biocompatibility of Amalgam (Exp.)

   

 

 

 

 

Total

Rev

Exp

oral

systemic

Berglund, A.

(1988-1994; 7 yrs)

University of Umea, Sweden Mercury release from amalgam.

9

1

8

0

0

Eley, B.M.

(1974-1994; 21 yrs)

King's College, U.K. 1.Oral reaction to implanted amalgam (tattoo).

2. Oral tissue inflammation.

15

4

11

9

2

Fan, P.L.

(1975-1994; 20 yrs)

American Dental Association Composite materials

4

4

0

0

0

Jones, D.W.

(1969-95, 26 yrs)

Dalhousie, Canada Plaster

Ceramics

Reviews

9

3

6

0

0

Larsson, K.S.

(1966-1994; 29 yrs)

No present affiliation Teratology

7

6

1

0

0

McCurdy, R.

(1984-1988; 11 yrs)

Nova Scotia Research Foundation Agricultural pesticides and arsenic poisoning

0

0

0

0

0

Siew, C.

(1965-1994; 31 yrs)

American Dental Association H.I.V. and Hepatitis in dentists  

0

0

0

0

0

TOTAL 145 man years    

 

 

44

18

26

9

2

The table indicates that the 7 C.D.A. international "experts" collectively published a total of 44 amalgam related articles over a cumulative of 145 man years. This amounts to a paultry 0.30 articles/man year. More importantly, of these 44 amalgam articles, only 11, or 25%, of the articles experimentally examined the biocompatibility of mercury fillings. Again, this amounts an extremely poor 0.08 experimental papers/man year. Surprisingly, only 1 individual (Eley) accounts for 100% of these biocompatibility research articles. This raises a critical question. Should C.D.A. members, the Government of Canada and the Canadian public place any confidence in recommendations put forth by this "expert panel", concerning the medical safety of mercury-containing dental fillings?

The C.D.A. specifically, highlighted the participation of Drs. Berglund and Larsson in their Panel.(3) Dr. Berglund recently graduated as a dentist in 1989 and then received his Dr.Odont. in dental materials engineering (equivalent to a Ph.D.) in 1992. Berglund trained under Dr. Maud Bergman, a well known Swedish dental materials engineer with very strong pro-amalgam opinions. Berglund has published 9 amalgam related articles since 1988, one being his thesis (customary in Europe). These articles have focused on the release of mercury from dental amalgam, attempting to develop a predictive mathematical model to explain the phenomenon. Berglund's model theoretically estimates that only an average of 1.7 µg mercury are absorbed/day in humans with amalgam.(5) However, the model is faulty, since it does not account for real measurable human urinary and faecal mercury excretion data attributable solely to amalgams.(6) Nor does it adequately account for mercury loss due to wear and corrosion(7) Indeed, others have suggested that the model is in error by as much as 800%!(8) In that case, the daily dose from mercury fillings would approximate 13.6 µg/day. Dr. Berglund has published no work investigating the medical consequences of mercury exposure from amalgam. Presently, he is affiliated with the Dental School at the University of Umea in Sweden.

Dr. K. Sune Larsson graduated as a dentist in 1955 and received a Dr. Odont. in 1963. His early research focused on the affects of various chemicals (eg. salicylic acid and phenoxy herbicides) on fetal development. However, analysis of the Medline® data base, indicates that since 1982, he has not published any significant experimental research in any field. Instead, he has limited his publications to review articles and Letters to the Editor. In 1984, he was involved as an expert in the Royal Commission on the Use and Effects of Chemical Agents on Australian Personnel in Vietnam, Sydney Australia, 11 April 1984. As a result of his participation, he was later accused by a group of his academic colleagues of giving false statements to the Commission and of suggesting he collaborated in particular research investigations, which they claim he did not.(9) Except for one recent publication, Larsson has never publish any experimental research on mercury or dental amalgam.

Dr. B.M. Eley, a British dental academic who's area of expertise involves oral soft tissue reaction to implanted amalgam and also periodontal inflammation, is the only member of the "expert panel" that warrants recognition. Dr. Eley has published 11 articles on the effects of amalgam implanted into the soft tissue of animals. His findings are consistent with previous investigators who showed a chronic localized giant cell granulomatous reaction to the implanted material. Eley has not examined systemic biologic effects extensively. Several studies he did report were inconclusive.

D.W. Jones' modest contributions to the amalgam debate have been reviewed in Part 1 of this report, previously disseminated.(4) The balance of the C.D.A. "expert panel" demonstrates no significant research expertise on the medical consequences of mercury exposure from dental amalgam. Drs. Fan and Siew are employees of the American Dental Association. Fan is a dental materials engineer with publication expertise primarily in bonding. He is partly responsible for the generally held misinformed view of many dentists that mercury exposure from food is significantly greater than the mercury exposure from amalgam fillings(10) (see Part 1, Appendix 2 for clarification). Dr. Siew has published medical and dental research papers, but none have had anything to do with amalgam biocompatibility. Several of his papers dealt with blood mercury levels as a result of occupational exposure.

Significantly, none of the C.D.A.'s "experts" have published any articles employing risk assessment protocols similar to that used in the Health Canada Report.

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Conclusions:

The data, presented herein, clearly demonstrates that this C.D.A. "expert panel" is not expert or qualified regarding the medical effects of mercury released from dental amalgam. Indeed, the approach of convening "expert panels" is not new to the amalgam debate. The international dental community has regularly taken such an approach to mask their obvious lack of research expertise and to support their anecdotal position of amalgam safety.

Recently, other national dental associations have also attempted to influence public and governmental opinion by endorsing quasi academic symposia pervaded with amalgam advocates. These gatherings are non-consensus meetings often under government auspices, where the moderators responsible for drawing the conclusions are typically inclined toward the prevailing dental orthodoxy and the conclusions reached often blatantly disregard the experimental data presented.(11) Most damning to the dental profession is that they have not advanced any reputable animal, cellular or molecular evidence of their own to support their belief in mercury filling safety.

On the other hand, some national governments have already begun to take regulatory action. In 1987, the government of Sweden commissioned an bona fide expert panel to evaluate the available evidence regarding mercury filling safety. The panel concluded that mercury fillings were "unsuitable from a toxicological point of view". Based on this panels advice, the Swedish Socialstyrelsen announced that steps would be taken to eliminate dental amalgam usage and recommended that comprehensive mercury filling treatment on pregnant women should be stopped to prevent mercury damage to the fetus.(12)

Shortly thereafter, the German Ministry of Health (Bundesgesundheitsamt, BDA) issued an similar advisory.(13)

In October of 1989, the Swedish Director of Chemical Inspection (KEMI), responsible for environmental protection, declared that amalgam would be banned.(14)

In January of 1992, the German Ministry of Health (BDA) informed manufacturers of its intention to ban the production of amalgam.(15) The German BDA removed low copper non-gamma-2-amalgam from the market and published a pamphlet recommending avoiding mercury filling use in individuals with kidney disease, children to age 6, and pregnant women.(16)

In August of 1992, the Swedish government suggested a timetable to phase out mercury fillings. Environmental concerns were used as the official reason for amalgam discontinuation, but the government did acknowledge the toxicological risk to patients and stated that mercury fillings should no longer be used in children by July 1993, in adolescents to age 19 by July 1995, and in all Swedish citizens by 1997.(17) Moreover, the Swedish government is prepared to pay for the replacement of mercury fillings with alternative materials in those Swedish citizens where medical evidence supports that amalgam mercury exposure is contributing to a medically diagnosed condition. (Unlike Canada, in Sweden dentistry is part of socialized health care.) In 1994, the Swedish Dental Association acknowledged that its leadership had previously been incorrect in their position regarding mercury filling safety. They now support a discontinuation of mercury use in dentistry.(18)

The Austrian Minister of Health announced that the use of mercury fillings in children would be banned in 1996 and discontinued for all Austrians by the year 2000.(19)

The extensively peer-reviewed results of the Health Canada Report(1) on amalgam and the overwhelming published medical experimental evidence,(20) both seriously question mercury filling safety and raise a critical question. Surely, it is now time to discard the self-appointed "experts" and rely on the hard experimental research data to form the Canadian Public Health Policy on amalgam safety?

"The character or beliefs of the scientist are irrelevant; all that matters is whether the evidence supports his contention. Arguments from authority simply do not count; too many authorities have been mistaken too often."

[Carl Sagan, from Broca's Brain, 1974]

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Bibliography:

1.     Richardson, G.M., Assessment of Mercury Exposure and Risks from Dental Amalgam: Final Report, Medical Devices Bureau, Environmental Health Directorate, Health Canada, Ottawa, August 18, 1995.

2. Brookfield, J.R., CDA President's Letter to Membership with Attached Material, November 20, 1995.

3. Canadian Dental Association, News Update: CDA Convenes International Panel of Experts to Analyze Mercury Exposure Report, Journal, Can. Dent. Assoc. 62:24, 1996.

4. Vimy, M.J., Pressey, W. and Riley, R. Mercury Usage In Canadian Dentistry: Part 1: Critical Questions About Credibility, Murray J. Vimy, Calgary, AB. Canada, January 1996.

5. Berglund, A., Estimation by a 24-hour study of the daily dose of intra-oral mercury vapor inhaled after release from dental amalgam., J. Dent. Res. 69:1646-1651, 1990.

6. Skare, I. and Engqvist, A., Human exposure to mercury and silver released from dental amalgam restorations. Arch. Environ. Hlth., 49:384-394, 1994.

7. Gross, M.J. and Harrison, J.A., Some electrochemical features of the in vivo corrosion of dental amalgam., J. Appl. Electrochem., 19:301-310, 1989.

8. Bengtsson, U., e-mail ulfbe@ikpgw.liu.se, Personal communication, 20 January 1996.

9. Hardell, L. and Eriksson, M., Letter to His Honour Justice Phillip Evatt, Royal Commission on the Use and Effects of Chemical Agents on Australian Personnel in Vietnam, November 6, 1984.

10. American Dental Association. Mercury:from fish to fillings, ADA NEWS, !986, Dec. 1: 6-7

11. Lorscheider, F.L. and Vimy, M.J., Evaluation of the safety issue of mercury release from dental fillings., FASEB J., 1993, 7, 1432-1433.

12. Socialstyrelsen (Sweden, Social Welfare and Health Administration). Redovisar; kvicksilver/amalgam halsorisker. Allanna Forlaget AB, Stockholm, 10 32-39, 1987.

13. Bundesgesundheitsamt (Germany, Ministry of Health), Machine Design, p. 274, August 25, 1988.

14. KEMI (Sweden, Chemical Inspection Agency), Amalgam will be banned. Dagens Nyheter, October 6, 1989.

15. Bundesgesundheitsamt (Germany, Ministry of Health), Letter to pharmacetical companies, January 29; Artezeitung (Physician's Daily), March 3, 1992

16. Bundesgesundheitsamt (Germany, Ministry of Health), Amalgame - nevbenwirkungen und bewertung der toxizitat, Zahnartzt Woche (DZW), 1992, 8, 1.

17. Socialstyrelsen (Sweden, Social Welfare and Health Administration), Press Release. August 28, 1992.

18. Swedish Dental Association, Swedish News Bureau, TT, January 17, 1994.

19. Austrian Minister of Health, Austria to be amalgam free by year 2000. FDI Dental World, March/April, 1993, p. 6.

20. Lorscheider, F.L., Vimy, M.J., Summers, A.O., Mercury exposure from "silver" tooth fillings: emerging evidence questions a traditional dental paradigm. FASEB J. 9:504-508, 1995.

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Bibliography

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