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Mercury usage in Canadian Dentistry:

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Part 1:    Critical Questions about the Politics and the Propaganda.

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

Contributions By:

Dr. Walter Pressey
Dr. Richard Riley

Position paper for submission to Health Canada

 "The significant problems we face cannot be solved at the same level of thinking we were at when we created them." [Albert Einstein]

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

A. Academic Research Productivity of Canadian Dental Schools.
   1. General Academic Research Data.
   2. Canadian Academic Research Contributions on the Dental Amalgam Issue.
   3. Conclusions from Section A

B. The Canadian Dental Association (C.D.A.)
    1. What is The C.D.A.?
    2. Who are the members of the C.D.A.?
    3.
The Role of the C.D.A. in the Dental Amalgam Issue.
        a. The C.D.A. Journal - Academic Journal or Trade Magazine?
b. The C.D.A.'s Council of Dental Materials and Devices
           Micrograms and Nanograms

C. Giving Science a Bad Name.

D. Giving Science a Bad Name - continued.

E. Conclusions.    

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Introduction:

The problem of the safety of mercury/silver dental fillings and the recent emotional debate regarding mercury exposure from such fillings is not new. Within the dental profession, the issue has cyclically recurred for almost two centuries.

The introduction of the modern dental amalgam occurred in 1812. A British chemist developed the "silver paste", which was a combination of silver filings from coins mixed with mercury, and it became fashionable for tooth restoration. Since the metal content in the coins was not pure, physical expansion of the material often resulted in tooth fracture and/or a "high bite". In America during the mid-19th century, concern regarding the possibility of mercury toxicity from this material induced the American Society of Dental Surgeons to make mercury usage an issue of malpractice. Members signed an oath refraining from using mercury-containing materials. However, mercury-filling usage increased because it afforded an economic advantage to those dentists employing it; it was user friendly, and because of its durability in the mouth. Dentists began to ignore the oath and by 1856, the American Society of Dental Surgeons was forced to disband due to dwindling membership over the mercury filling issue. In its place arose the American Dental Association, founded by those who advocated silver amalgam - mercury use in dentistry (1, 2, 3). Again in the 1920's, a controversy erupted after the publication of articles and letters by a German chemistry professor, who attacked mercury filling usage for the possible toxic effects (4, 5, 6, 7, 8, 9). That debate abated. And the dental profession's opinion still remained unchanged. Of all the materials and devices important to dentists, it has been dental amalgam, mercury/silver fillings, which transformed dentistry from a cottage industry into a multi-billion dollar enterprise world-wide.

Ironically today, 183 years later and without scientific justification, many national dental associations have amended their Codes of Ethics making the removal of serviceable mercury fillings an issue of unethical conduct when the reason for removal is to eliminate a toxic material from the human body; and if this recommendation is made solely by the dentist. In their view, a dentist is "ethical" if he places the mercury material and recommends its safety. But, if the dentist suggests that the mercury fillings are potentially harmful or that exposure to unnecessary mercury can result, then the dentist is acting "unethically". Dentists can remove mercury fillings upon a patient's request or under the prescription of a physician. This relegates the dentist into the role of a mere technician - a tooth carpenter.

The amalgam debates, amalgam wars as they are referred to in dental historical writings, had little to do with science and everything to do with politics. As the reader will see, dental amalgam safety is not a dental issue. It is a medical issue.

This document's primary purpose is to examine the role played by Canadian Dental Schools, dental professors and the Canadian Dental Association (C.D.A.) in the ongoing amalgam controversy in Canada. A second purpose is to disclose the limitation of expertise of these entities, as indicated by their experimental research publication productivity. Finally, this document will review specific examples of whether they have disseminated scientifically accurate information to the media and the Canadian people.

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A. Academic Research Productivity of Canadian Dental Schools.

1. General Academic Research Data

Jones has lectured to us that:

"Faculties of Dentistry, as part of the university system, are the repositories of the knowledge base upon which the dental profession is built. As applied scientists, we have the responsibility to undertake research in order to enlarge the knowledge base and to provide an increased understanding of the subject in our chosen field." (1)

This statement is admirable. But, the critical question is "Does the Canadian dental academic community live up to this ideal?".

Others have reported that:

"A commonly used measure of research productivity relies on individual or institutional publications (Harrington, 1987; McGuire et al., 1988). The rational is that the number of scientific publications and the type of these publication are useful indicators of 'an institution's contribution to knowledge' (Lipton, 1990)." (2) "Indeed, Harrington, 1987 concluded that the best predictor of institutional academic reputation was research productivity (measured by number of publications)." (3)

Such analyses are common place and are also very useful to substantiate whether or not a particular "expert" or organization is properly qualified to make public pronouncements and to give recommendations and advice. The purpose of subsection A-1 is to examine the overall experimental research productivity data of Canadian dental academics and to compare their performance to their Swedish peers.

Table 1 represents an analysis of the published dental literature as found in the Medline® database from 1991 to the present. All data was collected from the database in December 1995. Using the subject search field "dentistry" and accepting all publications in all subcategories, the database had 24,065 published dental articles from world-wide sources.

Table 1: Analysis of dental articles published from Canadian (10) and Swedish (4) Dental Schools: Medline® database search 1991-1995.

SEARCH TOPIC Total No. per YEAR per School
WORLD DENTAL REFERENCES 24,065    
CANADIAN DENTAL REFERENCES (10 Dental Schools) 596 119.2 11.9
SWEDISH DENTAL REFERENCES (4 Dental Schools) 734 146.8 36.7

Analysis of the total number of dental articles published between 1991-1995 (24,065) showed that 596 articles were published from Canada. Most of these publications came from Canada's 10 Dental Schools, and a few were from other institutions such as Medical Faculties. A similar search for Sweden indicates that its 4 Dental Schools published 734 academic papers during the same 5 year time period. Further analysis, shown in Table 1, indicates that Canadian Dental Schools collectively published an average of 119.2 articles/year, whereas their Swedish counterparts publish 146 articles/year. In other words, Sweden, with a population of only 8.7 million (Swedish Embassy, Ottawa) and only 4 Dental Schools, publishes approximately 20% more dental scientific research information on a yearly gross count basis than Canada, with a population of 27.3 million people (Statistics Canada, Ottawa) and 10 Dental Schools.

In fact, the research productivity discrepancy between the two countries is much more pronounced when calculations are made on a per Dental School basis. Canadian Dental Schools publish only 11.9 articles/year/school, while their Swedish counterparts publish 36.7 articles/year/school. This represents a 300% productivity advantage for Swedish dental academics, suggesting that Canadian Dental Schools are far less productive on a research basis when compared to similar institutions internationally.

Table 2 lists the 10 Dental Schools in Canada and indicates the number of full-time dental academic staff currently employed by each institution (Association of Canadian Faculties of Dentistry 1994-1995 Calendar). The largest number are in the province of Quebec, where 2 are French language and 1 is English language. In these 10 institutions, there are 443 full-time dental academic personnel registered in Canada. The two largest staffed Dental Schools are Toronto and Western Ontario. But, the University of Toronto has far and away the largest staffed dental school with 93 full-time dental academics, almost double the second largest school. At the other extreme, the University of Saskatchewan has the smallest dental faculty staff with only 22 full-time academics employed.

Table 2 also reports an analysis of the number of dental research articles published from each Canadian Dental School, as found in the Medline® database from 1991 to the present. All data was collected from the data base in December 1995, using the subject search field "dentistry" and accepting all publications in all subcategories. This was then sorted against a selected field search employing each "university name" against the dental database.

On a gross count basis, the University of Toronto Dental School published the largest number of papers (154 articles) for the 5-year period; while, the Universite de Montreal published the least (18 articles). Interestingly, on an articles/staff/year basis, the University of Saskatchewan was ranked first publishing only 0.35 articles/staff/year, while the Universite de Montreal is last with an incredibly low 0.07 articles/staff/year. As a group, all of the 443 Canadian dental academics published on average only 0.22 articles/staff/year.

Of particular interest was the finding that at each institution, the greater proportion of articles came from a few highly productive individuals, while the vast majority of the professors had extremely poor on non-existent research publication records.

Table 2: Analysis of dental articles published per dental academic staff member from all Canadian Dental Schools: Medline® database search 1991-1995.

Institution # Full-time academic staff Total Published articles 1991-95 Articles/staff/year
Alberta 38 37 0.19
British Columbia 34 56 0.33
Dalhousie 37 36 0.20
Laval 36 31 0.17
Manitoba 51 60 0.23
McGill 28 25 0.18
Montreal 52 18 0.07
Saskatchewan 22 39 0.35
Toronto 93 154 0.33
West. Ontario 52 49 0.19
TOTAL Canada 443 505 0.19

* Association of Canadian Faculties of Dentistry 1994-95 Calendar.

Indeed, the lack of research productivity in Canadian Schools of Dentistry is more problematic than even these statistics suggest. One analysis found that 50 dental institutions world-wide (including advanced education institutions) had 50 or more articles published in 1987 and 1988 in journals included in the Science Citation Index. Thirteen of these 50 institutions had 90 or more articles." (2) Not a single Canadian Dental School would be represented in this analysis since, even in the 5 year time period from 1991-1995, these institutions only averaged 11.9 articles/year.

Meagre Dental School research productivity, as demonstrated by the poor publication profile of Canadian Dental Schools, appears to due to be the lack of research motivated instructors within the dental educational system. In 1992-1993, the American Association of Dental Schools identified only 910 oral health research workers in the then 54 U.S. dental schools. That is only 17 research staff/dental school.(4) Since Canadian Dental Schools of Dentistry, are, in general, smaller and often more poorly funded than their American counterparts, they are less attractive as employment options to qualified research oriented individuals.

In comparison, the Faculty of Medicine at the University of Calgary (a typical medical institution with 273 full time academic staff), averages 2.35 articles/staff/year (Fact Book, Office of Institutional Analysis, 1991). This comparison is valid because both dental and medical faculties share some similarities. There are research professors, clinical professors and administrators. Both faculty types are in the business of research and education in the health sector. Thus, it appears that the typical medical professor is 10.7 fold more productive than his/her dental counterpart in Canada.

This raises a critical question, "With such poor research publication records, what specific expertise do Canadian Dental Schools have?".

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2. Canadian Academic Research Contributions on the Dental Amalgam Issue.

The modern silver amalgam (amalgam meaning mixed with mercury), traditionally known as a "silver" filling, has been employed as the principal tooth restorative material for over 180 years and presently accounts for 75-80% of all tooth restorations. These "silver" fillings contain approximately 50% mercury by weight, 35% silver, 13% tin, 2% copper and a trace of zinc.(5) Each tooth restoration has a mercury mass of about 750-1000 mg and should more properly be called a mercury filling.

Medicine takes the dental mercury issue very seriously and only during the past 5-6 years has become aware that dental fillings contain 50% mercury. On the other hand, the dental profession world-wide continually portrays the "amalgam issue" as a non-issue, usually denigrating the research and the researchers. But, the symptoms and effects of mercury exposure from amalgam are medical, outside the diagnostic scope of the average dentist. Certainly, Dental Schools do not have academic departments of Neurology, Nephrology, Cardiology, Haematology, Immunology, etc.. departments with the intellectual expertise and physical infrastructure needed to properly address the complex medical toxicology aspects of mercury exposure from fillings. Dental Schools have departments of Endodontics (root canals), Prosthodontics (false teeth), Periodontics (gum diseases), Dental Materials (physical and chemical properties), Oral Surgery etc., departments totally inappropriate to address medical life science issues. In the final analysis, the scientific "debate" regarding the medical effects of mercury fillings is totally outside the scope of the present day Canadian academic dental institution.

Review of published dental articles indicates that most dental material research is not biological in focus. Rather, dental material science centres, almost exclusively, on engineering properties of materials; such as, compressive and tensile strength, corrosiveness, elasticity, wear resistance and solubility in oral fluids. The purpose of subsection A-2 is to examine the experimental research contribution of Canadian dental academics concerning mercury fillings to disclose whether they have the expertise to render advice on the medical safety of dental mercury fillings. Again, comparisons will be made between Canadian and Swedish dental academic research productivity.

Table 3 is an analysis of the published literature concerning dental amalgam as found in the Medline® database between 1991-1995. The data was collected in December of 1995 and was searched using the subject category "amalgam", retaining all documents and subcategories. This data was further sorted using "Canada", "Sweden", and "University of Calgary" in the institutional field. The data was arranged into dental and medical sources directly from the hard copy material, using the institution as the defining criteria. Articles were not sorted into experimental and review categories, but were sorted for biological focus category.

Table 3: Analysis of Canadian and Swedish dental amalgam related publications: Medline® search 1991-95.

 

SEARCH TOPIC

TOTAL # per YEAR per School BIOLOGICAL EFFECTS
WORLDWIDE AMALGAM 869 173.8    
CANADIAN AMALGAM (DENTAL) 8 1.6 0.8 0
U of CALGARY (MEDICAL) 9 1.8   5
TOTAL CANADA 17 3.4   5
SWEDISH AMALGAM (DENTAL) 32 6.4 8 9*
(MEDICAL) 27 5.4   18
TOTAL SWEDEN 59 11.8   27

* 4 References lichen planus

As can be seen from Table 3, of the total 24,065 dental articles published between 1991-1995, (Table 1), there were 869 papers published world-wide on dental amalgam . This includes any article involving amalgam. Of these 869 references, 17 (1.9%) came from Canadian institutions, 8 from Dental Schools and 9 (more than half) from the University of Calgary Faculty of Medicine. This means that each Dental School in Canada contributed 0.8 articles/year; whereas, the University of Calgary Faculty of Medicine, alone, contributed 1.8 articles/year on the amalgam topic, a 200% difference. Of the articles published from any Canadian institutions, 5 articles investigated the biological effects of amalgam, and all of these research papers originated solely from the University of Calgary Medical Faculty. The total output of biological research studies on dental amalgam from Canadian Dental Schools between 1991-1995 was nil!

Table 3 also reports on the output of Swedish amalgam related publications. The total Swedish count for the period 1991-1995 is 59 articles, 32 from dental institutions and 27 from medical institutions. This amounts to an average of 8 amalgam-related articles/Swedish Dental School/year; as compared to the 0.8 articles/Canadian Dental School/year. This constitutes a 10-fold (1000%) research productivity advantage to the Swedish dental academics in this particular investigative area. Moreover, of the 32 Swedish dental references, 9 involved biological research as compared to none produced by Canadian Dental Schools in the same 5-year period. Of these 9 Swedish dental references, 4 identified oral complications from the presence of amalgam. The pathology identified in the mouths of humans and which reversed when amalgams were removed was oral lichen planus, an autoimmune condition. Of the 27 amalgam articles from Swedish Medical Faculties, 18 were biological investigations, most of which recommended caution about using amalgam.

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3. Conclusions from Section A:

In general, the data confirms that Canadian Dental Schools exhibit very poor academic research productivity, contributing little of significance to the world dental knowledge base. In particular, the present analysis of the published research literature clearly indicates that Canadian dental academics contribute nothing of significance to the study of the oral and systemic biological effects of mercury exposure from dental fillings.

A recent report from the U.S. Institute of Medicine has concluded that:

"Too many dental schools and dental faculty are minimally involved in research and scholarship. The low priority placed on research has important negative consequences. First, academic staff in such schools contributes little to the knowledge base for improving oral health or increasing the effectiveness and efficiency of oral health services. Second, students in these schools miss the stimulation and critical edge provided by a research-engaged faculty. Third, schools with low research productivity put themselves in jeopardy in most universities and academic health centers, and they may detract from the reputation of and dental research and education more generally. Fourth, lack of research and scholarship within a dental school tends to diminish the school's role as a disseminator of critically evaluated practice advice to dental practitioners."  (6)

This partly explains why the University of Alberta closed its Dental School and made it a part of the Faculty of Medicine. This analysis raises some critical questions. Should Canadians rely on the advise and recommendations coming from Canadian dental academics regarding the medical safety of mercury-containing tooth fillings? More importantly given their documented lack of research expertise, is Canadian dental academia acting responsibly by giving medical advice on amalgam safety?

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B. The Canadian Dental Association (C.D.A.)

1. What is The C.D.A.?

The C.D.A., like other national professional associations, is primarily a trade organization - a union, dedicated to promotion of its members needs. The C.D.A. is not a scientific body and has no standing in the international scientific community. Nor is it a regulatory body. That function is reserved for governmental organizations. According to C.D.A. information, it is a "national non-profit health association, incorporated under Part 2 of the Canadian Corporation's Act". (1) "Through its mission statement, the association is dedicated to meeting member's needs and the promotion of the provision of optimal oral health for Canadians".(1) This fascinating mission statement is to be found in the opening pages of every issue of the C.D.A. Journal. It is interesting that both the public and the C.D.A. members fall within the purview of this mission. It raises the critical question,

"Which group takes precedence should a conflict arise between what is good for the member dentists and what is in the public interest?".

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2. Who are the members of the C.D.A.?

The C.D.A. mission statement also claims that "the Canadian Dental Association is the authoritative national voice, resource, and focus of unity for the profession of dentistry in Canada...".(2) But, statistics furnished by the C.D.A. indicate this claim is, in many ways, tenuous.

Table 4 represents data supplied by the C.D.A. regarding its membership. According to their data, 15,580 dentists practise in Canada. Of this number, 9,562, or only 61.4%, are members of the C.D.A. Thus, 6,018, or 36.6% (almost 2 in 5) of all the dentists in Canada are non-C.D.A. members. It is true that the C.D.A. is a national voice for dentists in Canada, but this claim does not represent an overwhelming endorsement of the C.D.A. or its policies by Canada's dental practitioners.

Table 4: C.D.A. Membership Totals as of October 31, 1995.3

  NF PEI NS NB PQ ON MB SK AB BC YT NT Total
Members 140 48 422 251 1,133 2,979 533 343 1,418 2,266 25 4 9,562 61.4%
Non-members 4 0 4 0 2,578 3,302 11 4 74 9 27 5 6,018 36.6%
TOTAL 144 48 428 251 3,711 6,281 544 347 1,492 2,275 52 9 15,580 100%

Moreover, there are several glaring deficiencies in the regional representation within the C.D.A.. The two largest provinces in terms of total dentists are Ontario and Quebec, with 6,281 and 3,711 dentists, respectively. In other words, 64.1% of all Canadian dentists reside in central Canada (40.3% in Ontario and 23.8 % in Quebec). Yet, 47.4% of Ontario dentists (less than 1 in 2) and only 30.5 % of Quebec dentists (1 in 3), belong to the C.D.A.. Thus, it is fair to conclude that regionally, the C.D.A. poorly represents dentists from central Canada. Several other jurisdictions also demonstrate similar representations. Although sparsely populated, the Yukon and the Northwest Territories both have more non-C.D.A. members in the C.D.A. than members.

Most jurisdictions have some non-C.D.A. members. The high C.D.A. membership in provinces outside central Canada may be due to mandatory C.D.A. registration, when obtaining provincial dental licensure or the lack of information that a dentist has the option not to belong to the C.D.A. Provincial regulations in this regard were not polled for this review. Perhaps, if dentist were more aware that they have the option to resign from the C.D.A., the C.D.A. enrolment might be even less than its current 61.4% of all dentists, especially in light of registration patterns in Ontario, Quebec and the territories. This raises the critical question "Does the C.D.A. even have the political authority to claim that it is the official voice of Canadian dentistry on issues such the mercury fillings safety?

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3. The Role of the C.D.A. in the Dental Amalgam Issue.

On one hand, the C.D.A. claims that it -

"plays an advisory and consultative role in evaluating the non-pharmacological aspects of dental materials and devices used in dentistry, but it does not make unilateral judgements about product safety." (4)

Yet as the reader will see, the C.D.A. does indeed make unilateral judgements about the pharmacological safety of dental products and uses its own media - the C.D.A. Journal, its standing committees, and its regular newsletters to promote its view that mercury fillings are medically safe, despite overwhelming medical research evidence to the contrary. The purpose of section B-3 is to examine the competency of the C.D.A and its advisors?

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a. The C.D.A. Journal - Academic Journal or Trade Magazine?

Table 5 represents data obtained from the 1993 Science Citation Index as developed by the Institute for Scientific Information (ISI). This index, produced on a bi-annual basis, assesses the credibility and impact of 4,541 academic journals from a broad range of scientific and engineering disciplines and ranks them according to "impact factor". Table 5 gives examples for a number of biological and medical journals, including several representing dentistry. Medically oriented journals, such as Cell, Nature, Science and FASEB J. rank in the top 15 of all the 4541 journals, having high impact factors. Cell, the highest rated biomedical journal, has an impact factor of 37.192; whereas, the highest rated dental journal, the Journal of Dental research (ranked 350) has an impact factor of just 2.80. The Journal of the American Dental Association ranks 2,176 overall with an impact factor of only 0.61.

Table 5: 1993 Science Citation Index Overall Rank BY IMPACT FACTOR. 4541 journals ranked.

 

Journal Rank Title Impact Factor
4 Cell 37.192
9 Nature 22.326
10 Science 21.074
15 FASEB J. 16.634
41 PNAS 10.325
77 J. Biol. Chem. 6.793
350 J. Dent. Res. 2.802
2176 J. Am. Dent. Assn. 0.612

Appendix 1 shows the rank of the 33 dental journals rated by ISI. Within the Dentistry and Odontology category, the Journal of Dental Research ranks 1, with an impact factor of 2.802 and Cranio ranks 33, with an impact factor of 0.133. The Journal of the Canadian Dental Association is not ranked and has no impact factor in science according to the ISI. This raises another critical question "Exactly how much credibility should one place on material published in this `scientifically' not rated Canadian dental trade magazine?".

The Editorial Board of the C.D.A. Journal.

The credibility and stature of any academic research publication is based, in large part, on the international renown of its editorial board. Quality academics want their research investigations published in journals with rigorous review, performed by highly qualified and academically renowned peers. Such peer review adds credibility to the research findings. With this in mind let's examine the stature of the C.D.A. Journal's Editorial Staff. Such an evaluation may shed light on an important reason for the low international scientific reputation of the C.D.A. Journal in the international scientific community.

Table 6 shows data for the 30-year academic publication record of the Senior Editors and the Editorial Board members of the C.D.A. Journal. Information for this table was obtained from a standard Medline® search using the last name and initials of the individuals. The dates of first and last academic publication are shown and the total number of articles published to the present is also listed. Publication activity in years was calculated from the date of first publication to present (December 1995). Assessment of the number of articles published by each individual, which were ISI rated, was determined by assessment of the publication record from the Medline® source.

Table 6: Academic publication record for C.D.A. Journal 1995 Editorial Board Members from Medline® DATA BASE search, 1966 - present, indicating the numbers published in Institute for Scientific Information rated journals (Science Citation Index).

Name

1st Publ.

Last Pub.

No. Pub.

Activity

years

Pub/yr.

ISI rated

ISI Pub./ yr.

Crawford, Chief ed.

-

-

0

-

-

0

0

Trundle, Science ed. English

1974

1995

15

21

0.7

8

0.4

Diastoles, Science ed. French

1971

1992

14

24

0.6

0

0

Christie, Endodontic

1975

1994

9

20

0.5

3

0.2

Precious, Oral Surge.

1976

1995

37

19

1.9

14

0.7

Main, Oral Path.

1970

1994

52

25

2.0

25

1.0

Glover, Oath

1977

1994

2

18

0.1

1

0.05

Legally, Paediatric

1971

1990

3

24

0.1

0

0

Stake, Perry

1976

1994

6

19

0.3

1

0.05

machinate Prostho

1974

1994

55

21

2.6

34

1.6

Williams, Dent Mat

1978

1994

10

17

0.6

4

0.2

Dorion, Forensic

1970

1990

19

25

0.8

2

0.08

Sandor, Medicine

1982

1991

12

13

0.9

6

0.4

Neuman, Cosmetic

1988

1991

3

7

0.4

0

0

TOTALS    

237

253

0.88

98

 

The table indicates that the 14 Senior Editors and editorial staff of the C.D.A. Journal collectively published a total of only 237 articles over a cumulative 253 man-years. This represents an average publication profile of 0.82 articles/year/editorial staff person. But, a closer analysis indicates that 60.7% of the total research productivity comes from only three Editorial Board members, Drs. Precious, and Main. Research productivity of the remainder of the Editorial Board, without these three, was only 0.5 articles/year/editorial staff.

More importantly, of the 237 articles collectively published by this Editorial Board, only 98, or 41.3%, of the articles were in ISI rated journals. Not surprisingly, three individuals (Precious, Main and machinate) account for 74.5% (73 of the 98) of these ISI rated articles. With the exception of these three individuals, the Editorial Board of the C.D.A. Journal demonstrates a mediocre academic publication record. Collectively, the Senior Editors of the C.D.A. Journal have published less than 0.05 ISI rated articles/year/Editor!

In fact, much of the material published in the C.D.A. Journal is written by Canadian dental professors (including C.D.A. Journal Editors), who seek a quick publication to bolster their academic performance. Given the poor research productivity performance of the C.D.A. Journal's Editorial Staff raises the obvious question - "Is it any wonder that the C.D.A. Journal is not rated by the ISI and that it has no impact factor in the scientific community at large?"; and also the critical question -"Can we place any confidence in the scientific information and views espoused in this dental trade magazine?".

Finally, the role of an academic journal is, in part, to invite debate on issues on controversy and to foster the intellectual airing of ideas in a manner which allows the intelligent readership to assess the merits of the debate. The following sections of this report will demonstrate that the C.D.A. Journal has done just the opposite, stifling the free flow of information and propagandising the dental amalgam mercury issue. This is particularly alarming given the fact that the C.D.A. Journal is ranked as "the most read dental publication by a wide margin" by Canadian dentists!5

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b. The C.D.A.'s Council of Dental Materials and Devices

"Part of the problem in dentistry... is the strong tendency to have empiricists among those giving lectures in continuing education courses and in philosophical authority of the clinical faculty of some dental schools...To help segregate opinion from conclusions, please question such "experts" about the data upon which their beliefs are based."

[Shields, E.D., Letter: Unscientific Bias, J Can Dent Assn, 57:259, 1991.]

With regard to the amalgam mercury issue, the C.D.A.'s Committee on Dental Materials and Devices has played a significant role in disseminating information to the larger Canadian dental community. According to the C.D.A., "the C.D.A. Committee on Dental Materials and Devices has continued to monitor the literature, and the Committee's advice has been the backbone of C.D.A.'s position on the utilization of dental amalgam" (Letter from the President, Bryun Sigfstead, June 21, 1995). This standing C.D.A. committee is composed of a number of dental academics primarily from the dental materials research area. The purpose of the following analysis is to examine the academic research productivity of this group to determine whether they have the expertise to advise Canadians on the issue of the biological effects of mercury exposure from dental fillings.

Table 7 represents the publication productivity of some current and past members of the C.D.A.'s Committee on Dental Materials and Devices and selected others. Data base information retrieval was performed as described for Table 6 above. More than any other Committee of C.D.A. advisors, this group is directly responsible for the current C.D.A. advocacy of dental amalgam. Underneath each Committee member's name is the date of their first and last publication. Institutional affiliation and primary interest area are also reported. The total number of articles publish is then broken down into review and experimental papers. From the total articles, the amalgam related articles are analysed in terms of total number, then divided into review and experimental. Finally, Table 7 reports the number of ISI rated articles published by each Committee member and the number of studies each individual published which investigated the systemic biological effects of mercury exposure from amalgam tooth fillings.

Table 7 demonstrates that this group of 10 dental material specialists has collectively published 248 articles. However, of that total, 171, or 69%, came from only 3 Committee members (Jones, Roydhouse and Smith). Of the 248 studies produced, only 172 were experimental and Jones, Roydhouse and Smith were again responsible for 119, or 69% of the total experimental papers. With regard to studies involving dental amalgam, these 10 individual published only 25 articles, 11 of which were "reviews" and only 14 experimental. Examination of the database indicates that all the amalgam experimental papers focused on the engineering or physical properties of the mercury-containing fillings.(11) No articles investigated the systemic biological effects of mercury. Of the 248 articles published by these 10 dental academics, only 48 (19.3%) were ISI ranked. Again, two of these individuals (Smith and Jones) published a total of 38 (78%) of the 48 ISI ranked articles.

In general, the experimental research expertise of most members of this Committee, as exemplified by their publication records, is seriously wanting. Yet, this Committee, under the leadership of Derek W. Jones, has been instrumental in formulating the C.D.A.'s policy regarding dental amalgam. This influence persists in spite of the fact that collectively and individually their research profiles indicate that they have no expertise in biology, toxicology, physiology, or medicine. Nor are they proficient in animal model research, a critical tool in biomedical discovery. Indeed, the members of the Committee have not published any significant body of research on the biological effects of any dental material or device, including dental amalgam.

This raises another critical question, "Should C.D.A. members, the Government of Canada and the Canadian public place any confidence in recommendations put forth by this Committee, concerning the medical safety of mercury-containing dental fillings?

Table 7: Academic publication productivity of some current and past members of the C.D.A.'s Committee on Dental Materials and Devices and selected others from Medline® DATA BASE search, 1966 - present.

Name (duration of publ. act.) Institute Primary Interest Area

No. of Pub.
T - Total
R - Review
E -Experiment

No. of Amalgam Studies

# from ISI RankedJournals

Biological Effects of Amalgam

     

T

R

E

T

R

E

   
Barolet, R.Y.
(1974-95, 23 yrs)
McGill None

10

7

3

1

1

0

1

0

Diastoles, P.C.
(1971-95, 24 yrs)
Montreal Toothpaste abrasion

14

5

9

1

1

0

0

0

Johnson, L.N.
(1971-95, 24 yrs)
U.W.O. Composite

8

3

5

0

0

0

1

0

Jones, D.W.
(1969-95, 26 yrs)
Dalhousie Plaster Ceramics Reviews

53

18

35

9

3

6

18

0

Ruse, D.
(1988-95, 8 yrs)
U.B.C. None

2

0

2

0

0

0

1

0

Roydhouse R.H.
(1966-89, 23 yrs)
U.B.C. Bonding Occ. Haz. TMJ

31

8

23

1

 

0

1

2

0

Smith, D.C.
(1966-94, 28 yrs)
Toronto Cements Reviews

87

26

61

2

1

1

20

0

Williams, P.T.
(1978-94, 16 yrs)
Manitoba Bonding

10

1

9

2

1

1

4

0

others:                
Kasloff, Z.
(1971-91, 20 yrs)
Manitoba Pins

16

4

12

6

1

5

1

0
Newman, SM
(1980-95, 15 yrs)
Alberta Colorado None

17

4

13

3

3

0

3

0

TOTAL    

248

76

172

25

11

14

48

0

Micrograms and Nanograms: An Example of Collective Incompetence.

The C.D.A. Dental Materials and Devices Committee, led by Dr. D.W. Jones, advised the C.D.A. membership of the following in an information circular from Gilles Dubé (November 20, 1990). It clearly stated:

"Based on evidence from an FDA document on mercury in seafood, an intake of 40 mg/kg body weight per day is considered safe. This equals 2.44 mg per day for a 61 kg person. Clarkson (1988) estimates the daily dietary mercury intake for humans to be 600 mg, of which 60 mg is retained." (9)

This statement is factually incorrect and clearly misleading because the units in the documents they cite from were not micrograms (mg) as the Committee reported, but rather were nanograms (ng). This means that the C.D.A."Expert" Dental Materials Committee erred by a factor of 1000; not a small mistake. Not only did they report these wrong findings to the Canadian dental profession, but Jones also went on national media espousing the same false information. This misinformation was also included in his opinion article Giving Science a Bad Name (6)

Ironically in the same paragraph while attacking legitimate medical researchers, Jones cites Charles Darwin who wrote:

" False facts are highly injurious to the progress of science, for they often endure long; but false views, if supported by some evidence, do little harm, for everyone takes a salutary pleasure in proving their falseness; and when this is done, one path toward error is closed and the road to truth is often at the same time opened." (6)

Given the present discussion, this quotation has more relevance to Jones et al. than to those he attempts to disparage. This entire faux pas was exposed in a letter to the Editor of the British medical journal - Lancet (see Appendix 2). According to the Lancet Editor, the C.D.A. "experts" refused to respond! Nor has the C.D.A. ever come clean with its membership regarding this infamous episode.

This raises a critical question, "Should one place trust in a group of Canadian dental scientific "experts", who don't know the difference between a microgram and a nanogram?

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C. Giving Science a Bad Name

"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 C., from Broca's Brain]

Every time new research data unfavourable to amalgam is published or the general media gives the issue attention, the C.D.A. trots out its "experts" to shore up the rank and file. Their preferred "expert" in these matters is usually the dental materials engineer, Derek W. Jones from Dalhousie University. Jones has published a number of opinion articles on amalgam in the C.D.A. Journal. These articles have little to say about real science, but volumes about his personal prejudices. Jones lectures us that:

"as dental scientists, we have a responsibility to understand and interpret the cutting edge of the various aspects of science for the general dental profession as well as for the general public... We live in an era in which it is becoming much more difficult to keep up with the developments in one's own chosen field; we find it almost impossible to understand the complexities of the subjects being studied by our colleagues in other fields". (1)

An important insight, indeed. Too bad Jones has not restricted his public comments to information based upon his actual field of experimental research expertise, namely materials engineering.

Several general themes occur throughout Jones' opinion papers, including incorrect scientific facts, inappropriate recitation of philosophical quotations about science, and arguments ad absurdum. An example of the latter is found in Giving Science a Bad Name (1),

Here, Jones suggests that:

"the public would clearly be very alarmed and surprised to learn that out of the 65,725 chemical which they may come into contact with on a daily basis, we only have complete health hazard assessments on about 1.65%...". (1)

He then implies that one would be remiss to alarm the public about the toxic constituents of mercury filling. This reasoning, of course, is utterly absurd, since mercury is one of the 1.65% where the health hazards are very well known. Mercury is poisonous even in small doses. In The Whole Truth or Nothing? A Tale of Misinformed Consent (2), Jones, again uses this argument to suggest that dentists not give their patients proper full informed consent, since information regarding the safety of alternative dental materials is also unknown. Incredibly, dental materials engineers, who design and recommend dental materials for human use, apparently do so with little regard to experimental investigation into product biocompatibility.

Another example of a pointless argument employing false facts is Jones' proclamation that:

"when we purchase a packet of table salt with our groceries, it does not carry a label stating that this compound contains two poisonous elements, sodium and chlorine".(2)

Where Jones' argument fails is in the facts, which any high school biology student knows. There is no chlorine (Cl2) in salt. There is a chloride ion covalently bound to a sodium ion. Chlorine (Cl2) is a toxic gas. But, both the sodium ion (Na+) and the chloride ion (Cl-) are essential to life. Nor is table salt produced directly from chlorine gas!

Jones concludes this outrageous argument by asking:

"Does retail business need to inform the public that the sodium and chlorine contained in common salt are poisonous? Should dentists as responsible professionals be informing the public about the fact that a large number of elements and compounds used as constituents of dental materials are known to be toxic?" (2)

Jones suggests that the correct answer is "No". But, morally, ethically, and especially legally, the correct answer is a resounding "Yes". This suggests another critical question, "How can the C.D.A. Journal publish articles by a non-clinician which implies that it is unnecessary to give full informed consent to patients regarding the composition of materials being permanently implanted into their bodies?".

Jones also advises that "when the elements combine to for a compound they no longer possess the same properties that they had prior to the chemical reaction".(2) This is true in some circumstances. But, he insinuates that this is also factual for the constituents of amalgam. Jones fails to inform the reader that amalgam is a phased material - a solid emulsion. This is a well known materials fact.

"It is a fallacy that mercury is neutralized when it is combined with the other components of silver dental amalgam. The laws of physical chemistry are followed. Mercury is diluted by the other components of amalgam in what may be considered a solid solution. Although the vapour pressure of mercury is reduced, mercury vapour is still released. An identical situation arises when alcohol is diluted by water."

[Dun, A. (1988) Ont. Dent. 65: 37-39]

Amalgam has a phase of free mercury - the delta phase (3) - and amalgam corrodes (oxidises) releasing all the constituents. Jones informs us that "elemental mercury is excreted very rapidly and is also deposited into non-vital tissues such as hair and nails". (2) He supports this with the fact that "the half time for mercury elimination (50 per cent) from the lungs is two days and from the blood between 15-30 days". What he fails to tell the reader is that mercury collects in all vital organs and tissues; such as, the brain, the kidneys, the liver and the heart; and the half life of mercury in the kidney is 70 days and for some brain compartments it is 27 years. Additionally, Jones counsels that "the body burden of mercury from amalgam fillings is relatively small in comparison with that obtained from regular food sources". FALSE! See Appendix 2 for a proper scientific analysis. He also asserts that "organic forms of mercury, such as found in the food chain, are known to be up to 100 times more hazardous than elemental mercury". Again, FALSE! The WHO Expert Committee (1980) (4) clearly stated that "the most hazardous forms of mercury to human health are elemental mercury vapour and short chain alkyl mercurials". Finally , Jones tells us that:

"the fact that in spite of being exposed to higher levels of mercury, the dental profession as a group have a health status that is not significantly different than the rest of the population....supports the scientific consensus that mercury released from dental amalgam restorations does not present a health hazard to the patient". (2)

This fact is patently false! A large number of experimental research papers confirm exactly the opposite; dentists are apparently not as healthy as the general public. The evidence is as follows:

1. The established normal level of urinary mercury is 0-5 mg Hg/L in the general population. The Centers for Disease Control (CDC) consider the maximum acceptable level to be 30 mg Hg/L5. In a study done by the ADA on 4272 dentists (6), 10.9% had urinary mercury levels above the CDC maximum acceptable level. Based upon 150,000 American dentists, 16,350 practitioners have mercury exposures that are excessive. Of the total population of dentists 4.9% (7,350) have urinary mercury levels above 50 mg/L (6), a level that has been found to cause neurological tremors (7). Similarly, 1.3% (approximately 2,000 dentists) have urinary mercury levels in excess of 100 mg/L (6), a level known to cause overt tremors. The ADA data strongly suggests that a significant number of the membership have neurological tremor that is presently undiagnosed.

2. Dentists do demonstrate health problems that are directly attributable to mercury exposure. These complications include a variety of neurological and neuropsychological disorders (8, 9, 10) .

3. Death has also been reported from mercury exposure in the dental office (14).

4. Kidney function has been reported to be altered in subjects occupationally exposed to mercury vapour when their urine mercury concentrations exceeded 35 mg/L (15,16). Since 5-10% of the dentists have urinary mercury levels above this amount (6), it is probable that some of these practitioners have kidney pathophysiological effects that were not detected by the relatively insensitive methods used in the ADA studies.

5. The evidence for increased incidence of reproductive disorders attributed to occupational Hg vapour exposure in dental personnel has been reported (17).

D.W. Jones is neither a dentist, physician or qualified basic medical science researcher. He does hold a PhD in dental materials engineering. Because of this fact, D.W. Jones is not recognized by medicine as an expert in the field of the medical effects of mercury or dental amalgam. Nor has Jones published any relevant experimental research on amalgam safety. In the Enigma of Amalgam in Dentistry (18), he cites only four papers that he co-authored and these are either opinion papers, environmental assessments of mercury levels in the ambient air of dental offices, or corrosion engineering. Some examples of the failings in this article are:

Failure to frame the problem properly. On page 159 of the article, Jones states "this paper is not intended to be a review of the voluminous literature that has already been published on dental amalgam and the health hazards associated with mercury". And his paper lives up to that billing. Then he attempts to justify amalgam usage by reporting that millions of people have amalgams and that the material is durable and inexpensive. Characteristics that have little to do with amalgam biocompatibility and which are based solely on anecdotal evidence.

Failure to tell the entire truth. On page 160, Jones states that "no scientific evidence has been produced to show any valid causal relationship between the use of dental amalgam restorations and ill health". Evidence of the pathophysiological effects of dental amalgam mercury has now begun to be published from medicine over the last several years (19).

Another example of this tactic is Jones' claim on pages 163-166 that "Sweden's motives for examining the possible discontinuation of dental amalgam use are based entirely on environmental concerns, and not on the potential health hazards to patients". This is patently false! The present writer with a group of concerned Swedish citizens and dentists met with the Swedish Minister of the Environment, at her request, to discuss possible ways to eliminate amalgam without placing the dental profession in a bad light. The concern was the health hazards to the patient and the dental personnel (documented in the BBC Panorama film "Poison in the mouth." July 11, 1994), and then the environmental risks.

Nor is Jones shy about distorting simple details. In a recent C.D.A. Communique (1995) newsletter, Jones reported that "the 12th International Neurotoxicology Conference, held in Arkansas.... (October 30 to November 2, 1994), reviewed and discussed scientific data from 80 papers" without reaching the scientific conclusion that there are "ominous links between mercury from tooth fillings and serious illness". What Jones fails to tell the reader is that the conference had nothing particular to due with amalgam. Indeed, only three of the 80 papers were concerned with amalgam research.

Near the end of the article (page 166), Jones alludes to the misuse of the statistical method. Without specifically criticizing a particular research paper, he suggests that all anti-amalgam research must be statistically flawed, while the pro-amalgam opinion is statistically correct. It clearly demonstrates an approach void of scientific objectivity.

Failure to use authoritative sources. In The Enigma of Amalgam in Dentistry, (18) Jones counsels that "research results should be peer reviewed prior to publication, debate should be conducted by scientists and the experiments should be repeated before any data are released to the public". Yet in the same article, he is fully prepared to cite an anecdotal report by Osborne who recounts his recollection of a U.S. Food and Drug Administration meeting, were Malvin (a renal physiologist from the University of Michigan) suggested that Vimy et al starved their sheep! This assertion is made with no evidence of support. Interesting, Jones hypocritically supports using the scientific process, when it suits his purpose; but he is fully prepared to abandon this principle and cite the anecdotal opinion of Malvin (a paid "spin doctor" for the American Dental Association), when that suits his purpose. What Jones does not tell the reader is that at the same meeting, Dr, Lars Friberg, an eminent authority on inorganic mercury poisoning, stated on the record "that from the toxicological point of view, dental amalgam is unsuitable for human use". Apparently, Jones is not aware of the serious approach taken by medical researchers when they undertake their experimental investigations. All research animals are cared for by licensed veterinary staff. Food and water intake is monitored daily in the complex climate controlled vivariums. Such research is very different from dental materials engineering studies. By belittling legitimate medical research in this way, Jones embarrasses the entire dental profession.

After reporting that the Canadian Dental Association and the American Dental Association both recommend allergy patch testing by a board certified medical allergist or dermatologist, Jones goes on to designate dental materials engineers (Mackert, Horsted-Bindslev and Mjor) as his "experts" in immunology! There are many examples throughout the article where Jones erroneously advances dental materials engineers as medical experts. Another example of this failing is found on page 161, where Jones cites Enwonwu (1987). This paper is another example of a review by a researcher not directly involved in either mercury or amalgam research. This 8 year old study purports to claim that "hypersensitivity reactions only affect a small proportion of patients and members of the dental profession", while the published data supports a much higher incidence of allergy to amalgam and mercury.

Failure to address the real issues. Jones focuses a great proportion of his document on the different types of amalgam - a very engineering approach. He discusses the advantages and disadvantages of gamma-2-amalgam versus non-gamma-2-amalgam. He distorts the banning of gamma-2-amalgam by the Germany Public Health Department as insignificant because he claims that less than 5% of the amalgams placed in Germany are of that type. Then, when discussing the German government's recommendation to avoid amalgam use in patients with kidney complaints, in children under six years of age and in pregnant women, he claims that there is no evidence to support this recommendation. The WHO (1991) (20) report on mercury stated that "no information is available concerning age effects on humans". Jones twists this to imply that this supports the contention that children are not more susceptible to the toxic effects of mercury. Again, there is no evidence because up until recently no research had been undertaken on this issue. This is what the WHO (1991) (20) was reporting.

The Jones article is an excellent example of an opinion paper, written by an individual with no expertise in the area. Jones is a good dental materials engineer and a poor, unqualified "expert" on medical research. He should stay within his field of expertise. It is difficult to sum up the undue influence that this non-dentist, non-physician, non-biologist, non-toxicologist has had on the issue of the medical safety of mercury-containing fillings in Canada. Without any experimental research evidence of his own to support either his claim of expertise or his opinions, Jones belittles the research of others. He declares that "pronouncements made directly to the media from...Vimy and others serve only to confuse the public and, in the long run, tend to give science a bad name".1 To the contrary, the evidence, herein, suggests that it is Jones who is confusing the dental profession and the public with misinformation and in so doing giving both science and dentistry a bad name.

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D. Giving Science a Bad Name - continued.

"Only individuals who are involved in the study of a technique have the experience to write a review. A swift look at the references soon reveals if the author is a genuine expert in the field."

Mair, L.D. (1992):

Science, myths and lies in Dentistry.

Brit Dent J 10:24, 1991

The C.D.A. has encouraged the publication of a number of articles in the C.D.A. Journal to buttress support for the safety of amalgam. Since 1991 the following articles have been published in the Journal:

1. Interview by C.D.A. Journal with P.T.Williams and Z. Kasloff: Mercury (And the Debate goes on) 1991, 57, 113-118.

2. Molot, L.A. and McCulloch, C.A.G. Dose/response relationships in clinical studies of mercury toxicity: Statistical considerations. Journal Can. Dent. Assoc., 1991, 57, 317-18.

3. machinate, M.I. and Mojon, P. Issues in the amalgam debate. Journal Can. Dent. Assoc., 1991, 57, 931-36.

4. Henderson, B. Dental amalgam: Scientific consensus and C.D.A. Policy., Journal Can. Dent. Assoc., 1995, 61, 429-31.

5. Levy, M. Dental amalgam: Toxicological evaluation and health risk assessment., 1995, 61, 667-674.

A review of the bibliographies of each of these papers clearly establishes that none of the authors cite themselves in their own bibliographies Thus, they are not genuine authorities on the topics about which they write.

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E. Conclusions.

The data presented herein indicates that the Canadian dental academic community is not fulfilling its scientific responsibility - to create new knowledge. Because of this, there is a real lack of expertise, clear academic thinking and open mindedness. Analysis of the publication record of the C.D.A. Journal's Editorial Board shows clear deficiencies and explains why the ISI does not rate this publication. This journal has no merit within science. The C.D.A.'s Committee on Dental Materials and Devices is likewise questionable. As a group these academics have no expertise in the safety or toxicology of the materials they recommend. They are, in the main, materials engineers, experts concerned with the physical properties of dentally applied materials. Until now, this information has not been generally disseminated. And unfortunately, Canadian dentists and the Canadian public have relied on these advisors regarding the medical safety of dental amalgam.

By advocating opinions that a product is safe when the mounting medical evidence supports the contrary view is shameful at best, especially so when those advocating the information are not legitimate experts. Certainly, mercury from dental amalgam is not the etiology of a host of diseases of unknown origins as some radical anti-amalgamists suggest. Nor is amalgam a safe panacea as the dental establishment portrays and defends. Present knowledge strongly suggests that dental mercury is a complicating medical factor, acting to exacerbate existing conditions. At worst, further medical research may prove it to be the cause of some specific diseases. But, irrespective of this possibility, mercury exposure, like lead and arsenic exposure, results in heavy metal poisoning. The more you are exposed to it, the worse the problem. Moreover, some individuals are toxicologically sensitive and/or immunologically hypersensitive to even low levels of mercury. Dr. Carl Svare, an enlightened materials engineer and a dentist, realized early on that the safety of dental amalgam was tenuous at best. He prophetically stated the following at the NIDR/ADA Workshop on the Biocompatibility of Metals in Dentistry in 1984 (1):

"An example of a set of conditions is as follows: a number of corroded amalgam restorations, chronic mouth breathing, and habitual chewing. Under these conditions high levels of mercury vapour would persist and the E.P.A. guidelines would be exceeded as the result of the presence of dental amalgam."

Given all the evidence presented herein, the ultimate question is asked, "Should Canadians place their confidence on the medical advice regarding mercury filling safety from Canadian dental Schools, dental professors and the Canadian Dental Association?

In 1986, the Board of Governors of the C.D.A. approved the following position as put forth by the C.D.A. Committee on Dental Materials and Devices.

"Current research on the use of silver dental amalgam suggests that amalgam continues to demonstrate clear advantages in many applications over other restorative materials. Significant evidence of patient risk associated with its use has not been demonstrated. Most therapeutic materials involve potential side effects or risks as well as benefits and dentists are trained to be on their guard for these reactions at all times."

Today, almost 10 years later and after the publication of numerous medical research studies which the C.D.A. cannot refute with their own data, this exact statement remains the official position of the Canadian Dental Association on amalgam (C.D.A. letter, November 20, 1995).

At a 1993 international symposium in Germany, Dr. Lars Friberg, Professor Emeritus of the Karolinska Institute - Sweden and recognized as an eminent scientific authority on inorganic mercury poisoning, concluded his assessment of the dental amalgam controversy thus:

"The evidence from experimental and human studies at higher exposure levels clearly indicate that mercury from the toxicological point of view is an unsuitable element to use in dentistry. It is my opinion that it is prudent to conclude that mercury from dental amalgam is not safe to use for everyone.

If regulatory agencies and dental professions will continue to advocate for the use of amalgam they should do this because they are willing to accept certain risks until more suitable filling materials are at hand and tested. It is nothing exceptional that certain risks are accepted. They should however not try to conserve the use of amalgam based on false conclusions that amalgam is safe to use." (2)

Given the published medical research evidence to date, one cannot justify the potential serious medical risks from chronic low-level dental mercury exposure in order to maintain the minimal dental benefit of a cheap tooth filling material.(3)

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Bibliography:

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Introduction
Section A:
Section B:
Section C:
Section E:
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Introduction:

1. American Academy of Dental Science, A history of dental and oral science in America. Philadelphia: Samuel White, publ., 1876

2. Bremmer, D.K., The story of dentistry, revised 3rd ed. Brooklyn: Dental Items of Interest Publishing Co Inc., 1954

3. Ring, M., Dentistry, an illustrated history. Harry N. Abrams Inc., Publisher, New York, 1985.

4. Stock, A., Z Angew Chemie, 1926, 39, 984-989.

5. Stock, A., Z Angew Chemie, 1928, 41, 663-72.

6. Stock, A., Z Anorg Allgem Chemie, 1934, 217, 241-53.

7. Stock, A., Naturwissch, 1935, 28, 453-6.

8. Stock, A., Arch Gewerbepath Gewerbehygie, 1936, 7, 388-413.

9. Stock, A., Ber Dtsch Chem Ges, 1939, 72, 1844-57.

10. 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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Section A:

1. Jones Derek, W. Giving Science a Bad Name. Journal, Can. Dent. Assoc., 1991, 57, 291-93.

2. Dental Education at the Crossroads: Challenges and change. Committee on the Future of Dental Education, Fields, M.J. Editor, National Academy Press, Washington, D.C. 1995. p.150.

3. Ibid, p.159.

4. Ibid, p.156

5. Skinner, E.W. and Phillips, R.W., The Science of Dental Materials, 6th ed., Philadelphia: W.B. Saunders Co., 1969., Chapt. 20, p. 303 and Chapt. 22, p. 332.

6. Dental Education at the Crossroads: Challenges and change. Committee on the Future of Dental Education, Fields, M.J. Editor, National Academy Press, Washington, D.C. 1995. p.171.

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Section B.

1. News Update, Journal, Can. Dent. Assoc. 59, 330.

2. Header, Journal, Can. Dent. Assoc. 60, 751.

3. C.D.A.: Bertrand, L., Personal communication

4. Health and Welfare Canada's program for safer medical devices. Journal, Can. Dent. Assoc., 55, 497.

5. Dentists give CDA Journal top marks. Journal, Can. Dent. Assoc., 61, 1039.

6. Jones, D.W. Giving Science a Bad Name. Journal, Can. Dent. Assoc. 57, 291-93.

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Section C:

1.     Jones, D.W. Giving Science a Bad Name Journal, Can. Dent. Assoc., 1991, 57, 291-93.

2.      Jones, D.W. The Whole Truth or Nothing? A Tale of Misinformed Consent., 1993, 59, 592-95.

3.      Soderholm, K-J.M. 1987. An x-ray diffractometric investigation of the Sn-Hg binary system within the 0-40% Hg interval. J Dent Res 66:712-5.

4.      WHO (1980) Recommended health-based limits in occupational exposure to heavy metals. Report of a WHO Study Group, Geneva, World Health Organization, 116 pp. (WHO Technical Report Series, No. 647).

5.      U.S. Department of Health and Human Services. Centers for Disease Control Morbidity and Mortality Weekly Report 37:153-155, March 18, 1988.

6.      Naleway, C. et al. Urinary mercury levels in U.S. dentists 1975-1983: review of health assessment. J. Am. Dent. Assn. 111:37-42, 1985.

7.      Berlin, M. Mercury. In: Handbook on the Toxicology of Metals, vol. 2, 2nd ed., (Friberg, L., et al., eds.) Specific Metals. Elsevier, N.Y. 1986 pp.387-445.

8.     Shapiro, I.M. et al., Neurophysiological and neuropsychological function in mercury exposed dentists. Lancet 8282:1147-1150, 1982.

9.      Ship, I.I. and Shapiro, I.M. Mercury poisoning in dental practice. Compendium Continuing Education 4:107-110, 1983.

10.     Smith, D.L. Mental effects of mercury poisoning. S. Med. J. 71:904-905, 1978.

11.     Mantyla, D.G. and Wright, O.D. Mercury toxicity in the dental office: a neglected problem. J. Am. Dent. Assn. 92:1189-1194, 1976.

12.      Escheverria, D., Heyer, N., Martin, M.D., Naleway, C.A., Woods, J.S., and Bittner, A.C. (1995) Behavioral effects of low level exposure to Hg0 among dentists. Neurotoxicol. Teratol. 17, 161-168.

13.      Gonzalez-Ramirz, D., Maiorino, R.M., Zuniga-Charles, M., Xu, Z., Hurlbut, K.M., Junco-Munoz, P., Aposhian, M.M., Dart, R.C., Gama, J.H.D., Escheverria, D., Woods, J.S., and Aposhian, H.V. (1995) Sodium 2,3-dimercaptopropane-1-sulfonate (DMPS) challenge test for mercury in humans: II - Urinary mercury, porphyrins and neurobehavioral changes of dental workers in Monterrey, Mexico. J. Pharmacol. Exp. Ther. 272, 264-274.

14.     Cook, T.and Yates, P. Fatal mercury intoxication in a dental surgery assistant. Brit. Dent. J. 127:553-555, 1969.

15. Foa, V. et al., Patterns of some lysosomal enzymes in the plasma and of proteins in urine of workers exposed to inorganic mercury. Int. Arch. Occup. Environ. Hlth. 37:115-124, 1976.

16. Stewart, W.K. et al., Urinary mercury excretion and proteinuria in pathology laboratory staff. Brit. J. Indust. Med. 34:26-31, 1977.

17. Rowland, A.S., Baird, D.D., Weinberg, C.R., Shore, D.L., Shy, C.M., and Wilcox, A.J. (1994) The effect of occupational exposure to mercury vapour on the fertility of female dental assistants. Occup. Environ. Med. 51, 28-34.

18. Jones, D.W. The Enigma of amalgam in dentistry., Journal Can. Dent. Assoc., 59, 155-166.

19. American Academy of Dental Science, A history of dental and oral science in America. Philadelphia: Samuel White, publ., 1876

20. World Health Organization (1991) Environmental Health Criteria 118, Inorganic Mercury (Friberg L., ed) WHO, Geneva.

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Section E:

1. Svare, C.W., Dental amalgam related mercury exposure., J. Calif. Dent. Assoc. October 1984, pp. 54-60

2. International Symposium Proceedings: Status Quo and Perspectives of Amalgam and other Dental Materials., L.T. Friberg and G.N. Schrauzer Eds. Georg Thieme Verlag, Stuttgart, New York, 1995 p.136.

3. 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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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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