To explain how I came to change my opinion about water fluoridation, I must go back to when I was an ardent advocate of the procedure. I now realize that I had learned, in my training in dentistry, only one side of the scientific controversy over fluoridation. I had been taught, and believed, that there was really no scientific case against fluoridation, and that only misinformed lay people and a few crackpot professionals were foolish enough to oppose it. I recall how, after I had been elected to a local government in Auckland (New Zealand’s largest city, where I practiced dentistry for many years and where I eventually became the Principal Dental Officer), I had fiercely -and I now regret rather arrogantly- poured scorn on another Council member (a lay person who had heard and accepted the case against fluoridation) and persuaded the Mayor and majority of my fellow councillors to agree to fluoridation of our water supply.
A few years later, when I had become the city’s Principal Dental Officer, I published a paper in the New Zealand Dental Journal that reported how children’s tooth decay had declined in the city following fluoridation of its water, to which I attributed the decline, pointing out that the greatest benefit appeared to be in low-income areas . My duties as a public servant included supervision of the city’s school dental clinics, which were part of a national School Dental Service that provided regular six-monthly dental treatment, with strictly enforced uniform diagnostic standards, to almost all (98 percent) school children up to the age of 12 or 13 years. I thus had access to treatment records, and therefore tooth decay rates, of virtually all the city s children. In the study I claimed that such treatment statistics “provide a valid measure of the dental health of our child population”. The claim was accepted by my professional colleagues, and the study is cited in the official history of the New Zealand Dental Association .
I was so articulate and successful in my support of water fluoridation that my public service superiors in our capital city, Wellington, approached me and asked me to make fluoridation the subject of a world study tour in 1980 -after which I would become their expert on fluoridation and lead a campaign to promote fluoridation in those parts of New Zealand which had resisted having fluoride put into their drinking water.
Before I left on the tour my superiors confided to me that they were worried about some new evidence that had become available: information they had collected on the amount of treatment children were receiving in our school dental clinics seemed to show that tooth decay was declining just as much in places in New Zealand where fluoride had not been added
to the water supply…
LESSON FROM HISTORY
I now realize that what my colleagues and I were doing was what the history of science shows all professionals do when their pet theory is confronted by disconcerting new evidence: they bend over backwards to explain away the new evidence. They try very hard to keep their theory intact- especially so if their own professional reputations depend on maintaining that theory…
Surprise: Teeth Better. Without Fluoridation?
… I looked at the new dental statistics that had been collected while I was away for my own Health District, Auckland. These
were for all children attending school dental clinics -virtually the entire child population of Auckland. To my surprise, they showed that fewer fillings had been required in the nonfluoridated part of my district than in the fluoridated part. When I obtained the same statistics from the districts to the north and south of mine– that is, from “Greater Auckland” which
contains a quarter of New Zealand’s population- the picture was the same: tooth decay had deeclined, but there was virtually no difference in tooth decay rates between the fluoridated arid nonfluoridated places. In fact, teeth were slightly better in the nonfluoridated areas. I wondered why I had not been sent the statisties for the rest of New Zealand. When I requested them, they were sent to me with a warning that they were not to be made public. Those for 1981 showed that in most Health Districts the percentage of 12- and 13-year-old children who were free of tooth decay that is, had perfect teeth was greater in the nonfluondated part of the district. Eventually the information was published . …
1. COLQUHOUN, J. The influence of social rank and fluoridation on dental treatment requirements. N.Z. Dental J. 73:146-148, 1977.
2. BROOKING, T. W. H. A History of Dentistry in New Zealand. Dunedin: New Zealand Dental Assn., 1980. 214-215.
3. HOLLIS, M.J., and HUNTER, P. B. Official Instructions: Dental health statistics, Form II children. School Dental Serv. Gaz. 41 (3):19, 1980.
4. COLQUHOUN, J. New,evidence on fluoridation. Soc. Sci. Med. 19:1239-1246, 1984.