Vol. 489 No. 6
452 Mr. Gormley asked the Minister for Health and Children the plans, if any, which exist to review legislation on the fluoridation of drinking water supplies in view of the fact that the Ryan case, which foreshadowed the introduction of fluoridation, was predicated on the opinion that consumers could easily and at small expense, acquire filters to remove fluoride, when that has not been, nor is it currently, the case. [9147/98]
I understand that the High Court judgment in the Ryan case, and upheld in subsequent appeal to the Supreme Court, was that the fluoridation of the public water supplies was not a violation of any of the plaintiff's constitutional rights.
The judgment must of course be read in its entirety. A full reading of the judgment does not, in my view, support the interpretation that the judgment might have been otherwise if domestic water filters to remove fluoride proved ineffective.
453 Mr. Gormley asked the Minister for Health and Children the socio-political reasons referred to by him in previous parliamentary questions that led northern European countries to remove, or not to proceed with, the fluoridation of public drinking water supplies. [9148/98]
The key period of decision-making concerning fluoridation in the Scandinavian countries was in the 1970s and early 1980s. Public attitudes in Scandinavia traditionally have not shown the same level of support for fluoridation as, for example, in the USA. Studies from Denmark, Norway and Finland have shown between 20 per cent and 30 per cent in favour of fluoridation with 18 per cent to 30 per cent against.
An examination of the history of water fluoridation in Sweden illustrates the political dimension. Sweden is often cited as a country which is opposed to the measure. Burt and Petterson have described the events leading to the repeal of the Water Fluoridation Act in Sweden.
A trial fluoridation scheme was commenced at Norrkoping in 1952. This was challenged in the courts and in 1962 fluoridation was ruled to be illegal. The government, however was already preparing legislation to permit fluoridation where local authorities wished. Thus later in 1962 the Water Fluoridation Act was passed. An attempt to repeal the Act in 1968 failed. In 1971 the Swedish parliament referred the matter to the Standing Committee for Health and Welfare. The committee recommended that the Act should not be repealed.
This recommendation was returned to the House for further consideration and there was a narrow defeat for the Government. The resulting narrow defeat did not ban fluoridation but repealed legislation allowing it.
In 1982, the National Board of Health and Welfare recommended that fluoridation should be reintroduced.
454 Mr. Gormley asked the Minister for Health and Children if he will specify the precise biological mechanism whereby ingestion of fluoride from public water brings about changes in the teeth, including dental fluorosis, but has no effect on the bones such as skeletal fluorosis. [9149/98]
A natural process occurs in the mouth whereby enamel rods formed from hydroxyapitite are partially dissolved and reform when organic acids are present in saliva. When fluoride ions are present in saliva they become incorporated into the outer surface of the crystals, leading to the formation of a coating of fluoridated apatite, a form of apatite which is more resistant to organic acids. The presence of fluoride assists remineralization of tooth surface that is being exposed to repeated bouts of demineralization from plaque acids produced from fermentable carbohydrates.
Dental fluorosis is a condition of the dental hard tissues. It is not a generalised health effect. It occurs during the early enamel maturation phase. If excess fluoride is available it disrupts mineralization and results in excessive retention of enamel proteins. Most fluoride in the body is associated with calcified tissues. It is strongly but not irreversibly bound to calcium phosphate compounds in these tissues. In the long-term the fluoride ion is mobilized by the normal process of bone remodelling. There is no evidence to support the claim that skeletal fluorosis is a problem for countries with fluoridated water supplies.
