Dáil Éireann debate -
Tuesday, 14 Dec 1999

Vol. 512 No. 6

Written Answers. - Water Fluoridation.

John Perry

Question:

216 Mr. Perry asked the Minister for Health and Children if his attention has been drawn to the fact that the World Health Organisation concluded in 1994 that dental and public health administrators should be aware of the total fluoride exposure in the population before introducing any additional fluoride programme for caries prevention; if tests have been carried out on the people of north County Sligo before additional fluoride is used; if so, the tests carried out; and if he will make a statement on the matter. [26708/99]

Minister for Health and Children (Mr. Cowen)

The Department of Health and Children and health boards are fully aware of the observations and recommendations of the World Health Organisation regarding fluorides and oral health.

Estimation of total fluoride exposure is a feature of all fluoridation programmes. Prior to the introduction of water fluoridation in Ireland an investigation into the composition of Irish drinking waters with special reference to the distribution and significance of fluoride sponsored by the Medical Research Council was carried out by Drum. His studies of 42 water sources showed that only ten contained fluoride. Concentrations in these ranged from 0.1 to 0.3 parts per million fluoride. Prior to the introduction of water fluoridation to an area there is a statutory requirement to determine the level of fluoride in the existing water supply.

In an Irish context other sources of exposure with public health significance arise from the use of fluoride toothpaste and fluoride mouthrinsing. With the introduction of water fluoridation in an area the principal dental surgeon ceases fluoride mouthrinsing. This leaves a community with one systemic and one topical source of exposure, the ideal level of exposure recommended by the World Health Organisation. I have requested the North Western Health Board to write to the Deputy with the results of all tests and surveys carried out relating to the water fluoridation programme in north County Sligo.

John Perry

Question:

217 Mr. Perry asked the Minister for Health and Children if fluoridation of drinking water causes dental flurosis; if he will provide scientific references; and if he will make a statement on the matter. [26709/99]

Minister for Health and Children (Mr. Cowen)

The influence of fluoride on teeth has been known for almost 100 years.(1) In the United States in 1942, Dean demonstrated that in places where drinking water supplies had a natural fluoride content of one part per million (1pm), the prevalence of dental decay was significantly below average, yet the teeth did not have the mottled enamel, dental fluorosis, which was noticeable only when the level of fluoride was in excess of 2pm. (2) Research evidence suggests that periodic spikes of high fluoride in plasma such as that produced by inadvertent ingestion of fluoride toothpaste are more likely to produce fluorosis than a constant intake from day to day as with water fluoridation. Dental fluorosis associated with water fluoridation at 1pm is of the mildest variety and appears as barely discernible fine lacy markings on the teeth, detectable only by an experienced examiner.

(1) Black GV and McKay FS. (1916) Mottled teeth. Dent. Cosmos. 58; 129-156.

(2) Dean HT. The Investigation of Physiological Effects by the Epidemiological Method. In: Moulton RF,ed. Fluoride and Dental Health. Washington DC, American Association for the Advancement of Science, 1942:23-31.

(3) Murray JJ., Rugg-Gunn AJ., Jenkins GN. Eds. Fluorides in caries prevention. 3rd Edition. Butterworth-Heinemann Ltd 1991.

John Perry

Question:

218 Mr. Perry asked the Minister for Health and Children the way in which fluorine ion distinguishes between tooth and bone cells; if he will provide scientific references; and if he will make a statement on the matter. [26710/99]

Minister for Health and Children (Mr. Cowen)

The fluoride ion absorbed from the diet interacts with all calcified tissues as part of a normal physiological process even where there is no water fluoridation. At a cellular level ameloblasts, odontoblasts, cementoblasts and osteoblasts interact with fluoride. The effect of fluoride on enamel formation consists of the partial substitution of hydroxyapatite with fluorapatite, the effect on bone is similar. The negatively charged hydroxyl ion being replaced with the negatively charged fluoride ion. This results in a more stable apatite crystal structure in bone with the loss of impurities such as carbonate and magnesium ions. While enamel once formed does not regenerate throughout life bone undergoes constant remodelling as part of a normal physiological process.

References.

1. Fluoride in Dentistry. Ekstrand et al 1988: Pages 28 – 59. Munksgaard Publications

2. Intake and metabolism of Fluoride. G.M. Whitford 1994. Advances in Dental Research 8(1) 5 – 14

3. Allolio, B., et al. Drinking water fluoridation and bone. Exp Clin Endocrinol Diabetes. 1999 107: 12