asked the Minister for Health whether in view of the findings reported from a survey carried out in New Zealand that dental caries is less prevalent in areas where soils and drinking water have a high content of molybdenum he proposes to amend the Health (Fluoridation of Water Supplies) Bill in the light of those findings.
Ceisteanna—Questions. Oral Answers. - Incidence of Dental Caries.
12.
It is correct that a research project carried out in New Zealand suggests that molybdenum may have an inhibiting effect on dental caries. The research in question was commenced in 1954-55 in the two towns of Napier and Hastings which are situated within twelve miles of each other. Each town has a population of approximately 20,000. They are closely comparable in regard to rainfall, hours of sunshine, socio-economic conditions and racial composition of their population. Moreover their water supplies, which were drawn from the same artesian strata, were found to have a marked deficiency in fluoride content, which in fact was only 0.15 parts per million.
It having been decided to fluoridate the water supply to one of these towns, Hastings, dental examinations were undertaken of children in both towns who had always lived in them. The results of this initial survey were in one respect surprising. It showed that the incidence of dental caries in one of the towns, Napier was much lower than in Hastings, the water supply of which latter it was proposed to fluoridate. In Napier the survey established that children aged 6, 7 and 8 years respectively, had had 57, 46 and 21 per cent. fewer permanent teeth attacked by caries than in the case of Hastings. Notwithstanding this, it was decided to proceed with the fluoridation of the water supply to the latter town Where those children lived whose teeth had been found to be so much more vulnerable to the disease.
In 1957 dental surveys were again made in the same two towns. This second survey demonstrated that in 2½ years the incidence of dental caries in Hastings, the town with the fluoridated water supply had been reduced to approximately the same level as in 1954-55 and in 1957 in Napier. I am sure the Deputy will concede that this was a striking manifestation of the effectiveness of fluoride as an inhibitor of dental decay.
The unexpected result of the first survey showing a striking difference in the incidence of dental caries in two towns the water supplies of which were equally deficient in fiuorides, initiated further research into the cause. As a result it was found that, though the soils from the two areas showed little difference in the total content of some twenty elements, vegetables grown in the district of Napier, the town supplied with unfluoridated water, were higher in molybdenum, aluminium and titanium, and lower in copper, manganese, barium and strontium than in the area around Hastings. The research is being continued and the research workers engaged in it have stated that additional studies must be undertaken before definite findings can be established.
In view of the fact that the research suggesting a possible association between molybdenum and a lower incidence of dental caries has been of short duration and is far from conclusive, and in view of the further proof yielded by the New Zealand experiment that fluoridation is a strong inhibitor of dental caries and thus affords a large measure of protection to the teeth of children, it is not proposed to amend the Bill as suggested by the Deputy.