Introduction
The relationship between dental caries and fluoride in the drinking water has been studied for more than four decades. In the temperate climates, the optimum amount of fluoride in drinking water for preventions dental caries without causing fluorosis has been recommended at 1 ppm.
Effective methods for the prevention of dental caries is the prime issue in preventive programs in most developing countries. Dental caries prevention through water fluoridation by adding fluorides to public water supply is considered one of the most effective method because of its convenience, economicality and effectiveness.
Sources of Fluoride
Fluoride is ubiquitous and present in all foods, but its content is exceedingly small in most foods. However, it is contained in relatively large amounts in some foods that are common to most diets. Sea foods are highest in fluoride value, some ranging from 6 to 12 mg per kilogram. Meats and chicken provide amounts in the range of 1 to 2 mg per kilogram. Cereals in general, provide 0.5 to 1.0 mg per kilogram and fruits and vegetables contain a similar amount. Milk both human and cow, contains 0.1 to 0.2 mg per liter. The main dietary item providing unusual amounts of fluoride is tea Dry tea leaves contain 30 to 60 mgm per kgm and the fluoride level in tea as customarily prepared is approximately the same as that in fluoridated water, 1.0 ppm. It has been shown, for example, that the fluoride of fish protein concentrate contained mostly in the bone fraction, is less than 50% available. There is no evidence that fluoride intake from dietary sources consistantly exceeds 0.5 ppm. Thus, diet alone does not allow for a level of fluoride intake that consistantly inhibits the occurrence of dental caries. However, with the use of fluoridated water, intake reaches 1.5 mg per day on the average, which is an effective level. The estimated total daily intake of fluoride by children 1 to 12 years of age from water containing 1 ppm is based on the dry-weight of food. The maximum levels of daily intake of children in four age groups divided as follows, 1 to 3 years, 4 to 6 years, 7 to 9 years and 10 to 12 years are approximately 0.83 mgm, .1.11 mgm, 1.38 mgm, and 1.73 mgm respectively.
Following the 5 year fluoridation study in the USA before 1951 with remarkably good results, by the use of about 1.0 ppm fluoride in drinking water was sufficient to reduce the prevalence of dental caries quite safely and without any objectionable mottling of enamel. This resulted in a fluoridation scheme for Singapore towards the end of 1951. The natural fluorine content of Singapore water was found to be 0.2 ppm and it was necessary to determine the optimum content for this tropical city which lies only 2° north of the Equator. It was than decied that it would be correct and safe to add sufficient fluoride to raise the evel to 0.7 ppm.
Ten years observation showed that fluoridation of drinking water in Singapore lowered the prevalence rate of dental caries of children in the 7 to 9 years age group, the primary dentition by 30.8%. For the permanent dentition, fluoridated water reduced the prevalence rate of dental caries from 2.9 mean DMF teeth per child 1957 to 2.0 mean DMF teeth per child 1966, a reduction of 31.0% in Malay children 7 to 9 years of age. The mean DMF teeth per child of Chinese children 7 to 9 years of age was reduced from 4.4 to 2.1 representing a reduction of 52.2%.
Fluoride Intake For Infants
Although there is no firm consensus on the maximum safe daily dosage of fluoride, a total intake of between 0.05 to 0.07 mgm of fluoride per kilogram body weight generally is regarded as optimum. The supplemental flouride during the first 6 months of life and its effect have not been clearly established, although it has been estimated that the maximum daily fluoride intake for infants 6 months of age is 0.094 mgm/kg or slightly above the optimal level. This has been shown that fluoridated water used during the processing can significantly increase the fluoride content of fruit juices, dry cereals and commercially prepared milk formulas, significantly increase the total fluoride intake up to 6 months of age.
The prophylactic effect of fluoride in the prevention of dental caries is well established and its effect is known to be greatest when teeth are exposed during the period of calcilication. Since much of the enamel of deciduous teeth calcifies prior to birth, the possible benefit from maternal ingestion of fluoride during pregnancy is a subject of both practical and theoretical interest.
Flouride As a Nutrient
Fluoride is regarded as an essential nutrient and it is now well known to be effective in the maintenance of a tooth enamel that is more resistant to decay. It is a normal component of tooth enamel and bone. Studies in vivo and in vitro demonstrate that the calcified tissues of both enamel and bone are made up of a combination of hydroxyl and fluor apatites of varying composition, depending on the abundance of fluoride at the site of formation. These tissues are the principal sites of deposition of fluoride. As the plasma level of fluoride increases following absorption, fluoride is rapidly deposited in bony tissue, The hydroxyl ion hydroxy-apatite exchanges wM fluoride ion, and fluor apatite crystals are thus formed at the surface of bone and enamel.
Studies demonstrating the beneficial effect of fluoride in reducing the rate of dental caries under the guidance of the US Public Health Services about 1935 and continued until the mid 1950, demonstrated that the addition of fluoride to community drinking water at a level of 1 ppm led to a significant reduction in caries incidence. A summary of data from more than 7000 children in 21 different cities with fluoridated water supplies demonstrated a reduction of more than 60% in' the incidence of dental caries.
There is no precise agreement in which fluoride affects reduction in tooth decay. Probably, it is a combination of effects, but the most significatn is the assuring of a less soluble crystalline from of enamel. There is less evidence that fluoride exhibits a favorable or unfavorable effect on the gingival tissues or on the development of periodontal disease. But on the whole, fluoride is regarded as an essential nutrient and it is now well known to be effective in the maintenance of a tooth enamel that is more resistant to decay.
So far no arrangements have been made for the fluoridation of drinking water supplied to the public of Jakarta by Municipahty or national authorities. There is already ample evidence throughout the world of the effectiveness of fluoridation in controlling dental caries. Evaluation of 95 studies regarding the percentage caries reduction reported for primary and permanent dentitions, found that the reduction range for 55 studies giving results for primary teeth was 20 to 80% with a modal percent reduction of 40 to 50% (21 studies). For the permanent teeth the reduction range for the 72 studies was 20 to 90% with a modal reduction of 50 to 60% (30 studies).
In a study that was carried out in 1976 for deterrning various types of chronic impairments, functional limitation and disability the most frequently diagnosed condition in both males and females showed that below 35 years of age was chronic teeth problems, the prevalence rate per 1000 being 46.58 and 60.58 respectively, while above 35 years the prevalence rate per 1000 was 118.10 and 132.42 respectively.
Based on these reports, it is now time that steps be taken for the fluoridation of the Jakarta water supply. It is not just to look at the effectiveness of fluoridation in terms of more than a reduction in the DMF, but also at its cost benefit characteristics arising both from the reduction in the amount of caries and the complexity of dental treatment.
Studies that have been done regarding dental health in 5 year old children showed 36% less decay in the fluoridated area and a cost saving in treatment for this group was 29%. The benefits of fluoridation are better reflected in the older age group where there was a 42% reductibn of DMFT and a cost saving in treatment of caries of 50%. Therefore it is of utmost importance that water fluoridation is the preferred method of caries prevention.
Source: Kartari PS and Lelyanti Setiadi (Non communicable disease research centre) NIHR & D, Department of Health, Republic of I Indonesia, Jakarta
References:
- Committee on Nutrition (1972). Fluoride as a nutrient. Pediatrics, 49: 3
- Leon Singer et al (1979). Total fluoride intake of intants. J. Pediatrics 63: 460.
- Muhler, J.C. (1970). Ingestion from foods in fluorides and human health. Monogr. WHO. 32-40.
- Wang, M.Q. et al (1988). A ten year study fluondation of water in Singapore. Dental of Malaysia & Singapore.
Fluoride and Dental Health
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