Dietary fluorides ,dental fluorosis and dental caries in Tanzania populations

Abstract

High levels of dental fluorosis have been reported from several African countries which can not be explained by P- in the drinking water. Climate, altitude, diet and malnutrition have been suggested as possible factors. This study aimed to investigate the effect of climate, al ti tude, F- in drinking water and dietary F- on dental fluorosis in 3 Tanzanian populations from Tanga at sea level, and Singida and Iramba both at 1500 m altitude. The severity of dental fluorosis was assessed with the aid of 2 scoring systems. The TFI proved to be superior in determining mild and severe forms of fluorosis and was used in this study. Despite similar and low F- concentrations in the drinking water in the 3 populations, remarkable differences were noted in the prevalence and severity of dental fluorosis. The prevalence of dental fluorosis in Tanga was 22.8%, in ,

Singida and Iramba

was 72.0% and 99.3% respectively.

to

People in Singida and Iramba but not in Tanga consumed "magadi", a volcanic salt Na2(C03)2H20), which appeared to contain F- in the range of 28-9000 ppm F-. The severity of dental fluorosis in the three areas appeared to be strongly associated with the consumption of magadi.

- -- --~----~-- --- -~ ii Children with severe dental fluorosis i.e. with TPI> 5 were 2% in Tanga, 28% in Singida and 92% in Iramba. Samples of magadi collected from Sepuka in Singida contained P- in the range of 36 - 180 ppm P- with a median of 112 ppm P-, likewise samples collected from Kinyeto another location in Singida contained P- in the range of 28 - 900 with a median of 174 ppm P-. In Iramba the P- content in magadi samples ranged from 690 - 6800 ppm F- and the median was 1750. This association was further substantited by the finding that urine samples from infants in Singida and Iramba contained significantly higher P~ levels than in Tanga. Urine samples from Iramba revealed twice as high P- levels than urine samples from Singida. It was therefore established that Iramba with the highest fluorosis scores was the area with the highest F- content in magadi and in urine samples. The differences in prevalence and severity of fluorosis could therefore be attributed to the consumption of magadi. The prevalence of dental caries in Taqga was 21.1% with a mean DMPT of 0.4. This was in agreement with data from Dar es Salaam and Morogoro, areas which are similar to Tanga with respect to low P- content in drfnkJng water and the absence of magadi. The prevalence of, caries was 6% with mean DMFT 0.1 in Singida, and in Iramba the prevalence was 12.0% with mean DMPT 0.2. The lower caries levels in Singida and Iramba could be attributed to a higher P- exposure in these areas, but the effect of other factors like ethnic and socioeconomic variables, nutrition and dietary habits cannot be ruled out.

-- --~~~~-~- iii An analysis on the relationship between increasing dental fluorosis and the prevalence of caries on tooth level in Singida and Iramba indicates that severe fluorosis does not render teeth more susceptible to caries. This finding urges further and more extensive investigation on water analysis, on dietary habits and local customs regarding food preparation in endemic fluorosis areas in order to identify the main F- source as a first step in the control of fluorosis. In conclusion, the findings strongly suggest magadi as an important source of F- in endemic fluorosis areas. "