Dental fluorosis in Tanzania Great Rift Valley in relation to fluoride levels in water and in ‘Magadi’ (Trona)

Information on the extent of health problems caused by fluoride in Tanzania is scanty. To determine the prevalence and the severity of dental fluorosis in relation to fluoride level in water and in ‘magadi’ (Sodium Carbonate and Sodium Bicarbonate), 2912 school children aged 12–18 years from 96 villages within internal drainage basin (IBD) of the Great Rift Valley (in East Africa) were examined using Thylstrup Fejerskov Index (TFI). Fluoride level in water ranged from 1.5 to 24.9 FÀ mg/L (mean ¼ 4.6FÀ mg/L), whereas that of ‘magadi’ ranged from 2.7 to 31,000 FÀ mg/kg (mean ¼ 3455 FÀ mg/kg). The prevalence of dental fluorosis was 96.3% while the severity ranged from 3 to 7 TFI. A total of 83.3% of children had at least one tooth with TFI score !4. Although the findings of this survey did not reveal linear association between dental fluorosis and fluoride levels, probably due to complexity of factors such as ingestion of ‘magadi’, the high prevalence and severity of dental fluorosis calls for an immediate intervention.

This study has markedly revealed that the prevalence and severity of dental fluorosis in IDB area is very high, and this is certainly due to high fluoride levels in ingested water and food. Fifty percent of the water samples are from sources that have fluoride levels higher than or equal to 4.0 FÀ mg/L and none of the sampled water had normal fluoride concentration. The association between the severity of dental fluorosis and fluoride concentration in water could not be ascertained in this study. The high prevalence and severe dental fluorosis definitely calls for an intervention. Although the findings of this survey did not reveal linear association between dental fluorosis severity and fluoride levels in water it is still strongly recommended that efforts are made to get alternative water sources with optimum fluoride levels. Social economic studies on behaviors, Fig. 4. TFI versus fluoride level in the water.