Abstract:
This study was done to describe the association between source of drinking water and other potential risk
factors with dental fluorosis. Prevalence of dental fluorosis among 518 14-year-old students in the south of
Sri Lanka was 43.2%. The drinking water sources of the students were described and fluoride samples were
taken. There was a strong association between water fluoride level and prevalence of fluorosis. Tea
drinking before 7 years of age was also an independent risk factor in a multivariate analysis. Having been
fed with formula bottle milk as an infant seemed to increase the risk although the effect was not
statistically significant. No clear effects could be found for using fluoridated toothpaste, occupation of the
father, and socio-economic status. Drinking water obtained from surface water sources had lower fluoride
levels (median 0.22 mg l71) than water from deep tube wells (median 0.80 mg l71). Most families used
shallow dug wells and these had a median fluoride value of 0.48 mg l71 but with a wide range from 0.09 to
5.90 mg l71. Shallow wells located close to irrigation canals or other surface water had lower fluoride
values than wells located further away. Fluoride levels have to be taken into account when planning
drinking water projects. From the point of view of prevention of dental fluorosis, drinking water from
surface sources or from shallow wells located close to surface water would be preferable.
