THE RISK OF FLUOROSIS IN STUDENTS EXPOSED TO A HIGHER THAN OPTIMAL CONCENTRATION OF FLUORIDE IN WELL WATER

Objectives: In December 1991 the residents of the community of Rigolet , Labrador, Canada, discovered that they were exposed to higher than 2 .0 ppm fluoride in the drinking water from the new town well, which be came operational in December 1983. In 1993 an investigation of the occ urrence of fluorosis in children exposed to the high-fluoride water du ring different ages of life was carried out Methods: A dental examinat ion for fluorosis was conducted using Pendrys' Fluorosis Risk Index. O ut of 84 students in Rigolet, 74 were examined and the parents of 60 s tudents agreed to be interviewed. Out of the 60 students, 48 lived all of their first six years of life in Rigolet Results: Of the 48 childr en with life-long residence, the odds ratio of fluorosis on enamel zon es that began forming during the first year of life was 8.31 (95% Cl=1 .84, 38.59) for children exposed since birth or during the first year of life relative to those exposed after 1 year of age. The odds that a child had a maxillary central incisor with fluorosis were 5.69 (95% C l=1.34, 24.15) times higher if exposure occurred during the first year of life compared with exposure after 1 year of age. Only those expose d to the high-fluoride water during the first year of life developed f luorosis on the mandibular central incisors. Conclusions: Within the l imitations of this small population study, age relative to the date wh en the new water well became operational was a significant risk factor in development of fluorosis. The first year of life was a significant period for developing fluorosis on the mandibular and maxillary centr al incisors.