Dental fluorosis among persons exposed to high- and low-fluoride drinking water in western Norway

The aim of this project was to study the prevalence and severity of dental fluorosis among persons exposed to moderate- to high- or low-fluoride drink ing water in western Norway, and to assess the risk factors involved. Subje cts aged 5 to 18 years who had been lifelong consumers of moderate- to high -fluoride groundwater (greater than or equal to 0.50 mg F/L) were selected for the study (n = 113). A comparison group (n = 105) was chosen among cons umers of low-fluoride surface water (similar to 0.10 mg F/L) in the same di strict. The Thylstrup-Fejerskov (TF) Index was used to score dental fluoros is. A questionnaire was used to obtain information on fluoride exposure and other relevant factors. Among the consumers of low-fluoride water 14.3% sh owed dental fluorosis (TF score 1-2) as compared to 78.8% in the group cons uming moderate- to high-fluoride water (TF scores 1-7). Premolars were most frequently affected, but severe cases (TF scores 3-7) were equally prevale nt in maxillary central incisors and first molars. In logistic regression a nalysis with TF score 0 or TF score greater than or equal to 1 as the depen dent variable, only fluoride concentration in the drinking water was associ ated with a statistically increased risk of dental fluorosis (odds ratio: 1 8.9; 95% CI: 8.85-40.44). In the study area, which was characterised by mul tiple fluoride sources, uncontrolled groundwater with moderate to high fluo ride content was the most important factor in the development of dental flu orosis. In order to prevent dental fluorosis, groundwater wells should rout inely be analysed for fluoride.