Independent and Additive Effects of Different Sources of Fluoride and Dental Fluorosis

To investigate the contribution of different sources of fluoride related to dental fluorosis.

This population-based, matched, case-control study (67 pairs) used a representative sample of 271 schoolchildren. Dental fluorosis was measured using Dean's index. Children's caregivers were interviewed about nine risk factors. Data were analyzed using conditional logistic regression.

The prevalence of questionable cases was 18.8 percent, and the prevalence of very mild, mild, or moderate cases of dental fluorosis was 11.5 percent, with no severe case. Age of start of toothbrushing, drinking water from wells, frequency of toothbrushing, type of tooth-paste, standard/ children's mouthrinse usage, and fluoride supplements were not significant (P>0.15). Drinking water from wells and using supplements were underpowered (N less than six). Children who frequently ate toothpaste had an odds ratio of 5.56 (95% confidence interval (CI) 1.75 to 17.73) times more fluorosis; those applying toothpaste to cover the bristles had 5.55 times more fluorosis (95% CI 1.44 to 21.42); and those using an adult size toothbrush had 3.17 times more flurosis (95% CI 1.15 to 8.71). There was a significant additive interaction (P<0.01).

In a community with water fluoridation, the factors associated with dental fluorosis are intentional toothpaste ingestion and tooth-paste applied on the whole toothbrush.