RISK-FACTORS ASSOCIATED WITH FLUOROSIS IN A NONFLUORIDATED POPULATIONIN NORWAY

In Norway there is no water fluoridation and little naturally occurrin g fluoride in drinking water. Fluoride toothpaste is used by 95% of th e population and there is a long tradition of fluoride supplement use. The purpose of this study was to record the prevalence and severity o f dental fluorosis in 8-year-old children and relate this to systemic fluoride exposure (supplements and toothpaste). All children (n=551, b orn 1988) in a municipality in Norway were invited to participate. Den tal fluorosis on the buccal surface of the upper permanent incisors wa s recorded according to the Thylstrup-Fejerskov index (TF). Parents pr ovided data on use of supplements and toothpaste. Complete data were o btained from 383 children. Sixty-seven percent of the children had use d fluoride supplements regularly during childhood. At 8 months or earl ier, the teeth of 26% of the children, and at age 14 months or earlier the teeth of 82%, were being brushed. Among children who used fluorid e supplements regularly, periodically, seldom and not at all, 45%, 21% , 10% and 0%, respectively, had dental fluorosis. The dental fluorosis was mild (TF=1) in 87% of the cases. Bivariate and multivariate analy ses showed that, in addition to use of fluoride supplements, starting toothbrushing at an early age was associated with higher prevalence of dental fluorosis. The child's birth weight and liking for or swallowi ng of toothpaste did not influence the prevalence of fluorosis. Risk f actors for fluorosis were use of toothpaste before the age of 14 month s and regular use of fluoride supplements during childhood.