The risk of enamel fluorosis and caries among Norwegian children: implications for Norway and the United States

Abstract

Background: The authors investigated the associations between enamel fluorosis, caries and early fluoride use among Norwegian children who received fluoride supplementation under a protocol similar to the current U.S. protocol.

Methods: Two examiners whose techniques were calibrated examined randomly selected middle-school-aged children living in Bergen, Norway-where the water supply contains less than 0.10 milligrams of fluoride per liter-for both enamel fluorosis and caries by using the Fluorosis Risk Index and modified National Institute of Dental and Craniofacial Research criteria. The authors ascertained past fluoride exposure via a follow-up questionnaire mailed to parents.

Results: The questionnaire had an 88 percent response rate and 87 percent reliability. Adjusted analyses revealed a strong association between regular supplementation (given in the form of lozenges) and mild to moderate enamel fluorosis (odds ratio [OR], 6.85; P < .05), as well as fluorosis of lesser severity (OR, 3.07; P < .05). No children who had exclusively used only a pea-sized amount of toothpaste (0.1 percent fluoride) had mild to moderate fluorosis. The authors found a 40 percent reduction in caries risk associated with early use of pea-sized amounts of fluoridated toothpaste and a 46 percent reduction associated with regular use of fluoride supplement lozenges.

Conclusions: These findings suggest that both risk of fluorosis development and caries-preventive benefit are associated with regular use of fluoride supplements, and caries prevention was associated with early use of a pea-sized amount of toothpaste.

Clinical implications: These findings underscore the need for clinicians to consider thoroughly-and discuss with a child's parent or guardian-both the benefit and the potential risk of fluorosis development associated with preventive fluoride agents before introducing them. Clinicians also should emphasize the proper use of such agents.