Fluoridation effects on periodontal disease among adults.

Numerous studies report that water fluoridation reduces caries in children, but little current evidence exists about fluoridation's effects on the periodontal health of adults. To address this issue, we estimated fluoridation effects on periodontal disease among 1066 Washington state employees and their spouses, aged 20 to 34, with current residences divided evenly between fluoridated and nonfluoridated communities. Subjects were interviewed by telephone to collect residence histories, personal characteristics and other data. Each subject's lifetime years of fluoridation exposure (YFE) was calculated from the person's residence history and the U.S. Centers for Disease Control's Fluoridation Census. Oral assessments were conducted to measure the extent of periodontal disease. Relative to adults with no exposure, continuous lifetime exposure reduced the probability of attachment loss from 0.87 to 0.72. Similar benefits were obtained for bleeding gingiva and calculus. The estimates of fluoridation's benefits were not influenced by selection bias due to subjects' nonparticipation in the oral assessments.