摘要：Objectives. We sought to estimate the association between community water fluoridation (CWF) exposure at various stages of life and adult tooth loss. Methods. We used data from the 1995 through 1999 Behavioral Risk Factor Surveillance System, merged with data from the 1992 Water Fluoridation Census, to estimate interval regression models that relate CWF exposure with tooth loss. Results. Our results indicate that CWF levels in the county of residence at the time of the respondent's birth are significantly related to tooth loss but current CWF levels are not. In addition, the impact of CWF exposure is larger for individuals of lower socioeconomic status. Conclusions. This study suggests that the benefits of CWF may be larger than previously believed and that CWF has a lasting improvement in racial/ethnic and economic disparities in oral health. Community water fluoridation (CWF) is one of the most commonly provided local public goods in the United States. Studies have demonstrated a clear inverse relationship between dental caries and contemporaneous exposure to CWF, particularly among children, 1 – 5 but little is known about the long-term impact of CWF exposure on adult oral health. We focused on estimating the association between CWF exposure at various stages of life and adult tooth loss. Fluoride plays a crucial role in maintaining good oral health by combating the demineralization of enamel initiated by the caries process. 6 The addition of controlled amounts of fluoride to the public water supply could affect tooth loss in adulthood in 3 ways. First, by reducing the incidence of childhood dental caries, fluoride could reduce the likelihood of unchecked caries in which bacteria penetrate the underlying dentin and then progress into the pulp, resulting in pulpal necrosis and subsequent tooth extraction. 7 Second, exposure to fluoride prior to tooth eruption may alter the composition of enamel, a highly mineralized tissue composed almost entirely of hydroxyapatite crystals. 8 If fluoride is incorporated into these crystals, they become more permanently resistant to acid dissolution. 6 Third, exposure to CWF in adulthood may further improve oral health by providing continued protection of tooth enamel throughout life. 7 Despite the plausibility of these 3 mechanisms, dental caries can be effectively treated through dental interventions. Thus, inadequate treatment of dental caries must occur for CWF to have an impact on tooth loss. A fuller understanding of factors that may relate to tooth loss is important because healthy teeth are a vital and visible component of general well-being. Teeth help in maintaining general health via nutrition, 9 , 10 make a substantial contribution to one's physical appearance, 11 and have significant impacts on one's earnings 12 and employment opportunities. 13 – 15 Therefore, tooth loss may substantially affect an individual's quality of life. The goal of our study was to estimate the association between CWF exposure at various stages of life and adult tooth loss. We estimated this association by relating community-level measures of CWF at various time intervals, computed from data collected by the Centers for Disease Control and Prevention (CDC), to data on the oral health status of individuals who live in the same communities, obtained from the Behavioral Risk Factor Surveillance System (BRFSS), with controls for other characteristics of these communities. Community water fluoridation is, by design, a community-level intervention; thus, it is appropriate to assign a community-level measure of exposure to individuals. All individuals within a community are exposed to the identical CWF intervention, although individuals may vary in the amount of fluoride they ingest (because of differences in toothpaste choice or beverage consumption, for example).
