Before 1990, few studies investigated the caries-preventive effects of fluoridation in adults (Rugg-Gunn and Do, 2012). This probably reflected a view,now outdated (Beltran and Burt, 1988), that fluoridated water was effective only when ingested prior to tooth eruption. It raises a pragmatic public healthquestion that confronts a community contemplating the implementation of fluoridation: Will potential benefits be limited to people born after implementation,or might there be additional benefits for people born before implementation?
We addressed this question in two cohorts of people studied in the 2004–2006
National Survey of Adult Oral Health (Appendix Fig. 1): people born before
1960, prior to widespread fluoridation (n = 2,270); and people born between
1960 and 1990, when population coverage increased from < 1% to 67%.
Associations between percentage of lifetime exposed to fluoridated drinking
water and dental caries experience were evaluated in each cohort, with the
expectation that the association would be stronger in the 1960–1990 cohorts.