Objectives: To compare dental treatment experiences and costs in members of a health maintenance organization (HMO) in areas with and without community water fluoridation.
Methods: HMO members with continuous dental eligibility (January 1, 1990 to December 31, 1995) who resided in Oregon and Washington were identified using administrative databases. Fluoridation status was determined by geocoding subscriber address. Measures were utilization of dental procedures, fluoride dispensings, and associated costs. Costs were based on nonmember fees, adjusted to 1995 dollar values. Data were analyzed using analysis of covariance, controlling for age and interactions.
Results: About 85 percent of eligible members (n = 51,683) were classified as residing either in a fluoridated (n = 12,194) or nonfluoridated (n = 39,489) area. Mean age was 40.0 years; 52.3 percent were women. More than 92 percent of members had one or more dental visits. Community water fluoridation was associated with reduced total and restorative costs among members with one or more visits, but the magnitude and direction of the effect varied with locale and age and the effects were generally small. In two locales, the cost of restorations was higher in nonfluoridated areas in young people (<age 18) and older adults (>age 58). In younger adults, the opposite effect was observed. The impact of fluoridation may be attenuated by higher use of preventive procedures, in particular supplemental fluorides, in the nonfluoridated areas.
Conclusions: These results are particularly relevant to insured populations with established access to dental care. Differences in treatment costs (savings) associated with water fluoridation should be estimated and included in future cost-effectiveness analyses of community water fluoridation.