Not all teeth benefit from fluoride.

Some anthropologists are questioning the value of commonly accepted efforts for preventing cavities in children's teeth. Timothy Jones, an anthropologist at the University of Arizona in Tucson, and his colleagues analyzed tooth decay in Tucson children. The researchers obtained information about the concentration of fluoride in drinking water, household income, education, milk and school lunch consumption, participation in fluoridation programs, and tooth decay from municipal and school records. By analyzing household garbage, the researchers assessed toothpaste and dental floss use and estimated soda and sugar consumption.

At first, the data contradicted long-held assumptions. For example, the scientists noticed an increase in cavities and missing and filled teeth in children participating in fluoridation programs. Upon closer analysis, however, they realized that these findings held true only for Hispanic children. Yet the analysis of garbage indicated that Hispanic kids did not eat more cavity-inducing diets; they even tended to brush their teeth about twice as often as other children. These results need further study, Jones notes. But they lead him to suspect that certain genetic factors may outweigh the value of dental hygiene measures for some groups and may account for the sometimes conflicting results of fluoridation efforts.