Our public health system encourages fluoride use to prevent cavities. Dentists advise patients with multiple occurrences of tooth decay to brush their teeth with more concentrated fluoride toothpaste, to take fluoride tablets, or to undergo fluoride treatments. Aware of the public perception that use of fluoride products combats tooth decay, manufacturers of toothpaste and mouthwash tout the benefits of fluoride in their products. And public health officials credit the addition of fluoride to drinking water with vast improvements in dental health, especially among populations that do not regularly visit dentists. The continuation of this practice, however, is now in doubt.