Water fluoridation
Water fluoridation is used in the United States, United Kingdom, Ireland, Canada, Australia, Israel, Hong Kong and a handful of other countries. Most countries failed to adopt fluoridation, yet experienced the same or greater decline in cavities as those countries that did fluoridate during the later half of the twentieth century. The following nations previously fluoridated their water, but stopped the practice, with the years when water fluoridation started and stopped in parentheses: