Community water fluoridation (CWF) adds a controlled amount of fluoride to the water supply to prevent cavities.
It is a preventative measure that costs roughly $1 per person in a community. The benefits, on the other hand, have been estimated at about 100x the investment.
The Center for Disease Control in the United States declared CWF to be among the ten greatest public health advances of the twentieth century. We may not need it much longer because of the addition of Fluoride now to toothpaste, formula, etc.
But, it seems to have worked well while it lasted.
Water fluoridation reminded me of the impact of the addition of Chlorine into the water supply.
Both are great examples of upstream measures that are both invisible to us and incredible in their contribution to our wellbeing.