After it being a mystery for 50 years, scientists are now able to tell how having fluoride in drinking water, mouth rinses, and toothpastes is able to prevent decay of teeth. Their latest findings appear in the ACS journal Langumir. Karin Jacobs and her colleagues explain that even though there is about fifty years of scientific research, there is still controversy over whether or not fluoride compounds reduce the risk of teeth decaying. The research that was done long ago showed that fluoride helps to harden the enamel that coats teeth and protects them from the bacteria that produces acid. More recent studies found that fluoride benefits teeth by penetrating into a much thinner layer of enamel that was believed previously and this leads credence to some of the other more recent theories about the way that fluoride works. Another finding of the report is that fluoride also works because it impacts the adhesion force of bacteria that stick to teeth and produce the cavity causing acid. The experiments for this study were done with artificial teeth and showed that fluoride reduced the ability of tooth decay causing bacteria to stick. This makes it easier to wash away this bad bacteria by means of brushing one’s teeth.