Apparently Dasani is reverse osmosis filtered, so it will have little to no fluoride from tap water. I found this on another website where someone emailed them. Here's the response:
"Fluoride is not an added ingredient in DASANI or any of our
carbonated beverage brands. However, since our brands contain water
from the local water supply where the product is produced, whether
they contain fluoride or not will depend on whether fluoride is
present in the local water supply. The Reverse Osmosis process does
remove more of the fluoride, thus DASANI will contain less fluoride
than our carbonated beverage brands."
"Fluoride is not an added ingredient in DASANI or any of our
carbonated beverage brands. However, since our brands contain water
from the local water supply where the product is produced, whether
they contain fluoride or not will depend on whether fluoride is
present in the local water supply. The Reverse Osmosis process does
remove more of the fluoride, thus DASANI will contain less fluoride
than our carbonated beverage brands."