"Determination of exposure and probable ingestion of fluoride through tea, toothpaste, tobacco..."
"Levels of water soluble and acid soluble fluoride in tea, toothpaste, tobacco and pan masala (mouth freshener) were estimated. These items are ignored while calculating the total dietary intake of fluoride. Tea, toothpaste, tobacco, pan masala (with tobacco & w/o tobacco) expose the human body to 3.88-137.09, 53.5-338.5, 28.0-113.0, 16.5-306.5 and 23.5-185.0 microg of fluoride per gram of these items, respectively." PMID: 16979289
Per "Science Daily" July 14, 2010 "Most published reports show 1 to 5 milligrams of fluoride per liter of black tea, but a new study shows that number could be as high as 9 milligrams." http://www.sciencedaily.com/releases/2010/07/100714104059.htm
On PubMed.gov http://www.ncbi.nlm.nih.gov/pubmed/11355098
"Dental caries among 10- to 14-year-old children in Ugandan rural areas with 0.5 and 2.5 mg fluoride per liter in drinking water"
"The purpose of this study was to report on dental caries among Ugandan children residing in rural areas with either a low or high fluoride concentration in the drinking water... In one low fluoride area, Kyabayenze, all children were caries-free compared to 75% to 86% in the other areas. In Kyabayenze, tea with sugar was taken significantly less frequently than in the other low-fluoride area. In the high-fluoride district, age and consumption of tea with sugar were positively and significantly correlated with caries." PMID: 11355098
So it doesn't appear as though the high fluoride content of tea prevents caries.
On PubMed.gov http://www.ncbi.nlm.nih.gov/pubmed/15341143
"The association between environmental tobacco smoke and primary tooth caries"
"After adjusting for age, SES, toothbrushing frequency, total ingested fluoride, and combined intake of soda pop and powdered drink beverages, the relationship of smoking and caries still remained significant..." PMID: 15341143
It doesn't look like the high fluoride found in tobacco reduces caries either.
How does one make sure they aren't exceeding the "recommended level" of fluoride? The fluoride content isn't listed on tea, tobacco, iceberg lettuce, soft drinks, juice, beer, wine, wheat flour, pharmaceuticals, grapes, raisins, candy, etc. But if you take the time to research it, you find that the majority of people in the USA are exceeding the recommended levels of fluoride.
Can fluoride levels in people be determined simply by counting cavities? Or does it require lab work?