Natural fluoride (calcium-fluora-phosphate) helps to build healthy bones and teeth. It is an organic edible salt found in raw fruits and vegetables.
Sodium fluoride, which is used to fluoridate water and products, is not the same. According to the Merck Index, sodium fluoride is a rat and cockroach poison.
It is still promoted that fluoride added to drinking water and oral hygiene products helps to fight cavities.
There has never been any demonstrated difference in tooth decay between countries with fluoridated and non-fluoridated water. Now German scientists proofed, that fluoridation does not prevent cavities.
What is more concerning is that sodium fluoride ingestion is not harmless. Overwhelming evidence from recent studies show that it is a potent accumulative toxin and has a direct toxic effect on the brain. Scientists at the Seibersdorf Research Center in Austria have shown that even 1 ppm of sodium fluoride impairs the DNA repair system of the immune system.
Dean Burk, Chief Chemist Emeritus of the US National Cancer Institute, states that "In point of fact, fluoride causes more human cancer death, and causes it faster, than any other chemical." 
Sodium fluoride is also present in products made with fluoridated water, for example in Diet Coke at 2.96 ppm and in 42% of ready-to-drink fruit juices. 
Dental fluorosis is rapidly rising due to the practice of fluoridating water, food, toothpaste, mouth rinse and other products and their use during early childhood when teeth are forming. This irreversible condition not only discolors and damages the teeth. According to Dr. Paul Connett, it also negatively impacts bone metabolism. 
Dr. Paul Connett states that 27 studies are in existence indicating that even moderate exposure to fluoride lowers IQ in children.
Enjoy Nature's Fluoride in Raw Fruits and Veggies ;-)
Jeannette von Johnsbach
1Elemental depth profiling of fluoridated hydroxyapatite: saving your dentition by the skin of your teeth?; Mueller F, Zeitz C, Mantz H, Ehses KH, Soldera F, Schmauch J, Hannig M., Huefner S, Jacobs K. Experimental Physics, Faculty of Natural Sciences and Technology, Saarland University, 66123 Saarbrücken, Germany.http://www.ncbi.nlm.nih.gov/pubmed/21090577
2 Fischer, William L.; How to Fight Cancer & Win, Baltimore, MD: Health Books,
2000, p. 278
3Dr. Gabriel Cousins, Spiritual Nutrition, page 433
4Associations Between Fluorosis of Permanent Incisors and Fluoride Intake From Infant Formula, Other Dietary Sources and Dentifrice During Early Childhood, Steven M. Levy, DDS, MPH, Barbara Broffitt, MS, Teresa A. Marshall, PhD, RD/LD, Julie M. Eichenberger-Gilmore, PhD, RD/LD andJohn J. Warren, DDS, MS http://jada.ada.org/cgi/content/abstract/141/10/1190