Studies made in 1950's show that fluoride is beneficial for your teeth. Study was made by Dr. Harold Hodge, who was a respectable member of scientific community. Later, it was found that he was involved in experiments injecting radioactive plutonium in test subjects at University of Rochester in November 1945 Dr. Harold Hodge took his part in Manhattan project.

More information's can be found in the book: "The Plutonium files: America's secret medical experiments in the Cold War" by Eileen Welsome.

Test subjects who were injected with plutonium were:

1. Edna Schultz Carlton "HP-3" November 27, 1945

2. Jean Daigneault "HP-4" November 27, 1945

3. Paul Gallinger "HP-5" November 30, 1945

                                    4. Daniel Nelson, HP-10" July 16,1946

                                    5. and others

Fluoride was used in atomic bomb production, and Dr. Harold Hodge was a chief toxicologist in Manhattan project. Atomic bomb production required large quantities of fluorides. The copy of declassified study made by University of Rochester "Atomic energy project" clearly shows that fluoride is a highly toxic component. Atomic energy commission as well as other contractors were playing a major role in the cover-up and now face lawsuits.

Another study was made by Gerald J. Cox from the Mellon Institute of Industrial Research at Pittsburgh Philadelphia. Gerald J. Cox was asked by Francis C. Freary to research fluoride pollution effects caused by Aluminum Plant. Francis C. Freary was a Director of Aluminum Plant Laboratory. He suggested to Gerald C. Cox to investigate dental effects of sodium fluoride, what is totally absurd? Actually, Francis C. Freary was more interested how to dispose sodium fluoride. At that time, it was very expensive to dispose sodium fluoride. Obviously, the fastest and fewer expensive way was a trough public water supply.
In 2004 Christopher Bryson published a book "The fluoride deception" after 10 years of researching facts about fluorides. Mellon Institute was one of the supporters of asbestos usage. They claimed that mesohyloma is caused by something other than asbestos.
Fluorides airborne have done more damage than any other air pollutant.
Dr. Edward Groth claims that fluoride is responsible for more health damage than all 20 monitored air pollutant combined.
Denora Halloween pollution incident in Pennsylvania is the most notorious air pollution incident in history of USA, which caused 19 deaths and couple of thousands of injured, because of gas emission from the steel plant.
Philip Saddler, young chemist at that time analyzed the blood of deceased ones and found a high concentration of fluorides in their blood. The analysis was published in Chemical and Engineering News. Uncovered memo from the Aluminum Company later confirmed the analysis of Phillip Saddler. Sodium fluoride is a highly toxic ingredient of rat poison. Main usage of fluoride is in atomic bomb production and aluminum production where sodium fluoride is a by-product. Sodium fluoride is also used in medical drug production. 
Sodium fluoride can cause:

1. Lung empizema,
2. Bone cancer,
3. Breathing problems
4. Poisoning
5. Detention deficit disorder
6. Passivity
7. Liver damage
8. Muscle tension
9. and some other health problems
Studies made in Germany, British Columbia - Canada, New Zealand and Finland have shown that tooth decay has decreased in non fluoridated areas. The study made in U.S.A. on 39 207 children has shown reduced decay of deciduous teeth in 5-year old children in fluoridated areas. However, this isn't a case in the reduction of teeth decay in permanent teeth. In 1994 The Journal Fluoride, Volume 27, #1,13-22 shows a study made in New Zealand on 14-year old. Teeth decay correlated more with social-economic  status than with fluoridation.

The study made in India on 400.000 children hasn't shown any benefits of water fluoridation. 98% of European  countries don't use water fluoridation and those that do are considering to end it.

Dr. Phyllis Mullinex was hired by USA Army Medcom, while working at Harvard University Dental School found that rats fed with fluorides developed large numbers of neurological defects. She lost her job soon as she advised against water fluoridation.