“Most epidemiological research has indicated that an intake of at least 10 mg/day for 10 or more years is needed to produce clinical signs of the milder forms of the condition.”
Institute of Medicine - “Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride” National Academy Press, Washington D.C. pp. 307 (1997)
“Crippling fluorosis as an occupational disease follows exposures estimated at 10 to over 25 mg of fluoride daily during periods of 10-20 years.“
Hodge HC - “The Safety of Fluoride Tablets or Drops“ In: Johansen E, Taves DR, Olsen TO, Eds. Continuing Evaluation of the Use of Fluorides. AAAS Selected Symposium. Westview Press, Boulder, Colorado. pp. 253-274 (1979)
“Most estimates indicate that crippling skeletal fluorosis occurs when 10-20 mg of fluoride have been ingested on a daily basis for at least 10 years.”
Whitford G - “The Metabolism and Toxicity of Fluoride” 2nd Revised Edition. Karger: Basel. pp. 138 (1996)
"Osteomalacia and osteoporosis may occur in older persons who ingest excessive fluorides (over
Ellenhorn MJ, Barceloux DG - “Medical Toxicology: Diagnosis and Treatment of Human Poisoning”. Elsevier; New York. pp. 534 (1988)
"It is generally stated that a dose of 10-20 mg/day for at least 10 years is necessary for the development of crippling skeletal fluorosis, but individual variation, variation in nutritional status, and the difficulty of determining water fluoride levels in such situations make it difficult to determine the critical dose."
Agency for Toxic Substances & Disease Registry [ATSDR] - “Toxicological profile for Fluorides, Hydrogen Fluoride, and Fluorine” Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. (2003)
"First signs of skeletal fluorosis can be observed after the ingestion of more than 10 mg F-/day over a period of at least 10 years."
Zimmer S, Jahn KR, Barthel CR - "Recommendations for the use of fluoride in caries prevention"Oral Health Prev Dent 1(1):45-51 (2003)