While fluorosis is most severe and widespread in the worlds two most populous countries – India and China – UNICEF estimates that "fluorosis is endemic in at least 25 countries across the globe. The total number of people affected is not known, but a conservative estimate would number in the tens of millions. "In India, 20 states have been identified as endemic areas, with an estimated 60 million people at risk and 6 million people disabled; about 600,000 might develop a neurological disorder as a consequence. Effects on animals
The histological changes which are induced through fluorine on rats resemble those of humans. See also
Dental fluorosis
Fluoride poisoning
Kaj Roholm

References
Further reading
Fluorosis from drinking very large amounts of tea: Naveen Kakumanu, M.D. & Sudhaker D. Rao, M.B., B.S. (2013-03-21). "Skeletal Fluorosis Due to Excessive Tea Drinking". New England Journal of Medicine. 368 (12): 1140. doi:10.1056/NEJMicm1200995. PMID 23514291. {{cite journal}}:  CS1 maint: multiple names: authors list (link)


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Pain in the mouth present daily and persisting for most of the day,
B. Oral mucosa is of normal appearance,
C. Local and systemic diseases have been excluded. Classification
A burning sensation in the mouth may be primary (i.e. burning mouth syndrome) or secondary to systemic or local factors. Other sources refer to a "secondary BMS" with a similar definition, i.e. a burning sensation which is caused by local or systemic factors, or "where oral burning is explained by a clinical abnormality". However this contradicts the accepted definition of BMS which specifies that no cause can be identified. "Secondary BMS" could therefore be considered a misnomer. BMS is an example of dysesthesia, or a distortion of sensation.Some consider BMS to be a variant of atypical facial pain. More recently, BMS has been described as one of the 4 recognizable symptom complexes of chronic facial pain, along with atypical facial pain, temporomandibular joint dysfunction and atypical odontalgia. BMS has been subdivided into three general types, with type two being the most common and type three being the least common. Types one and two have unremitting symptoms, whereas type three may show remitting symptoms. Type 1 - Symptoms not present upon waking, and then increase throughout the day
Type 2 - Symptoms upon waking and through the day
Type 3 - No regular pattern of symptomsSometimes those terms specific to the tongue (e.g. glossodynia) are reserved for when the burning sensation is located only on the tongue.