Neurological menifestations of fluorosis occur , when the duration of ingestion is:
10 years
15 years
20 years
25 years.
The fluoride dosage necessary to produce pathological skeletal fluorosis is estimated to be 20-80 mg/day for a period of 10 to 20 years. In India, it is most commonly seen in Punjab. Neurological Manifestations of fluorosis occur if the duration of ingestion is more than 20 years.