• Fluoride can be toxic, if administered in excess quantity.
• The toxic effects of fluoride can be either acute or chronic.
• Acute toxicity occurs due to a single ingestion of large amount of fluoride.
• Chronic toxicity occurs dụe to long-term ingestion of small amounts of fluoride excessive than the required optimal level.
Acute Fluoride Toxicity:
• Acute fluoride poisoning can occur either as a result of accidental ingestion or from deliberate attempts like suicide
• This can be from the use of fluoride containing products such as toothpaste, mouth rinse, tablets or household insecticides.
• Acute fluoride poisoning can also occur from overfeeds in community and school water fluoridation systems.
• Most of the time overfeeds occur in small water supplies.
Terms used in relation to fluoride toxicity:
Safely Tolerated Dose (STD): Dose below which symptoms of toxicity are unlikely to occur
(1 mg/kg of body weight).
Potentially Lethal Dose (PLD): Lowest dose associated with a fatality.
(5 mg/kg of body weight).
Certainly Lethal Dose (CLD): Survival after consuming this amount of fluoride is unlikely (32-64 mg/kg of body weight).
Features of acute toxicity of fluorides are:
- Nausea
- Vomiting
- Diarrhoea
- Abdominal pain
- Hypocalcaemia
- Acidosis
- Progressive hypotension
- Ventricular tachycardia and fibrillation.
The ingested fluoride combines with hydrochloric acid in the stomach to form hydrofluoric acid which exhibits a corrosive effect on the gastric mucosa causing nausea, vomiting, diarrhoea and abdominal pain.
*Hypocalcemia is caused by the affinity of fluoride to cations in the serum.
**Hypocalcemia is associated with paresthesia, paresis, muscle fibrillation, tetany, convulsions, decreased myocardial contractility and cardiovascular collapse.
Death usually occurs due to:
- Convulsions
- Cardiac arrhythmias
- Coma.
Chronic Fluoride Toxicity:
• Long-term ingestion of small amounts of excessive fluoride will lead to chronic fluoride toxicity which is often referred to as fluorosis.
• Fluorosis usually affects the bones and the teeth.
• Fluorosis of the bone is called as osteofluorosis and the fluorosis of the teeth is called as dental fluorosis.
MANAGEMENT:
REFERENCES:
- Pediatric Dentistry: Principles & Practice, MS Muthu(2nd Edition)
- downtoearth.org.in
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