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What is True about certain lethal dose (CLD): and explain in detail?
Fluoride toxicity:

Safety recommended dose — Above 3 yrs old child is 1mg/day and adult 1.7 - 3.3 = 2.2 approx.
STD (safety tolerated dose) — 8 to 16 mgF/kg wt.
CLD (certain lethal dose) — 32 to 64 mgF/kg wt (4 times of STD) = 56 g.
Probable lethal dose = 5 mg/kg wt.

Essentials of preventive and community dentistry 
Soben Peter 
5th edition