<prompt> True about certain lethal dose CLD:2 times of safely tolerated dose4 times of safely tolerated dose5 times of safely tolerated dose6 times of safely tolerated dose  <response>: Fluoride toxicity:Safety recommended dose Above 3 yrs old child is 1mgday and adult 1.7 - 3.3 2.2 approx.STD safety tolerated dose 8 to 16 mgFkg wt.CLD certain lethal dose 32 to 64 mgFkg wt 4 times of STD 56 g.Probable lethal dose 5 mgkg wt.Essentials of preventive and community dentistry Soben Peter 5th edition 