GrzBear had posted about the possibility that calcium neutralizes fluoride. I did some research and discovered he may be right. For those who dont know what the LD50 rating is, LD stands for "Lethal Dose". LD50 is the amount of a material, given all at once, which causes the death of 50% (one half) of a group of test animals. The LD50 is one way to measure the short-term poisoning potential (acute toxicity) of a material.
the LD50 rating of elemental fluoride is 52 mg/kg, which is very low. In other words its a very toxic substance.
HOwever! the LD50 rating for Calcium-Fluoride is 4,250 mg/kg! That is about the same rating that table salt gets. In other words while pure fluoride is highly toxic, calcium fluoride is about as toxic as table salt .
This is truly amazing. It would seem the calcium nearly totally neutralizes the fluoride.