E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Teeth are Drawn (His).
His power of doing mischief is taken from him. The phrase comes from the fable of The Lion in Love, who consented to have his teeth drawn and claws cut, in order that a fair damsel might marry him. When the teeth were drawn and claws cut off, the father of the maid fell on the lion and slew him.