"He (the coroner) turned and motioned to Doliffe, who came forward with the bridle. A cage for the head, a stone in weight, black-painted hoops of iron in the shape of a helmet. Brigge looked at the protusion of spiked metal attached to the inner part of one of the lower bands, the bit that would stop Shay's tongue. He had seen women retch and vomit when the bit was forced into their mouths and the bridle locked in place. He had seen smashed teeth and broken jaws and gashed lips and gums."
--"Havoc, in its third year", by Ronan Bennett
I had no idea such a thing existed, but why should I be surprised. Yet another reason I am happy to be living in the 21st century.