A former colleague of my brother's, with whom we used to do a fair bit of fishing, had a crown on one of his front teeth. One day he inadvertently swallowed it and, working in the Essex Water Co laboratory, had enough in the way of sieves and buckets on hand that every time he need to go for a crap he would search through the turds for his tooth, it being an expensive one and all. He found it, sterilised it, took it to the dentist and had it re-fitted.
Sadly to no avail. Only a few weeks later we were swimming in the sea off the Dengie Peninsula, it being 1976 and the water being warmer than your average heated pool, and his tooth came out once more and fell into the sea, sadly never to be seen again.