Although a prison does not seem the most appropriate place to use as an example of cleanliness and hygiene, the fact is that one of the benchmarks of hygiene, in this case dental, was invented in a prison in Newgate (England).
In 1780, the vicissitudes of life, it is said that due to street disturbances, led William Addis to prison. At that time, the traditional way of brushing teeth was to rub them with a rag or linen cloth with salt or other substances, the fact is that prison rags should not be very "reliable" and he decided to find a more hygienic substitute. He saved a bone from dinner and got some bristles by bribing a guard, put them together and glued them into the holes he had made in the bone... we already have the first toothbrush as we know it today .
When he got out of prison he founded the company ADDIS , which still exists today, and he began to market toothbrushes
Sources:Wisdom, Trivia Library, Gargles