Early versions of toothbrushes with animal hair was not beneficial, as the animal hair used to fall out and did not really fight the bacteria. The first toothbrush with bristles was manufactured in China in 1498. The bristles were made of the stiff hairs from the back of a pig’s neck. Pig hair was used in toothbrushes until 1938, when nylon bristles were introduced. The average toothbrush contains around 2,500 bristles.
The modern toothbrush was developed in England in 1780. While languishing in jail, William Addis decided to drill holes into a sheep's tibia, and pulled through the bristles of boar hair.
You can read more about the history of toothbrush and what changed since in our blogette.