Long ago, people did not have toothbrushes like we do today. They used their fingers or small sticks to clean their teeth. It was hard to get teeth really clean this way!
A very long time ago, in a country called China, someone had a clever idea. They took stiff hairs from pigs, called bristles, and put them into a bone handle. This was the first toothbrush! People used these brushes to scrub their teeth clean. The bristles were quite hard, so brushing could feel a bit scratchy.
Many years later, scientists made a new material called nylon. Nylon was special because it could be made into soft, smooth threads. Someone thought, "What if we use nylon for toothbrush bristles instead of pig hairs?" This was a wonderful change! Nylon brushes felt much softer in people's mouths. They were also easier to keep clean than the old pig hair brushes.
Today, almost everyone uses a toothbrush with nylon bristles. We use them every day to keep our smiles bright and healthy. It's amazing how a simple tool like a toothbrush has changed so much to help us!