Between 1963 and 1998 more than 3,000 toothbrush designs were patented in the United States.
Toothbrush bristles have been made of nylon since the late 1930s.
The average toothbrush contains about 2,500 bristles grouped into about 40 tufts per toothbrush. The tufts are folded over a metal staple and forced into pre-cored holes in the head or fused into the head with heat.
Toothbrush designers have researched how people hold the toothbrush to figure out how to design toothbrush handles.
Research conducted by Oral-B says people hold toothbrushes in five basic ways. Most people don't use just one grip, but rather a combination of two or three.