put just the bristles under hot water
Many, many countries make toothbrushes.
nothing
Toothbrushes for dogs come in a variety of colors. My dog's toothbrush is blue.
Yes, peanut butter people can eat toothbrushes.
toothbrushes weren't invented then!
Any toothbrush is only as effective as the person using it. If used properly, most manual toothbrushes can adequately clean your mouth. I typically recommend electric toothbrushes to people who have some kind of physical limitation, such as arthritis.
It is difficult to provide an exact number, but it is estimated that there are billions of toothbrushes used around the world. This number is constantly changing as toothbrushes are manufactured, sold, and disposed of.
No. it is not.
nothing
no
It's not common but probably somewhere in the world it is possible, especially in countries where toothbrushes are in short supply.