Toothpaste is an abrasive paste (an abrasive is something that will scratch or grind something).

The flavours of toothpaste are usually from plants like Spearmint or Peppermint and sweetened with artificial sweetener.

Before toothpaste, people used all kinds of dry, rough things as an abrasive to clean their teeth – crushed eggshell, pumice, burnt animal hooves, twigs or their fingers 

A couple of hundred years ago, when people didn’t know about brushing their teeth, most people had black rotten teeth especially if they ate lots of sugar like Queen Elizabeth the first.

Source: www.toothpasteworld.com