When reading A Dream of Red Mansions, we found Sister Lin gargling with salt, which was really an unfortunate discovery. I checked1from the end of the 8th century to the beginning of the 9th century1toothpaste was sold as a commodity in metal hoses. What did people use to clean their mouths before that? /kloc-before the 0/8th century, people used salt or grass to brush their teeth; /kloc-in the 0 th and 9 th centuries, I switched to tooth powder to brush my teeth; It was not until the 20th century that I switched to toothpaste to brush my teeth. In order to whiten teeth and prevent tooth decay, Egyptians in Pharaoh's period wiped their teeth with vinegar and pumice powder; Medieval surgeons used aqua regia (not a mixture of concentrated hydrochloric acid, sulfuric acid and nitric acid in middle school chemistry textbooks, but weakly acidic nitrogen water here) to file their teeth; Women in ancient Rome gargled with urine. Bill Focha, the father of modern dentistry, suggested in the Outline of Modern Dentistry that people gargle with urine: "Before getting up and going to bed, scoop up some urine that has just been pulled out with a spoon, put it in your mouth for a while and then spit it out." Well, it sounds flattering, but urine contains ammonia, which can really protect teeth. The other methods mentioned above can whiten the teeth, but they can also dissolve the protective enamel of the teeth, which will eventually lead to gum ulceration. One of the signs that there is nothing wrong with human organs is that we can't feel it, but we always have a chance to know that we have teeth: at least, we will replace our deciduous teeth and grow wisdom teeth. Tooth nerves are very dense, and it is very painful to extract teeth before anesthesia is used. But in the 17 and 18 centuries, the poor would make a living by selling their teeth. Yes, yes, just like people now sell blood to pay their children's tuition, people used to ask dentists to pull out their good teeth and sell them, because porcelain teeth were not widely used for filling teeth at that time. Dental surgery is to pull out a patient's bad tooth, insert a new tooth pulled out of someone else's mouth into the gum, and wait for it to take root, blossom and bear fruit. Of course, it is also easy to spread diseases. In addition to getting teeth from the poor, corpses on the battlefield are also one of the sources of teeth. It is said that President Washington's doctor brought back a bucket of teeth from Europe (really creepy). This tradition continued until the American Civil War, and countless young soldiers killed in Gettysburg had only gums in their mouths. A book popular a few years ago is called Style (