> [!info] Metadata > - publication:: [[The Iceberg]] > - related:: > - [S] shared on 2021-09-26 to Facebook > - #articleseed/addendum the erupted tooth of the narwhal isn't just for fighting between the males, it also [functions as a sensory organ](https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.22886). > I was working on an article for the upcoming issue of Worldbuilding Magazine about different ways that people can signal identity with their appearance and so went down the rabbithole of ways people change their teeth. ## Fun Facts %% last 4 from [[pinchiDentalRitualMutilations2015.pdf]] %% - Babylonian chew sticks from 3500 BC are probably the oldest oral hygiene artifacts on record. - Some Indigenous South Americans from the Amazon Valley file their top two incisors to a point in order to resemble the feared piranha fish. - Some Peruvians and Ecuadorians blacken their teeth in hopes that it will help prevent cavities. - People from Canada to the Maldives break their top four incisors so that all their teeth are aligned at the same "height" — differentiating them from animals. - Some Senegali women deliberately force their incisors into an "overjet," creating buck teeth. ## Beholding Beauty Some Indigenous African tribes in Sudan extract the lower incisors as a rite of passage; the purpose of the procedure is to enhance beauty, to show their tribal identity, to allow the emission of specific linguistic sounds and to facilitate fellatio. The phenomenon also occurs in South Africa. You can read more about ritual dental mutilations in this [review of the literature](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4945341/). ## Hog Brushes The [bristle toothbrush was probably invented in China](https://museumofeverydaylife.org/exhibitions-collections/previous-exhibitions/toothbrush-from-twig-to-bristle-in-all-its-expedient-beauty/a-visual-history-of-the-toothbrush) during the Tang Dynasty. People took the coarse, stiff hairs of northern (read: Siberian) hogs and inserted them into tiny holes in bone or bamboo. Before this, people mostly used chew sticks; Babylonian chew sticks date from 3500 BCE and mostly come from the "toothbrush tree," Salvadora persica, which really does help prevent ulcers and inhibit oral bacteria and plaque. %% [[the sordid history of the toothbrush via the museum of everyday life]] %% ## Transparent Teeth Dragonfish have razor-sharp, transparent teeth that make them effective deep-sea predators because the teeth allow light to pass through them, making them functionally invisible. They have sharper teeth than piranhas; the thinness helps with making them difficult for prey species to detect... which is important because dragonfish are lure-based hunters that rely on camouflage. Also they look amazing seriously brace yourself and [check out this picture](https://www.newscientist.com/article/2205559-dragonfish-have-invisible-teeth-to-help-them-sneak-up-on-their-prey/). %% [[scullyDragonfishHaveInvisible2019|scullyDragonfishHaveInvisible2019]] %% ## Teeth Worms Ancient Egyptian dentists thought that [cavities were caused by worms](https://www.mkdmd.com/how-would-your-teeth-fare-in-ancient-egypt/), since cavities look so similar to the holes worms bore through wood. But they were surprisingly advanced given the limitations of the time period; they didn't have access to great antibiotics for infections (Hatshepsut died from a dental abscess), but they could wire lost teeth back into the mouth with gold or silver. %% [[How Would Your Teeth Fare in Ancient Egypt]] %%