Gene-Engineered Mouth Bacteria
A conversation with my friend who was a dentistry student, ~2013.  > [The friend, let's call her L, trying to dissuade me from drinking some fizzy drink]
  > J: But I won't get a cavity if the liquid doesn't touch my teeth.
  > L: Cavities are caused by the ensuing low ph environment, not by contact with teeth
  > J: Does that mean I can drink as much of it as I want as long as I rinse my mouth with water afterwards?
  > L, with a hint of defeat in her voice: yes.

After this conversation, I started the practice of rinsing my mouth with water after eating anything sugary or associated with tooth decay, as well as using interdental toothbrushes. My rate of cavities dropped from one on most years to zero - I haven't had a cavity since. Even the one noticed by my dentist at the time and left untreated for being too small hasn't developed yet, and that was ~ten years ago.On a sidenote, I have yet to find interdental toothbrushes whose use doesn't lead to ingesting nylon.