Lantern Bioworks says they have a cure for tooth decay. Their product is a genetically modified bacterium which infects your mouth, outcompetes all the tooth-decay-causing bacteria, and doesn't cause tooth decay itself. If it works, it could make cavities a thing of the past (you should still brush for backup and cosmetic reasons).

I talked to Lantern founder Aaron Silverbook to get an idea of how this works, both in a biological and an economic sense. Aaron was very knowledgeable and forthcoming, although he uses the phrase "YOLO" somewhat more often than most biotech founders. This post isn't a verbatim interview transcript, just a writeup of what I learned based on his answers.

[Conflict of interest notice: Lantern is mostly rationalists and includes some friends. My wife consulted for them early on. They offered my wife and me free samples (based on her work, not as compensation for writing this post); she accepted, and I'm still debating. Consider this an attempt to spotlight interesting work that people I like are doing, not a hard-hitting investigation.]

https://www.astralcodexten.com/p/defying-cavity-lantern-bioworks-faq