system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What would happen if you never got a cavity filled?

edit: Should clarify that I don't have any cavities I'm currently ignoring! It's just a matter of curiosity.
gpt
The cavity deepens until it fully pierces through the enamel on the outside of your tooth. Once that happens, the vulnerable dentin and pulp inside the tooth come under attack (this would require extensive drilling and a crown), and eventually the infection reaches the nerve at the base of the tooth (requiring a root canal). At this point it would be hard to ignore, given that it'd hurt like hell, but if you did ignore it the infection could continue down into your jaw and bloodstream, which can be fatal.