Let’s say you are dying of starvation. You pull one of your teeth out, causing blood to slowly seep into your mouth, which you swallow. The calories from the blood getting digested will delay the time you die of starvation, right? Or will losing blood while starving kill you faster?
You can never, ever get a net gain from self cannibalism of any kind. Digesting takes energy, and you’re also having to heal/replace whatever it is you’re eating.
Besides, the amount of blood that will come from a pulled tooth isn’t enough to do anything useful. You wouldn’t even gain minutes from it if the source was external.