I originally had a good dentist, never had a cavity, ever. He retired, next dentist I had a cavity nearly every time. I stopped going, then one of the fillings came out. I went to a new dentist and they said ok, we can fix it. Then drilled my tooth off and literally while I was numbed up and after ~30 minutes of drilling, they freak out and are like.. OOOOOHHHH, you need a root canal, it's $2000, or the other option is extraction.