Core tip: Is it necessary to fill a tooth after a decayed tooth? Clean the decayed tooth first, and pull it out if possible! Then dig out the black stuff inside. And disinfect and clean up, etc. Then it’s up to you how you want to deal with it! But before that, you will see where your tooth is! Clean the decayed tooth first, and pull it out if possible! Then dig out the black stuff inside. And disinfect and clean up, etc. Then it depends on how you want to deal with it. Yes! But before you will see where your tooth is!