Tooth pain nerves can be very painful. To kill tooth pain nerve in 3 seconds permanently, you can use warm water and a teaspoon of salt, rinse your mouth for 30 seconds before spitting it out. You can also apply clove directly to the afflicted tooth by dipping a cotton ball in clove oil. Many doctors recommend peppermint tea for toothache. To create a mouthwash, you can mix a solution of water and hydrogen peroxide in your mouth for around 30 seconds before spitting it out. It will reduce the pain. Vanilla extract can also be used.