When a crown comes off of a tooth, it is very important that you do not re-cement it yourself permanently. Cementing a crown permanently should only be done by a licensed dentist. The dentist will need to check the remaining tooth structure, and verify that there is no underlying decay present that can jeopardise the health of your tooth. Instead, you can place it on the tooth temporarily by using a few household goods. This should be done as soon as possible to avoid unwanted movement of the tooth.
Clean the inside of the crown using a toothbrush and toothpaste. Clean the tooth by brushing gently. Move the brush in small circles around the tooth. Rinse the tooth with lukewarm water to avoid sensitivity.
Dry the inside of the crown and the top of the tooth with a cotton swab.
Insert a small amount of toothpaste into the crown. Rotate the crown into the proper placement direction. Gently press the crown onto the tooth. Wet the cotton swab. Wipe away any extra toothpaste.
Call your dentist immediately and schedule an appointment.
Never re-cement a crown with super glue.