It is important to follow up with your general dentist after root canal therapy has been completed. They would like to know your symptoms have been resolved and seal the tooth with a definitive restoration. The filling and crown will prevent leakage and re-contamination of the tooth to prevent problems in the future. It is best to complete this step within weeks to ensure the tooth does not break apart before it can be restored. Back teeth need crowns to ensure successful treatment. Studies show teeth are lost after root canals five to six times as often when crowns are not placed!