How long does a root canal take? It’s typically a two to three appointment process. After numbing with a local anesthetic, Dr. Rovirosa opens the canal and cleans out infected tissue. A sealant, medicine, and a temporary filling are put in. A crown is then crafted to fit your tooth specifically. A crown is seen by some as an optional procedure after a root canal but crowns provide a more stable biting structure. Because just a thin shell can be left, the tooth could be prone to breakage if left without a crown, which covers it and blends with your smile.