A root canal is the treatment used to repair and save a tooth that is badly decayed or is infected. During the root canal procedure, the inflamed or the infected pulp are removed and the inside of the tooth is cleaned and disinfected, then filled and sealed with material. After which the tooth is restored with a crown and filling for protection.. Without the treatment, the tissue surrounding the tooth will become infected and abscesses may form. A root canal can be completed in one sitting. Painless Single Sitting Root Canal Treatment