A root canal treatment addresses a tooth infection from the tooth's surface. The oral surgeon opens the tooth, removes the infected pulp from the root canal, and sterilizes the root canal before filling it with a substance called gutta-percha and sealing the tooth with a crown.
In contrast, an apicoectomy addresses a tooth infection from the very bottom of the tooth. The oral surgeon makes a hole in the gums' close tip, removes the root tip, and cleans it before filling it.