A root canal is necessary when: the nerve and blood supply of a tooth is disrupted by trauma, a deep cavity, or infection; if there is not enough tooth for a restoration; or the individual suffers from a toothache.
A root canal allows the individual to keep the tooth. The alternative to a root canal is an extraction.
A root canal is usually a longer appointment duration.
Root canal treated teeth are usually more brittle and more susceptible to fracture. Consequently, a crown is usually necessary to restore and stabilize a root canal treated tooth.
Not all teeth requiring crowns need a root canal, but most teeth requiring a root canal need a crown.