Root canal treatment leaves a tooth brittle and weak. The tooth is weakened because we had to remove the center of it to get at the infected nerve. This leaves only the sides of the tooth for support. The nerve and blood supply are also removed during root canal treatment, so the remaining tooth structure may become brittle over time.
Crowns strengthen and protect A tremendous amount of force is applied to the edges of teeth when you bite together. If a tooth is not crowned after root canal treatment, that force can cause some of the tooth to break away. If a tooth breaks, it is much more difficult to repair.
After root canal treatment, a crown is an important step that covers, strengthens and protects your tooth.