A root canal may be necessary when the soft tissue inside the tooth has become infected. Other causes include a tooth that has deep decay, or has been subjected to repeated dental procedures, or has become cracked or chipped. Most often, a root canal is a relatively simple procedure involving little or no discomfort. And with proper care, an endodontically treated tooth will function normally for many years. However, a tooth treated in this way can still develop cavities or gum disease, so regular checkups are necessary.