One of the most common dental emergencies is a fracture in one or more teeth, but the fracture doesn't always appear in a visible spot. Blows to the mouth or between the jaws can lead to a crack that is only present in the root of one or more teeth. Getting the right treatment for this kind of emergency, whether you discover it right away or only later after deep pain sets in, provides you with the best chance at keeping every tooth.
Root canals are the primary treatment used to stabilize a tooth that experiences a serious fracture affecting the root. Unless the fracture is primarily above the gum line, a dentist can only stabilize the fractured part of the tooth by coming from the interior and removing the pulp material inside the shell. A timely root canal prevents the fracture from allowing bacteria to settle into the tooth pulp and causing decay and more pain. A dentist won't do the root canal immediately, but will stabilize the tooth until they can complete the procedure so there's no further damage while you're waiting.
If the root has fractured into multiple and separate pieces, a minor surgery is necessary so the dentist can extract loose bits of root before they migrate through the gum tissue. Regardless of the other treatments used on the main portion of the tooth, fracture removal protects the rest of the gums from localized infections and abscesses. Many dentists recommend both a root canal and fracture removal to make sure the tooth has the best chance of healing in place rather than needing extraction later.
In some limited cases, a minor root fracture can be treated with splinting instead of a root canal. The fracture has a chance to heal naturally with the root pulp intact, leading to a tooth that is basically the same as it was before the emergency. However, you'll need immediate treatment after a fracture for a splint to be an option. Waiting even a few hours or days allows bacteria to move in that will complicate the healing process. Only your dentist can tell you if a splint is an option or if you're limited to a root canal or extraction. Some fractures simply won't heal regardless of how much the tooth is immobilized, and you don't want to deal with a long-term infection by trying to save a tooth that's gone too far