What the pulp is, and what infection does to it
The pulp is nerve fibers and blood vessels running from a chamber in the crown of the tooth to the tip of each root. It builds the tooth while it develops, and a formed tooth does not need it.
Bacteria reach the pulp through deep decay, a crack, a leaking filling, or an old knock. It sits in rigid walls, so once it swells the pressure has nowhere to go and past a point it cannot recover. Bacteria then pass into the bone at the root tip and the body walls the infection off. That is an abscess, showing on an x-ray as a dark area. Sometimes it drains through a pimple on the gum and stops hurting, which is not the same as better.
Symptoms that point to the nerve inside a tooth
Not every toothache needs root canal therapy, and some teeth that need one never hurt.
- Pain that lingers after cold. Sensitivity gone in a second is usually not a dying nerve. Pain that runs on for thirty seconds is.
- Pain on biting, or on releasing. Tenderness to pressure means inflammation has reached the ligament around the root. Pain as you release points to a crack.
- Spontaneous pain, especially at night. Pain with no trigger, or pain that wakes you after lying down, points to an irreversibly inflamed pulp.
- A pimple on the gum, or a tooth gone dark. A bump that drains and returns means an abscess found a way out, and a grey tooth means the pulp died. Heat that hurts while cold relieves it says the same.
Facial swelling is urgent. Dead teeth also turn up on routine x-rays with no symptoms. Referred pain is common, so the tooth that hurts is not always the one at fault.
What a root canal appointment involves
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Numbing the tooth
Local anesthetic, as for a filling. An actively painful infected tooth, a hot tooth, is harder to numb, because inflamed tissue changes the chemistry the anesthetic depends on. There are answers for that: supplementary, intraligamentary or intraosseous injections, or anesthetic into the pulp chamber. Say so if you feel anything sharp.
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Placing the rubber dam
A thin sheet clamped around the tooth, keeping saliva and its bacteria out of the canals.
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Cleaning and shaping the canals
A small opening reaches the pulp chamber. Each canal is measured to its exact length with an electronic apex locator, because cleaning must finish at the end of the root and not beyond. Nickel titanium files shape it, irrigated between files with sodium hypochlorite.
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Filling, sealing and restoring
The dried canals are filled with gutta-percha and a sealer so bacteria cannot recolonize the space. A core filling closes the opening, and back teeth then need a crown, because a treated back tooth without full coverage can split.
Does it hurt, and how long does a root canal take
Most people describe it afterwards as no worse than a large filling. The pain associated with root canals is really the pain of the abscess that brought you in, and that is what the treatment removes. A front tooth with one canal often takes about an hour, a molar ninety minutes or more, sometimes split across two visits.
The tooth is usually tender to bite on for a few days, and an over-the-counter anti-inflammatory covers it. Call if pain increases after two or three days, if swelling appears, or if the bite feels high.
Root canal and crown compared with extraction
Both are legitimate. Extraction is not a failure and is sometimes the more sensible choice.
| Consideration | Root canal and crown | Extraction |
|---|---|---|
| What you end up with | Your own root, keeping the bone loaded, with the ligament intact. | A gap, a resorbing ridge, and a decision about an implant, a bridge or a partial denture. |
| Time and cost | One or two visits, then a crown. | The extraction alone costs less. Replacing the tooth afterwards costs more than saving it would have. |
| If it does not settle | Retreatment, or an apicoectomy, which removes the root tip and seals the canal from the end. Extraction is still available. | The decision cannot be reversed. |
Root canal questions
Will I need a crown afterwards, and how long will the tooth last?
Back teeth almost always, because a molar has lost structure to decay and to the access opening while taking the heaviest forces in your mouth. A front tooth can sometimes take a bonded filling. A properly restored tooth can serve for many years. See crowns and caps.
What if the root canal does not work?
Infection sometimes persists, often because of an extra canal that is hard to find. The options are retreatment, cleaning and sealing the canals again, or an apicoectomy at the root tip. Complex cases are often referred to a specialist.
Can I just take antibiotics instead?
No. An infected canal has no blood supply left, so a drug carried in the bloodstream does not reach the bacteria. Antibiotics can settle swelling, but the infected tissue has to be physically removed.