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 down to the tip of each root. It builds the tooth while the tooth is developing, and a fully formed tooth can function without it.
Bacteria reach the pulp through deep decay, a crack, a leaking filling, or an earlier injury to the tooth. The pulp sits inside rigid walls, so once it swells the pressure has nowhere to go, and past a certain point it cannot recover. Bacteria then pass into the bone at the root tip and the body walls the infection off, which is an abscess, visible on an x-ray as a dark area. Sometimes it drains through a small bump on the gum and the pain settles, though the infection remains.
Symptoms that point to the nerve inside a tooth
Not every toothache needs root canal therapy, and some teeth that do need it never hurt at all.
- Pain that lingers after something cold. A twinge that disappears as soon as the cold is gone is common. Pain that continues well afterward can mean the nerve is inflamed.
- Pain on biting, or on releasing a bite. Tenderness to pressure can mean inflammation has reached the ligament around the root. Pain on releasing a bite can point to a crack.
- Pain with no obvious trigger, especially at night. Pain that arrives on its own, or that wakes you after you lie down, can point to a pulp that is inflamed beyond recovery.
- A bump on the gum, or a tooth that has darkened. A bump that drains and returns can mean an abscess has found a path out, and a grey tooth can mean the pulp has died. Heat that hurts while cold relieves can point the same way.
Facial swelling needs urgent attention. Teeth with dead pulps also appear on routine x-rays with no symptoms at all. Pain is often referred, so the tooth that hurts is not always the tooth at fault, which is why the diagnosis is made with tests and x-rays rather than from symptoms alone.
What a root canal appointment involves
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Numbing the tooth
Local anesthetic is used, as for a filling. A tooth that is actively painful and infected can be harder to numb, because inflamed tissue changes the chemistry the anesthetic relies on. There are established ways to manage that, including supplementary injections and anesthetic placed directly into the pulp chamber. Tell us at once if you feel anything sharp at any point.
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Keeping the tooth isolated and dry
The tooth is isolated from the rest of the mouth so that saliva, and the bacteria it carries, stay out of the canals while they are being cleaned.
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Cleaning and shaping the canals
A small opening is made to reach the pulp chamber. Each canal is measured so that cleaning ends at the tip of the root rather than beyond it, then the canals are cleaned, shaped and rinsed until the infected tissue and the bacteria within it have been removed.
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Filling, sealing and restoring
The dried canals are filled with gutta-percha and a sealer, so that bacteria cannot recolonize the space. A core filling closes the opening, and a back tooth then needs a crown, because so much structure has been lost to the decay and the access opening that the tooth can split without full coverage.
Does it hurt, and how long does a root canal take
Patients often describe the procedure afterward as no worse than having a large filling placed. The pain associated with root canals is largely the pain of the abscess that prompted the visit, and that is what the treatment addresses. A front tooth with a single canal is usually quicker than a molar with several, and some teeth are treated over two visits rather than one. Ask when you call what to expect for the tooth in question.
The tooth is often tender to bite on for a few days afterward. Ask your pharmacist or physician what is suitable for you to take for that. Call the office if the 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 treatments. Extraction is a reasonable choice in many cases and is sometimes the more sensible one.
| Consideration | Root canal and crown | Extraction |
|---|---|---|
| What remains afterward | Your own root, keeping the bone loaded, with the ligament intact. | A gap, a ridge that resorbs, 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 usually costs less, though replacing the tooth afterward adds to the total. |
| If it does not settle | Retreatment, or an apicoectomy, which removes the root tip and seals the canal from the end. Extraction remains available after either. | The decision cannot be reversed. |
Root canal questions
Will I need a crown afterwards, and how long will the tooth last?
Back teeth usually do, because a molar has lost structure to the decay and to the access opening while carrying heavy chewing forces. A front tooth can sometimes be restored with a bonded filling instead. 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 additional canal that is difficult to locate. The options are retreatment, which means cleaning and sealing the canals again, or an apicoectomy at the root tip. Complex cases are often referred to a specialist.
Can I take antibiotics instead?
No. An infected canal has no blood supply left inside it, so a drug carried in the bloodstream does not reach the bacteria there. Antibiotics can help settle swelling, and the infected tissue still has to be removed from the canal.