Pulp capping is a treatment that tries to save the living nerve of a tooth when decay or a crack has brought a filling very close to it. Instead of going straight to a root canal, the dentist places a protective material over or near the exposed pulp so it can heal and lay down new dentine. When it works, you keep a fully alive tooth. Research on direct pulp capping with modern materials such as MTA reports success rates of around 80 to 90 percent in the first year, which is why it is worth considering in the right situation.
Key takeaways
- Pulp capping protects a tooth nerve that is close to being exposed, aiming to avoid a root canal.
- Indirect capping leaves a thin layer of softened dentine over the nerve; direct capping treats an actual pinpoint exposure.
- Modern materials like MTA and Biodentine outperform older calcium hydroxide, with roughly 80 to 90 percent success at one year.
- It works best when the nerve is healthy or only mildly inflamed and there is no ongoing severe pain.
- If the tooth later flares up, a root canal is still possible as a backup.
When a dentist considers pulp capping
The pulp is the soft tissue at the centre of the tooth that holds the nerve and blood supply. When decay gets deep, bacteria and their toxins irritate the pulp. If the pulp is still healthy or only mildly inflamed, a condition called reversible pulpitis, it has a good chance of settling down once the decay is removed and sealed off. If the pulp is badly inflamed or already dying, capping is unlikely to hold and a root canal is the more reliable choice. Signs that point away from capping include severe spontaneous pain, pain that lingers for minutes after something hot or cold, and a tooth that has changed colour, which we cover in our guide to a dead or dying tooth.
Indirect versus direct pulp capping
There are two versions, and which one you have depends on whether the nerve is actually exposed.
| Type | What it treats | What the dentist does | General success at 1 year |
|---|---|---|---|
| Indirect pulp cap | Deep decay very close to the nerve, no exposure | Leaves a thin layer of firm dentine, seals with a protective liner and filling | Around 90 percent |
| Direct pulp cap | A small pinpoint exposure of healthy pulp | Places MTA or Biodentine directly on the exposure, then seals | Around 80 to 90 percent with MTA |
Why the material matters
For many years calcium hydroxide was the standard capping material, but its results faded over time, dropping to around 56 percent success at four to five years in some studies. Newer bioactive cements such as MTA and Biodentine seal better and encourage the pulp to form a stronger dentine bridge, holding closer to 80 percent over the same period. A dentist will usually recommend one of these modern materials for a direct cap.
What to expect afterwards
The tooth may be a little sensitive for a few weeks while the pulp settles. A dentist often places a temporary or interim filling first and reviews the tooth before finishing the permanent restoration, sometimes a few months later. During that time you watch for warning signs: increasing pain, pain that wakes you at night, or swelling. If those appear, the pulp has not recovered and a root canal is the next step. Because capping keeps the tooth alive, it is always worth trying first when the signs are favourable, knowing the fallback is still available.
Frequently asked questions
Is pulp capping better than a root canal?
They are not competing so much as suited to different situations. Capping is more conservative and keeps the nerve alive, but only works when the pulp is healthy enough. A root canal is more predictable when the nerve is already badly damaged.
How long does a capped tooth last?
If the pulp heals, the tooth can last for many years like any restored tooth. The key risk period is the first year, when most failures show up.
Will I know if it fails?
Usually yes. Ongoing or worsening pain, night pain or swelling suggest the pulp did not recover. A dentist can confirm with testing and an X-ray and move to a root canal if needed.
Does it hurt to have done?
The procedure is done under local anaesthetic, so it is comfortable at the time. Mild sensitivity afterwards is normal and usually settles.
Can any deep filling be capped?
No. It depends on how inflamed the pulp is, not just how deep the decay is. That is why the dentist tests the tooth and reviews an X-ray before deciding.
If you have a deep cavity or a tooth that has started to ache, an early assessment gives the nerve the best chance. You can book a check and see current options on our offers page, or read our comparison of root canal versus extraction if the tooth is already badly damaged.
