What to Do When the Nerve Dies in an Immature Permanent Tooth: A Guide to RET vs. Apical Plug

Key points first

Goals: keep the tooth for the long term and help the root grow as much as possible.
Two main options:
1. Regenerative Endodontic Treatment (RET): clean the inside and use the body’s healing power to encourage root growth.
2. Apical plug (Apexification): create a hard “cap” at the root tip to seal and stabilize it (using calcium silicate materials: MTA/CSM).
Age, root development stage, and ability to attend follow-up visits are the keys to choosing the treatment.

It’s a permanent tooth whose root is still thin/short and the tip (apex) is open.
If injury or decay kills the nerve (pulp), root growth stops and the tooth becomes easier to fracture.
Choosing the right treatment early raises the chance of saving the tooth without extraction.

Regenerative Endodontic Treatment (RET)
- Aim: boost root growth (length/thickness) using the body’s healing.
- Pros: the root may continue to develop, improving future tooth strength.
- Watch-outs: results vary by person; follow-up is essential; small risks include discoloration, reinfection, fracture, or root resorption.
Apical plug (using MTA/CSM-type calcium silicate materials)
- Aim: form a hard “plug” at the root tip to seal and stabilize.
- Pros: simpler, more predictable, often doable in a single visit; newer materials handle well and discolor less.
- Watch-outs: further root growth is generally not expected.

Root development (Cvek stages, simplified):
- Stages 1–3 (about half to two-thirds grown): RET is often the first choice.
- Stage 4 (almost full length but apex still open): either RET or an apical plug can be suitable.
Age
- Younger patients (especially around middle school age) have higher chances of root growth with RET.
- In adults, root growth is unlikely; an apical plug is often preferred.
Follow-up commitment
- RET requires checks at 6, 12, and 24 months, then yearly. If follow-up is hard, an apical plug may be more realistic.
Infection status and restorability
- Heavy inflammation or pus calls for caution; if healing lags, switching strategies may be needed.

Materials (MTA/CSM) form hydroxyapatite when exposed to tissue fluid, helping seal and antibacterial action.
A 4–5 mm plug thickness is a common target.
To avoid pushing material beyond the root tip:
- Use faster-setting materials, place gently in 2–3 mm increments, and confirm with periodic radiographs.
- A temporary collagen barrier can help support placement (though it can’t prevent extrusion 100%).
In strong inflammation, the local environment can become acidic, weakening material set/strength. A short course of calcium hydroxide may be used first to stabilize conditions.

Follow-up is critical (check symptoms and X-rays):
- Typical schedule: 6, 12, and 24 months, then annually.
- Up to two years, failures can be hard to detect—don’t skip visits.
Warning signs (see your dentist promptly):
- Pain, swelling, sinus tract, progressive external resorption, or a growing dark area on X-ray.
If things don’t go as planned
- Repeat RET with adjusted disinfection,
- Switch to an apical plug,
- If the root is already mature, do conventional root canal treatment,
- In selected cases, consider apical surgery,
- Last resort: if the tooth can’t be saved, decoronation or extraction.

If you’re young and the root still has a lot to grow, “RET to help the root develop” is often the first choice.
If regular follow-up is difficult, if you’re older, or if root growth is unlikely, a “reliable apical plug” is a practical option.
In every case, keeping up with follow-up visits is the shortest path to keeping the tooth long term.

Mini glossary

Immature permanent tooth: a permanent tooth whose root is still thin/short with an open tip.
Pulp necrosis: when the tooth’s nerve/blood supply stops functioning.
RET (Regenerative Endodontic Treatment): a method that leverages the body’s healing to encourage root growth.
Apical plug (MTA/CSM): creating a hard cap at the root tip to seal and stabilize the canal.

Reference

Hasel 2026 Decision-making for Managing Immature Permanent Teeth with Necrotic Pulp.