Your root canal failed. Your dentist said you need “more treatment.” Now you’re hearing two options: retreatment or apicoectomy. Both sound intimidating. And you’re not sure which one actually fixes the problem.
I perform both procedures every week at our Torrance office, so here’s a straightforward explanation of what each one does, when each is the right choice, and how to think about this decision.
First — What’s the Difference?
These two procedures attack the same problem (a persistent infection at the root) from opposite directions:
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Retreatment goes through the top of the tooth. I reopen the crown, remove the old root canal filling material, find and fix whatever was missed the first time, re-clean the canals, and re-seal them.
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Apicoectomy goes through the bottom — through the gum. I make a small incision, remove the infected root tip (about 3mm), place a seal at the cut end of the root, and stitch the gum closed.
Same goal — eliminate the infection and save the tooth. Different approach.
When Retreatment Is the Right First Step
Retreatment is usually my first recommendation when a root canal fails. Here’s why: it addresses the cause of failure from the inside — the missed canals, the incomplete cleaning, the contamination that let bacteria survive.
Retreatment works best when:
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A canal was missed during the original treatment. This is the most common reason root canals fail. Upper molars have a tiny canal called the MB2 that’s present in ~90% of cases but gets missed without a microscope. If we find it and treat it, the problem is usually solved.
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The original cleaning was incomplete. Some areas of the canal system may not have been reached — lateral canals, isthmus connections, or the apical third (the tip of the root). Modern techniques like GentleWave cleaning can reach these areas on the second attempt.
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The seal failed or bacteria re-entered. A leaky crown margin, delayed crown placement, or a cracked restoration can let bacteria back into the root canal system. The solution is re-cleaning and re-sealing from the top.
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There’s a post or large restoration that can be safely removed. If the original treatment was done through a crown, we need to access the canals again. If the existing restoration can be removed without destroying the tooth, retreatment is straightforward.
Why retreatment first? Retreatment addresses the root cause of failure. If the original treatment missed a canal, an apicoectomy (which only treats the root tip) won’t fix that — the missed canal will continue to harbor bacteria. You have to fix the inside problem before the outside healing can happen.
When Apicoectomy Is the Better Choice
Apicoectomy makes more sense when retreatment either can’t be done or won’t solve the problem:
Apicoectomy is preferred when:
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The root canal was well-done but the infection persists at the tip. Sometimes the original treatment was technically good — all canals found, properly cleaned and filled — but there’s a persistent lesion at the root tip that won’t heal. This can happen when the apical anatomy is complex (multiple foramina, delta patterns) and can’t be fully sealed from the top.
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There’s a post or restoration that can’t be safely removed. Some teeth have large metal posts cemented into the root canal. Removing these risks cracking the root. In those cases, apicoectomy avoids disturbing the existing restoration entirely.
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Previous retreatment was already attempted. If the tooth has been retreated once and the infection persists, apicoectomy is the logical next step. Going through the top a third time rarely adds benefit.
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There’s a suspected root-end issue — like a root-end fracture, a calcified canal that can’t be navigated from the top, or an extra canal visible only at the apex on CBCT imaging.
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Retreatment access is blocked. The tooth has a bridge or implant-supported crown where removing the restoration would damage adjacent teeth or hardware.
Side-by-Side Comparison
| Factor | Retreatment | Apicoectomy |
|---|---|---|
| Approach | Through the crown (top) | Through the gum (bottom) |
| What it fixes | Missed canals, contamination, incomplete cleaning | Persistent apical infection, root-tip pathology |
| Success rate | 75–85% | 90%+ (microsurgical) |
| Cost | $1,500–$2,500 | $800–$1,500 |
| Procedure time | 60–120 minutes | 30–60 minutes |
| Requires new crown? | Usually yes | No — existing crown stays |
| Recovery | 1–2 days | 1–2 weeks (surgical healing) |
| Invasiveness | Non-surgical | Minor oral surgery |
| Can be done after the other fails? | N/A (first step) | Yes — this is the backup plan |
The Logical Sequence
In most cases, the decision isn’t “either/or” — it’s about the right sequence:
Retreatment First
Address the inside problem — missed canals, recontamination, incomplete sealing. This is non-surgical and handles the most common causes of failure.
Apicoectomy If Needed
If retreatment doesn't resolve the infection (typically assessed at 6–12 months), apicoectomy addresses the root tip surgically. 90%+ success rate.
Extraction Only as Last Resort
If both retreatment and apicoectomy have been attempted and the tooth continues to have problems, extraction and implant is the final option.
This stepwise approach gives your natural tooth every possible chance before moving to replacement. Each step preserves the option for the next.
There are exceptions. Sometimes I skip retreatment and go directly to apicoectomy — for example, when CBCT shows a well-obturated canal system with a clearly localized apical lesion and a post that shouldn’t be disturbed. The imaging often tells us which approach makes the most sense before we start.
How I Decide for Each Patient
At our office, the decision process looks like this:
Step 1: CBCT 3D scan. This shows me the quality of the existing root canal treatment, whether canals were missed, the size and location of the infection, and whether there are root fractures or other complications.
Step 2: Evaluate the original treatment under the microscope. I can see whether the filling material looks adequate, whether the seal is intact, and whether there’s evidence of contamination.
Step 3: Assess the restoration. Can the crown be safely removed for retreatment access? Is there a post that complicates things? What’s the condition of the remaining tooth structure?
Step 4: Honest discussion. I walk you through what I see on the scan and the microscope, explain which approach I’d recommend and why, and tell you what I’d do if it were my own tooth.
What Happens If I Need Both?
Occasionally, the best outcome requires both procedures — retreatment followed by apicoectomy months later if the tooth doesn’t heal completely. This sounds like a lot, and I understand the frustration. But consider the alternative: extraction ($200–$600) plus implant ($4,000–$6,000+), with 4–9 months of treatment and surgical procedures.
Retreatment ($1,500–$2,500) plus apicoectomy ($800–$1,500) is still significantly less expensive than an implant, keeps your natural tooth, and has a combined success rate that’s very high when both are performed by a specialist with a microscope and CBCT.
The Bottom Line
Retreatment and apicoectomy aren’t competing options — they’re sequential tools for saving your tooth. Retreatment comes first in most cases because it addresses the most common causes of failure from the inside. Apicoectomy comes second when the problem is localized at the root tip or retreatment access isn’t possible.
Together, they give your natural tooth an excellent chance before extraction ever enters the conversation.
Dealing With a Failed Root Canal?
If your root canal hasn’t worked and you’re trying to figure out the right next step, a specialist evaluation gives you the clearest picture. We’ll take a 3D scan, examine the tooth under the microscope, and tell you exactly which approach — retreatment, apicoectomy, or both — makes the most sense for your situation.
Call (310) 378-8342 to schedule a consultation at Phan Endodontic Partners in Torrance. We see patients from across the South Bay — Redondo Beach, Hermosa Beach, Manhattan Beach, Palos Verdes, Carson, Gardena, and beyond.