Root Canal Redo: Can a Root Canal Be Redone?

Root canal therapy is designed to remove infection from inside a tooth, disinfect the canals, and seal the space so the tooth can heal. In most cases, it works very well. But sometimes a treated tooth can become painful or infected again weeks, months, or even years later. When that happens, patients often ask: can a root canal be redone?

The short answer is: yes, many teeth can be treated again through a procedure called root canal retreatment (also called endodontic retreatment, root canal redo, or root canal revision). Retreatment focuses on removing the old root canal filling material, re-cleaning and disinfecting the canals, and resealing the tooth to address residual or new infection.

Quick Answer: Can a Root Canal Be Redone?

In many cases, a root canal can be redone. If a tooth that previously had root canal therapy develops persistent symptoms (pain, swelling, gum bump, or recurring infection), root canal retreatment may be recommended to remove old filling material, clean and disinfect the canal system again, and reseal the tooth.

Retreatment is not always the right choice for every tooth. A focused exam (and imaging when indicated) helps determine whether the tooth is a good candidate for retreatment versus another solution.

Why Root Canals Can Fail or Get Reinfected

Root canal issues can happen for several reasons. Common contributors include:

• Residual infection: bacteria or infected tissue can remain if anatomy is complex or canals are difficult to access.
• Missed or unusual anatomy: tiny, narrow, curved, or extra canals can be challenging to detect and clean completely.
• New decay: a new cavity can expose the tooth and allow bacteria to reach the root canal filling.
• Crown or filling breakdown: a loose, cracked, or leaking restoration can allow salivary contamination and reinfection.
• Tooth fracture: a new crack can create a pathway for bacteria and may limit what retreatment can accomplish.
• Delayed restoration: waiting too long to place or repair a definitive restoration can increase reinfection risk.

Patients sometimes search terms like reinfected root canal, root canal infection years later, or root canal tooth hurts years later. The underlying issue is often leakage, new decay, a crack, or anatomy that requires re-evaluation.

Signs You May Need a Root Canal Redo

Not every ache means failure. Mild tenderness can occur after dental work and may improve with time. However, these symptoms commonly prompt evaluation:

• Persistent pain that does not trend better, or pain that returns after a period of comfort
• If the discomfort seems related to clenching, muscle soreness, or jaw tenderness, read Jaw Pain After Root Canal: Causes and Relief Tips.
• Swelling of the gum, cheek, or face near the treated tooth
• A pimple-like bump on the gum (gum boil, fistula, draining sinus tract)
• Bad taste or drainage (possible infection or leakage)
• Temperature sensitivity that persists or worsens
• Tooth discoloration (can have multiple causes, but may accompany internal issues)
• Tooth feels loose or painful to bite (needs clinical assessment)
• If the main complaint is pain when chewing, read Pain When Biting After Root Canal.
• "2 root canals on same tooth still pain" or ongoing symptoms after prior retreatment (re-evaluation is important)

If you have spreading swelling, fever, worsening pain, or difficulty swallowing/breathing, seek urgent care.

How an Endodontist Evaluates a Previously Treated Tooth

A proper evaluation is more than a quick glance. It typically includes:

• Reviewing symptom timing (when it started, what triggers it, whether it is improving or worsening)
• Testing bite and tenderness (including checking for a "high bite")
• Assessing gums for swelling, drainage, or a sinus tract
• Dental radiographs, and CBCT imaging when indicated, to assess the root tip region, anatomy, and surrounding bone

The goal is to identify the cause: residual infection, missed anatomy, leakage under a crown/filling, new decay, or a crack/fracture.

Root Canal Retreatment: Step-by-Step

A root canal redo is typically meticulous and technique-sensitive. While steps vary by case, retreatment commonly includes:

1) Access and isolation

The tooth is isolated (often with a rubber dam) to reduce salivary contamination. The endodontist gains access to the canal system, sometimes through an existing restoration.

2) Removal of old filling material

The prior root canal filling is carefully removed to allow inspection, cleaning, and disinfection. If posts or complex restorative materials exist, additional steps may be needed to safely reach the canals.

3) Cleaning, shaping, and disinfection

The canals are cleaned and disinfected again. Magnification and illumination help identify additional canals or unusual anatomy. Advanced techniques (including ultrasonic instrumentation) may be used when appropriate.

4) Resealing the canals

Once cleaned, the canals are filled and sealed again to reduce the risk of reinfection.

5) Temporary seal and definitive restoration

A temporary filling may be placed. You will typically need a stable final restoration (often a crown) to protect the tooth and maintain a tight seal. Delays or breakdown of the final restoration can increase the risk of future reinfection.

Can Retreatment Be Done Through a Crown?

Sometimes, yes. In select cases, an endodontist can perform root canal retreatment through a crown by creating a conservative access opening. In other cases, the crown (or post/core) may need to be removed or replaced to properly address the tooth. The decision depends on crown condition, leakage risk, access needs, and the likelihood of saving the tooth with a predictable seal afterward.

How Many Visits and How Long Does Retreatment Take?

Many retreatments are completed in 1 to 3 visits, depending on complexity (number of canals, canal curvature, calcification, presence of a post, degree of inflammation, and anatomy).

• Appointment length: commonly around 60 to 90+ minutes per visit, and longer for complex cases.
• Multi-canal teeth (premolars/molars) and teeth with posts often require more time.

Is Root Canal Retreatment More Painful? Recovery and Aftercare

With modern anesthesia, retreatment is usually no more painful than the original root canal. After treatment, it is common to experience mild to moderate tenderness for a few days. Most patients improve steadily.  If you’re also planning recovery time after treatment, see Root Canal Recovery Tips: Can I Go to Work After?.

Common aftercare guidance

• Avoid chewing hard foods on the treated side until the tooth is definitively restored.
• Use OTC pain relievers (ibuprofen or acetaminophen) only if medically safe for you and as directed.
• Maintain normal oral hygiene; keep the area clean.
• Follow your dentist/endodontist instructions and schedule the final restoration promptly.

Contact your dental team promptly if you have worsening pain, increasing swelling, fever, drainage/bad taste, or symptoms that do not trend better.  For the broader symptom timeline and when to call your dentist, see Pain After Root Canal: Causes, Timeline, and What to Do (Start Here).

Root Canal Redo Success Rate and What Affects Outcomes

Root canal retreatment success rates are generally favorable, but they vary by tooth, anatomy, extent of infection, and restorative status. Many sources cite success ranges commonly around 70% to 88% for retreatment in appropriate cases.

Key factors that influence outcomes

• Reason for failure (leakage/new decay vs. root fracture)
• Quality of the final restoration (tight seal, timely crown placement, repair of broken restorations)
• Tooth anatomy (calcified, curved, narrow, or extra canals)
• Extent and duration of infection and bone involvement
• Presence of cracks/fractures (may reduce predictability)
• If you want help deciding whether your symptoms suggest failure, start with Root Canal Failure Signs: How to Tell if It Failed.

Alternatives If Retreatment Is Not the Best Option

If nonsurgical retreatment is not feasible or not expected to be predictable, alternatives may include:

• Endodontic surgery (apicoectomy): a microsurgical approach to address infection near the root tip in select cases.
• Extraction with replacement options such as a dental implant, bridge, or partial denture (when the tooth cannot be predictably saved).

When possible, preserving a natural tooth is often preferred. However, the right decision depends on restorability, crack status, periodontal support, and long-term prognosis.

Frequently Asked Questions

How long does a root canal retreatment take?

Many cases take about one to two hours per visit, with 1 to 3 visits depending on complexity.

Is root canal retreatment more painful than the first root canal?

Usually not. Most patients do well with local anesthesia and experience temporary tenderness afterward, similar to other dental procedures.

Can a root canal get reinfected years later?

Yes. Reinfection can occur years later, often due to new decay, restoration leakage, or cracks that allow bacteria back into the tooth.

Do I need a new crown after retreatment?

Not always, but the tooth must have a stable, well-sealed restoration. Your dentist will advise whether the existing crown can be repaired, accessed and resealed predictably, or should be replaced.

How much does root canal retreatment cost?

Costs vary widely by tooth type (front tooth vs premolar vs molar), complexity, and restoration needs. Many sources commonly cite ranges such as $750 to $2,400 without insurance, with molars often higher. Coverage varies, and some plans limit coverage for repeat procedures on a tooth.

Conclusion: The Goal Is to Save Your Natural Tooth

If you are dealing with persistent symptoms after a prior root canal, it is reasonable to ask: can a root canal be redone? In many situations, the answer is yes. Root canal retreatment (redoing a root canal) can remove old filling material, locate and address missed or complex anatomy, disinfect the canal system again, and reseal the tooth so it can heal.

The most important decision point is not the label (root canal redo, re-root canal, revision, or retreatment) but the diagnosis: Why is the tooth symptomatic now? A careful endodontic evaluation, with radiographs and CBCT imaging when indicated, helps distinguish between problems that retreatment can predictably fix (leakage, reinfection, untreated anatomy) and problems that may require other solutions (significant fractures, non-restorable structure, or compromised support).

If you suspect a reinfected root canal, a gum bump, swelling, or ongoing pain, do not rely on guesswork. A timely evaluation can often preserve the tooth, reduce complications, and clarify whether retreatment, apicoectomy, or extraction is the safest next step.

Medical disclaimer: This page is for general education and does not replace an in-person dental evaluation or individualized medical advice.