Root Canal Retreatment Dental Code (D3348): Molar

What D3348 covers

D3348 reports nonsurgical endodontic retreatment of a permanent molar. The tooth had a root canal before, it failed (persistent infection, a missed canal, a leaking restoration, new decay reaching the canal space), and the treatment is being redone. The procedure includes removing the existing filling material, removing accessible posts or separated instruments when present, re-cleaning and reshaping the canals, and refilling them. As with initial therapy, the final restoration is separate.

It does not cover:

• Initial root canal therapy on a molar that has never been treated. That’s D3330.
• Retreatment of an anterior tooth. That’s D3346.
• Retreatment of a premolar. That’s D3347.
• A surgical root-end resection on a molar. That’s D3425 (apicoectomy).
• The core buildup or the final crown. Those are separate codes, D2950 for the buildup and the appropriate D27xx crown code.

When to bill D3348

Bill D3348 when:

• The pre-op radiograph shows an existing root canal filling in a molar.
• That prior treatment failed and is being redone nonsurgically through the crown.
• The retreatment is completed and the canals are refilled.

Do not bill D3348 for:

• A molar with untreated canals. That is initial therapy, D3330.
• An anterior or premolar retreatment. Use D3346 or D3347.
• A surgical apicoectomy. Use D3425 (molar) for the surgical root-end procedure.
• An incomplete retreatment. The code reports the completed procedure on the obturation date.

Retreatment versus initial therapy

The distinguishing axis is treatment history, read off the pre-op film, layered on top of tooth type. D3330 and D3348 are both molar endo. What separates them is whether the tooth was root-canaled before. A molar with clean, untreated canals is D3330. A molar with visible existing fill that is being redone is D3348.

This is the single most consequential decision on the code, and it cuts both ways:

• Code a genuine retreatment as D3330 and you underbill. D3348 carries the higher allowable on most plans, so the practice leaves money on the table.
• Code an initial molar as D3348 and the claim fails on audit. When the carrier reviews the pre-op film and sees untreated canals, the retreatment code is not supported.

Read the pre-op radiograph before you pick the code. Existing fill means D3348. No prior treatment means D3330.

The retreatment family by tooth type

Retreatment splits by tooth type the same way initial therapy does:

• D3346: retreatment of an anterior tooth.
• D3347: retreatment of a premolar.
• D3348: retreatment of a molar.

Code by the tooth, not the canal count. A molar with an unusual number of canals is still D3348. A premolar retreatment with molar-level difficulty is still D3347. The allowables step up from anterior to premolar to molar, mirroring the initial-therapy fee ladder (D3310, D3320, D3330), and for the same reason: average case complexity per tooth category.

Top reasons D3348 gets denied or downgraded

1. Missing pre-op radiograph. The film that shows the existing fill is the proof the tooth was treated before. Without it, some carriers pend the claim for documentation. Submit it up front.
2. Coded as initial therapy. The retreatment was billed as D3330, which underbills the case. When corrected, the recode-and-resubmit cycle delays payment.
3. Frequency and history conflicts. The carrier’s records may show the original root canal and apply a lifetime-per-tooth limit or a waiting period on the retreatment. A narrative documenting the failure of the first treatment supports the claim.
4. Tooth prognosis questioned. Some plans deny retreatment on a molar with poor restorability or advanced periodontal involvement, reading it as not indicated. Predetermination on borderline teeth heads this off.
5. Missing narrative on the reason for failure. Retreatment needs a why: persistent apical pathology, a missed canal, coronal leakage, recurrent decay. A claim that does not document the failure of the original treatment is more likely to pend.

Documentation that supports the claim

The claim needs:

• Pre-op periapical radiograph showing the existing root canal filling and the reason for retreatment (apical radiolucency, missed canal, post space, coronal leakage).
• Post-op periapical radiograph showing the completed retreatment.
• Date of service (the completion date).
• Correct tooth number.
• A narrative explaining why the original treatment failed and retreatment is indicated.

For the patient record, document:

• The status of the previous root canal and how the failure presented.
• Removal of the prior obturation material and any posts or instruments.
• Number of canals located and retreated, including any canal missed on the first treatment.
• Working lengths and the obturation material used.
• The planned final restoration.

Example case

A patient returns with recurrent discomfort and swelling around the lower right first molar (tooth #30), which was root-canaled by another office four years earlier. The pre-op periapical shows an existing root canal filling with a persistent apical radiolucency on the mesial root and what appears to be an untreated second mesial canal. The clinician plans nonsurgical retreatment.

Treatment sequence:

1. Visit 1: access reopened, existing gutta percha removed, the previously missed canal located and negotiated, canals re-cleaned and shaped, calcium hydroxide placed, temporary restoration.
2. Visit 2 (two weeks later): retreatment obturation completed, post-op periapical taken showing the refilled canals including the previously missed one, temporary restoration replaced.

Billing steps:

1. Submit D3348 on the obturation date (visit 2). Attach the pre-op film showing the existing fill and apical lesion, and the post-op film showing the completed retreatment.
2. Add a narrative: prior root canal on #30 with persistent apical periodontitis and a previously untreated second mesial canal, nonsurgical retreatment completed, all canals now obturated.
3. Do not code this as D3330. The existing fill on the pre-op film makes it a retreatment.
4. Schedule the buildup (D2950) and crown on their own dates of service. Bill each separately, not on the retreatment date.

If the carrier pends for proof the tooth was previously treated, the pre-op film answers it. If the carrier denies for lifetime frequency because it has the original RCT on record, appeal with the narrative documenting the failure and the clinical need for retreatment.

What to get right in your PMS

1. Read the pre-op film before you pick the code. Existing fill means D3348. Untreated canals mean D3330. This one check drives the whole claim.
2. Attach both pre-op and post-op films to the claim line. Many systems store images at the patient level. The clearinghouse needs them linked to the specific claim.
3. Write the failure narrative. Retreatment needs a documented reason the first treatment failed. A claim without it is more likely to pend.
4. Keep the retreatment family straight. D3346 anterior, D3347 premolar, D3348 molar. Code by tooth type, not canal count.
5. Separate the retreatment date from the buildup and crown dates. Bill D3348 on the obturation date and the restorative codes on their own dates of service to avoid same-day sequencing denials.