Root Canal Retreatment Dental Code (D3348): Molar

What D3348 covers

D3348 reports nonsurgical endodontic retreatment of a permanent molar whose root canal failed, from persistent infection, a missed canal, a leaking restoration, or new decay reaching the canal space. The procedure includes removing the existing filling material, removing accessible posts or separated instruments, re-cleaning and reshaping the canals, and refilling them.

It does not cover:

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

When to bill D3348

Bill D3348 when the pre-op radiograph shows an existing root canal filling in a molar, the failed treatment is redone nonsurgically through the crown, and the canals are refilled. The code reports the completed procedure on the obturation date, not an incomplete retreatment.

Retreatment versus initial therapy

D3330 and D3348 are both molar endo. What separates them is whether the tooth was root-canaled before, read off the pre-op film. A molar with untreated canals is D3330. A molar with visible existing fill being redone is D3348.

The decision cuts both ways:

• Code a genuine retreatment as D3330 and you underbill, because D3348 carries the higher allowable on most plans. When corrected, the recode-and-resubmit cycle delays payment.
• Code an initial molar as D3348 and the claim fails on audit when the carrier sees untreated canals on the pre-op film.

The retreatment family by tooth type

• 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, and a premolar retreatment with molar-level difficulty is still D3347. The allowables step up from anterior to premolar to molar, mirroring the initial-therapy codes (D3310, D3320, D3330), because average case complexity rises by tooth category. The root canal dental codes guide covers the retreatment windows and the first-treatment codes together.

Top reasons D3348 gets denied or downgraded

1. Missing pre-op radiograph. It is the proof the tooth was treated before. Without it, some carriers pend the claim.
2. Coded as initial therapy. Billed as D3330, which underbills the case.
3. Frequency and history conflicts. The carrier has the original root canal on record and applies a lifetime-per-tooth limit or a waiting period to the retreatment.
4. Tooth prognosis questioned. Some plans deny retreatment on a molar with poor restorability or advanced periodontal involvement as not indicated. Predetermination on borderline teeth heads this off.
5. No narrative on the reason for failure. Retreatment needs a documented reason: persistent apical pathology, a missed canal, coronal leakage, recurrent decay. Without it the claim is more likely to pend, and the same narrative supports the claim against a frequency or history denial.

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.

Attach both films to the claim line. Many systems store images at the patient level, and the clearinghouse needs them linked to the specific claim.

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 missed in 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), root-canaled by another office four years earlier. The pre-op periapical shows an existing root canal filling, 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 missed canal located and negotiated, canals re-cleaned and shaped, calcium hydroxide placed, temporary restoration.
2. Visit 2 (two weeks later): obturation completed, post-op periapical 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. Bill the buildup (D2950) and crown on their own dates of service, not on the retreatment date, to avoid same-day sequencing denials.

If the carrier pends for proof of prior treatment, the pre-op film answers it. If it 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.