D3426 is the CDT code for each additional root treated beyond the first during the same apicoectomy surgery.
- When to use: A premolar or molar apicoectomy treats more than one root, billed as one unit per root beyond the first.
- When not to use: The first root goes on D3421 for premolars or D3425 for molars, and front teeth use D3410 as a single per-tooth code.
- Billing note: D3426 rejects without D3421 or D3425 on the same tooth and date, so post the whole surgery on one date.
What D3426 covers
D3426 is the apicoectomy family’s add-on: one unit for each root beyond the first that is resected during the same surgical session. The base code, D3421 on a premolar or D3425 on a molar, pays for the surgery itself (flap, bone access, closure) and the first root. D3426 pays for the additional root-end work inside the already-open field. Its descriptor calls it typical of premolar and molar surgery and, like every code in the family, excludes retrograde filling material, which is D3430 per root sealed.
Because it is an increment and not a procedure, three rules follow:
- It never stands alone. Without a base apicoectomy on the same tooth and date, the line has nothing to attach to.
- Its unit is the root, counted from the operative note.
- A sealed additional root is always two lines: the D3426 unit plus a D3430 unit.
Where the code attaches, and where it doesn’t
D3421 and D3425 both say first root in their nomenclature, and both direct you to D3426 when more than one root is treated. D3410, the anterior code, has neither the root qualifier nor the pointer, so an anterior apicoectomy is a per-tooth service. The whole surgical block, from apicoectomy to hemisection, is set out in the root canal dental codes guide.
That leaves a two-rooted anterior tooth, occasionally a mandibular incisor, in a gap the codebook doesn’t squarely address. The typically-premolar-and-molar language describes the usual case rather than banning others, but because D3410 has no cross-reference, carrier claim edits are generally built around the premolar and molar pairings.
Treat a D3410-plus-D3426 claim as an exception to document: an operative note naming both roots and a radiograph showing them. If the add-on still rejects, the codebook’s fallback for procedures its codes don’t describe is D3999 with a narrative.
Counting units the way an auditor does
An auditor reads the unit count against two documents:
- The operative note. Roots resected must be named individually (mesiobuccal, distobuccal, palatal), because the count is roots treated, not roots the tooth has. A three-rooted molar with only two root ends resected supports one unit, not two.
- The radiograph. The pre-op film establishes the lesion; the post-op film, where the plan wants one, shows the resections. A unit count that outruns what the images show is the claim that gets refunded.
D3426 counts roots, not canals. Upper first premolars often have two roots, lower molars sometimes have an extra distolingual root, and the mesiobuccal root of an upper molar is one root even when it carries two canals. Bill from what the surgeon documented.
Pricing: an increment, not a downgrade
Fee schedules price D3426 well below the base code, because the expensive parts of the surgery (anesthesia, flap, access, closure) are paid once through D3421 or D3425. A low allowance on the add-on is the design, not a bundling error to appeal. What to check on the EOB:
- Unit count paid versus billed. Plans occasionally process multi-unit lines as one.
- Units on one line or repeated lines. Clearinghouse and payer preferences differ, and a rejected multi-unit line sometimes just needs re-splitting.
- Frequency rules on the family. These are plan-dependent, and the window catches the add-on along with the base code. Hawaii Dental Service’s published endodontic guidelines, for one, make a repeat apicoectomy by the same office within 24 months not billable to the patient.
The base code carries the clinical justification, meaning why surgery rather than retreatment on D3348 or its siblings. D3426 needs no separate narrative beyond the named roots.
Getting it right in the PMS
- Link D3426 to its base codes. A dependent-procedure rule requiring D3421 or D3425 on the same date and tooth stops orphan lines at entry.
- Allow multiple units on both D3426 and D3430, or every three-rooted molar undercounts.
- Put the unit logic in the procedure label. “Apicoectomy, each additional root (add-on to D3421/D3425)” makes the structure visible at selection.
- Post the whole surgery on one date. Split-date posting is the most common way the add-on gets separated from its base.
- Check units against the operative note’s root list before submission, not after the EOB.
For how multi-unit lines are entered on the claim form, see the ADA dental claim form guide.
FAQs
- Which codes does D3426 go with?
- D3421 (premolar, first root) and D3425 (molar, first root). Both descriptors direct you to D3426 when more than one root is treated at the same surgery, and its own descriptor says it is typically used with premolar and molar surgeries. It cannot be billed alone: a D3426 with no base apicoectomy on the same tooth and date rejects as an unsupported add-on. The anterior code D3410 has no first-root language and no pointer to D3426, so pairing them is a rare, documented exception for a genuinely two-rooted anterior tooth, not a standard combination.
- How many units of D3426 do I bill?
- One per root treated beyond the first, at the same surgical session, on the same tooth. A two-rooted upper first premolar with both root ends resected is D3421 plus one unit. A three-rooted upper molar with all roots treated is D3425 plus two units. The count must match the roots named in the operative note, not the tooth's typical anatomy, because root anatomy varies and a reviewer will not assume the extra roots were treated.
- Does D3426 include the retrograde filling on that root?
- No. Like the base codes, D3426 excludes retrograde filling material. The seal is D3430, reported per root sealed, so an additional root that was resected and sealed generates two lines: a D3426 unit and a D3430 unit. More than one filling in a single root goes to D3999 with a description rather than a second D3430.
- Why did the plan pay D3426 at a fraction of the base code?
- Because add-on codes are priced as increments, not as full procedures. The flap, access, and closure are paid once through the base code, and D3426 covers the extra work of resecting another root in the same surgical field, so most fee schedules set it well below D3421 or D3425. That is expected pricing, not a downgrade to appeal. Check the unit count on the EOB instead: a plan that paid one unit against a claim for two made a processing error. Plan-dependent frequency rules on the family can also clip repeat surgeries.
Related codes
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CDT codes are maintained by the American Dental Association. This page is an editorial billing guide, not the official ADA code descriptor. Verify current coverage policies with each carrier before submitting claims.