D5120 Dental Code: Lower Complete Denture Billing Guide

What D5120 covers

D5120 reports a conventional complete denture on the mandibular (lower) arch: a full-coverage removable prosthesis with a complete set of artificial teeth seated on an acrylic resin base, shaped to the patient’s healed lower alveolar ridge. The code includes diagnostic impressions, bite registration, wax try-in, laboratory fabrication, delivery, and initial post-delivery adjustments that fall within the standard delivery workflow.

It does not cover:

• Conventional complete denture on the maxillary arch. Use D5110.
• Immediate complete denture on the mandibular arch (delivered same day as extractions). Use D5140.
• Immediate complete denture on the maxillary arch. Use D5130.
• Partial dentures for patients who still have natural teeth in the lower arch. Use the D5211 to D5226 series for resin-based partials or D5213 to D5214 for cast metal frameworks.
• Implant-supported overdentures. Use the D6110 to D6113 series.
• Post-delivery adjustments after the standard included period. Use D5411 (adjust complete denture, mandibular).
• Relines, rebases, or repairs. Use D5731 or D5751 for mandibular relines, D5711 for rebases, and D5511 (repair base) or D5520 (replace teeth) for repairs.

The code is for the conventional workflow only: extractions have healed, the ridge has stabilized, and the denture is fabricated on a post-healing model.

When to bill D5120

Bill D5120 when:

• The patient has a fully edentulous mandibular arch (no remaining lower teeth).
• All extraction sites have healed sufficiently for definitive impressions (typically 6 to 8 weeks minimum after the last extraction, sometimes longer for the mandible).
• A conventional complete denture has been fabricated and delivered.

Do not bill D5120 for:

• Immediate dentures delivered the same day as lower-arch extractions. Use D5140.
• Partial dentures on a partially edentulous lower arch.
• Denture relines, rebases, or repairs performed on an existing lower denture.
• Same-day delivery following extractions, even if the denture was pre-fabricated weeks earlier. If the denture seats the day teeth come out, the workflow is immediate and the code is D5140.

D5120 versus D5140: conventional versus immediate

The code choice depends entirely on the delivery workflow, not the prosthesis itself.

Conventional (D5120):

• All lower teeth extracted first, with a healing period of weeks to months.
• Final impressions taken on a healed, stable mandibular ridge.
• Denture fabricated to fit the post-healing anatomy.
• Delivered at a later appointment.
• Better initial fit because the ridge has stabilized before fabrication.

Immediate (D5140):

• Impressions taken before extractions (typically a few weeks earlier).
• Denture fabricated on a pre-extraction model with the teeth to be removed cut off the cast.
• Delivered the same day as the extractions. Patient leaves the surgical visit with the denture in place.
• Requires reline or remake as the ridge resorbs over the following months.
• Allows the patient to have teeth during the healing period.

Billing D5120 on a case where the denture was delivered the day of extractions misrepresents the procedure and creates an audit risk. The clinical notes and the extraction dates will show the discrepancy if the carrier reviews.

Top reasons D5120 gets denied

Five issues account for most problems on this code:

1. Missing tooth clause (pre-existing edentulism exclusion). The patient lost their lower teeth before the policy effective date. Plans with this clause deny the entire denture. This is the single most common denial on complete denture codes for patients who are new to a plan.
2. Frequency limit hit. Most plans allow one complete denture per arch every 5 to 10 years. If the patient’s prior lower denture falls inside that window, the claim denies without an appeal documenting why a new fabrication is necessary (ridge changes beyond what a reline can address, structural failure, loss).
3. Wrong code for immediate denture. D5120 billed when the denture was delivered the same day as extractions. The carrier cross-references the extraction dates and either denies or requests a correction to D5140.
4. No pre-authorization. Many plans require predetermination on major prosthodontics. Submitting D5120 without prior approval when the plan requires it triggers a denial that’s hard to appeal.
5. Documentation of edentulism missing. Some carriers require proof that the arch is fully edentulous, typically a panoramic radiograph or a chart entry listing all missing teeth with extraction dates. Without it, the claim pends.

The missing tooth clause and dentures

The missing tooth clause is the most frustrating denial on complete denture cases because it catches offices after the work is done.

Here’s how it works: some plans exclude prosthetic coverage for teeth that were already missing when the patient enrolled. For a complete denture, that means if the patient was fully edentulous in the lower arch before the policy start date, the plan won’t pay for D5120 at all.

This clause is more common on individual and marketplace plans than on employer-sponsored group plans. It’s also more common on plans with lower premiums.

How to catch it: During benefits verification, ask the carrier directly whether the plan has a missing tooth clause or pre-existing condition exclusion on prosthodontics. If it does, ask what documentation would satisfy an exception (some plans allow coverage if the patient had a prior covered denture that needs replacement). Get the answer in writing or note the reference number from the call.

Documentation that supports the claim

The claim needs:

• Date of service matching the delivery date (not the impression or try-in dates).
• Arch designation for the mandibular arch (most PMS systems use area-of-oral-cavity code 02 or the lower arch indicator LA/MA).
• Panoramic radiograph or other documentation of edentulism if the plan requires it.

For the patient record, document:

• Impression dates and bite registration dates.
• Wax try-in date and patient acceptance.
• Delivery date.
• Material and shade selected.
• Initial post-delivery instructions and follow-up schedule.
• Date of last extractions (relevant to confirm the conventional rather than immediate workflow).
• Condition of the mandibular ridge (this supports later reline claims and helps if the carrier asks why a new denture was needed over a reline of the existing one).

If this is a replacement denture, also document:

1. The date the prior denture was first delivered (for frequency calculations).
2. The clinical reason the prior denture can no longer be serviced with a reline (ridge resorption, base fracture, material breakdown).
3. A pre-treatment panoramic radiograph showing the current ridge anatomy.

Relines and adjustments after delivery

Lower dentures need more post-delivery work than upper dentures. The mandibular ridge resorbs faster, and without palatal suction the prosthesis depends entirely on ridge fit and border seal. Plan for this in the treatment presentation so the patient knows what to expect and you have the follow-up codes ready to bill.

Adjustments:

• D5411 (adjust complete denture, mandibular). Bills per visit after the plan’s included adjustment period (usually 30 to 90 days post-delivery). Frequency varies by carrier.

Relines:

• D5731 (reline complete mandibular denture, chairside). For quick-turnaround adjustments to the tissue surface at the chair.
• D5751 (reline complete mandibular denture, laboratory). For a lab-processed reline that replaces the entire tissue surface.

Most plans don’t cover relines within 6 to 24 months of the original denture delivery. After that initial exclusion period, reline frequency limits are typically once every 12 to 36 months.

Repairs:

• D5511 (repair broken complete denture base, mandibular).
• D5520 (replace missing or broken teeth on the denture).

Example case

A 62-year-old patient had their remaining lower teeth extracted eight weeks ago. The extraction sites have healed and the ridge is stable. The patient has been wearing a maxillary complete denture (placed three years ago) and is now ready for a mandibular complete denture to restore the lower arch.

Treatment sequence:

1. Visit 1: diagnostic impressions and shade selection.
2. Visit 2: final impressions on custom trays.
3. Visit 3: bite registration and verification of vertical dimension with the existing upper denture.
4. Visit 4: wax try-in and patient verification of tooth position, phonetics, and esthetics.
5. Visit 5: delivery of the completed mandibular denture.

Billing steps:

1. Verify the patient’s plan and confirm denture coverage. Pull the frequency rule and confirm there’s no prior lower denture within the window. Check for a missing tooth clause (the extractions were recent, so the clause is less likely to apply, but confirm).
2. Submit a predetermination if the plan requires pre-authorization for major prosthodontics. Attach a panoramic radiograph showing the healed edentulous mandibular ridge.
3. After delivery, submit D5120 on the delivery date with arch designation 02 (lower).
4. Schedule the patient for a post-delivery adjustment at one week. Expect to see the patient for two to three adjustments in the first month as the lower denture settles.
5. Plan for a reline evaluation at six months. If the ridge has changed enough to affect retention, submit D5731 or D5751 after verifying the reline frequency rule on the plan.

What to get right in your PMS

The field names vary across Open Dental, Dentrix, Eaglesoft, Curve, and Carestream. The steps that matter:

1. Code the procedure as D5120, not D5110 or D5140. D5110 is the upper arch. D5140 is the immediate lower denture. A code mismatch is a common preventable rejection.
2. Bill on the delivery date. The impression, try-in, and bite registration visits are included in the D5120 fee and don’t get separate codes.
3. Set the arch designation correctly. Mandibular is arch 02 (or LA/MA depending on your system). Submitting with the wrong arch indicator will reject.
4. Attach the panoramic radiograph to the claim, not just the patient chart. The clearinghouse needs the image linked to the specific claim for carriers that require proof of edentulism.
5. Confirm your fee comes from your office fee schedule, not the carrier’s allowable. Submitting at the allowable undercuts secondary insurance coordination and reduces your recovery on dual-coverage patients.
6. Queue the post-delivery codes separately. D5411 adjustments and D5731/D5751 relines are distinct procedures on distinct dates of service. Don’t bundle them into the D5120 claim.

If your office sees recurring issues on complete denture claims, the root cause is almost always a missed frequency check or a missing tooth clause that wasn’t caught during verification. A pre-treatment checkpoint that confirms both before the first impression prevents most denials on this code.