D5120 is the CDT code for a conventional complete denture for the lower (mandibular) arch — a full removable prosthesis that replaces all of the patient's natural lower teeth. It's reported for a standard (non-immediate) complete lower denture, distinct from the maxillary version (D5110) and the immediate-denture codes (D5130/D5140).
Informational only — confirm the official CDT descriptor and your payers' rules independently. This is general guidance, not billing, coding, or clinical advice.
When to Use the D5120 Code
Report D5120 when a patient who is already edentulous in the lower arch (or has healed after extractions) receives a conventional complete mandibular denture. The ridge has had time to heal, so impressions are taken on settled tissue and the denture is delivered after laboratory fabrication rather than placed the same day teeth are removed.
Pick the code by arch and timing: D5120 is the lower conventional denture; D5110 is the upper (maxillary) conventional denture; D5140 is an immediate mandibular denture inserted the same day teeth are extracted. Don't use D5120 for an immediate denture, or for a partial denture (D5211–D5214) when natural teeth still remain in the arch.
Documentation & Clinical Scenarios
Complete dentures are a reviewed prosthetic benefit, so the chart should establish that the arch is edentulous and the prosthesis is warranted:
- Arch (mandibular) and confirmation the patient is fully edentulous there, or the dates teeth were removed and the arch has healed.
- Clinical notes covering the master impression, bite registration, wax try-in, and delivery/insertion date — many payers tie the benefit to the seat date.
- Prior-denture history — whether this is a first denture or a replacement, since replacements carry frequency limits.
- The code generally includes routine post-delivery adjustments within the normal delivery period; relines (D5750/D5751) and rebases are billed separately later.
Insurance & Billing Tips
- Verify benefits and the frequency rule first. Complete dentures commonly carry a replacement frequency limit (often once every 5–7 years per arch); a replacement filed inside that window may be denied.
- Confirm the seat-date rule. Many plans pay on the insertion/delivery date, not the impression date — this matters for claims that span a benefit year.
- Watch for missing-tooth and waiting-period clauses. Some plans exclude teeth lost before coverage began or impose a waiting period on new plans.
- Pre-authorize when in doubt. A pre-estimate confirms coverage, the patient portion, and whether the arch qualifies.
- Bill relines/rebases separately with their own codes; they are not part of the D5120 fee.
Example Case
A 71-year-old patient lost the last of her lower teeth months ago and the ridge has fully healed. The dentist plans a conventional complete mandibular denture. The office verifies benefits, confirms there is no lower denture on file within the plan's 5-year frequency limit, and submits a pre-estimate. The master impression, bite registration, and wax try-in are completed, and the finished denture is delivered. The claim is filed as D5120 with the insertion date. Because benefits were verified and the arch was confirmed edentulous, the claim is paid at the expected level.
Patients call about "getting a lower denture," not D5120. DentalReception AI answers and books those calls 24/7, captures insurance details for clean intake, and routes clinical and billing questions to your team. See denture calls, or book a demo.
Frequently Asked Questions
What's the difference between D5120 and D5140?
Timing. D5120 is a conventional complete mandibular denture delivered after the arch has healed, while D5140 is an immediate mandibular denture inserted the same day the remaining teeth are extracted. Both cover the lower arch, but immediate dentures involve same-day insertion and typically need a reline or rebase later as the ridge remodels — so code by whether teeth were removed that day.
Does D5120 include later relines or adjustments?
It generally includes the routine post-delivery adjustments within the normal delivery period. It does not include later relines (D5751) or rebases, which are separate procedures with their own codes billed when clinically needed. Document each subsequent reline or rebase on its own with its own justification.
How often will insurance pay for a complete lower denture?
Most plans apply a replacement frequency limit, commonly once every five to seven years per arch, and some impose a waiting period on new plans or exclude teeth lost before coverage began. Verify the specific frequency and any missing-tooth clause before treatment so the patient knows whether a replacement denture is covered.
Do I need a pre-authorization for a D5120 denture?
Many plans recommend or require a pre-estimate for complete dentures. Submitting one confirms the frequency limit hasn't been hit, clarifies whether the plan pays on the impression or insertion date, and establishes the patient's out-of-pocket portion — letting you quote an accurate estimate before fabrication begins.
Confirm the current CDT descriptor and your specific payer policies before billing — browse the full dental code library or see our insurance verification feature.