D5120 is the CDT code for a complete denture, mandibular - the full removable prosthesis that replaces all teeth in the lower jaw. It covers a definitive, custom-fabricated lower denture for a fully edentulous mandible. This code pairs with D5110 when both arches are being restored.
Last updated June 2026 · Reviewed by the PracticeAlpha billing team
Get help with D5120 claims →Use D5120 when fabricating and delivering a definitive complete lower denture for a fully edentulous mandible. The patient must have no remaining natural teeth in the lower arch. This is a custom-fabricated removable prosthesis, not a temporary or immediate denture.
Common clinical scenarios: Patient who has been fully edentulous in the lower arch for some time and needs a first full lower denture. Patient replacing an old, worn lower denture that cannot be adequately relined or repaired. Patient completing full-mouth rehabilitation where both arches are being restored (bill D5110 for the upper and D5120 for the lower).
Do NOT use D5120 for: Immediate complete lower dentures placed on the same day as extractions (use D5130). Partial lower dentures where some natural teeth remain (use D5213 or D5214 for removable partial dentures). Implant-supported lower dentures (use implant prosthetics codes such as D6110-D6119 range). Relining an existing lower denture (use D5731 or D5741). Tissue conditioning (use D5851).
The missing tooth clause is a major billing consideration for D5120. Many plans exclude coverage for teeth that were already missing before coverage began. Always confirm the patient's coverage effective date and compare it to the extraction history before submitting the claim.
This is the most common denial for complete denture claims. Many dental plans will not cover a prosthesis for teeth that were already missing before the patient enrolled in the plan. If the patient lost all lower teeth before their coverage started, the plan may deny D5120 entirely. Check the patient's enrollment date and confirm extraction timing. Some plans have a waiting period before prosthetic benefits apply (often 12 months). Learn more about how this affects claims on our missing tooth clause guide.
Most plans allow replacement once every 5 to 7 years. If the patient received a complete lower denture within that window and is requesting a replacement, the claim will likely be denied unless you submit documentation that the existing denture is unserviceable. "Patient wants a new denture" is not sufficient. Document that the prosthesis cannot be adequately relined, repaired, or adapted.
D5120 requires the arch to be completely edentulous. If the patient has any remaining natural teeth in the lower arch, this code is incorrect. Use a removable partial denture code instead. Billing D5120 when teeth are present triggers an automatic denial.
Many plans require pre-authorization before fabrication begins. Skipping this step and submitting the claim after delivery often results in a denial or reduced reimbursement. Verify the plan's pre-auth requirements, submit with a panoramic or full-arch radiograph and clinical notes, and wait for approval before starting the case.
Confirms complete edentulism of the lower arch. Documents bone levels and any retained roots or pathology. Most payers require this as part of the pre-auth submission.
Document that the mandible is fully edentulous and the clinical rationale for the prosthesis. For replacements, explain why the existing denture cannot be relined or repaired.
Verify coverage start date and compare it to the patient's extraction history. Confirm whether the missing tooth clause applies and whether a waiting period has been satisfied.
Check the patient's plan before starting fabrication. Submit pre-auth with radiographs and clinical notes. Document the approval number and include it on the claim form.
For replacement dentures, documenting when the patient became edentulous helps establish that the frequency limitation has been met and supports the clinical need for a new prosthesis.
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Learn about our billing servicesD5120 is the CDT code for a complete denture, mandibular. It covers the fabrication and delivery of a definitive full lower denture for a patient who has no remaining natural teeth in the lower arch. It is the lower-arch equivalent of D5110.
D5110 is for the complete upper (maxillary) denture. D5120 is for the complete lower (mandibular) denture. The arch is the only distinction. Both are billed when a patient receives full dentures in both arches at the same time.
Yes. Many plans apply a missing tooth clause that excludes coverage for teeth already absent before coverage began. If the lower teeth were lost before the patient enrolled, the plan may deny D5120. Always verify the enrollment date and extraction history before treatment.
Most dental plans allow a replacement complete denture every 5 to 7 years. Replacing before that window requires documentation that the existing denture is unserviceable and cannot be relined or repaired.
A panoramic or full-arch radiograph confirming complete edentulism, clinical notes with the rationale for the prosthesis, verification of coverage and enrollment date, and pre-authorization (if the plan requires it). For replacements, also document why the existing denture cannot be adequately serviced.
No. D5120 is a definitive denture delivered after healing. Immediate dentures placed on the same day as extractions use D5140 for the mandibular arch. D5120 is the final, permanent prosthesis - not the transitional one.
Search all 206 CDT codes in our dental coding guide.