D5228 is the CDT code for an immediate lower partial denture on a flexible nylon base, seated the same day the failing lower teeth are extracted.
- When to use: The patient keeps some lower teeth, and a definitive flexible partial made before surgery goes in on the same date as the extractions.
- When not to use: A flexible lower on a healed ridge is D5226, the upper immediate is D5227, a resin lower immediate is D5222, and a temporary stayplate is D5821.
- Billing note: The nylon base resists relining, so the signed estimate should include a remake after healing, which usually lands inside the plan's partial frequency window.
What D5228 covers
D5228 reports an immediate partial denture on the mandibular arch with a flexible base. The prosthesis is a tissue-toned, metal-free nylon thermoplastic with clasps formed from the base material. It is made from impressions taken while the failing lower teeth are still present, then seated over the fresh extraction sites the day of surgery.
Clasping, rests, replacement teeth, records, fabrication, delivery, and the code’s limited follow-up care are all in the one fee. The code was added in CDT 2022; the conventional lower flexible partial has its own long-standing code, D5226.
It does not cover:
- The healed-ridge lower flexible partial (D5226) or the immediate upper flexible partial (D5227).
- Immediate lower partials in other materials: resin is D5222, and cast metal framework is D5224.
- The same-day extractions, billed per tooth on D7140 or D7210.
- A transitional lower flipper or stayplate worn while definitive treatment is pending. That is D5821.
- An immediate complete lower denture when the arch is fully cleared. That is D5140.
Three problems, one prosthesis
Each part of this code is manageable alone. Together, they define the case:
- Immediate means the ridge will change under the prosthesis. That is the nature of seating over fresh extraction sites, and it is why the code’s scope excludes future relines from the delivery fee.
- Mandibular means the change comes fast and retention starts out worse. The lower ridge resorbs more aggressively than the upper, and there is no palatal coverage to stabilize the base.
- Flexible means the standard fix doesn’t apply cleanly. Nylon thermoplastic is the partial material labs most often decline to reline, and it generally can’t be repaired or added to. That is the same limitation as on the conventional D5226, now on a prosthesis certain to need a refit.
The billing consequence: a resin immediate (D5222) plans for a reline claim that may be covered or denied (D5741 chairside, D5761 lab). A flexible immediate plans for a second prosthesis, either a remade flexible partial or a conversion to resin or cast metal on the healed ridge. Because the D5228 claim starts the plan’s partial frequency clock, that second prosthesis typically processes as patient-pay.
Frequency windows and their exceptions are plan-dependent. In every plan, the conversation has to happen before the first prosthesis, not after.
Coverage behavior to verify
Flexible bases draw the same payer responses on the lower arch as elsewhere, and the immediate version adds one more:
- Downgrade. Paid at the resin-immediate allowable under an alternate-benefit clause; the patient owes the gap.
- Exclusion. Flexible bases are not a covered benefit; the patient owes the fee.
- Code recognition. D5228 is a 2022 addition, and plans administered against older certificates sometimes pend it or map it to the nearest listed partial benefit. A brief narrative stating material, arch, and same-day delivery shortens the review.
Verification should return which of the first two applies, the partial frequency window and any prior-prosthesis history, and how the plan treats a replacement prosthesis after an immediate. Those answers, not the fee schedule, set the case price.
Top reasons D5228 loses money
- The second prosthesis wasn’t in the estimate. The remake or conversion denies on frequency and becomes a surprise balance. This is the expensive one.
- Flexible base downgraded or excluded. Inherited from the material class; which form it takes is plan-dependent.
- Wrong sibling code. Healed-ridge delivery billed as immediate, or the reverse (the extraction dates on the claim expose it), or the upper D5227 billed on a lower case.
- Missing-tooth clause applied to teeth lost before the effective date, per tooth or against the whole prosthesis depending on the plan.
- Interim intent billed as definitive. A flexible appliance the treatment plan calls temporary belongs on D5821. Putting it on D5228 starts a frequency clock the definitive prosthesis will collide with.
Documentation and follow-up codes
On the claim: the delivery-date service line with the mandibular arch designation, extractions per tooth on the same date, the pre-extraction radiograph and treatment plan attached or ready, and a short narrative if the plan predates the 2022 codes.
In the chart: the material (flexible nylon, metal-free, with the brand if the office tracks it), the date each replaced tooth was lost, and ridge condition at delivery. Most important on this code, document the conversation that the nylon base likely cannot be relined, and that the healed-ridge plan is a remake or conversion at the patient’s cost if frequency blocks coverage. The signed pre-treatment estimate should show the numbers for both prostheses.
In the PMS, set up follow-up on the lower partial codes: adjustments on D5422, and reline attempts (if a lab accepts one) on D5741 or D5761, not the maxillary or complete-denture codes. Schedule the healing-phase evaluation at delivery so the second stage is a planned decision, not an emergency.
FAQs
- What's the difference between D5228 and D5226?
- Delivery timing. D5226 is the conventional lower flexible partial, delivered on a healed ridge. D5228, added in 2022 with its maxillary counterpart D5227, is made before the extractions and seated the same day the lower teeth come out. The material and arch are the same; the surgical date of service separates them.
- What's the difference between D5228 and D5227?
- The arch. D5228 is mandibular and D5227 is maxillary. It matters beyond the claim field: the lower ridge resorbs faster and offers less bearing surface, so the post-healing fit problem every immediate case has arrives sooner on a D5228, and the flexible material's resistance to relining leaves few ways to fix it short of a remake.
- How should the office price a D5228 case for the patient?
- As two prostheses, in the worst case. The first is the immediate flexible partial, which many plans downgrade to the resin allowable or exclude as a non-covered flexible base (plan-dependent, so verify which). The second is the healed-ridge solution: a reline if a lab will attempt one on the nylon, but more often a remade flexible partial or a conversion to resin or cast metal. That second claim usually falls inside the plan's partial frequency window as patient responsibility. The signed estimate should show both numbers.
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.