The short version
# D4355 Dental Code: Full-Mouth Debridement Before an Exam
D4355 is the CDT code for a full-mouth debridement performed when heavy deposits prevent the dentist from completing a comprehensive evaluation and diagnosis. The purpose is to expose the teeth and tissues so the patient can return for the full exam on another date. It isn't a hard prophy and it isn't periodontal treatment selected after diagnosis.
- Bill D4355 when plaque and calculus are so extensive that the dentist can't complete the planned comprehensive evaluation.
- The patient returns for the full evaluation and diagnosis on a later date. D0180 can't be completed on the same date as D4355.
- D1110 is a preventive cleaning after evaluation. D4346 follows a gingivitis diagnosis. D4341 and D4342 treat diagnosed periodontitis.
- Minnesota Medicaid allows D4355 once every five years and bars it on the same date as D1110, D0150, D0160, or D0180. Delta's clinical policy lists once per lifetime.
- In a worked PPO claim, a $200 fee becomes a $140 allowable. At 80%, the plan pays $112, the patient owes $28, and the office adjusts $60.
- Record the deposits that blocked the examination, the areas debrided, the incomplete evaluation, and the scheduled return for diagnosis.
What is D4355?
D4355 removes enough full-mouth deposits to let the dentist perform a comprehensive evaluation at a later visit. It's a preliminary service.
| Fact | D4355 |
|---|---|
| CDT category | Periodontics |
| Unit | Full mouth |
| Trigger | Deposits prevent a comprehensive evaluation and diagnosis |
| Required next step | Comprehensive evaluation on a subsequent date |
| Descriptor history | Revised for CDT 2023 to make the later-evaluation sequence explicit |
| Public fee reference | Oregon Medicaid listed $115.62, effective January 1, 2025 |
The ADA's D4355 guide explains that the service is reported even if the patient fails to return, as long as the debridement was delivered with the expectation of the later evaluation.
When do you bill D4355?
Bill D4355 when the dentist begins the evaluation but can't see or measure enough because heavy deposits cover the teeth and gingival margins.
- Document that the planned comprehensive evaluation could not be completed.
- Describe the amount and distribution of plaque and calculus that blocked the examination.
- Debride the full mouth enough to permit the later diagnostic visit.
- Schedule the patient to return for the comprehensive oral or periodontal evaluation.
- Delay the treatment diagnosis until the dentist completes that later evaluation.
Difficulty and chair time alone don't support D4355.
D4355 vs D1110, D4346, and D4341
The deciding point is whether diagnosis came before treatment or had to wait until after deposit removal.
| D1110 prophy | D4355 | D4346 gingivitis scaling | D4341 root planing | |
|---|---|---|---|---|
| Evaluation | Completed | Prevented by deposits | Completed first | Completed first |
| Diagnosis | Generally healthy or localized gingivitis | Deferred to later visit | Generalized moderate or severe gingivitis without periodontitis | Periodontitis |
| Purpose | Preventive cleaning | Enable diagnosis | Treat gingival inflammation | Treat diseased root surfaces |
| Unit | Full mouth | Full mouth | Full mouth | Per quadrant |
The common miscode is D4355 for a difficult recall cleaning after the dentist already completed the exam. Once the diagnosis is known, report the procedure that matches it.
What does insurance actually do with D4355?
Frequency can be unusually restrictive. Minnesota Health Care Programs allows D4355 once every five years and won't pay it with D1110, D0150, D0160, or D0180 on the same date. Delta Dental's clinical criteria list D4355 once per lifetime. Those limits are payer examples, so verify the patient's actual contract and prior history.
The ADA says D0120 or D0150 can be reported on the debridement date only if every component of that evaluation was actually completed. D0180 is different: it must occur later. Don't force an evaluation code onto the first visit when deposits prevented its full scope.
- Office fee: $200
- Contracted allowable: $140
- Contractual adjustment: $60
- Plan payment at 80%: $112
- Patient coinsurance: $28
Why does D4355 get denied?
- The note calls the cleaning difficult but doesn't state that deposits prevented a comprehensive evaluation.
- D0180 or another conflicting evaluation appears on the same date.
- D1110, D4346, D4341, or D4342 is reported as though diagnosis and definitive treatment were also completed.
- The patient has a prior D4355 inside a five-year or lifetime plan limit.
- The claim lacks a return plan for the later comprehensive evaluation.
If the clinical note shows a completed diagnosis before scaling, review whether another code is correct instead of appealing the wrong sequence.
What documentation gets D4355 paid?
- Name the intended comprehensive evaluation and state which parts could not be completed.
- Describe the deposit amount, locations, and how it blocked visual or periodontal assessment.
- Record the full-mouth debridement work completed and the patient's tolerance.
- Avoid a final periodontal diagnosis that the dentist could not yet establish.
- Document the return date or follow-up plan for D0150, D0180, or the evaluation that fits.
- Check prior D4355 history under the patient's plan before submission.
Common questions about D4355
Can D4355 and D0180 be billed on the same day?
No. The ADA says D0180 must be delivered on a later date because D4355 exists to make that comprehensive periodontal evaluation possible. Document why deposits blocked the evaluation, complete the removal, and schedule the periodontal evaluation for a subsequent visit rather than placing both lines on one date.
Can D4355 and D0150 be billed together?
They can be reported together only if the dentist actually completed every part of D0150 despite the deposits. That's different from the common D4355 case where the evaluation remains incomplete. Minnesota Medicaid explicitly bars the combination on one date, so plan rules can be stricter.
What if the patient never returns after D4355?
The ADA says the delivered D4355 remains reportable when the office expected the patient to return for the comprehensive evaluation. Keep the return recommendation and outreach in the record. The patient's later decision doesn't change what was performed at the first visit.
Is D4355 a substitute for scaling and root planing?
No. D4341 and D4342 treat diagnosed periodontal disease by quadrant. D4355 comes before the comprehensive diagnosis when deposits block it. The later evaluation determines whether the patient needs root planing, gingivitis treatment, a prophylaxis, or another plan. Don't use D4355 as a holding code after the diagnosis is already complete.
Find the missing second appointment
Don't close a D4355 visit until you've scheduled the later comprehensive evaluation.
Sources
- ADA, Guide to Reporting D4355
- ADA News, six CDT codes you should know
- ADA, Guide to Reporting D4346
- Delta Dental, clinical criteria and utilization management
- Minnesota Health Care Programs, Dental Services
- Oregon Medicaid, June 2025 fee schedule
- ADA, Frequent General Questions Regarding Dental Procedure Codes
- FAIR Health Consumer, dental cost lookup
CDT codes and nomenclature are copyright © American Dental Association. This guide explains the code in plain language; the current CDT manual is the authoritative source.
