The short version
# D1120 Dental Code: Child Prophylaxis by Dentition
D1120 reports prophylaxis for a patient with child dentition. CDT separates D1120 from D1110 by dentition, not by a birthday. Plans can still use age in benefit design, which is why an accurate claim sometimes returns with a child-rate or adult-rate adjustment.
- Bill D1120 when the prophylaxis performed matches child dentition.
- Use D1110 when adult dentition is present. The ADA says neither code has an age restriction in its descriptor.
- A payer can apply an age-based benefit, but the office should still report the procedure performed.
- The service removes plaque, calculus, and stains to control local irritants in child dentition. It isn't periodontal maintenance or generalized-inflammation scaling.
- One public Delta 2026 plan limits D1120 to once every six months.
- In a worked claim, a $110 office fee becomes a $75 allowable. The plan pays $75, the patient owes $0, and the office adjusts $35.
What is D1120?
D1120 is the prophylaxis code for child dentition. The provider removes local deposits and stains from the teeth present. The code isn't selected from the patient's age alone, and a difficult prophylaxis doesn't create a different prophylaxis code.
| Fact | D1120 |
|---|---|
| CDT category | Preventive |
| Code criterion | Child dentition |
| Unit | One prophylaxis visit |
| Age in CDT criterion | None |
| Public fee references | Oregon Medicaid: $54.85; DC Medicaid: $47 in 2025 |
When do you bill D1120?
Use D1120 when the patient's dentition and completed cleaning support the child procedure.
- Record the dentition present at the visit.
- Note plaque, calculus, stains, inflammation, and bleeding.
- Document the instrumentation and polishing performed.
- Check prior D1110, D1120, D4346, and D4910 history.
D1120 vs D1110
Dentition selects the prophylaxis code. Plan age affects payment, not the clinical report.
| D1120 | D1110 | |
|---|---|---|
| CDT decision | Child dentition | Adult dentition |
| Fixed age in code | No | No |
| Main chart evidence | Dentition and deposits | Dentition and deposits |
| Oregon Medicaid example | $54.85 | $71.15 |
What does insurance actually do with D1120?
A published Delta California plan allows D1120 once every six months. Other plans can group D1110 and D1120 in one prophylaxis frequency or define child and adult benefit tiers by age.
- Office fee: $110
- Contracted allowable: $75
- Contractual adjustment: $35
- Plan payment at 100%: $75
- Patient balance: $0
Why does D1120 get denied?
- The prophylaxis history doesn't clear the shared frequency limit.
- The payer doesn't pay the submitted code under its age tier.
- The chart doesn't identify child dentition.
- The note doesn't support a prophylaxis service.
- Eligibility wasn't active on the service date.
What documentation gets D1120 paid?
- Record the dentition present.
- Document plaque, calculus, stains, inflammation, and bleeding.
- Describe instrumentation and polishing.
- Note oral-hygiene instruction.
- Check all prophylaxis and periodontal-maintenance history.
- Save the plan's age and frequency response.
Common questions about D1120
What age is D1120 for?
CDT doesn't set an age. The ADA says dentition, not age, chooses between D1120 and D1110. A payer may still apply an age edit, so verify the member contract. Record the patient's dentition and the preventive work completed in the chart and claim.
Can a teenager receive D1120?
Yes, when child dentition supports the procedure. A teenager with adult dentition supports D1110 instead. Document whether the patient has primary, transitional, or permanent dentition instead of using the birthday alone. Then check whether the payer applies an age-based benefit edit.
Can fluoride be billed with D1120?
Yes, when a separate fluoride procedure is delivered and documented. The D1206 guide covers varnish. Record the product, route, and separate clinical reason. Payment can still depend on age, risk, frequency, and the member's fluoride benefit for that treatment date.
Does more calculus change D1120 to D1110?
No. Dentition separates the two prophylaxis codes. Heavy deposits can make the appointment harder, but they don't change the patient's dentition. If disease findings support another procedure, document that diagnosis and select the service the dentist actually performed that day.
Let the dentition lead the claim
Before filing, match the prophylaxis to the patient's dentition and service history.
Sources
- ADA, bundling and downcoding examples
- ADA News, Dear ADA: Downcoding
- ADA, frequently asked questions regarding dental codes
- ADA, Downcoding PDF
- Delta Dental, 2026 California prophylaxis frequency
- New York Medicaid, January 2025 dental fee schedule
- Oregon Medicaid, June 2025 fee schedule
- Washington, DC Medicaid fee schedule, May 17, 2025
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.
