D1110 vs D1120: Prophylaxis Coding Compliance Explained

September 12, 2023

Updated 01/2026

In dental billing, compliance isn’t optional — it’s your professional duty.

Every CDT code you enter represents more than a billing choice; it’s a legal and clinical record of the care you provided. Yet even the most experienced dental professionals can be caught off guard by something as “simple” as D1110 and D1120.

Let’s make sure your team is fully aligned with ADA guidelines, HIPAA regulations, and best documentation practices — so your claims stand up to scrutiny every time.

Where the Confusion Begins

In recent years, the CDT code set has evolved rapidly — with 201 changes since 2021 and 60 more coming in 2026. For compliance-focused teams, that’s not just trivia. It’s a reminder that coding accuracy must evolve with regulation.

But the confusion isn’t always about new codes. It’s often about long-standing ones like D1110 (Adult Prophylaxis) and D1120 (Child Prophylaxis).

According to the ADA, these codes are defined as follows.

D1110 – Adult Prophylaxis:

Removal of plaque, calculus, and stains from the tooth structures and implants in the permanent and transitional dentition. It is intended to control local irritational factors.

D1120 – Child Prophylaxis:

Removal of plaque, calculus, and stains from the tooth structures and implants in the primary or transitional dentition. It is intended to control local irritational factors.

What the ADA and Federal Regulations Require

Under HIPAA, CDT codes are the national standard for reporting dental services. The ADA’s Council on Dental Benefit Programs maintains those codes under strict regulatory oversight.

In 1991, the ADA adopted its “Age of Child” policy, which clarifies:

“When dental plans differentiate coverage of specific procedures based on child or adult status, this determination should be based on the clinical development of the patient’s dentition.”

That means if a patient has permanent dentition, the proper code to report is D1110, regardless of the patient’s chronological age. This point is re-emphasized by several entries in the ADA’s 2026 Coding Companion manual.

The insurance company may remap D1110 to a child prophy (D1120) with a lower reimbursement, per the provisions outlined in the dental benefit plan guidelines — but your responsibility is to document and code for what you actually do. Report the correct code based on dentition, but attach a narrative (or a copy of the clinical notes) justifying your code selection. Also, make a request for alternate benefits if the code selection does not meet the payor’s guidelines. In this case, the attached note may state, “The patient has lost all primary teeth and is therefore considered a D1110 adult prophylaxis, as per ADA definitions. If benefits are not available for D1110, please pay the alternate benefit of a D1120 child prophylaxis.”

The Compliance Checklist Every Dental Office Should Follow

Stay on the right side of documentation, coding, and regulatory accuracy by following these three core principles:

Verify and Document Coverage Rules

Before treatment, verify the insurance plan’s age limitation for D1110.

Code For What You Actually Do

Always report procedures based on clinical presentation — not insurance plan age limitations

Document Clearly

Include a concise narrative to justify the code selection.

Example: “Patient presents with permanent dentition. D1110 performed per ADA definition.”

Why Compliance-Minded Practices Choose eAssist

At eAssist Dental Solutions, our certified Success Consultants specialize in HIPAA-compliant dental billing and documentation support.

We don’t just file claims — we ensure your coding practices reflect clinical accuracy, regulatory integrity, and ADA-defined standards. That means fewer compliance risks, better documentation, and more confidence in your reporting process.

👉 Complete this quick form to learn how eAssist can strengthen your team’s compliance.