D2140 is the CDT code for a one-surface amalgam (silver) filling on a primary or permanent tooth — a single-surface restoration that repairs decay or damage on one surface of a tooth. It is reported per restoration, and the code is chosen strictly by the number of surfaces involved.
Informational only — confirm the official CDT descriptor and your payers' rules independently. This is general guidance, not billing, coding, or clinical advice.
When to Use the D2140 Code
Report D2140 when a tooth is restored with amalgam material and the restoration involves a single surface — for example, a small occlusal cavity on a molar or a one-surface lesion on a baby tooth. It applies to both primary and permanent teeth, since amalgam codes are not split by dentition.
Pick the code by surface count: D2140 is one surface, D2150 is two surfaces, D2160 is three surfaces, and D2161 is four or more. Don't confuse amalgam codes with the resin-based composite (tooth-colored) codes — a one-surface composite on a posterior tooth is D2391, and a one-surface anterior composite is D2330. Coding by the actual material placed matters, because amalgam and composite are different procedures and may be reimbursed differently.
Documentation & Clinical Scenarios
Fillings are routine, but the chart should still show what was treated and why:
- Tooth number and the specific surface restored (e.g., occlusal on tooth #19).
- The diagnosis — caries, fracture, or a failing prior restoration — that justifies the filling.
- The material (amalgam) and that exactly one surface was involved.
- Supporting evidence such as a bitewing radiograph or chart note when decay isn't clinically obvious.
When a restoration spans more than one surface, code up to the appropriate multi-surface code rather than reporting two single-surface fillings on the same tooth. Local anesthesia and the exam are reported under their own codes when applicable, not bundled into D2140.
Insurance & Billing Tips
- Verify the restorative benefit. Most plans cover basic fillings, often at a coinsurance level (commonly around 80%) after any deductible.
- Count surfaces accurately. Billing two separate one-surface codes on the same tooth and date is typically combined by the payer into a single multi-surface restoration.
- Check replacement frequency. Plans often limit how soon the same surface on the same tooth can be re-restored (e.g., once every 24 months).
- Confirm the deductible. Basic restorative work usually applies the plan deductible, which affects the patient's portion on the first claim of the year.
- Report each tooth on its own line with the correct surface designation so the claim adjudicates cleanly.
Example Case
A patient presents with a small cavity on the chewing surface of a lower molar. The dentist removes the decay and places a single-surface amalgam restoration. The visit is coded D2140 for tooth #19, occlusal surface, with a bitewing on file showing the lesion. Because the office verified the patient's basic restorative benefit and reported one surface accurately, the claim is paid at the expected coinsurance with no surprise to the patient.
Patients call about "getting a filling" or "a cavity that hurts" — not D2140. DentalReception AI answers and books those calls 24/7, captures insurance details for clean intake, and routes clinical and billing questions to your team. See how it handles filling calls, or book a demo.
Frequently Asked Questions
What's the difference between D2140 and D2150?
Surface count. D2140 is a one-surface amalgam filling, while D2150 is a two-surface amalgam filling on the same kind of tooth. The material (amalgam) is identical — only the number of surfaces restored changes the code. If a single restoration covers two surfaces, report D2150 once rather than two D2140 lines.
Is D2140 for silver fillings or tooth-colored fillings?
D2140 is specifically for amalgam (silver) material. A tooth-colored, resin-based composite filling uses a different code — D2391 for one posterior surface or D2330 for one anterior surface. Code by the material actually placed, since some plans reimburse amalgam and composite at different rates.
How often will insurance cover a filling on the same tooth?
Many plans apply a replacement frequency limit, commonly allowing the same surface on the same tooth to be re-restored only once every 24 months or so. Re-treating sooner can be denied as a frequency conflict, so verifying the patient's history and benefit before treatment helps set an accurate estimate.
Do I need a pre-authorization for a D2140 filling?
Routine single-surface fillings usually don't require pre-authorization, but verifying the basic restorative benefit and any deductible beforehand lets you quote the patient an accurate out-of-pocket amount. Keep the diagnosis and surface clearly documented in case of a post-payment review.
Confirm the current CDT descriptor and your specific payer policies before billing — browse the full dental code library or see our insurance verification feature.