D2393 is the CDT code for a three-surface, tooth-colored (resin-based composite) filling on a posterior tooth — a premolar or molar. It's reported when decay or fracture involves exactly three surfaces of a back tooth and is restored with composite, distinct from two-surface (D2392) and four-or-more-surface (D2394) posterior composites.
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 D2393 Code
Report D2393 when a posterior tooth is restored with a resin-based composite covering three surfaces — for example, a mesial-occlusal-distal (MOD) restoration. Common indications include decay or fracture that spans both interproximal surfaces and the chewing surface, or replacing a large failing restoration that now involves three surfaces.
Code by tooth location and surface count, not by cavity size or chair time:
- D2392 is two surfaces, posterior.
- D2393 is three surfaces, posterior (this code).
- D2394 is four or more surfaces, posterior.
Don't confuse D2393 with the anterior three-surface composite (D2332) or with a crown. When a tooth is too broken down to hold a multi-surface filling reliably, the dentist may plan a crown (D2740 or a PFM such as D2750) instead — that's a clinical decision made at the chair, not a coding shortcut.
Documentation & Clinical Scenarios
A three-surface posterior composite is a larger restoration, so payers review it more closely:
- Tooth number and the specific surfaces restored (e.g., MOD).
- The diagnosis and extent — caries, fracture, cusp involvement, or a failing prior restoration.
- Radiographs or intraoral photos supporting the surfaces and diagnosis.
- A narrative when the size of the restoration or the surface count needs explanation.
Anesthesia, liners, bases, and isolation are part of the restoration. If the tooth also needs a separate procedure — a core buildup, D2950, or a separately justified restoration — document each so surfaces aren't double-counted across line items.
Insurance & Billing Tips
- Verify benefits up front. Larger fillings carry a higher patient portion, and an alternate-benefit downgrade to amalgam (D2160 for three surfaces) is common.
- Match surfaces to the code. Three genuine surfaces = D2393. Padding surfaces to reach D2394 is an audit risk.
- Check frequency limits. Replacing the same restoration within a set window (often 24 months) may not be covered.
- Watch the crown threshold. Some plans question very large composites and may prefer a crown benefit; documentation helps justify the restoration chosen.
- Submit clean documentation. Tooth number, surfaces, and a clear diagnosis reduce requests for additional information and speed payment.
Example Case
A 41-year-old patient breaks the mesial marginal ridge on a lower-left first molar (tooth #19) that already had decay on the distal. The dentist removes the decay, finds it involves the mesial, occlusal, and distal surfaces, and places a composite restoration across all three. The office files D2393 with tooth #19 and surfaces "MOD." Because benefits were verified and the bitewing supported the surfaces billed, the claim is paid at the plan's posterior-composite allowance with the patient's estimate already accurate.
Patients call about "a big filling" or "a broken molar," not D2393. DentalReception AI answers those calls 24/7, books the restorative visit live into your schedule, and captures insurance details for clean intake, while coverage and treatment questions route to your team. See how it handles filling calls, or book a demo.
Frequently Asked Questions
What's the difference between D2393 and D2394?
Surface count. D2393 covers a three-surface posterior composite, while D2394 covers four or more surfaces on a back tooth. Code strictly by the number of surfaces actually restored, not by the size of the cavity or the time it took. Reporting an extra surface to move from D2393 to D2394 is a classic down-coding and audit trigger, so the surfaces in the chart and on the claim should match the restoration that was placed.
Does D2393 include the anesthesia, liner, and polishing?
Yes. Local anesthesia, bases and liners, isolation, and routine finishing and polishing are part of the single restoration fee under D2393 and aren't billed separately. A truly distinct procedure on the same tooth — such as a core buildup when clinically necessary — carries its own code and documentation, but the ordinary steps of placing a three-surface filling are included in the one charge.
Will insurance pay the full rate, or could it down-code to amalgam?
Many plans apply an alternate benefit, paying a posterior composite at the rate of the equivalent amalgam (D2160 for three surfaces) and leaving the patient the difference. Some also question very large composites and may steer toward a crown benefit. Verifying benefits and frequency limits before treatment lets you quote an accurate out-of-pocket amount and avoid a surprise on the explanation of benefits.
Do I need a pre-authorization for D2393?
Routine fillings usually don't require pre-authorization, but a large three-surface restoration is more likely to draw a request for radiographs to confirm the diagnosis and surfaces. Verifying benefits ahead of the visit — and keeping the bitewing and a short narrative in the chart — means the claim is ready if the payer asks, and the patient's estimate already reflects any alternate-benefit downgrade.
Confirm the current CDT descriptor and your specific payer policies before billing — browse the full dental code library or see our insurance verification feature.