D2791 Dental Code: Full Cast Base Metal Crown Billing

What D2791 covers

D2791 reports a full-cast crown on a permanent tooth made entirely of predominantly base-metal alloy. Full cast means all metal, with no porcelain or ceramic on any surface. Predominantly base metal means the casting contains less than 25% noble metal by weight, the bottom tier of the ADA’s casting-alloy classification. Nickel-chromium and cobalt-chromium are the common alloys. The code covers the prep, impression, lab fabrication, try-in, and cementation.

Bill D2791 when the lab invoice confirms an all-metal, predominantly base-metal crown and the crown is seated and cemented at the delivery visit.

It does not cover:

• A full-cast crown in high noble alloy. That’s D2790.
• A full-cast crown in noble alloy. That’s D2792.
• A full-cast crown in titanium or titanium alloy. That’s D2794.
• A crown with porcelain on any surface. That’s the PFM series, such as D2751 for base metal.
• An all-ceramic or all-porcelain crown. That’s D2740.
• A core buildup. That’s D2950.
• A post and core. That’s D2952 (cast) or D2954 (prefab).
• A provisional or interim crown. That’s D2799.
• Recementing an existing crown. That’s D2920.

D2790, D2791, D2792, and D2794: alloy class off the lab invoice

The four full-cast crown codes are identical except for the alloy class, and that class is a number on the lab invoice, not the tooth or the color of the metal.

• D2790 is high noble: at least 60% noble metal with at least 40% gold.
• D2792 is noble: at least 25% noble metal, below the high noble cutoff.
• D2791 is predominantly base metal: under 25% noble metal.
• D2794 is titanium and titanium alloys, a separate material category.

The metals counted toward the percentage are gold plus the platinum group, which the classification of materials lists as platinum, palladium, rhodium, iridium, osmium, and ruthenium. On a base-metal invoice the practical read is that gold, palladium, and platinum together came to less than a quarter of the casting. A crown is D2791 because the invoice shows that, not because it went on a molar or the alloy looked pale.

This family is miscoded by one alloy tier more than almost any other. Keep all four full-cast codes as distinct, clearly labeled line items in the PMS, and confirm the alloy class and all-metal construction on the invoice before the claim goes out, not at the prep visit before the lab work is back.

Full cast versus PFM: the D2791 and D2751 mix-up

The code most often confused with D2791 is D2751, its porcelain counterpart. Both use base-metal alloy and both are the budget option, but D2751 has porcelain fused over a base-metal coping and D2791 is bare metal. Label the two by construction in the fee schedule, not just by alloy, since they are easy to swap.

D2791 as the downgrade floor

D2791 is the cheapest full-cast alloy tier, so it is the fee plans use when they downgrade the family. Both patterns below are plan-dependent:

• Downgrade to D2791 on alloy. A plan pays the predominantly base-metal allowable against a D2790 or D2792 claim, reasoning that any full-cast crown gives the same function regardless of alloy cost. The unpaid difference is not automatically the patient’s; the contract decides where it lands.
• No downgrade below D2791. When you bill D2791 itself, there is usually nothing cheaper in the family to drop to.

A downgrade is plan design, not a denial, and no appeal overturns it. The EOB shows the billed code, the allowed amount, the plan percentage, and what went unpaid.

Some plans exclude full-cast crowns entirely and cover only PFM or all-ceramic. The denial reads as a non-covered service, and the balance falls to the patient, subject to the contract’s terms on fees for non-covered services. Confirm the plan’s crown rules before the prep.

Top reasons D2791 gets denied or reprocessed

1. Construction mismatch with D2751. A full-cast crown billed as the base-metal PFM code, or the reverse. The alloy class is the same, so only the construction catches it.
2. Wrong alloy tier. D2791 on a crown cast in noble or high noble alloy collects the base-metal fee on a restoration that cost more to make. D2790 or D2792 on a base-metal crown reprocesses to the D2791 allowable when the invoice is pulled.
3. Frequency limit on a replacement crown. Most plans allow one crown per tooth every 5 to 10 years. A replacement inside the window pends without a narrative documenting the clinical failure of the prior crown.
4. Full-cast exclusion. Plans that cover only PFM or all-ceramic deny the claim as a non-covered service.
5. Submitted at the prep visit. The fee covers the completed, cemented restoration, so billing before the seat gets the claim rejected or pended.

Documentation that supports the claim

The claim needs:

• A date of service for the seat visit, not the prep.
• The correct tooth number.
• The lab invoice showing the base-metal composition, when the carrier requests alloy confirmation.
• A narrative when the crown is a remake inside the carrier’s frequency window, citing the clinical reason.

In the patient record, keep:

• The lab invoice with the alloy composition. It settles an alloy-class dispute and the construction question with D2751.
• Prep, impression, and seat dates.
• The clinical reason for the crown.
• Any prior crown on the same tooth and its placement date.

Example case

A 63-year-old patient has tooth #31 with a fractured lingual cusp and a large failing amalgam. The dentist plans a full-cast crown and, for cost, specifies a base-metal alloy. The lab invoice confirms nickel-chromium, all metal, no porcelain. The plan covers crowns at 50%, and since the crown is already at the base-metal tier, no further alloy downgrade applies.

Billing steps:

1. At treatment planning, verify crown coverage, frequency status on tooth #31, and any waiting period.
2. Read the lab invoice: base-metal alloy, all metal, no porcelain. That is D2791, not the PFM code D2751.
3. If the tooth lacks retention, place a core buildup and code D2950 separately on the same claim.
4. Submit D2791 at the office fee on the seat date, with a one-line narrative on the fracture.
5. Post the carrier’s payment and bill the patient the coinsurance and any deductible.