D2644 — Porcelain onlay — four or more surfaces
An onlay is a lab-made or milled restoration that covers one or more cusps of a back tooth. D2644 is the four-or-more-surface version in porcelain.
This code belongs to a set of nine covering onlay. The clinical detail lives in the onlay guide; the code-level detail is here.
Below: the conditions built into this particular code, a realistic fee range, what happens when it reaches an insurer, and a side-by-side comparison with the codes most often substituted for it.
Reading D2644
Extent — four or more surfaces. Four or more surfaces is the largest band in the group and the one most likely to be questioned on a claim, because plans expect full-coverage treatment once a tooth is this broken down.
Material — porcelain. Porcelain is a fired dental ceramic, chosen because it reflects and transmits light much as enamel does and because it does not stain. It is harder than enamel, so it holds a polish for decades, and brittle, so it depends on the strength of the bond underneath it and on an even bite to avoid chipping. The material is part of the code rather than a choice made afterwards, so D2644 is only the right code if that is what was actually used.
Told apart from the codes it is confused with
D2643 — Porcelain onlay — three surfaces: It covers three surfaces instead of four or more surfaces.
D2642 — Porcelain onlay — two surfaces: It covers two surfaces instead of four or more surfaces.
D2662 — Composite onlay — two surfaces: It covers two surfaces instead of four or more surfaces.
D2663 — Composite onlay — three surfaces: It covers three surfaces instead of four or more surfaces.
D2644 sits in a group of nine codes in total; the remainder are linked at the foot of this page. None of these are interchangeable, even though they sound as though they might be. Checking that the code on your estimate is the one that matches the planned treatment takes a minute and prevents most billing surprises.
Every code in this group
These codes describe the same broad procedure and differ in one respect each. Each has its own page with its own fee range and coverage notes.
| Code | Procedure |
|---|---|
| D2644 | Porcelain onlay — four or more surfaces — this page |
| D2542 | Metallic onlay — two surfaces |
| D2543 | Metallic onlay — three surfaces |
| D2544 | Metallic onlay — four or more surfaces |
| D2642 | Porcelain onlay — two surfaces |
| D2643 | Porcelain onlay — three surfaces |
| D2662 | Composite onlay — two surfaces |
| D2663 | Composite onlay — three surfaces |
| D2664 | Composite onlay — four or more surfaces |
Questions about D2644
What is D2644 on my dental bill?
On a claim, D2644 tells the insurer that what was performed was porcelain onlay, four or more surfaces.
What should I expect to pay for D2644?
$1,460–$3,080 covers most of the country. Specialist practices and big-city addresses tend to sit in the upper half.
Does dental insurance cover D2644?
Yes on most policies, treated as major work at typically 50%. A waiting period on a new policy is the commonest reason it is not.
What is the difference between D2644 and D2643?
D2643 is porcelain onlay, three surfaces: it covers three surfaces instead of four or more surfaces. The rest of the procedure is the same, which is why the two get substituted for one another on estimates.
Also known as: onlay, partial crown, cusp coverage, indirect restoration, cracked tooth restoration.