The CDT code protective restoration is D2940, billed once per tooth rather than per surface. It covers a restorative material placed directly to protect tooth or tissue form, to relieve pain, promote healing, or prevent further deterioration, when the definitive restoration is not being done that day. The descriptor rules out two uses that practices attempt anyway: closing an endodontic access, and serving as a base or liner under a restoration placed on the same date. The material used does not qualify the code. The intent does.
The number has been stable for years. The name has not, and that is where the confusion starts.
What the descriptor permits, and what it rules out
Three things decide whether a line is legitimately D2940.
The intent is protection, not definitive treatment. Deep caries where pulpal status is unclear, a fracture stabilized until the plan is settled, a tooth too symptomatic to restore today. If the definitive restoration could have been completed at that visit, the line is hard to defend on review.
The material is irrelevant. Zinc oxide eugenol, glass ionomer, a flowable composite placed as a temporary: all D2940 when the intent is protective. Anyone hunting for a separate sedative filling code is hunting for a name that no longer stands alone.
It is one unit per tooth. D2940 carries no surface designation. A temporary covering occlusal, mesial and distal is one unit with one tooth number, not three. Converting surfaces into units turns a clean line into a rejection.
Then the exclusions. An endodontic access closed between visits belongs to the endodontic procedure. A material placed under a restoration completed the same day is a base or liner, included in that restoration. Both are coding errors rather than payer quirks, so appealing them wastes hours.
The name changed, the number did not
CDT is republished every year and takes effect on January 1, and the edition governing a claim is the one in force on the date of service, not the date you submit. D2940 has been renamed across editions. Older printings called it a sedative filling. It became known to a generation of billers as a protective restoration. The CDT 2025 edition revised the nomenclature again, toward wording describing the placement of an interim direct restoration. As of this writing, confirm the current wording against the edition covering your date of service before quoting it in an appeal.
That churn costs money in two places. Practice software stores its own procedure descriptions and nobody updates them, so a list still reading "sedative filling" trains staff to search by a name the payer dropped. And payer policies get rewritten on the new nomenclature, so a search for the old name returns nothing and the biller concludes there is no policy. Every January, reconcile your software descriptions against the new edition for the codes you bill most.
The codes that show up on the same claim
A protective restoration rarely travels alone. It belongs to an unscheduled visit for pain, which means a small, predictable code set.
| Code | Nomenclature | The rule that trips practices |
|---|---|---|
| D0140 | Limited oral evaluation, problem focused | The problem visit, not a recall exam moved forward |
| D0220 | Intraoral periapical, first radiographic image | First image only, then D0230 for each additional |
| D0210 | Intraoral complete series of radiographic images | Frequency limits apply even on an emergency visit |
| D9110 | Palliative treatment of dental pain, per visit | Per visit, not per tooth, and often not paid with D2940 |
| D2940 | Protective restoration | Per tooth, with a tooth number on the line |
| D2941 | Interim therapeutic restoration, primary dentition | Primary teeth after caries debridement, not a D2940 substitute |
Whether D9110 and D2940 pay on the same date is a plan term, not a universal rule, and it differs across plans sold by the same carrier because the employer group writes the design. Ask what this plan does, and record the answer with a date and a reference number. If the visit is accident trauma belonging to a medical payer, the code set changes entirely, as medical billing for TMJ treatments in a dental office shows.
What the plan calls it decides what the patient owes
The same D2940 line pays three ways depending on the benefit category the plan files it under. Take an illustrative case: your fee is 110 dollars, the contracted allowable is 70, the deductible is met.
| Plan files D2940 under | Coinsurance | Plan pays | Patient owes | You write off |
|---|---|---|---|---|
| Basic restorative | 80 percent | 56 | 14 | 40 |
| Palliative or adjunctive | 50 percent | 35 | 35 | 40 |
| Diagnostic or emergency, paid in full | 100 percent | 70 | 0 | 40 |
The arithmetic is illustrative, but the spread is the point. A 35 dollar swing on one tooth is small. Across a year of emergency visits it is not. Verification should capture the category, not just a yes on coverage.
Two more terms belong on the same call: whether a deductible applies to that category, and whether the plan bundles D2940 into a definitive restoration on the same tooth within a stated window. When a bundle happens on a participating claim, read the group code before you move money. A contractual group code makes the amount a write off, while a patient responsibility code moves it to the patient, the same logic that drives the denials in why was my dental bone graft claim denied. Where treatment is deferred for months, sending the plan for review first protects the sequence, as in how to get a pre-determination for dental veneers approved.
Reading a CDT number you have never seen before
Most of these searches come from someone holding a number with no context: a code on an EOB, a plan from another office, a line a temp entered. The band tells you the family before you look anything up.
| Band | Category | Example |
|---|---|---|
| D0100 to D0999 | Diagnostic | D0140 limited oral evaluation, problem focused |
| D2000 to D2999 | Restorative | D2940 protective restoration |
| D3000 to D3999 | Endodontics | D3333 internal root repair of perforation defects |
| D5000 to D5899 | Removable prosthodontics | D5422 adjust partial denture, mandibular |
| D6000 to D6199 | Implant services | D6010 surgical placement of implant body |
| D6200 to D6999 | Fixed prosthodontics | D6240 pontic, porcelain fused to high noble metal |
| D9000 to D9999 | Adjunctive services | D9110 palliative treatment of dental pain |
From there: read the nomenclature and the full descriptor in the edition covering the date of service, check the payer's policy for that code, then decide. If the number does not exist in that edition, the claim rejects rather than denies, and the fix is a corrected code, never an appeal. The same discipline applies on the diagnosis side, covered in using free code lookup tools, and in the differences between CDT and CPT codes in dentistry.
What does the dental code D5422 represent?
D5422 is an adjustment to a mandibular partial denture. Its maxillary pair is D5421, and the complete denture adjustments are D5410 maxillary and D5411 mandibular. It reaches this topic because a patient in pain from a sore spot under a partial gets assumed into something restorative, when the visit is an adjustment. Many plans include adjustments in the prosthesis fee for a period after delivery, then cap the frequency, so verify both terms.
What does the dental code D3333 represent?
D3333 is internal root repair of perforation defects, a perforation sealed from inside the canal. Practices land on it hunting for a way to code a temporary in an opened tooth, and it does not do that: the interim seal between endodontic visits is part of the endodontic procedure. If you do bill D3333, expect a radiograph and a narrative naming the perforation site.
Before you bill it, one question
Could the definitive restoration have been done at that visit? If the honest answer is yes, the line is a convenience rather than a protective restoration, and the note will not survive review. If no, say why in the chart: the finding, the tooth number, the material, the reason treatment was deferred, and the date the definitive procedure is planned.
Curo reads the full benefit detail before the appointment, including the category a plan files a code under, and works the lines that come back short, which is the denial management side of it.
The rest is scheduling. A protective restoration that sits for nine months stops looking interim to the plan, and stops being interim clinically. Book the definitive appointment before the patient leaves the chair.