D4341 vs D4342, D4910 and D4355: A Billing Guide to Periodontal Codes

D4341 vs D4342 is a question of how many teeth in a quadrant need scaling and root planing. D4341 is reported when four or more teeth in a quadrant are treated, and D4342 when one to three are. Together they are the scaling and root planing dental codes most offices call SRP, and they sit beside two related codes: D4910 for periodontal maintenance after active therapy, and D4355 for a full mouth debridement done before a full evaluation is possible.

Periodontal claims are reviewed closely, and Delta Dental, for one, has published guidance stating which records it wants with SRP claims. This guide explains how these codes work on a claim, what to chart, how quadrant counting works in general terms, how D4910 and D4355 fit into the sequence, and the denials offices see most.

A note on codes. CDT codes are maintained by the American Dental Association, and the official nomenclature and descriptors are copyrighted. This article cites code numbers and describes them in our own short, plain words, which are not the official wording. Always check the current CDT manual for the exact nomenclature. Choosing a code is the treating dentist’s decision, based on the clinical record. This post is general information about dental billing, not coding advice or advice about any specific patient or plan.

What is the difference in D4341 vs D4342?

Both codes report therapeutic scaling and root planing for patients with periodontal disease, meaning attachment loss and bone loss. The only difference is the count of teeth treated in a quadrant:

On the claim, each SRP line needs the area of the oral cavity code for the quadrant (upper right, upper left, lower left, lower right). Tooth numbers are not the reporting unit, but the chart should still show which teeth were treated so the count supports the code.

How are quadrants counted for SRP dental codes?

The ADA’s guide on quadrant procedures that cross the midline explains the counting. A quadrant starts at the midline of the arch and runs back to the last tooth. When a series of treated teeth crosses the midline, the teeth on each side are counted in their own quadrant. The ADA’s example: SRP on teeth 6 through 12 is reported as three teeth in the upper right (D4342) and four teeth in the upper left (D4341), not as one quadrant of seven.

That rule matters for offices that treat anterior segments as a block, because the D4341 vs D4342 choice is made separately for each quadrant. Counting teeth by quadrant, then picking the code that matches each count, keeps the claim consistent with the chart. Some carriers also apply their own clinical thresholds for which teeth count as diseased, so check each plan’s policy.

What perio charting and x-rays support D4341 and D4342?

Most SRP denials trace back to documentation. Carriers commonly want:

• A full periodontal chart with pocket depths at six points per tooth, bleeding on probing, recession and, where possible, clinical attachment levels. Delta Dental’s 2026 guidance asks for probing charts taken within the past 12 months.
• Current radiographs that show bone levels. Delta Dental’s 2026 guidance asks for bitewings within the last 12 months showing both arches and bone levels, or periapicals, and states that images must show crestal bone loss of at least 2.0 mm measured from the cementoenamel junction.
• A clinical note with the periodontal diagnosis, stage and grade, the quadrants treated and, if used, local anesthetic. Delta Dental notes that stage and grade notes may be requested.

Other carriers set different pocket depth or bone loss thresholds, so keep a per-carrier list. Also note that Delta Dental’s same 2026 guidance says it does not allow a separate charge, to the plan or the patient, for gingival irrigation or adjunctive techniques such as laser or perioscopy when done as part of SRP. Other carriers may handle those add-ons differently, so check each plan.

How many SRP quadrants can be billed on one day?

CDT does not limit the number of quadrants per visit. Carriers, however, often review claims with three or four quadrants on one date more closely and may ask for time spent, anesthetic used and full records. Many plans also limit SRP to once per quadrant in a set period, commonly 24 or 36 months, so a retreatment claim inside that window is likely to be denied unless the plan allows an exception.

The ADA claim form has a field for the date of the patient’s last scaling and root planing, added in the 2024 version. Filling it in helps the carrier apply the right history, especially for D4910 claims that depend on earlier therapy.

When is D4910, the periodontal maintenance code, used?

D4910 is the perio maintenance dental code for patients who have completed active periodontal therapy, such as SRP or periodontal surgery. In plain words, it is an ongoing recall visit for a periodontal patient that can include site-specific scaling and root planing where needed. The ADA describes it as care that continues for the life of the dentition, at intervals the dentist sets.

The ADA’s article on D4910 notes that the CDT sets no fixed waiting period after SRP, but many payers expect roughly 8 to 12 weeks, and some limit when they will pay D4910 after therapy. Some plans also require prior therapy in two or more quadrants. When a plan’s D4910 limit is reached, many carriers pay an adult prophylaxis amount instead as an alternate benefit, because a prophylaxis is part of the larger maintenance service. The ADA’s position is that offices should still report the service that was actually done.

For D4910 claims, send the date of active therapy and, if the patient is new to the plan, the periodontal history and charting with the first claim. The ADA also notes that unusual intervals should be explained with the original claim rather than after a denial.

Where does D4355 full mouth debridement fit?

D4355 is the full mouth debridement code, used when heavy deposits prevent the dentist from doing a full evaluation. The ADA’s guide calls it an enabling procedure: it comes before the comprehensive evaluation, not after a diagnosis. Key sequencing points from the ADA guide:

• A comprehensive (D0150) or periodic (D0120) oral evaluation can be reported on the same date as D4355, if all parts of that evaluation were completed.
• A comprehensive periodontal evaluation (D0180) is done at a later visit, not on the same date as D4355.
• If the patient never returns for the follow-up evaluation, D4355 is still the correct report for the debridement that was done.
• A limited, problem-focused evaluation can lead to D4355 when the patient’s complaint, such as bleeding gums, is caused by heavy deposits.

D4355 covers the whole mouth; it is not a substitute for SRP in one or two quadrants. Plan coverage for D4355 varies, and many plans limit it to once in a lifetime or once in several years.

What are the most common periodontal claim denials?

1. Insufficient documentation: no chart, an old chart, or images that do not show bone loss.
2. Quadrant count mismatch: D4341 billed when the chart shows fewer than four qualifying teeth.
3. Frequency: SRP within the plan’s retreatment window, or D4910 beyond the annual limit.
4. Sequence problems: D4355 and D0180 on the same date, or D4910 with no record of active therapy.
5. Same-day conflicts: a prophylaxis or D4346 billed alongside SRP.

Our Denial Management & Appeals team reviews each perio denial against the chart and the plan terms before choosing a corrected claim, an appeal with records, or a patient balance. Our guide on how to appeal a denied dental claim covers appeal letters.

How does our dental RCM team check periodontal claims?

Our Dental Claims Management team works inside your Open Dental, Dentrix or Eaglesoft system. Before a perio claim goes out, we compare quadrant codes with the chart, confirm images and charting are recent and attached, add the date of last SRP where it applies, and check verification notes for frequency and history limits. If something does not match, we ask your team; code decisions stay with the dentist. Periodontal practices can read more on our periodontics page, and our dental billing codes guide covers the wider CDT code set.

Want fewer periodontal claims returned?

If SRP or maintenance claims keep coming back for records, book a free consultation. We will review recent periodontal claims with you and show which charting, x-ray or sequencing gaps are causing the most rework.