Dental billing denials are expensive, frustrating, and — in most cases — preventable. The good news: the vast majority of dental claim denials cluster around the same 10 CARC codes. Learn to recognize and resolve them, and you'll recover thousands in revenue your practice is currently writing off.
Here are the 10 dental denial codes that matter most, what causes them, and exactly how to fix each one.
1. CARC 4 — The service/claim does not indicate the correct insurance carrier and/or too many providers were listed for the service/claim
More commonly encountered as a timely filing denial, CARC 4 means the claim was received outside the payer's filing window.
Why it happens: Dental claims sometimes get lost in clearinghouse queues, or practices hold claims pending coordination of benefits (COB) verification and inadvertently exceed the timely filing limit.
Fix: First, verify the original submission date — you need proof of timely filing (clearinghouse confirmation, portal logs, or certified mail receipt). If you have it, appeal with the submission evidence attached. If not, check whether the payer allows a late filing exception for circumstances beyond your control (staff turnover, natural disasters, etc.).
Prevention: Set your PM system to flag claims approaching the 90-day mark and submit well within the payer's window.
2. CARC 16 — Claim/service lacks information or has submission/billing error(s)
CARC 16 is the most common dental denial code. It means something is missing or incorrect on the claim — NPI issues, missing tooth number, incorrect date of birth, or a mismatched subscriber ID.
Why it happens: Dental claims have more data fields than medical claims. A single field mismatch — even a transposed digit in the patient's DOB — will trigger CARC 16.
Fix: Read the associated RARC code carefully — it specifies exactly what's missing. Correct the error and resubmit. Do not appeal CARC 16; just fix and resubmit quickly.
Prevention: Run eligibility verification on every patient 48 hours before the appointment. Standardize your intake forms to capture NPI, group numbers, and subscriber IDs accurately.
3. CARC 27 — Expenses incurred after coverage terminated
CARC 27 means the patient's insurance had lapsed by the date of service.
Why it happens: Delta Dental and other dental insurers have strict effective date rules. Group plan terminations mid-year, aging-off dependents, or open enrollment lapses all create this denial.
Fix: Verify the patient's current coverage status. If coverage was active, appeal with the subscriber's enrollment confirmation from their employer or the insurer's eligibility portal. If coverage was truly terminated, bill the patient.
Prevention: Always verify dental benefits at the time of service, not at checkout.
4. CARC 29 — The time limit for filing has expired
CARC 29 is the strict timely filing denial. Unlike CARC 4, CARC 29 often doesn't offer room for appeal — the window is simply closed.
Why it happens: Primary-to-secondary coordination delays, disputes over which payer is primary, or billing backlogs.
Fix: If you have proof of an earlier timely submission, appeal immediately with documentation. Most payers accept timely filing appeals with clearinghouse confirmation logs within 90–120 days of original submission.
Prevention: Establish a 30-day follow-up rule — if a claim hasn't been adjudicated in 30 days, actively investigate.
5. CARC 50 — These are non-covered services because this is not deemed a 'medical necessity' by the payer
Medical necessity denials (CARC 50) are common for procedures that fall in gray zones — periodontal treatment, implants, and some orthodontics.
Why it happens: Dental payers apply strict clinical criteria. A procedure documented as treatment for aesthetics will be denied even if the clinical rationale includes function.
Fix: Write a clinical necessity letter referencing the payer's own coverage criteria. Include periodontal charting, radiographs, and clinical notes that support the functional necessity. Request a peer-to-peer review if the payer allows it.
Prevention: Document clinical necessity in the chart before submitting. A well-documented D4341 is far less likely to be denied than a bare-code submission.
6. CARC 96 — Non-covered charge(s)
CARC 96 means the procedure is simply not covered under the patient's benefit plan — not a billing error, not a medical necessity question.
Why it happens: Many dental plans exclude whitening (D9975), implants (D6010–D6067), or cosmetic procedures entirely.
Fix: Do not appeal CARC 96 for truly non-covered services — you won't win. Bill the patient and collect at the time the service is rendered next time. Provide patients with advance written notice of non-covered services.
Prevention: Run a pre-treatment estimate (PTE) before any procedure that might not be covered. This sets patient expectations and eliminates surprise billing.
7. CARC 97 — The benefit for this service is included in the payment for another service
CARC 97 indicates bundling — the payer considers this procedure included in another service already paid.
Why it happens: Delta Dental and other dental payers bundle certain CDT codes. Common examples: D0220 (periapical X-ray) bundled into the exam visit, or D9930 (treatment of complications) bundled with the original procedure.
Fix: Review the payer's bundling rules. If you believe the procedure should be separately payable, appeal with clinical documentation supporting why it was distinct and necessary. If bundling is correct per the plan, write off the amount.
Prevention: Know your payer's bundling edits before submitting. Most payers publish them or will provide them upon request.
8. CARC 252 — An attachment/other documentation is required to adjudicate this claim/service
CARC 252 means the payer is requesting additional documentation — X-rays, periodontal charts, clinical notes — before they'll process the claim.
Why it happens: Dental payers frequently require attachments for high-value procedures: crowns (D2710–D2799), root canals (D3310–D3330), and periodontal surgery (D4240–D4341).
Fix: Gather the requested documentation and resubmit through the payer's preferred method (electronic attachment via Vyne, NEA, or DentalXChange, or paper). Include the payer's reference number.
Prevention: Attach X-rays and narratives proactively on your first submission for procedures you know trigger attachment requests. This reduces the claim cycle by 3–4 weeks.
9. CARC 253 — Sequencing of therapy and/or diagnostic services is incorrect
CARC 253 is a sequencing denial — the payer believes a prerequisite service hasn't been completed before billing the current procedure.
Why it happens: Payers often require conservative treatment before approving more complex procedures. For example, some plans require evidence of failed conservative treatment before authorizing a crown.
Fix: Review the payer's clinical guidelines for the denied procedure. If you can demonstrate that prerequisites were met (via chart notes, prior EOBs), appeal with that documentation.
Prevention: Understand payer-specific step-therapy requirements before proceeding with treatment. A pre-authorization avoids sequencing denials entirely.
10. CARC 4 + CARC 253 in Combination: The Pre-Auth Trap
When you see CARC 4 and CARC 253 together, it often means the authorization request was filed but the claim wasn't submitted within the authorization window. This is extremely common with Delta Dental's orthodontic authorizations.
Fix: Check the authorization expiration date. If the auth is still valid, resubmit the claim within the window. If it expired, request a re-authorization — most payers will grant one if treatment is in progress.
The Recovery Opportunity
These 10 codes don't have to mean permanent write-offs. Most dental denials are recoverable — if you work them within the payer's appeal window and with the right documentation.
The average dental practice loses $50,000+ per year to unworked denials. A systematic approach to the codes above — combined with the right tooling — can recover most of it.
Ready to see what your practice is leaving on the table? Calculate your estimated revenue loss →