Why do dental insurance claims get denied?

Dental claim denial rates climbed past 19% in 2025 and continued upward in 2026 as carriers tightened automated adjudication. The good news is that the majority of denials trace to a handful of recurring root causes, all of which can be caught before submission.

Eligibility issues are the single largest category. The patient's coverage isn't active, the dependent age cutoff was hit, the plan changed, or the deductible reset on a date the practice didn't know about. Verifying within 48 hours of the appointment catches almost all of these.

Coding mistakes are next. A small mismatch between the procedure performed and the CDT code submitted — or between what was billed and what the plan covers — triggers automatic denial. Frequency limits (such as one cleaning every six months) and downgrades (where an insurer pays the lesser-cost alternative) are heavily enforced by automation.

Missing pre-authorizations cause denials for major procedures like crowns, implants, and orthodontics. Some carriers require pre-auth even on procedures other carriers approve automatically. Missing tooth clauses deny replacement of teeth that were already missing before the policy started.

Coordination of benefits errors happen when the practice doesn't capture a patient's secondary insurance. If the primary pays without the secondary on file, the secondary may deny entirely. Documentation gaps — missing x-rays, narratives, periodontal charting — round out the list.