How does coordination of benefits work in dental insurance?

Coordination of benefits is the set of rules carriers use when a patient is covered by more than one dental plan — for example, a patient covered through their own employer and as a dependent on their spouse's plan. The two carriers coordinate to make sure they collectively don't pay more than the total cost of the procedure.

The patient's own plan is usually primary. For dependent children, the birthday rule typically applies — the plan of the parent whose birthday falls earlier in the calendar year is primary. Divorce decrees and custody arrangements can override this rule, which is why complete patient demographics matter at verification.

The primary plan pays first, based on its own coverage rules. The claim is then submitted to the secondary carrier with the primary's explanation of benefits attached. The secondary may pay the patient's remaining responsibility up to its own coverage percentage, with some plans capping payment at the difference between the primary's payment and the secondary's allowed amount.

Three coordination methods exist: standard COB, non-duplication, and carve-out. Standard COB pays the patient's balance up to the secondary's allowance. Non-duplication only pays if the primary paid less than the secondary would have. Carve-out reduces the secondary's payment by the primary's amount.

Missing a secondary insurance is a common cause of denied secondary claims, and front desks should always confirm at the visit whether a patient has additional coverage. Capturing both policies during verification is what makes coordination work smoothly downstream.