Coordination of Benefits (COB): Does Your Patient Have Dual Dental Insurance Coverage?

When a patient has dual insurance coverage, the two insurance companies will, in most cases, “coordinate benefits” for the patient – this process is called Coordination of Benefits (COB). In order for DDKS to coordinate benefits with another insurance company, the patient must complete our Dual Coverage Information Request form by visiting, or by completing the online form by signing in to their member account so that we know what other insurance company we need to work with, and which plan will pay first, second, etc.

How Does It Work?

When a patient is covered by more than one dental plan, one plan will pay first (the primary plan), and one plan will pay second (the secondary plan) and so on. Here are two of the many rules about the order in which plan benefits pay:

  • The patient’s plan through his or her employment is primary and the plan through the spouse is secondary.
  • For dependent children, the “birthday rule” is used when the parents are married or living together. This means that the dental plan covering the parent whose birthday (month and day) occurs earlier in the calendar year will be the primary plan and the plan covering the parent whose birthday falls later in the year will be the secondary plan.

Things To Remember

  • Do not determine an adjustment until after you receive the secondary Explanation of Benefits (EOB). The secondary payment may cover all of part of the adjustment.
  • Not all Coordination of Benefits (COB) will result in your office receiving the maximum plan allowance or your submitted fee (whichever is less). Therefore, you still may have to make an adjustment (take a write off).

Standard Coordination of Benefits:

DDKS uses Standard Coordination of Benefits. This is when the secondary plan payment is based on the balance left after the primary has paid, but does not exceed the amount it would have paid as primary or the total amount of the claim. For example, Bob and Sarah Johnson both have dental coverage. Due to their state’s law, Bob’s plan pays as primary and Sarah’s plan pays as secondary. Bob had a filling on his last visit to the dentist. Standard COB is as follows:

Procedure: Filling

Sample Allowed Amount: $100

Bob's Plan is Primary (pays 80%): $80

Sarah's Plan is Secondary (pays remainder): $20

Because Bob’s plan is primary, his plan pays first and Sarah’s plan pays as secondary. Bob’s plan pays $80 (80% of $100) and Sarah’s plan pays the remainder, or $20 (does not exceed amount we would have paid as primary).

For more details on determining primary and secondary dental plans, log in to your Dentist Account at to view the Dual Coverage Processing Guidelines Flowchart and COB Document for Calculating Patient Balance/Write-off.