«  View All Posts

10 standard Coordination of Benefits rules for dental insurance billing

February 9th, 2022 | 6 min. read

10 standard Coordination of Benefits rules for dental insurance billing Blog Feature

Print/Save as PDF

When a patient shows up with dental benefits from multiple insurance plans, how should you file your claims? Sending claims correctly can get confusing without knowing the Coordination of Benefits rules. When you do know Coordination of benefits rules, you can submit accurate claims leading to higher payments AND gain more patient trust. 

By getting up to speed on Coordination of Benefits (COB) rules, you’ll know which plan is primary or secondary and have the confidence to properly file insurance claims and remain compliant with insurance and HIPAA rules. 

We understand that Coordination of Benefits rules are complicated! How can anyone remember all of these rules and regulations off the top of their head? At Dental ClaimSupport, we actually do know people who know this information off the top of their heads! We’ve pooled our knowledge from our coordination of benefits training and our experts to help you succeed in all things insurance billing, including Coordination of Benefits.

In this article, we will list the standard 10 coordination of benefits rules dental professionals need to know. Keeping these rules top of mind will help your dental team confidently file claims for patients with multiple insurance plans. This confidence and knowledge can lead to fewer claim denials, which leads to more revenue for the practice.

What is Coordination of Benefits for dental practices?

Coordination of benefits defines the order in which to file insurance claims for patients covered by multiple insurance plans. One plan will be the primary insurance, while the other is secondary, and occasionally there is a third (tertiary) and fourth (quaternary). 

Because these rules can get so confusing, a lot of offices don’t even accept secondary insurance benefits from patients. But you’ll bring much more value to your practice if you do.

Why is it important to know Coordination of Benefits rules?

It’s important for your dental team to know the rules of COB because it’s important that your practice accepts multiple insurance plans from patients. It increases the pool of patients and revenue that your practice can bring in. 

This knowledge is crucial when accepting multiple insurance plans because if you make mistakes, it will lead to claim denials which will lead to payment delays from insurance companies. 

There are plenty of rules and caveats when it comes to COB, which is what makes it hard to keep up with. To keep it a little simpler, we’ll go over 10 standard rules of COB that you can keep in your back pocket when filing multiple insurance claims for one patient. 

These rules will help you determine which of the patient’s insurance plans is primary, depending on the situations described in each rule. 


1. Employee/member/subscriber vs dependent

This rule applies when a patient is subscribed to more than one insurance plan, one as a member, and the other as a dependent. In this case, the plan in which they are subscribed to as a member would be the primary insurance. The plan in which they are a dependent would be the secondary insurance. 

This might be the case for a 20-something who just got their first full-time job with insurance benefits, but they’re still officially a dependent on their parent’s insurance plan. 

2. Actively employed vs retired/laid off/COBRA

This rule applies to those that have either been laid off or retired. The plan they were covered by before they retired or were laid off (assuming their benefits are still active for the time being), would be the primary plan, over the coverage they now have as someone who is inactively employed. That coverage would be the secondary insurance. 

This would be the case if you were laid off or retired, and your old job’s insurance benefits might still be active for another month or two. But before those are up, you enroll in another insurance plan. COBRA is a federal law that protects a person’s right to insurance coverage when one of these events occurs (being laid off or retiring). 

3. 1 Subscriber, 2 jobs

This is an easy one! This rule applies when a person has two jobs, and both offer benefits packages. So, the person enrolls in both. Whichever plan they enrolled in first, will be the primary insurance. 

Then, the insurance plan they enrolled in later with their second job, would be the secondary insurance. 

4. Spousal coverage

This rule applies to two spouses who each have their respective insurance plans from their own jobs, but are still enrolled in each other’s plans as well. Their own insurance plan, through their own job, would be their primary insurance, while their spouse’s plan would be the secondary insurance. 

5. Dependent children of parents who are not separated or divorced (birthday rule)

Say a child is covered by both of their married parent’s insurance plans. Each parent has their own plan, and both have added the child to their own insurance. 

The child’s primary insurance is the plan covering the parent whose birthday occurs earliest in the year. This does not mean whoever is the oldest. It just means whoever is born earliest in the calendar year. 

If both parents are born on the same day, the primary insurance would be whoever has been covered by that insurance plan the longest. 

Coordination of benefits for dentists - buy book

6. Dependent children of parents who are separated or divorced

If the parents of a child are divorced or separated, and the child is a dependent on both parents' respective insurance plans, the birthday rule we mentioned above applies: Whichever parent was born earliest in the year will have the primary insurance for the child. This of course applies if the parents have joint custody. 

If the parents do not have joint custody but the child is still covered by both parents’ insurance plans, their primary insurance will be whichever parent has custody according to a court of law.

7. Dependent children who also have coverage under a spouse’s dental plan

This rule applies to patients who have gotten married but are still on their parent’s insurance, and have then been added to their spouse’s insurance plan. 

The primary insurance would be whichever plan the patient has been a dependent on the longest. 

8. Medical plan vs. dental plan

If the insurance for a procedure performed by a doctor is available under the patient’s dental AND medical plan, the medical plan will be the primary insurance. 

This rule applies typically when the procedure is oral surgery, trauma-related, or pathology.

9. Medicaid

Medicaid is an insurance program provided by the government. Sometimes people who are enrolled with Medicaid also have private insurance as well. If the patient is covered by Medicaid, it is almost always secondary to any other private dental plan they have.

10. Medicare vs retiree plan

This rule applies to patients covered by Medicare and a retiree plan. Medicare would be primary while the retiree plan would be secondary - once the patient turns 65 years old.

If a patient has a retiree plan, is also on their spouse’s insurance plan, AND has Medicare coverage, their spouse’s plan covering them as a dependent would be primary, Medicare would be secondary, and the retiree plan would be tertiary. 

Confidently accept primary and secondary insurance from dental patients

Wow, that was a lot! This simplified list should give your dental team easy access to rules they can always turn to when questioning COB. Knowing these rules and feeling confident about how to apply them when dealing with patients covered by multiple insurance plans can help you collect more from insurance. 

You will avoid denials, get paid by insurance in a more timely manner, and feel empowered to embrace patients in these unique situations to educate them on their benefits. 

Dental ClaimsSupport is always there to support dental offices when it comes to understanding the rules of insurance and to help teach you how to collect more. 

To learn more about how COB knowledge is valuable to your dental team, visit our Learning Center. 


1. Profitable Guide to Coordination of Benefits for Dentists  (book)

2. Coordination of Benefits (Dental billing training course)

3. Administration With Confidence: The “Go To” Guide For Insurance Administration by Charles Blair, DDS.

5 tips to collect more from insurance billing

Related Posts

Dental billing resources