I understand that if an employee becomes Medicare eligible prior to going on COBRA, they get full access to their COBRA rights.

I also understand that if an employee becomes Medicare eligible after going on COBRA, they lose their COBRA rights. In that event their dependants/spouse would be eligible for up to 36 months of COBRA protection.

How would these rules apply if an employee is not on a group health plan, but selects COBRA on their group dental? Even though Medicare does not have dental, would a terminated employee (who has coverage elsewhere) becoming eligible for Medicare cause that person to lose their COBRA rights regarding the dental plan.?