If I have dental coverage through work can I also buy another plan for all dental costs, crown root canels.ect.

If I have dental coverage through work can I also buy another plan for all dental costs dcrowns etc.

You may buy it, but often one will not pay along with the other. Also there are long waiting periods for some work like crowns and the such.

You may want to check costs of private policy, most cost a lot compared to what little they will pay each year. Most have max pay out, that is not much more than cost of plan

As Chuck says, there is something called coordination of benefits. So, the primary plan pays what it will pay and the secondary plan will pay only the balance.

And both companies may only pay a certain portion and probably deductibles with each that have to be met so don't assume that the secondary will automatically pick up all the costs that the primary did not pay.