Which contract fee the dentist should be based on if I have two dental insurances?

I have two dental plans through my company and my hus company. My dentist is an in-network provider of both plans. I wonder which fee schedule should she be based on? The primary or the loweres one? For example, I need to do an onlay. The primary plan covers 50% of $1000 while the second plan covers 50% of $700. The way it works in this office is that I pay 50% of what they charge first and they file a claim to my primary insurance company. Once the EOB from the primary company is available, I will have to file a claim to the second insruance company for the remaining balance. Since my doctor is in both networks, should I pay 50% of $1000 or 50% of $700 the first time?
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This depends on the contract the dentist signed with the insurance companies. Generally speaking, you cannot charge the patient any more than the lower contracted fee, less the other company's payment. Since the dentist is contracted with both companies, they would not be allowed to charge more than $700 for the onlay (assuming you had only one plan). It should not make a difference if you have another plan which allows the dentist to charge $1000; YOU are not obligated to pay more than your co-payment on the lowest contracted fee. If you have any doubts, call the secondary company and ask what the dentist may collect from you up front.
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