Dental maximum contract allowances are the amounts on which a dental insurance company bases its payments for dental services.
It's a very sneaky way for companies, such as Delta Dental, to advertise 100% coverage for a service like dental cleanings, when in reality it might only be 30% coverage if a dentist charges more than what Delta Dental deems appropriate for said service.
More information is available in this reddit thread: https://www.reddit.com/r/Insurance/comments/nv9ou6/causa_dental_insurance_anyone_able_to_explain/
I requested a list of allowances from Delta Dental, but was told that Delta Dental does not provide a list of maximum contract allowances. I was told that they will only disclose individual allowances when a dentist provider submits a Pre-Treatment Estimate needed treatment.