Recently my mother received some dental treatment that ensued over a month's time. The dental facility informed my mother that she was fully covered for the removal of the remainder of bottom teeth plus the formation of a denture plate. The treatment continued until my mother went for her last removal and the fitting of the denture. After removing the rest of the teeth and before fitting the denture the Dentist notified that her "insurance had changed" and that she owed 500+ dollars or they couldnt give her the denture. My mother had to get my grandmother to pay for the treatment because she didnt have that kind of money at the time. My mother called to rectify the situation with her social worker's office to find out why her insurance had changed, her social worker then indicated that it had not changed and that the dental office had known that she would owe the money for treatment/dentures since beginning treatment. My question is, if my mother didnt know this information before agreeing to treatment is the dental office liable to cover the charges?