I don't know why Dental offices do this. I go in for a cleaning am quoted 11$ after insurance, but the cleaning was charged 108$. In the process of the cleaning, the dental technician spoke some medical terms about level 3-5 progression, which I didn't know at the time ended up being 25$ extra - this without them even telling me prior to doing the procedure. Then I asked (you can fault me for this) to have a cap of a tooth grounded down which the dentist said okay to and did it in 5 minutes, but increased my bill by another 60$. This again without even telling me prior to the procedure, if i had known I would have not gone through with it.