that is good question. Just to be sure, if I was you, I would setup an appointment with ur local USCIS office to speak to someone about it and to show them what you are about to send. They would assist you but they won't be able to tell you anything about ur case.
Try going to the dental office or hospital that you go to and see if they can give you copies of the times you took them, surely you signed some papers each time you went right?
I would think the dental office and clinics had you sign privacy notices and consents to treat so go ahead and call them to see if any of the registration paperwork is available and make a copy of them because they most certainly will have dates. That would help I bet.
