I am glad they got it fixed....but I would still go in and ask to talk to someone in charge of the office, or at least her dentist about that receptionists behavior! I would hate to think that she would get away with treating another patient like that, and she needs to be talked to about that.
You have a lot more self control than I do. If I were in your situation, i would go in there, and ask to speak to her in private...and I would...as calmly and politely as possible, rip her a new one and tell her if she ever did that to my loved one again, I would come after her for abuse, as that was complete emotional and verbal abuse right there.

If you don't want to take the extra steps...i understand, but I think it may be wise to. It also may be an emotionally therapeutic thing to to have your mom go with you and talk to the person in charge together!

I have no filter anymore, so if someone does something that I know is wrong, they will hear about it right then and there. Thank goodness I can stop myself from using inappropriate language now, lol.

I am in the healthcare field, and after being a patient...i know no what it feels like to be walked all over and not listened to and treated inappropriately. Some medical offices have a person dedicated to strictly being a patient advocate or a grievance associate, so maybe ask about that.

I hope she never has to go through that again and I would make that office give her a sincere apology and some "free" services to make up for it!