It sounds like she could have slight nerve damage. Well not damage as such, when you are anaethetised you are obviosley unable to move, in your sleep you automatically move thus pressure does not remain in the same area which would cause nerve damage. In theatre patients are usually padded in problem areas, such as heels, hips, arms etc. Any area that will be in contact with a surface is usually padded to protect the area. As she was just in to remove teeth the chances of permenant damage are slim. Her leg might be tight for a few days, but she should be fine. If it does continue, she needs to seek medical help.
Hope she is feeling better.