Getting her to comply with grooming or teeth brushing is similar to any other training routine, it takes repetition, patience and some expression from you that these are the rules and she needs to learn to play by them. Brushing her hair may benefit by using the same techniques as a professional groomer. Take a look at any grooming parlor and you will see they all use an elevated, slightly slippery surface. You will also see the dog has a fixed leash attached to the collar to help restrain the head. You can mimic this at home by placing her on a counter and having an extra person to help restrain, after a little training you can probably do it without the help af a second person.
Teeth brushing is an admirable task but in all honesty many owners cannot do it often enough and complete enough to truly help. Using a finger brush can help, also an oral mouth rinse such as C.E.T is an alternative.