First the medications -- did she decide to stop or did the doc's decide it was time to try a go without it ? If she just plain quit, then you have to decide whether that's appropriate or not.
On the hygiene stuff ? I don't think ADD has anything to do with it. Our oldest NEVER wanted to take a shower. We forced her EVERY time she needed a shower. We didn't require showers EVERY night, however. We required them ever other night until grade 7 at which time it changed to every night, with Friday nite off unless they had plans for Sat. and needed to look good. I wouldn't worry so much about the deoderant until she starts puberty, but I would push the teeth. She can brush them or you can brush them. I think a few times of mom stepping into the bathroom to brush her teeth would let her know you mean business. It's a health issue and it's a money issue. Cavities cost a whole lot of money to fill, and they hurt.
You DO have to pick your battles -- so make a list of your expectations and prioritize them. There are absolute requirements and there are other things that you may need to let slide. You don't want to be harping ALL the time, but you DO want to enforce the behaviors she needs to keep up for health.
And the dress style? Does she have friends who come over? how do they dress ? Are you pushing her to be all grown up and dress nicely like you do, or is she really dressing unlike kids at her school? Dressing to "not be seen" can be a symptom of low self-esteem, or it could simply be a way to rebel. As long as she is modest in her cothing taste, I wouldn't make a battleground of it.
But on the self-esteem issue . . . do you listen to her ? Do you praise her for the things she does do well ? I have a friend who has terrific kids, but whenever I listen to her, all she tells me is what is wrong with them. I am convinced that that's all they hear, also. And I'm amazed that they are such wonderful young ladies. (13 and 16). It's really important to listen toyour kids if you want to know WHY they are doing what they are doing. Sometimes it's hard to get them to start talking, but the more you practice listening, (without passing judgement), the more they will open up.
I have a thing I do -- it started about 4 or 5 years ago when my oldest two were in college. I decided that if they or I should die, I would want to be sure that their last contact with me told them I loved them. So whenever I talk to them on the phone, when we say good-bye, I say, I love you. they usually respond, "Love you, too, mom" Every single day I hug my teens and tell them I love them. whether we have argued during the day, or they've snapped at me or whatever -- if I were to die, I would want them to know beyond a shadow of a doubt that their Mom loved them.
Home is where you child comes to let her hair down and stop "behaving" the way everyone expects her to behave. While there are things you need to push her to do, be sure it is a place where she feels loved and accepted, and cared for, just the way she is. :-)