How do i get my stepdaughter to improve her hygiene?

My 12 year old stepdaughter has bad hygiene. Her mother and i have talked and we do everything we can to explain to her how important it is to brush your hair and teeth. Also to use the proper material when it is your time of the month. She either won't use a pad or she'll use toilet paper instead. We have had countless talks with her and she wont listen. PLEASE HELP US!!