What's the best toothpaste for your health?

I was watching Martha Stewart last week and she had a dentist on and he said that most toothpastes were created by soap companies (colgate =palmolive). Most tp's kill the good bacteria that helps in your dental health. I don't want to be putting unnecessary crap in my mouth that's only going to hurt my health. I don't have really strong teeth so I know I need a tp with floride. I would love any suggestions and would also like to know why the ingredients in reg. tp are bad for you. Thanks