In Jane Eyre, why does Miss Temple have a lasting positive effect on the girls while Mr. Brocklehurst does not? Any examples from the book would be...

Miss Temple has a lasting effect on the girls because she genuinely cares about them and shares their trials. Mr. Brocklehurst, on the other hand, is a hypocrite who lives well while lecturing the girls on their need for humility and austerity. He doesn't see them as fully human, is insensitive to their needs, and doesn't genuinely care about them.

While Mr. Brocklehurst specializes in humiliation, such as making Jane stand on a stool while he tells the whole school she is a liar, Miss Temple is kind and merciful, putting her arm around Jane after the ordeal, kissing her and saying she believes Jane's side of the story. Helen Burns says of her: 

Miss Temple is full of goodness; it pains her to be severe to any one, even the worst in the school: she sees my errors, and tells me of them gently; and, if I do anything worthy of praise, she gives me my meed liberally.

When Jane breaks her slate, Miss Temple says she won't be punished because she knows it was an accident.

While Mr. Brocklehurst keeps the girls on a starvation diet, Miss Temple encourages them to keep up their spirits and be "stalwart soldiers." When their breakfast is inedible, she orders up extra cheese and bread for lunch so they won't go hungry. Mr. Brocklehurst, on the other hand, scolds Miss Temple for doing this, saying "my plan in bringing up these girls is, not to accustom them to habits of luxury and indulgence, but to render them hardy, patient, self-denying."

When Mr. Brocklehurst sees a girl with curls, he insists on hair cuts for the girls, saying his mission is to "mortify" them. 

Mr. Brocklehurst is a cold-hearted man who the girls hate and hold in contempt; Miss Temple is a kind, caring person who the girls love because she loves them. Because they respect her goodness, she makes a lasting imprint on her students.