Should I punish my daughter for her poor dental hygiene?

No.. Scare tactics may help but sitting her down and talking to her about why she does not want to clean her teeth properly is usually the best option. See if there is a way to make it fun. There is a company that makes tooth brushes that vibrate a popular tune when they are used. I think they are called tooth tunes brushes (not 100% sure). Positive reinforcement will go a long way as well.
Reinforce & educate. I agree with the other two providers. In general, positive reinforcement tends to lead to change better than punishment. I think it is reasonable to educate your daughter (if old enough to comprehend) about the potential consequences of not brushing teeth.