Is this considered tacky or unprofessional?

No, not tacky at all. However, definitely give an introduction as well. Leaving it in person is good, as well as mail and email. Do not call on the phone- they will not have time precisely at that moment, and will blow you off. I think the best thing to do is leave it or mail it, and then write a follow-up email a week or so later. You have to leave it up to their timetables, not your own.

Not at all, but do preface it with "Hello, I'm a dental assistant [or whatever position] and currently looking around for a position. I was wondering, is this office hiring at the moment?" If they say yes, then ask if you might fill out an application, if they say no, then it's still polite to ask if it might be okay for you to leave a resume. Do accept a "no" for a final answer and be gracious, but most places will at least take it if you're polite.

Check online and see who's hiring too, you might have better luck sending it to those places in email rather than in person.

They'll throw it straight in the dustbin (or use it to steal your identity)! The best approach is to actually ask to see the boss and then ask him/her if there's a position you can apply for. There is nothing more impressive than going straight to the top. (You'll get nowhere with monkeys, you need to see organ-grinders)!

No they will realize that here's a woman that has a good head for business.

This is considered s.m.a.r.t! It is definitely not tacky nor unprofessional.

Neither - it's called networking. Go for it. Good luck!

Neither.

Good luck.

KD