Hm, I'm thinking that we're going to be getting to this point soon. Our boy is 18 weeks on Friday.
He loves his dummy and sometimes does wake for it in the night. He doesn't always need it to go down, esp after his 7 and 10.30pm feeds, but it helps him for his short naps during the day.
The way I look at it is, we had dummies when we were little and even though my sister had teeth trouble following hers (she put the plastic bit in her mouth and it pushed her teeth out, cue tons of orthadonal (sp?) appointments!) but as long as we are prepared to keep an eye on this I am not willing to take it off him yet.
As a friend of mine says, it helps them sleep which is a good thing and when do you see a 21 year old with a dummy?!
We're going to wait until he's older and can be bargained with (!) to take it off him, though I don't think it's going to be hard with him, he's not mad for it.
But the waking in the night thing is tres annoying...wouldn't know what to do about that really. Just see if he settles before rushing in to plug him?!
Interested to see other replies.