I was very anti-dummy - until I had no. 2. She had classic 3 months colic - screamed from 6-10 every night, and a dummy - resorted to in desperation - was the only thing that seemed to give her any relief.
She didn't give it (and her bit of blanky) up entirely until she was 6. Her teeth were always perfect. I'd never have dreamt of putting any sort of syrup on it though!
Dd1, OTOH, found her thumb very early on and didn't give that up entirely until after she'd passed her driving test! And yes, her teeth were slightly affected.
After my experience with dd2, I'd never be judgemental about dummies. If they're a comfort and help them get to sleep easily, what the hell. Dd2 would happily go to sleep anywhere if she had her dummy and blanky.
Dd1 has 2 little ones who've been exhausting little devils for getting off to sleep. If dummies would have helped she wouldn't have thought twice, but they never would take them.
You don't see children going to school with dummies in their mouths, which is more than you can say for thumbs.