I really don't have an answer for you. But just something for you to think about. My 5 yr old never ever had a binky or sucked fingers/thumb. His baby teeth were beautiful. He has lost 2 teeth and the adult teeth are the poster teeth for braces. Both DH and I had braces, so that might have something to do with it, so you can never be too careful.
As for the binky. Start by letting him have it only at bedtime. Distract him by cuddles and a story, or doing something fun, finger painting, running in the sprinklers. Then maybe have him leave the bedtime one for the binky fairy and let him help a baby somewhere whose parents need to give him one. Or something like it.
at 7:06 PM on Jul. 31, 2010