It seems that your two-year-old is experiencing some sort of emotional distress that the bread is helping to relieve.
Do you know why bread is so important to him? Is it specifically bread, or just food of any kind? Is it the sucking on it that placates him, or do you think he is actually hungry?
Depending on your situation, I could see a few different potential actions:
- If he's truly hungry, you could try feeding him a snack right before brushing teeth (maybe get on pyjamas, read a story while eating bread/something else, then brush teeth and get into bed).
- If he just wants something to suck on, I think using a soother/pacifier (I assume that's what you mean by "dummy") is fine. If that's what gives him comfort, let him go for it, and when he doesn't need it anymore, he'll give it up. If you're concerned about him (or you) being ridiculed for using it, emphasize to him that it's only for sleeping, and it gets put away first thing in the morning. Alternatively, a chew-toy of some sort (like babies use for teething) might fit the bill.
- Could he have security issues around food? Perhaps something that was said or done (even inadvertently) gave him the impression that there might not always be access to food, so he's trying to make sure he gets enough before it's "all gone." Try getting ahead of the situation by deciding for a full week that you will offer him bread at bedtime before he asks for it. I would not be at all surprised if after not much more than a week, he decides he doesn't need it anymore.
There could potentially be other issues at play, too. In my mind, the most crucial thing is to determine exactly why he's requesting bread (hunger, emotional insecuity, food issues, etc.), and act to alleviate that particular problem.
Two years old is too young to expect any sort of "disciplinary" approach to work. He wants bread because he wants bread, and telling him he can't have it, no matter how carefully-explained and logical your reasoning, will be met with the logic-defeating response, "But I WANT it!"