Hi there. I have a few questions. Are you still BF'ing a lot? What I mean is, have you introduced solids yet? I've heard that babies who have been comfortably sleeping through the night, and then start to wake can be requiring more substantial foods during the daytime. Molly started waking up at 5.5 months, and we started solids early (she had reflux also, so this helped that too), but my point is, when the solids started, she was feeling fuller and more satisfied, and therefore slept better. That could be one thing.

Another, as you say could be the teeth - your baby is at an age where they know they are going to get comfort from you (from the BF in the night) and even though they are young and sweet, babies are also conniving and great learners! If you get up every time they cry out, they will realise that this works as an attention seeking tool, and will milk you for all you are worth (literally!).

I'd try the solids first - if you are already feeding solids, then maybe ramp it up a little - introduce more variety or more volume and see if anything improves. You've probably heard this all before, but your baby is a unique individual, and they need to learn at the same time you do. If this doesn't work, then maybe try an infant feeding/sleeping clinic - we did and it worked wonders for us.

Hope this helps.