Ah, the teeth. When I was 29/30 I had braces on my top teeth but needed an "anchor" across the roof of my mouth (kind of like an arch) connecting the two molars second from the back to hold them firm. I had a dream that my braces were like an old fashioned canning jar? http://antiques.lovetoknow.com/Antique_Canning_Jars and when I pulled that "top" bar down all the individual braces on each tooth were able to roll around on their bar and I panicked, not able to get them to line up in the right direction, facing my teeth so I could push the bar back up and lock them in place again

I think the most common meaning of teeth falling out is "change" http://www.dreamdictionary.org/common/teeth-dreams/ If I had your dream I would think I was looking for my next way forward, "growing up" as avlady suggests, looking for the key to the next move in my future but not liking any choices I perceive or being afraid I am "not enough" to succeed at what I want to do/be.