I have had similar dreams where my teeth fall out. I have noticed that whenever I have these dreams I actually need to go to the dentist, and when I do go, there is always a tooth that needs pulled or a root canal or something.
I also think that there may be some truth to what you said about communication problems and not being able to say what you need to say to someone and having a lot of stress in your life at the time of the dreams. I sometimes have those same problems too.