Every once in a while I also dream about crumbling or breaking teeth.

found this, not sure how true it is:

Dreams of Losing Your Teeth

Although you may have some concerns about your dental hygiene, dreams of your teeth falling out, crumbling, cracking, turning black or becoming decayed are usually about a communication problem you experienced the day before. Symbolically, teeth represent your personal power as it relates to what comes out of your mouth--your speech. The dream may comment that you failed to assert your opinion, were unable to clearly and concisely say what you wanted to say or silenced yourself when it was important to speak up. A blackened tooth can represent something you said that made you feel ugly. A broken front tooth can suggest a breakdown in communication in which you felt powerless to effect a change with your opinion. Loosing a slew of teeth may remark you are far too timid and as a result you are ineffective. These dreams may amplify feelings of inferiority and suggest it's time to remove the blocks and adjust your communication style.