There are many facets to a tooth/teeth dream. Except for dentists....we take teeth for granted, even though they are very important to us.

Literal meaning: In your sleep you felt the molar losen, which made you dream about losing one of the all important 'smile teeth'. Especially knowing that one has been previously damaged.

If that's not the case, losing one's teeth could be a warning of financial loss or difficulty.
 Maybe a warning against an investment just now. Maybe someone told you how you could make money, but you find the idea just a bit 'hinky'. The dream may be you inner alarm going off. Trust your instincts, you have them for a reason.

It could be that you've already experienced a loss of some sort, and you're now left wondering, "What could be next..?"

It could also be a fear of aging or unattractiveness. Did you recently start or end a relationship? Or have a fight in a current one...?
Humans are visual creatures by nature, and we put a lot of store in how we look to others. We perceive the loss of teeth as unappealing.

Hope that helps.