To dream of a dentist means you need healing for your bite. Do you feel you are losing a grip on things? This dream can be triggered by a feeling that you have bitten off more than you can deal with at this moment in time? It is a healing dream, with the intention of giving you the assertiveness you need to deal with the situation.
If the dentist is filing your teeth it means that you are too aggressive or assertive when it comes to the subject matter of the dream. There is no need for you to sink your teeth into whatever it is that’s going on right now.