Your Dentist is a total psychopath! Your supposed to replace them with white (color of your teeth) composite fillings. He's just one of those idiots that wants to do it the old way no matter what.
Your teeth need to be filled in! That bastard is such a jerk! You never leave teeth like that exposed! Sounds like a good law suit. Also if you have your lower molars done you will probably have to have crowns put on them.
So much damage is done by Amalgam fillings that when you remove them much of the tooth is gone and they have to be reworked by a specialist.