"My gums have receded, and my dentist wants to cover my exposed roots with white fillings."

If there is decay on a root surface, it will need a filling to stop and prevent further decay. Placing white fillings over root surfaces for aesthetic reasons though is sometimes a bad idea. If the objection is gum recession, why not cover the exposed root with gum tissue? This is generally the best option, as it prevents further recession, reduces sensitivity, and looks more natural. Once a filling has been placed on a root surface, it is more difficult to get a gum graft to adhere. Before you get a root filling, see a periodontist for a consultation. He can tell you if there is a better alternative.