Exposed tooth roots are the result of gum recession. The procedure for preventing additional bone loss and recession is called gum graft surgery. Soft Tissue Grafts, which provide regeneration of your gums, is a procedure that can be done prior to Porcelain Crowns that your General Dentist provides.
The goal is to create a zone of gum tissue to prevent further recession and to attain whatever root covering as possible. The root coverage is not guaranteed and not the primary goal of the graft.