Guided tissue regeneration is a surgical procedure that utililizes a barrier membrane which is placed under the gum and over the remaining bone. The purpose of the procedure is to enhance and allow for the regeneration of new bone in an area where teeth are being extracted or have already been removed. 
This surgical procedure is usually done to increase the bony support in an area where a dental implant is about to be placed. The surgery results in an improvement in the shape and contour of the area.