Guided tissue regeneration for implants placed into extraction sockets: a study in dogs.

Twelve 10 mm implants were placed into immediate extraction sockets in dogs. Six implants were isolated with PTFE membranes and 6 sites served as controls. Standardized clinical measurements were taken at test and control sites. At 18 weeks the dogs were anesthetized and flaps were laid for the purpose of obtaining clinical measurements. The average gain of bone around augmented implants was 2.6 mm, while control sites had an average bone gain of 1.0 mm. Ridge width adjacent to augmented sites increased by 1.2 mm and control sites had an increased width of 0.6 mm. Histologic evaluation of test and control specimens showed greater bone formation around augmented implants. Implants augmented with PTFE membranes had clinically significant amounts of bone regeneration when compared with controls.