On the whole , the total rate of all complications amounts to 30%. We are extremely limited in terms of prevention or treatment of an OCN patient. We intend to study a biological autologous sediment obtained from a blood sample for its capacity to avoid these complications supervening. The collection of a coagulum called Platelet Rich Fibrin or PRF susceptible to provide the essential ingredients for the mucous membrane and the bone healing is obtained by centrifugation. This biomaterial rich in autologous fibrin is a concentrate of leukocytes, platelets and a number of factors favouring cicatrisation and immune response. Clinical applications are already well documented in orthopaedic, thoracic and cardiac surgeries and, also in dermatology. The use of PRF in dental surgery is more recent. Literature on this topic is very limited but these new techniques give rise to high hopes. Since February 2007,thanks to the classification as a medical treatment by the AFSSAPS, the PRF technique has been authorized.