Repair Effect Of Platelet Rich Fibrin On Rabbit Mandibular Defects

Oral and maxillofacial region is a special part of human body, whichserves as a hub of utterance, respiration, mastication, and deglutition. Musclegroups are coordinated to express various kinds of emotions, while cooperatingwith lips, tongue, maxilla and mandible to accomplish sophisticatedphysiological processes. Many causes such as developmental defect, tissue lostdue to trauma, and tumor excision would lead to maxillofacial tissue defectswhich may cause functional disorder and affect physical and psychologicalhealth. Repair and reconstruction have always been a major and difficult taskfor maxillofacial surgeons and researchers. With multiple methods, bioactivematerial filling is commonly adopted-for its relatively convenient operation,high biosafety, good compatibility, and with much fewer compensatory donortrauma. A large number of preclinical and clinical researches focusing onconcentrated preparation from autologous blood have been carried out byscholars around the world, which have proved its function of facilitating tissuerepair and regeneration. As for the new technology put forward in recent years,the effect of platelet rich fibrin （PRF） is still on a trial basis. Objective: Theexperiment is aim to analyze the repair effect of the platelet rich plasma fibrinon maxillofacial tissue defect and discuss the possible regeneration promotingmechanism, by implanting the platelet rich plasma fibrin centrifuged fromrabbit autologous blood into tooth extraction wound, and constantly observing the samples in different stages by some iconographic and histological methods.Method:1. Experimental animal model:55rabbits are randomly divided into5groups according to the different times of execution, with bilateral mandibularfirst molars extracted. Draw certain amount of peripheral autoblood to get PRFafter centrifugation. The extraction wound on one side is filled with PRF as theexperimental group, the other one with no treatment on the other side as thecontrol group.2. Observational method: to continuously observe bone healingin the wounds of the two groups in the2^nd,4^th,6^th,8^th, and12^th week aftersurgery. An assessment would be made to categorize bone healing in differentgroups, with excellent, good and poor three levels; and measure the density ofthe new bone based on panoramic radiographs. Then analyze the two kinds ofstatistics. Last, make histological slides from decalcified, dehydrated andparaffin-embedded specimen in order to observe angiogenesis and osteosisunder microscope. Result:1. Radiological observation: bone density in thewounds showed in the panoramic radiographs of the two groups in the2^nd,4^th,6^th,8^th, and12^th week after surgery: experimental group> control group, P<0.05with statistical meaning; bone density measured through statistical analysissoftware, experimental group> control group at the corresponding time points,P<0.05with statistical meaning.2. Histological observation: in the2^nd,4^th,6^th,8^th, and12^th week after surgery, the number of osteoblasts in experimentalgroup is bigger, compared with control group, and osteoblasts are more active.The number of new bones of experimental group is also bigger, with moremature and mineralized bone trabecula and higher bone density compared with control group-as for the number of new bone tissue, experimental group alsooutperforms control group. Conclusion:1. PRF is a kind of fibrin gel madefrom centrifuged autologous blood with no auxiliary agents and no immuneresistance. It is an ideal filling material for it can be quickly obtained and easyto be used with high biosafety.2. In the repair process of rabbit extractionwound, conditions of new bone tissue in PRF experimental group outperformscontrol group, indicating PRF could accelerate healing of the bone tissue.3.The amount of blood circulation and allowable loss is limited, so PRF thatcould be obtained from one time is limited. Therefore, supplementing bloodcirculation should be taken into consideration when PRF is needed to repairlarge defect.