The Experimental Research On Vertical Alveolar Distraction Osteogenesis In Mandible And Developing Of And Implant-distraction Device

Department of Oral and Maxillofacial Surgery, Stomatological College, Fourth Militory University. Xian China Abstract Distraction osteogenesis has been used for alveolar ridge augmentation in dental implantation surgery to treat the defect of implant bed in recent years and will be used widely in the future. Because of the special anatomical conditions with the alveolar ridge, the traditional intraoral or extraoral distraction device was not suitable for it. Hence, we developed a new implant-distraction device for alveolar ridge augmentation, and examined its suitability in the following animal study. Objectives: To develop a new implant-distraction device for alveolar ridge augmentation, and observe the effect of distraction osteogenesis and synostosis following the placement of implant-distraction device. Material and method: The pure TAi2 was adopted as the metal material to fabricate the device in mechanic way. Both sides of the mandibular premolar were extracted from 6 native male mongrel dogs weighted 15kg to 20kg. After 12 weeks, one side of the mandibular alveolar ridge was chose randomly as experimental side, another was chose as control side without any operation. A box-shaped osteotomy of the experimental side of the alveolar bone was carried out and two implant-distraction apparatus were placed. After a latent period of 1 week, the alveolar ridge was augmented vertically by distraction for four days, the distraction rate was 1.05mm per day, the distraction frequency was once per day respectively. Then, the retention period continued for 2 to 10 weeks. The animals were killed in batch 2,4,10 weeks after distraction. The distraction device, together with the surrounding bone and soft tissues were removed. The effect of distraction osteogenesis and 4 the type of connection and formation of the interface were observed by X-ray, light microscope, scanning electron microscope and bone mineral density analysis. Results: The new plant-distraction device was successfully produced, and its maximum distraction was 5mm. All of the animals tolerated the entire experiment well. During the experimental period, well healing was found between the distraction device and surrounding tissues except one device was removed due to inflammation. 10 weeks after distraction, the augmentation on average was 4.00?.3mm. The X-ray examination showed that the new bone generated in the distraci;ion site was obviously demonstrates at an early stage of 2 weeks after distraction, and became dense and turned to maturation in following time. The well osteointegration of the interface was observed 10 weeks after distraction. The mechanism of distraction osteogenesi s of the alveolar ridge was conformed to like membranous bone genesis by histological observation. New bone formation was found at the interface 2 weeks after distraction, and complete osteointegration of the interface was observed 10 weeks after distraction. The bone mineral density analysis showed that there is no statistic difference between experimental side and control sidel0 weeks after distraction. Conclusion: The experiment showed that the structure of the implant-distraction device is simple and the process is easy, and animals tolerated the entire experiment well. The implant-distraction device can be used for vertical augmentation of the alveolar ridge and get good osteoint...