Mandibular Condensability and Length Contraction: An Animal Experimental Study
LI Yong+1, TIAN Wei-dong+2,ZHANG Zhi-jie+1, DENG Feng+1, ZHONG Da-wen+1,WANG Zhi-bing+1,DAI Hong-wei+1,HE Mei+1.(1.Dept. of Oral and Maxillofacial Surgery,Hospital of Stomatology, Chongqing Medical University, Chongqing 400015, China;2.Dept. of Oral and Maxillofacial Surgery,West China College of Stomatology, Sichuan University, Chengdu 610041,China)
Objective To investigate the condensability of mandibular length.Methods In six goats were used in the study. Corticotomy at right mandibular angles was performed via extral-oral accession. Special devices were applied to shorten the mandible by 0 5 mm per three days respectively.Results ①Mandibular angles of the six goats were shorten by 0 8 cm to 1 3 cm respectively in 48 days to 78 days;②In spite of the lower ascending ramus moving forward and angles being blunt, the occulusion scarcely varied because of contralateral bite-lock;③X-ray demonstrated that, at first, bone density in contracted areas declined ,and then increased gradually to almost normal density;④Under microscope there were three tissues layers from central to lateral within the bone gap: fiber layer, cartilage layer and bone layer, and fiber layer gradually transform into cartilage layer with the fixed time. At the end of fixation they all transform into bone tissue.Conclusion Contraction osteogenesis is actually a process of compression, absorption and rebuilding. It is feasible that using contraction osteogenesis to shorten the mandible via cortcotomy.