title: Prototyped flexible grafting tray for reconstruction of mandibular defects.
abstract: In our previous studies, prototyped individual bone-grafting trays have been used to restore discontinuous mandibular defects. However, the attempts have shown that the trays have shielded the graft from stress, which caused considerable resorption of bone. To eliminate the shielding, we designed a flexible tray. Finite element analysis was used to compare the distribution of strain on the bone grafts that were placed in flexible and conventional trays. The analogue computation suggested that most of the strain on the graft in the flexible tray resulted in a beneficial mechanical environment, while in the conventional tray more than half of graft was in the lowest class of strain (disuse - <50 μstrains). Animal experiments were conducted on hybrid dogs, and the prototype flexible tray was used to carry particles of autologous cancellous iliac bone to reconstruct a 40 mm defect in the mandibular body. Sequential radionuclide bone imaging was used to monitor the bone metabolism. Animals were killed at 4, 12 and 24 weeks, and specimens processed for quantitative histological examination. The data from the flexible trays were compared with those from the conventional trays, as in our previous study. The results showed that bone metabolism was more active in the flexible tray than in the conventional tray during the early stages. There was increased bony adaptation in the flexible tray. These results indicate that the flexible tray can efficiently eliminate the shielding from stress, and allow more occlusive force to be conducted on to the bone graft, which results in better remodelling of the graft.
authors.affiliation: Department of ENT Head & Neck Surgery, the 306th Hospital of PLA, Beijing 100101, PR China.
authors.forename: Libin
authors.initials: L
authors.lastname: Zhou
authors.forename: Hongtao
authors.initials: H
authors.lastname: Shang
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Feng
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Ding
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Dichen
authors.initials: D
authors.lastname: Li
authors.forename: Jinlong
authors.initials: J
authors.lastname: Zhao
authors.forename: Yanpu
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D001862:Bone Resorption / Q000517:prevention & control*; D016025:Bone Transplantation / Q000000981:diagnostic imaging / Q000379:methods*; D017076:Computer-Aided Design; D003799:Dental Stress Analysis; D004285:Dogs; D020342:Finite Element Analysis; D008338:Mandibular Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D008341:Mandibular Prosthesis / Q000009:adverse effects; D011474:Prosthesis Design; D011877:Radionuclide Imaging; D019651:Plastic Surgery Procedures / Q000379:methods*