A Novel Animal Model for Three-Dimensional Horizontal and Vertical Bone Regeneration Using Osseous Shell Technique: A Pre-clinical In-Vivo Study in Rabbits

Abstract

Background: Bone grafting is commonly used for reconstructing skeletal defects in the craniofacial region. Several bone augmentation models were developed to optimize bone regeneration in both vertical and horizontal dimesions. Aim: The aim of this study was to develop a surgical animal model for establishing a three-dimensional (3D) grafting environment in the animal's mandibular ramus for horizontal and vertical bone regeneration using osseous shell technique, as in human patients. Materials and methods: Initial osteological and imaging survey were performed on a postmortem skull of a New Zealand White (NZW) rabbit skull, Oryctolagus cuniculus, for feasibility assessment for performing the surgical procedure. 3D osseus defect was created in the mandibular ramus through a submandibular incision and the osseous shell plates were stabilized with osteosynthesis fixation screws and defect filled with particular bone grafting material. The in-vivo surgical procedures were conducted in four 8-week-old NZW rabbits utilising two osseous shell materials: xenogenic human cortical plates, and autogenous rabbit cortical plates, and the created 3D defects were filled using xenograft and allograft bone grafting materials. The healed defects were evaluated for bone regeneration after 12 weeks using histological and Cone Beam Computed Tomography (CBCT) imaging analysis. Results: Clinical analysis at 12 weeks after surgery revealed the stability of the 3D grafted bone augmentation defects using the osseous shell technique. Imaging and histological analyses confirmed the effectiveness of this model in assessing bone regeneration. Conclusion: The rabbit model is an efficient and reliable biological method for creating a seizable three-dimensional horizontal and vertical bone regeneration model in the mandibular ramus using osseous shell technique for testing various bone-substitute materials testing without compromising the health of the animal. The filled defects could be analyzed for osteogenesis, quantification of bone formation, and healing potential, using histomorphometric analysis, in addition to 3D morphologic evaluation using radiation imaging.