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Although autogenous bone grafts are an optimal filling material for the induced membrane technique, limited availability and complications at the harvest site have created a need for alternative graft materials. We aimed to investigate the effect of an rhBMP-2-coated, 3D-printed, macro/microporous CaO-SiO2 -P2 O5 -B2 O3 bioactive ceramic scaffold in the treatment of critical femoral bone defects in rabbits using the induced membrane technique. A 15-mm segmental bone defect was made in the metadiaphyseal area of the distal femur of 14 rabbits. The defect was filled with polymethylmethacrylate cement and stabilized with a 2.0 mm locking plate. After the membrane matured for 4 weeks, the scaffold was implanted in two randomized groups: Group A (3D-printed bioceramic scaffold) and Group B (3D-printed, bioceramic scaffold with rhBMP-2). Eight weeks after implantation, the radiographic assessment showed that the healing rate of the defect was significantly higher in Group B (7/7, 100%) than in Group A (2/7, 29%). The mean volume of new bone formation around and inside the scaffold doubled in Group B compared to that in Group A. The mean static and dynamic stiffness were significantly higher in Group B. Histological examination revealed newly formed bone in both groups. Extensive cortical bone formation along the scaffold was found in Group B. Successful bone reconstruction in critical-sized bone defects could be obtained using rhBMP-2-coated, 3D-printed, macro/microporous bioactive ceramic scaffolds. This grafting material demonstrated potential as an alternative graft material in the induced membrane technique for reconstructing critical-sized bone defects.

Although characterization and numerical modeling of anisotropic rock is a longstanding difficulty in rock mechanics, development and advances are being made for anisotropic rock mechanics in spite of the hurdles associated with it. This chapter provides an overview of anisotropic rock mechanics issues and introduces a series of experimental and numerical anisotropic rock mechanics studies conducted in the past 15 years. Experimental investigations are made on elastic, thermal conductivity, seismic and permeability anisotropy of rock based on cores taken from directional coring system. The first part of numerical anisotropic rock mechanics introduces the numerical experiments to determine the compliance tensor of fractured rock mass with Discrete Fracture Network (DFN) modeled as equivalent continuum anisotropic rock. Blocky Discrete element method (DEM) is employed for this numerical experiment using three boundary conditions in two dimensions. The second part deals with representation of transversely isotropic rock using bonded-particle DEM model with smooth joint model as layers. Both deformation and strength behavior modeled by DEM showed a reasonable agreement with analytical solutions, and laboratory observations. Upscaled model applied to anisotropic foundation demonstrate that large scale application anisotropic DEM model is also feasible., Part of book ISBN: 978-131531961-2 978-113802759-6QC 20181219