| With the rise of three-dimensional laser printing,material science has developed rapidly.A variety of research have demonstrated that the 3D-printed porous scaffold is capable of achieving favorable osseointegration and osteogenesis in the absence of the mechanical stimulation during the early healing period.However,mechanical stimulation is a non-negligible factor that affects the osseointegration and osteogenesis.The purpose of this study is to evaluate the impact of immediately static loading on bone regeneration and osseointegration around the 3D-printed porous scaffold.Thirty porous scaffolds with optimal configuration were installed bilaterally into femurs of 15 rabbits.The Loading group on the left side was applied the maximal initial loading of 10 N offered by a diminutive and built-in loading device and the Non-loading group was on the contralateral side.At 2,4,and 8 weeks post-operatively,the specimens were harvested for push-out test to measure the biological fixation strength.The quantity and quality of new bone were evaluated by the means of histological examination,Micro-CT and bone density analysis.Moreover,the animal data were integrated into finite element models to assess the biomechanics of peri-scaffold bone.The results indicated that the structure and biomechanical properties of the new bone optimized along with the healing time despite the disused bone loss at 8 weeks after surgery.It was also demonstrated that the immediately static loading increased the volume of new bone with inferior density and quality in 2 weeks after surgery,and the adverse effects emerged gradually as time extended.Moreover,finite element results demonstrated that the early structures of new bone around porous scaffold were not suitable for large mechanical loading.This study also indicated both the mineralization modes of distance osteogenesis and contact osteogenesis may exist in the porous scaffold.Accordingly,the immediate loading protocol was not recommended for porous scaffold. |
PDF Full Text Request