Use Of Easy-handing And Self-setting Bone Paste Of Calcium Phosphate For Bone Repair And Regeneration

Objectives To elucidate the biological effects of the easy-handling calcium phosphate paste on pre-osteoblastic cells (MC3T3-E1 subclone 14) and to estimate its biocompatibility and osteoconductivity in the subcutaneous and bone defects of rabbits.Materials and methods In vitro experiment:After setting for 24 h. calcium phosphate cement paste (6 mm diameter,2 mm thickness) were sterilized by autoclaving at 120℃for 20 min. MC3T3-E1 subclone 14 were than co-cultured with the material. Cell adhesion was evaluated by counting cell numbers at 0.5h,2h and 4h. The MTT assay and the pNPP phosphatase assay were used for cell proliferation and differentiation measurement. Cell morphology was examined with scanning electron microscope. In vivo experiment:20 healthy adult New Zealand rabbit were used. After creation of bone defect model on both side, the animals were randomly divided in to experimental group and control group. There should be 10 rabbits in each group. For the experimental group, the defect hole was filled with easy-handling CPC. while in the control, commercial CPC were used as repair material.5 animals in each group were sacrificed after 6 and 12 weeks post-operation respectively. Histological evaluation and histomorphometrical analysis were carried out on the samples.Results For the in vitro experiment. results of cell adhesion rates were (39.85±14.20)%, (62.23±11.09)% and (89.57±13.00)% on the time point of 0.5h,lh and 2h respectively. The OD values in MTT test increased from (0.16±0.04) to (0.28±0.03) and (0.56±0.06), as time went from 1d,3d to 7d. ALP values also increased, from (1.69±1.04) U/g to (9.51±2.16)U/g in the 3rd day to the 14th.On the other hand, in the in vivo test, both histological evaluation and histomorphometrical analysis results suggested that the amount of newly formed bone and the degradation of calcium phosphate paste in the bone defects at the 12 weeks implantation period was more than those at the 6 weeks implantation period.Conclusions All the results suggest that the novel moldable, self-setting calcium phosphate paste presents great potential in the field of dental, craniofacial and orthopedic repair as an ideal bone filler or artificial bone.