Optimal Diameter of Honeycomb Tunnel Structure induces Bone Regeneration and Metabolism by Promoting Angiogenesis for an Implant Circumference Bone Defect

Abstract

To develop an effective method of bone augmentation for dental implants, particularly for patients with a scarce amount of bone, we introduced a new honeycomb-like -tricalcium phosphate (H--TCP) as a scaffold, whose unique geometrical properties induce bone formation along with vasculature. A total of six beagles from 6 to 7 years old were used for this study. Autologous bone marrow-derived mesenchymal cells (BMC) cultured with H--TCP were implanted around the dental implants, and healing was compared with conventional bone augmentation using autogenous bone. The 2-wall peri-implant defects were filled with the scaffold material pre-coated with BMP-2 and cultured with BMCs. Judging from the surface contact area between the bone and the implant, at 12 weeks the highest bone formation was found in the experimental group using the BMP-2 coated H--TCP with BMCs. This was significantly higher than the control H--TCP with BMP-2-coating but without BMC. It was noted that within the tunnels of the implanted H--TCP, one or two blood vessels with a diameter of 50-100 micro meter were generated in most cases after 2 weeks. These results suggested that the geometry of the honeycomb like -TCP with, gave advantages in terms of initial induction of blood vessel formation which is essential for bone augmentation.

Effect of Honeycomb β-TCP Geometrical Structure on Bone Tissue Regeneration in Skull Defect

“…Furthermore, biomaterials other than TCP need the presence of growth factors and stem cells for bone formation, whereas honeycomb TCP do not need their factors for bone formation [22][23][24][25][26][27][28]. In addition, there are many studies focusing on geometrical structures, and it has been reported that it is necessary to provide an appropriate microenvironment such as pore structure for bone tissue formation [4,5,8,9,[12][13][14][15][16]18,20,21]. However, although there are some studies that change the pore size of the same material, there is no study that changes the direction of the holes as in this experiment.…”

“…In particular, it has been reported that the geometrical structure of artificial biomaterials exerts a great influence on the process of hard tissue formation [12,13], and porosity is particularly important for cell proliferation and differentiation and vascular invasion [14]. Generally, when the pores of artificial biomaterials are too large, the stiffness of the porous body becomes weak, and when the pores are too small, the stiffness increases but cells and blood vessels have difficulty entering the pores [12][13][14][15][16]. At present, artificial biomaterials with high porosity have been developed and have already been clinically applied.…”