title: Comparison of the long-term effects on rabbit bone defects between Tetrabone and β-tricalcium phosphate granules implantation.
abstract: Tetrabone is a newly developed granular artificial bone. The 1-mm Tetrabone has a four-legged structure. In this study, the long-term effect of implanting Tetrabone or β-TCP granules in rabbit femoral cylindrical defects was evaluated. The rabbits were euthanized at 4, 13, and 26 weeks after implantation. Micro-CT was conducted to evaluate the residual material volume and the non-osseous tissue volume. New bone tissue areas were measured by histological analysis. Micro-CT imaging showed that the residual material volume in the β-TCP group had decreased significantly at 4 weeks after implantation (P < 0.05) and that the β-TCP granules had nearly disappeared at 26 weeks after implantation. In the Tetrabone group, it did not significantly change until 13 weeks after implantation; it then continued to decrease slightly until 26 weeks after implantation. The non-osseous volume increased in the β-TCP group, whereas that of the Tetrabone group decreased (P < 0.05). Histological examination showed that the new bone areas were significantly greater in the Tetrabone group than in the β-TCP group at 13 and 26 weeks. In conclusion, resorption of β-TCP granules occurs before sufficient bone formation, thereby allowing non-osseous tissue invasion. Tetrabone resorption progressed slowly while the new bone tissues were formed, thus allowing better healing. Tetrabone showed better osteoconductivity, whereas the β-TCP granules lost their function over a long duration. These results may be caused by the differences in the absorption rate of the granules, intergranular pore structure, and crystallinity of each granule.
authors.affiliation: Laboratory of Veterinary Surgery, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
authors.forename: Sungjin
authors.initials: S
authors.lastname: Choi
authors.forename: I-Li
authors.initials: IL
authors.lastname: Liu
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Muneki
authors.initials: M
authors.lastname: Honnami
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Ohba
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Echigo
authors.forename: Takamasa
authors.initials: T
authors.lastname: Sakai
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Igawa
authors.forename: Shigeki
authors.initials: S
authors.lastname: Suzuki
authors.forename: Ryouhei
authors.initials: R
authors.lastname: Nishimura
authors.forename: Ung-Il
authors.initials: UI
authors.lastname: Chung
authors.forename: Nobuo
authors.initials: N
authors.lastname: Sasaki
authors.forename: Manabu
authors.initials: M
authors.lastname: Mochizuki
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001861:Bone Regeneration / Q000502:physiology*; D018786:Bone Substitutes; D002130:Calcium Phosphates; D005269:Femur / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology*; D011817:Rabbits
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; C485817:beta-tricalcium phosphate