The effect of the microstructure of beta-tricalcium phosphate on the metabolism of subsequently formed bone tissue.
The response of bone cells to a newly developed porous beta-tricalcium phosphate composed of rod-shaped particles (RSbeta-TCP), beta-TCP composed of conventional non-rod-shaped particles (Cbeta-TCP), and hydroxyapatite (HA) was analyzed using in vivo implantation and in vitro osteoclastogenesis systems. Implantation of the materials into the rabbit femur showed that RSbeta-TCP and Cbeta-TCP were bioresorbable, but HA was not. Up to 12 weeks after the implantation, bioresorption of RSbeta-TCP and Cbeta-TCP accompanied by the formation of new bone occurred satisfactorily. At 24 weeks post-implantation, most of the RSbeta-TCP had been absorbed, and active osteogenesis was preserved in the region. However, in the specimens implanted with Cbeta-TCP, the amount of not only the implanted Cbeta-TCP but also the newly formed bone tissue decreased, and bone marrow dominated the region. The implanted HA was unbioresorbable throughout the experimental period. When osteoclasts were generated on RSbeta-TCP, Cbeta-TCP, or HA disks, apparent resorption lacunae were formed on the RSbeta-TCP and Cbeta-TCP, but not HA disks. Quantitation of the calcium concentration in the culture media showed an earlier and more constant release of calcium from RSbeta-TCP than Cbeta-TCP. These results showed that the microstructure of beta-TCP affects the activity of bone cells and subsequent bone replacement.
Okuda
Takatoshi
T
Department of Oral Pathology and Bone Metabolism, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
Ioku
Koji
K
Yonezawa
Ikuho
I
Minagi
Hideyuki
H
Kawachi
Giichiro
G
Gonda
Yoshinori
Y
Murayama
Hisashi
H
Shibata
Yasuaki
Y
Minami
Soichiro
S
Kamihira
Shimeru
S
Kurosawa
Hisashi
H
Ikeda
Tohru
T
D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D018786:Bone Substitutes / Q000737:chemistry / Q000378:metabolism*; D002130:Calcium Phosphates / Q000737:chemistry / Q000378:metabolism; D005260:Female; D005269:Femur / Q000033:anatomy & histology / Q000378:metabolism; D006882:Hydroxyapatites / Q000737:chemistry / Q000378:metabolism; D020007:Implants, Experimental; D008422:Materials Testing; D010010:Osteoclasts / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D011817:Rabbits
D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; D006882:Hydroxyapatites; C485817:beta-tricalcium phosphate