title: Preparation and in vivo evaluation of apatite/collagen packed composite by alternate immersion method and Newton press.
abstract: Further development of bio-compatible, bio-absorbable, and osteo-conductive bio-materials is desired for bone grafts in dental and medical clinics. One candidate material might be a high-density apatite/collagen composite, which cures relatively large bone defects. To produce such a composite, we freeze-dried type I collagen solution, cross-linked the formed sponge by 2 wt % glutaraldehyde, immersed the insoluble sponge in CaCl(2) and Na(2)HPO(4) solutions alternately five times, and compacted the sponge by Newton press at 5000 kgf. For comparison, cross-linked collagen without alternate immersion was also pressed. SEM/EPMA, XRD, and FTIR analyses clarified that alternate immersion successfully coated the collagen sponge with hydroxyapatite. Packed apatite/collagen composite and collagen disks 6 mm in diameter and 0.5 mm in height were implanted in the subperiostea of rabbit tibiae for 2, 4, 8, and 12 weeks to assess bio-compatibility, bio-absorbability, and osteo-conductivity. Histological observations showed that the packed apatite/collagen composite was biocompatible, osteo-conductive for up to 8 weeks, and largely bio-absorbed at 12 weeks, while the packed collagen sponge caused an undesirable foreign body reaction, which worsened with the implantation period. The overall findings suggest that this packed apatite/collagen composite might be used as a new bio-absorbable bone graft material.
authors.affiliation: Department of Dental Materials Science and Technology, Iwate Medical University School of Dentistry, Morioka, Japan. mtaira@iwate-med.ac.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Taira
authors.forename: Takashi
authors.initials: T
authors.lastname: Nezu
authors.forename: Kaori
authors.initials: K
authors.lastname: Sasaki
authors.forename: Setsuo
authors.initials: S
authors.lastname: Saitoh
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Kagiya
authors.forename: Hidemitsu
authors.initials: H
authors.lastname: Harada
authors.forename: Yukyo
authors.initials: Y
authors.lastname: Takada
authors.forename: Yoshima
authors.initials: Y
authors.lastname: Araki
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001031:Apatites / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D018786:Bone Substitutes / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry; D004867:Equipment Design; D005549:Foreign-Body Reaction; D005976:Glutaral / Q000737:chemistry; D008297:Male; D008422:Materials Testing; D010010:Osteoclasts / Q000378:metabolism; D019736:Prostheses and Implants; D011817:Rabbits; D013997:Time Factors
chemical_list: D001031:Apatites; D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; D003094:Collagen; C020243:calcium phosphate; D005976:Glutaral