Journal of Oral Tissue Engineering

Bone Regeneration of Rat Critical-size Calvarial Defects Using a Collagen/Porous-apatite Composite: Micro-CT Analyses and Histological Observations

Wataru HATAKEYAMA1, Masayuki TAIRA2, Kouji IKEDA1, Hirotaka SATO3, Hidemichi KIHARA1, Shinji TAKEMOTO2, and Hisatomo KONDO1

1Department of Prosthodontics and Oral Implantology,
Iwate Medical University School of Dentistry, Morioka, Iwate, Japan
2Department of Biomedical Engineering,
Iwate Medical University, Yahaba-chou, Shiwa-gun, Iwate, Japan
3Division of Anatomical and Cellular Pathology, Department of Pathology,
Iwate Medical University, Yahaba-chou, Iwate, Japan

J Oral Tissue Engin 2017; 15(1): 49-60.

We formed collagen/porous-HAP composite (Col/p-HAP) and collagen control (Col) specimens using freeze-drying technique and de-hydrothermal heat treatment. Critical-size bone defects (6 mm) were generated in the cranial bones of twelve 10-week-old Wistar rats, in which Col/p-HAP and Col specimens were implanted. After feeding for 1 day, 4 weeks, or 8 weeks, the rats were sacrificed (n=6 each), followed by micro-CT and histological analyses. Micro-CT revealed that the defect zones implanted with Col/p-HAP became significantly X-ray opaque with time whereas those with Col did not. Histological observations revealed that Col/p-HAP became considerably fragmented, exerting osteo-conductive effects in the defect zone at 8 weeks whereas Col was little osteo-conductive. Double staining showed dynamic new bone formation near p-HAP digested by nuclear cells in the defect zone. Col/p-HAP appears to be a useful new bone substitute material that is applicable to dental implantology.

Key words: Porous apatite, Collagen composite, Bone-regeneration, Micro-CT, Histological observation