ヒドロキシアパタイトの顎骨欠損部への応用に関する実験的研究 特にアパタイト界面部の血管像と骨形成について

Abstract

A study was performed on the correlation between vascularization and osteogenesis on the interface after implantation of hydroxylapatite (HAP:) to a mandibular defect. Bone defect of 2×3×4 mm was formed on the lower edge of bilateral mandibules in each of 24 rabbits, to which a porous HAP block (porosity 55%; pore-size 5-2, 000 μm) of the same type was implanted. The result was histologically evaluated at every time of observation by means of Indian ink i.v. injection method, double labelling method and contact microradiography (CNIR).As the result, vascularization was observed only around the surface of HAP block on 7th day and inside the pore on 14th day. It reached a peak on 28th day and declined thereafter. On 168th day, approximately the same vascular distribution as the recipient bones were seen. Forosteogenesis, the labelling on 7th, 8th, 12th and 13th days (14-day experiment group) was observed as new cancellous bone, and the labelling on 22nd, 24th and 26th days (28-day experiment group) appeared as Haversian lamellae. Calcification of the new bones progressed with time. On 168th day, HAP block was completely covered by new bones although their calcification was still somewhat inferior to that of the recipient bones. On HAP block interface, vascularization developed first followed by the formation of new bones, indicating a close relationship between them.Vascularization and osteogenesis developed vigorously at the interface of HAP block after implantation and the interface was closely enclosed by new bones. It suggests that the above results exhibited an excellent tissue compatibility.