Fabrication of fine apatite/collagen composite for osteoconductive apical barrier material

Aiming at creating an apical barrier material that promotes recovery of defects in the root canal, a composite of apatite and collagen was developed. To achieve this, reconstitution and cross-link of atelocollagen, and calcification of reconstituted collagen fibers, were conducted under controlled stirring at 37°C. Deposits were identified as CO3-containing apatite and its crystallinity was comparable to that of bone apatite. After 20 hours of calcification, the composite contained apatite of about 60 wt%. The composite and saline mixture had a pH of about 9. The mixture was easily set into a narrow space, such as the root canal, and was liquid permeable after being set into a root canal. The biological property of the composite was examined in vivo using the molar teeth of dogs. After 8 weeks, a thin layer of new bone-like tissue was formed along the inner wall of root canal. Without the composite paste, such a new bone-like tissue was not observed. Thus, the apatite/collagen composite showed potential as an apical barrier material with osteoconductivity.