Comparative study of hydroxyapatite block bone and bovine hydroxyapatite incorporated with collagen on the healing of 1-wall intrabony defects in dogs

Abstract

Bone grafts are often used as part of a surgical protocol to regenerate periodontal structures. HA and Bio-oss are used as bone graft materials for periodontal regeneration, and some studies using them in periodontal defects showed good results. But, due to the limitation of particulated bone grafts, periodontal regeneration was not enough in critical periodontal defects such as 1 wall defects. Therefore block type bone graft like HA block or Bio-oss collagen are being developed to enhance the early period wound stability and easy manipulation.We evaluated the periodontal regenerative potential of HA block bone and Bio-oss collagen for clinical applications. In five male beagle dogs, we bilaterally created 4x5 mm one-wall intrabony defects at the distal aspect of the second mandibular premolars, and at the mesial aspect of the fourth mandibular premolars. These defects were either experimentally treated with HA block bone, Bio-oss collagen or surgery with no filling material as a control group. The dogs were sacrificed eight weeks after surgery, analyzed using micro CT, and block sections of the defects were collected for histologic and histometric analysis.Postoperative healing was uneventful. On micro CT analysis, HA block showed greater ability of space maintenance than control group, and Bio-oss collagen has irregular results. But, histological analysis revealed that HA block showed relatively small amount of new bone formation, and cementum formation was not different from contol. In this study, we expected that HA block preserve the clot and enhance bone formation because of the space maintaining and wound stabilizing ability, however, the bone formation was limited compared to prominent space maintenance.