[Study of regeneration in periodontal tissue after implantation of bone ceramic and collagen gel compound materials. Evaluation of histopathological finding and autoradiography].

The aim of this study is to determine the process of periodontal tissue regeneration and the metabolic activity of osteoblasts after implantation of bone ceramic and collagen gel compound materials (BC). Bone defects were artificially prepared in the alveolar septa of the bilateral upper first and second molars of Wistar rats. Subsequently, BC were implanted into the defective sites on the left side, and the gingival flaps were closed. At the defective sites on the right side, as a control, gingival flaps were closed without implantation. Rats were sacrificed 1, 3, 5, 7 or 14 weeks after implantation, and prepared tissue sections were observed both pathologically and autoradiographically using 3H-Proline. The results obtained were as follows: Pathological Findings One week after BC implantation, inflammatory cellular infiltration of the surrounding gingival connective tissue was relatively mild. Three weeks after implantation, BC were present in fibrous connective tissues, and some directly bound to the marices of regenerated bone. Observation 5 weeks after implantation revealed that BC had become embedded in the regenerated bone matrices and that there was giant cell reaction to foreign bodies at the margin of BC located in connective tissue. BC were directly bound to the regenerated bone matrices without intermediary fibrous tissues 7 and 14 weeks after implantation. Connective tissues showed high grade regeneration of collagen fiber bundles, in an arrangement that tended to be fixed in mesial and distal directions. Autoradiographic Findings There was no uptake of 3H-Proline into the regenerated bone matrices or the gingival connective tissue surrounding BC, while uptake of 3H-Proline into the entire area around the root apex and in the vicinity of the alveolar septum was observed with time (weeks) after BC implantation. These results suggest that BC provide nuclei for bone regeneration through inclusion in newly-generated periodontal bone tissue, although it is difficult to produce definite induction of bone tissue by BC alone. It is also apparent that these are useful bone implantation materials for restoration of the physiological morphology of alveolar bone in periodontal surgical treatment.