[Observation on implants of porous hydroxyapatite granules in periodontal osseous defects]

The purpose of this study was to observe the regeneration of the periodontal tissue using porous hydroxyapatite granules in experimental periodontal lesions. The upper lateral incisors of three Macaca fuscatae were extracted. After a 12-week recovery period, three wall infrabony defects were surgically prepared on the distal surface of the central incisors. In order to accumulate the plaque and cause inflammation, a wire with dental floss was placed inside the defects for a period of four weeks and then removed. Flap operations were performed and porous hydroxyapatite granules were placed into the defects. Twelve weeks after surgery, the samples were taken out and fixed in glutaraldehyde solution. They were embedded in polyester resin and undecalcified sections were prepared. The specimens were stained with toluidine blue and observed under light microscope.

1) The implanted area was divided into three distinctive zones. The first zone was located distally and occupied two-thirds of the total area. A large quantity of osseous tissue was detected. The second zone was situated near the root and presented only a small quantity of osseous tissue; Fibrous connective tissue predominated in the third zone adjacent to the root. 2) Bone apposition and resorption caused by physiologic mobility and movement of the teeth were observed. These results suggest that the elimination of the functional forces is advisable during the healing period whenever hydroxyapatite granules are placed into the periodontal defect.