Hydroxyapatite biomaterial implanted in human periodontal defects: an histological and ultrastructural study

The purpose of the present work was to study the response of human periodontium to hydroxyapatite biomaterial particles (180-200 microns). The biomaterial was implanted in two infra-osseous periodontal defects (two patients) after clearing of the granulation tissue. At two months post-surgery, biopsies were studied using light and electron microscopy. No sign of inflammation was observed, the biomaterial aggregates were surrounded either by typical fibroblasts or larger phagocytotic cells with phagocytosis vesicles containing biomaterial crystals. These intracellular crystals were noticeably smaller than the non-phagocytized ones. Some of the phagocytized crystals showed morphological signs of intracellular dissolution. The spaces between the crystals constitutive of the aggregates were filled with organic substance containing collagen fibers.