IMMUNO-INFLAMMATORY RESPONSES IN THE TISSUE ADJACENT TO TITANIUM MINIPLATES USED IN THE TREATMENT OF MANDIBULAR FRACTURES

The immune-inflammatory responses to titanium miniplates used in the t reatment of mandibular fractures were studied immunohistochemically at light and electron microscope levels, Titanium miniplates were stably situated on the cortical bone surface, In the soft tissue adjacent to the surface of titanium miniplates, double layered connective tissue was observed, which consisted of dense fibrous connective tissue, and relatively loose connective tissue contained proliferated blood vessel s with hypertrophied endothelial cells, These vascular endothelial cel ls expressed HLA-DR, CD54 and CD62P antigens, In some cases they were CD62Epositive. CD68+ and CD11c+ round or spindle-shaped macrophages ha d infiltrated around the small vessels, Fine titanium particles were o bserved in the cytoplasm of these macrophages, Both CD4+ and CD8+ T ly mphocytes had also infiltrated around venules in some cases, They were CD4+ T lymphocyte-dominant. Immunoelectron microscopically, CD68+ and CD11c+ macrophages contained titanium particles in the lysosomes, Mos t of the macrophages showed varying degrees of degenerative change, Th e presence of titanium was confirmed by energy-dispersive X-ray analys is.